bluuebunny/crossref_metadata_2025 huggingface dataset:
Parameter‐field estimation for atmospheric dispersion: application to the Chernobyl accident using 4D‐Var
Authors: Bocquet M.
Published: November 2011

Atmospheric chemistry and air‐quality numerical models are driven by uncertain forcing fields: emissions, boundary conditions, wind fields, vertical turbulent diffusivity, kinetic chemical rates, etc. Data assimilation can help to assess these parameters or fields of parameters. Because such parameters are often much more uncertain than the fields diagnosed in meteorology and oceanography, data assimilation is much more of an inverse modelling challenge in this context. In this article these ideas are experimented with by revisiting the Chernobyl accident dispersion event over Europe. A fast four‐dimensional variational scheme (4D‐Var) is developed, which seems appropriate for the retrieval of large parameter fields from large observation sets and the retrieval of parameters that are nonlinearly related to concentrations. The 4D‐Var, and especially an approximate adjoint of the transport model, is tested and validated using several advection schemes that are influential on the forward simulation as well as on the data‐assimilation results. Firstly, the inverse modelling system is applied to the assessment of the dry and wet deposition parameters. It is then applied to the retrieval of the emission field alone, the joint optimization of removal‐process parameters and source parameters and the optimization of larger parameter fields such as horizontal and vertical diffusivities or the dry‐deposition velocity field. The physical parameters used so far in the literature for the Chernobyl dispersion simulation are partly supported by this study. The crucial question of deciding whether such an inversion is merely a tuning of parameters or a retrieval of physically meaningful quantities is discussed. Even though inversion of parameter fields may fail to determine physical values for the parameters, it achieves statistical adaptation that partially corrects for model errors and, using the inverted parameter fields, leads to considerable improvement in the simulation scores. Copyright © 2011 Royal Meteorological Society
Distributed denial‐of‐service attack detection scheme‐based joint‐entropy
Authors: Rahmani Hamza , Sahli Nabil , Kamoun Farouk
Published: November 2011

Distributed denial‐of‐service (DDoS) attacks present an increasing threat to the global inter‐networking infrastructure. While entropy schemes are highly robust to diverse network conditions, they remain vulnerable to distribute attacks that are similar to legitimate traffic. With the knowledge that the objective of a DDoS attack is to saturate as soon as possible the resources of the target, this would engender an unexpected disproportion between the number of received packets and the number of connections. However, in the case of flash crowds, an increase in the number of packets is always accompanied by an increase in the number of connections. In this work, we used joint‐entropy that quantifies the degree of disproportion to detect traffic anomalies. We investigate a class of intelligent attacks, which, unlike high‐rate attacks, are difficult for entropy schemes to detect. The experimental results indicate that our joint‐entropy scheme can detect this type of attacks accurately. Compared with an entropy‐based scheme, the improvement is 40% for the distributed attacks. Copyright © 2011 John Wiley & Sons, Ltd.
An adaptive dose‐finding approach for correlated bivariate binary and continuous outcomes in phase I oncology trials
Authors: Hirakawa Akihiro
Published: November 2011

In this study, we developed a novel adaptive dose‐finding approach for inclusion of correlated bivariate binary and continuous outcomes in designing phase I oncology trials. For this approach, binary toxicity and continuous efficacy outcomes are modeled jointly with a factorization model. The basic strategy of the proposed approach is based primarily on the Bayesian method. We based the dose escalation/de‐escalation decision rules on the posterior distributions of both toxicity and efficacy outcomes. We compared the operating characteristics of the proposed and existing methods through simulation studies under various scenarios. We found that the recommendation rate of the true recommended dose (RD) in the proposed method was more favorable than that in the existing method when the true RD was relatively at the tail end among the tested doses. It was similar to that of the existing method when the true RD was relatively at the top end. Copyright © 2011 John Wiley & Sons, Ltd.
Weighted multiple testing correction for correlated tests
Authors: Xie Changchun
Published: November 2011

Virtually all clinical trials collect multiple endpoints that are usually correlated. Many methods have been proposed to control the family‐wise type I error rate (FWER), but these methods often disregard the correlation among the endpoints, such as the commonly used Bonferroni correction, Holm procedure, Wiens' Bonferroni fixed‐sequence (BFS) procedure and its extension, and the alpha‐exhaustive fallback (AEF). Huque and Alosh proposed a flexible fixed‐sequence (FFS) testing method, which extended the BFS method by taking into account correlations among endpoints. However, the FFS method faces a computational difficulty when there are four or more endpoints. Similar to the BFS procedure, the FFS method requires the prespecified testing sequence and the type I error rate used for first endpoint in the sequence (usually the most important endpoint) cannot be adjusted for the correlation among the endpoints or from the rejection of other null hypotheses for other endpoints. Thus, the power for this test is not maximized. In this paper, I present a weighted multiple testing correction for correlated tests. By using the package ‘mvtnorm’ in R, the proposed method can handle up to a thousand endpoints. Simulations show that the proposed method shares the advantage of the FFS and the AEF methods (having high power for the second or later hypotheses in the testing sequence) and has higher power for testing the first hypothesis than the FFS and the AEF methods. The proposed method has higher power for each individual hypothesis than the weighted Holm procedure, especially when the correlation between endpoints is high. Copyright © 2011 John Wiley & Sons, Ltd.
Who should own it? An agency‐based explanation for multi‐outlet ownership and co‐location in plural form franchising
Authors: Perryman Alexa A. , Combs James G.
Published: November 2011

Plural forms exist when managers use two owners to perform one activity. Franchising is a plural form explained by agency theory, however, the theory is unable to explain two franchisor actions: 1) allowing franchisees to own multiple outlets and 2) co‐locating company‐owned and franchised outlets. We use research that describes a symbiosis between company‐owned and franchised outlets to extend agency theory and explain these actions. Our investigation of ownership patterns among 4,339 outlets of 16 plural form franchisors is consistent with our theory that multi‐outlet franchising is cost efficient and that co‐location occurs when franchisors fill market gaps left by franchisees. Copyright © 2011 John Wiley & Sons, Ltd.
Application of vehicular communications for improving the efficiency of traffic in urban areas
Authors: Katsaros Konstantinos , Kernchen Ralf , Dianati Mehrdad , Rieck David , Zinoviou Charalambos
Published: November 2011

This paper studies the impacts of vehicular communications on efficiency of traffic in urban areas. We consider a Green Light Optimized Speed Advisory application implementation in a typical reference area and present the results of its performance analysis using an integrated cooperative intelligent transportation systems simulation platform. In addition, we study route alternation using vehicle‐to‐infrastructure and vehicle‐to‐vehicle communications. Our interest was to monitor the impacts of these applications on fuel and traffic efficiency by introducing metrics for average fuel consumption, average stop time behind a traffic light and average trip time, respectively. For gathering the results, we implemented two traffic scenarios defining routes through an urban area including traffic lights. The simulations are varied for different penetration rates of application‐equipped vehicles, driver's compliance to the advised speed and traffic density. Our results indicate that Green Light Optimized Speed Advisory systems could improve fuel consumption, reduce traffic congestion in junctions and the total trip time. Copyright © 2011 John Wiley & Sons, Ltd.
Protecting Sensitive knowledge in association patterns mining
Authors: Lee Guanling , Chen Yi Chun
Published: November 2011

Mining association rules from huge amounts of data is an important issue in data mining, with the discovered information often being commercially valuable. Moreover, companies that conduct similar business are often willing to collaborate with each other by mining significant knowledge patterns from the collaborative datasets to gain the mutual benefit. However, in a cooperative project, some of these companies may want certain strategic or private data called sensitive patterns not to be published in the database. Therefore, before the database is released for sharing, some sensitive patterns have to be hidden in the database because of privacy or security concerns. To solve this problem, sensitive‐knowledge‐hiding (association rules hiding) problem has been discussed in the research community working on security and knowledge discovery. The aim of these algorithms is to extract as much as nonsensitive knowledge from the collaborative databases as possible while protecting sensitive information. Sensitive‐knowledge‐hiding problem was proven to be a nondeterministic polynomial‐time hard problem. After that, a lot of research has been completed to solve the problem. In this article, we will introduce and discuss the major categories of sensitive‐knowledge‐protecting methodologies. © 2011 Wiley Periodicals, Inc.

This article is categorized under:

Algorithmic Development > Association Rules

Commercial, Legal, and Ethical Issues > Social Considerations
The relationship between adolescents’ news media use and civic engagement: The indirect effect of interpersonal communication with parents☆
Authors: Boyd Michelle J. , Zaff Jonathan F. , Phelps Erin , Weiner Michelle B. , Lerner Richard M.
Published: November 2011

Using data from the 4‐H Study of Positive Youth Development, a longitudinal study involving U.S. adolescents, multi‐group structural equation modeling (SEM) was used to evaluate whether news media use is predictive of a set of civic indicators (civic duty, civic efficacy, neighborhood social connection, and civic participation) for youth in Grades 8, 9, and 10, via an indirect effect of interpersonal communication about politics with parents. The proposed model had a good fit within each grade. News media use was predictive of interpersonal communication with parents and in turn, interpersonal communication was predictive of civic duty, civic efficacy, neighborhood social connection, and civic participation. The cross‐group comparison of the structural model suggests that the predictive qualities of news media use and interpersonal communication are comparable across grades. The role of media use and interpersonal communication in fostering civic development and socialization as well as implications for future research are discussed.
Constructing positive futures: Modeling the relationship between adolescents’ hopeful future expectations and intentional self regulation in predicting positive youth development☆
Authors: Schmid Kristina L. , Phelps Erin , Lerner Richard M.
Published: November 2011

Intentional self regulation and hopeful expectations for the future are theoretically‐related constructs shown to lead to positive youth development (PYD). However, the nature of their relationship over time has not been tested. Therefore, this study explored the associations between hopeful future expectations and intentional self regulation in predicting positive developmental outcomes. Participants were in Grades 7, 8, and 9 of the 4‐H Study of PYD (N = 1311), a longitudinal study involving U.S. adolescents. A cross‐lagged panel analysis using Structural Equation Modeling assessed the relations among hopeful future expectations and intentional self regulation across time in predicting PYD. Results indicated that earlier hopeful expectations for the future may be influential for later intentional self‐regulation abilities, although both constructs were strong predictors of PYD in middle adolescence. We discuss implications for research and practice of hopeful expectations in adolescents’ constructions of their positive futures.
Breaking and Dissipation of Ocean Surface Waves
Authors: Babanin Alexander
Published: November 2011

Wave breaking represents one of the most interesting and challenging problems for fluid mechanics and physical oceanography. Over the last 15 years our understanding has undergone a dramatic leap forward, and wave breaking has emerged as a process whose physics is clarified and quantified. Ocean wave breaking plays the primary role in the air-sea exchange of momentum, mass and heat, and it is of significant importance for ocean remote sensing, coastal and ocean engineering, navigation and other practical applications. This book outlines the state of the art in our understanding of wave breaking and presents the main outstanding problems. It is a valuable resource for anyone interested in this topic: researchers, modellers, forecasters, engineers and graduate students in physical oceanography, meteorology and ocean engineering.
A Tropical Dependency
Authors: Shaw Flora
Published: November 2011

Flora Shaw, Lady Lugard (1852–1929) was the first female reporter for The Times, and colonial editor from 1893 to 1900. She travelled widely, and wrote hundreds of articles promoting the British Empire and in favour of its expansion as a world power. She became very involved in South African politics as a friend of Cecil Rhodes, and in 1897 coined the name 'Nigeria' for the colony under the administration of the Royal Niger Company. In 1902 she married Sir Frederick Lugard, then High Commissioner of Northern Nigeria. In 1905 she published A Tropical Dependency, her most extensive work. Although expressing views which assume European superiority, she stressed the fact that the vast majority of the British Empire was not white, and the book is valuable for its information on pre-colonial northern Africa. For more information on this author, see http://orlando.cambridge.org/public/svPeople?person_id=shawfl
Making Constitutions in Deeply Divided Societies
Authors: Lerner Hanna
Published: November 2011

How can societies still grappling over the common values and shared vision of their state draft a democratic constitution? This is the central puzzle of Making Constitutions in Deeply Divided Societies. While most theories discuss constitution-making in the context of a moment of revolutionary change, Hanna Lerner argues that an incrementalist approach to constitution-making can enable societies riven by deep internal disagreements to either enact a written constitution or function with an unwritten one. She illustrates the process of constitution-writing in three deeply divided societies - Israel, India and Ireland - and explores the various incrementalist strategies deployed by their drafters. These include the avoidance of clear decisions, the use of ambivalent legal language and the inclusion of contrasting provisions in the constitution. Such techniques allow the deferral of controversial choices regarding the foundational aspects of the polity to future political institutions, thus enabling the constitution to reflect a divided identity.
The Consul at Rome
Authors: Pina Polo Francisco
Published: November 2011

In modern times there have been studies of the Roman Republican institutions as a whole as well as in-depth analyses of the senate, the popular assemblies, the tribunate of the plebs, the aedileship, the praetorship and the censorship. However, the consulship, the highest magistracy of the Roman Republic, has not received the same attention from scholars. The purpose of this book is to analyse the tasks that consuls performed in the civil sphere during their term of office between the years 367 and 50 BC, using the preserved ancient sources as its basis. In short, it is a study of the consuls 'at work', both within and outside the city of Rome, in such varied fields as religion, diplomacy, legislation, jurisdiction, colonisation, elections, and day-to-day politics. Clearly and accessibly written, it will provide an indispensable reference work for all scholars and students of the history of the Roman Republic.
Homotopy Theory of Higher Categories
Authors: Simpson Carlos
Published: November 2011

The study of higher categories is attracting growing interest for its many applications in topology, algebraic geometry, mathematical physics and category theory. In this highly readable book, Carlos Simpson develops a full set of homotopical algebra techniques and proposes a working theory of higher categories. Starting with a cohesive overview of the many different approaches currently used by researchers, the author proceeds with a detailed exposition of one of the most widely used techniques: the construction of a Cartesian Quillen model structure for higher categories. The fully iterative construction applies to enrichment over any Cartesian model category, and yields model categories for weakly associative n-categories and Segal n-categories. A corollary is the construction of higher functor categories which fit together to form the (n+1)-category of n-categories. The approach uses Tamsamani's definition based on Segal's ideas, iterated as in Pelissier's thesis using modern techniques due to Barwick, Bergner, Lurie and others.
Women Writers and Journalists in the Nineteenth-Century South
Authors: Wells Jonathan Daniel
Published: November 2011

The first study to focus on white and black women journalists and writers both before and after the Civil War, this book offers fresh insight into Southern intellectual life, the fight for women's rights and gender ideology. Based on new research into Southern magazines and newspapers, this book seeks to shift scholarly attention away from novelists and toward the rich and diverse periodical culture of the South between 1820 and 1900. Magazines were of central importance to the literary culture of the South because the region lacked the publishing centers that could produce large numbers of books. As editors, contributors, correspondents and reporters in the nineteenth century, Southern women entered traditionally male bastions when they embarked on careers in journalism. In so doing, they opened the door to calls for greater political and social equality at the turn of the twentieth century.
Three Expeditions into the Interior of Eastern Australia
Authors: Mitchell T. L.
Published: November 2011

Sir Thomas Livingstone Mitchell (1792–1855) was an acclaimed surveyor and explorer of Australia. After attending the University of Edinburgh Mitchell joined the British Army in 1811. He took part in major battles of the Peninsular War and difficult military surveys in the Pyrenees. In 1827 he was appointed Deputy Surveyor of New South Wales, and he became Surveyor General in 1828. This fascinating two-volume work, first published in 1838, contains Mitchell's illustrated account of his three expeditions into the then unexplored interior of modern eastern Victoria and southern New South Wales between 1831 and 1836, for which he received a knighthood in 1839. Drawing on Mitchell's personal journals, Volume 2 describes in vivid detail the difficulties and dangers of exploring the Murray–Darling river systems, and provides valuable first-hand descriptions of the lives and society of the indigenous Australians his expedition encountered.
Unification Grammars
Authors: Francez Nissim , Wintner Shuly
Published: November 2011

Grammars of natural languages can be expressed as mathematical objects, similar to computer programs. Such a formal presentation of grammars facilitates mathematical reasoning with grammars (and the languages they denote), as well as computational implementation of grammar processors. This book presents one of the most commonly used grammatical formalisms, Unification Grammars, which underlies contemporary linguistic theories such as Lexical-Functional Grammar (LFG) and Head-driven Phrase Structure Grammar (HPSG). The book provides a robust and rigorous exposition of the formalism that is both mathematically well-founded and linguistically motivated. While the material is presented formally, and much of the text is mathematically oriented, a core chapter of the book addresses linguistic applications and the implementation of several linguistic insights in unification grammars. Dozens of examples and numerous exercises (many with solutions) illustrate key points. Graduate students and researchers in both computer science and linguistics will find this book a valuable resource.
Travels in North America, in the Years 1827 and 1828
Authors: Hall Basil
Published: November 2011

Captain Basil Hall (1788–1844) was a Scottish seaman and travel writer. After attending the Royal High School in Edinburgh he joined the Navy in 1802, and was appointed captain in 1814. He served on many diplomatic and scientific naval missions, and on his retirement from the Navy began to publish accounts of his experiences, based on his journals. These volumes, first published in 1829, contain his detailed and controversial account of his journey across America and Canada between 1827 and 1828. Hall provides a fascinating and engaging description of social conditions, political structures and political tensions in Canada and America in the period, while also illustrating contemporary English prejudices concerning American society. Volume 3 contains his description of Washington D.C. and his journeys through South Carolina, Georgia, Kentucky, Alabama and along the Mississippi river. Hall also includes an analysis of slavery and cotton farming in the southern states.
Travels through Canada and the United States of North America in the Years 1806, 1807, and 1808
Authors: Lambert John
Published: November 2011

In the opening decades of the nineteenth century, the writings of John Lambert renewed the British public's fascination with the landscapes, peoples, flora, and fauna of the Canadian colonies and the United States. First published in 1811, and ultimately running into four editions, this two-volume work is packed with closely-observed descriptions, facts and figures about colonial life, as well as lively anecdotes. The 'corrected and improved' second edition reissued here was published in 1814, towards the end of the Napoleonic Wars. It promised to 'enable the British reader to form a just opinion of the Canadian colonies, and to appreciate the character of the neighbouring enemies who threaten their existence'. A trained painter, Lambert illustrated his account with lithographs based on his own watercolours. Volume 1 contains accounts of Lambert's outward voyage, Newfoundland and Quebec, covering subjects as diverse as chimney sweeps, French Jesuits, maple sugar, and 'stinking cheese'.
Three Visits to America
Authors: Faithfull Emily
Published: November 2011

The Victorian printer Emily Faithfull (1835–95) published Three Visits in 1884. The work is an account of her American lecture tours that took place in 1872–3, 1882–3 and 1884. Faithfull, a controversial and independently minded figure, campaigned for the employment and education rights of women. In 1860, Faithfull set up a printing establishment for women, the Victoria Press, where, despite fierce resistance from the printing trade, she employed and trained women as compositors. In 1862, she was made Printer and Publisher in Ordinary to Queen Victoria. Faithfull, a talented speaker, lectured widely on how America was dealing with the changing position of women, and the campaign for women's employment rights. This account remains a key source for the history of liberal feminism and the emancipation of nineteenth-century women.
Stability and bifurcation of planetary dynamo models
Authors: Dormy E.
Published: November 2011

Rapidly rotating dynamos, relevant to the origin of the Earth magnetic field, are difficult to model owing to the extreme parameter regimes that occur in their dynamics. Numerical models alone fail to approach the correct regime. However, progress can be achieved by combining numerical and analytical methods. This can offer a better understanding of the variety of behaviour observed near the onset of dynamo action, as seen in the recent study of Sreenivasan & Jones (J. Fluid Mech., this issue, vol. 688, 2011, pp. 5–30).
The Social Experience of Entertainment Media
Authors: Shedlosky-Shoemaker Randi , Costabile Kristi A. , DeLuca Haylee K. , Arkin Robert M.
Published: November 2011

People often look to others for guidance when selecting narrative entertainment. Previous work has demonstrated that this social guidance forms the basis of people’s expectations and subsequently affects people’s experience. The current work extends previous research by exploring the influence of peer evaluations of a story, on enjoyment of and psychological transportation in the written narrative. In two experiments, participants read peer evaluations prior to reading the story. Results of Experiment 1 revealed that social influence guides readers’ expectations, attention to elements in the narrative, reported enjoyment, and feelings of transportation in the narrative. This influence was particularly apparent when readers were given unfavorable reviews of the stimulus. In the second experiment, readers were given peer evaluations that were either confirmed or disconfirmed by other readers. Results indicated that valence of peer evaluations influenced both transportation and enjoyment. Additionally, inconsistent evaluations increased feelings of transportation, but consistency alone had no effect on reported enjoyment. Implications for social media experiences and future directions in research on entertainment media are discussed.
Parasocial Interaction as More Than Friendship
Authors: Dibble Jayson L. , Rosaen Sarah F.
Published: November 2011

This study supports the refinement of the concept of parasocial interaction (PSI) to apply to mediated personae that viewers might dislike. By contrast, traditional approaches have treated PSI as a sort of friendship with the mediated persona. Participants (N = 249) were randomly assigned to self-select a liked or disliked television persona. Various viewer reactions to that character were measured using two different measures of PSI. The data revealed that participants did experience PSI with disliked characters as well as liked characters, and that the two measures of PSI did not appear to assess the same construct. Implications for future research are discussed.
The Division of Household Tasks and Household Financial Management
Authors: Antonides Gerrit
Published: November 2011

Both the standard economic model and bargaining theory make predictions about financial management and the division of household labor between household partners. Using a large Internet survey, we have tested several predictions about task divisions reported by Dutch household partners. The division of household labor was mainly explained by partners’ job status, wife’s levels of education, and number of children, pointing to the relevancy of social class effects and life cycle stage to the division of household labor. The spouses’ wage rates were not significant in explaining the division of household labor. Financial management was almost evenly divided between household partners. The participation of the husband in financial management was positively related with his wage rate, and negatively with wife’s level of education, pointing to the relevance of bargaining theory. Furthermore, wife’s education was positively associated with household’s quality of financial planning, whereas the wife having a paid job, income going into separate accounts, and the number of children negatively affected financial planning. In addition, without indication of causality, the husband’s share in paying bills was negatively associated with the household easily making ends meet, the husband spending freely, and frequent debate about money. Also, financial planning was positively associated with the household making ends meet and the spouses’ frequent debate about money, and negatively with the spouses spending freely, indicating the importance of associations with psychological variables.
The Accuracy of Consumers’ Perception of Future Inflationary Price Changes
Authors: Christandl Fabian , Gärling Tommy
Published: November 2011

Four laboratory experiments were conducted to investigate the extent to which and how consumers encountering inflationary increases in product prices are able to accurately extrapolate future price increases. Between 32 and 48 undergraduates participated in the different experiments. In Experiment 1 it was found that participants were more able to extrapolate a proportional increase when presented with two consecutive proportional price increases compared to one price increase. This finding was not replicated for decreasing prices in Experiment 2. Experiment 3 showed that varying the time interval between prices counteracted an accurate extrapolation of proportional price increases despite that two price increases were presented. In Experiment 4 it was found that presenting the same (vs. different) proportional price increases for two products made participants able to extrapolate the common proportional price increase.
Formation of nitrogen‐ and sulfur‐containing light‐absorbing compounds accelerated by evaporation of water from secondary organic aerosols
Authors: Nguyen Tran B. , Lee Paula B. , Updyke Katelyn M. , Bones David L. , Laskin Julia , Laskin Alexander , Nizkorodov Sergey A.
Published: November 2011

Aqueous extracts of secondary organic aerosols (SOA) generated from the ozonolysis of d‐limonene were subjected to dissolution, evaporation, and re‐dissolution in the presence and absence of ammonium sulfate (AS). Evaporation with AS at pH 4–9 produced chromophores that were stable with respect to hydrolysis and had a distinctive absorption band at 500 nm. Evaporation accelerated the rate of chromophore formation by at least three orders of magnitude compared to the reaction in aqueous solution, which produced similar compounds. Absorption spectroscopy and high‐resolution nanospray desorption electrospray ionization (nano‐DESI) mass spectrometry experiments suggested that the molar fraction of the chromophores was small (<2%), and that they contained nitrogen atoms. Although the colored products represented only a small fraction of SOA, their large extinction coefficients (>105 L mol−1 cm−1 at 500 nm) increased the effective mass absorption coefficient of the residual organics in excess of 103 cm2 g−1 ‐ a dramatic effect on the optical properties from minor constituents. Evaporation of SOA extracts in the absence of AS resulted in the production of colored compounds only when the SOA extract was acidified to pH ∼ 2 with sulfuric acid. These chromophores were produced by acid‐catalyzed aldol condensation, followed by a conversion into organosulfates. The presence of organosulfates was confirmed by high resolution mass spectrometry experiments. Results of this study suggest that evaporation of cloud or fog droplets containing dissolved organics leads to significant modification of the molecular composition and serves as a potentially important source of light‐absorbing compounds.
Two-dimensional infrared spectral signature and hydration of the oxalate dianion
Authors: Kuroda Daniel G. , Hochstrasser Robin M.
Published: November 2011

Ultrafast vibrational spectra of the aqueous oxalate ion in the region of its carboxylate asymmetric stretch modes show novel relaxation processes. Two-dimensional infrared vibrational echo spectra and the vibrational dynamics obtained from them along with measurements of the anisotropy decay provide a picture in which the localization of the oxalate vibrational excitation onto the carboxylate groups occurs in ∼450 fs. Molecular dynamics simulations are used to characterize the vibrational dynamics in terms of dihedral angle motion between the two carboxylate planes and solvation dynamics. The localization of the oxalate vibrational excitation onto the carboxylates is induced by the fluctuations in the carboxylate vibrational frequencies which are shown by theory and experiment to have a similar correlation time as the anisotropy decay.
Influences of gradient profile on the band gap of two-dimensional phononic crystal
Authors: Cai Bei , Wei P. J.
Published: November 2011

Propagation characteristics of elastic waves in two-dimensional (2D) phononic crystal consisting of parallel cylinders or cylindrical shells embedded periodically in a homogeneous host are investigated. The cylinders or cylindrical shells with varying material parameters along the radial direction are considered. The influences of the gradient profile on the band gap are the main concern. First, the multiple scattering method and the Bloch theorem are used to derive the dispersive equation. Second, the transfer matrix of graded medium is derived based on the laminated cylindrical shell model. Three cases of combination are considered: (1) Solid cylinders embedded in solid host (solid-solid type). (2) Solid cylinders embedded in liquid host (solid-liquid type). (3) Hollow cylinder filled with liquid embedded in liquid host (liquid-solid-liquid type). Next, the dispersive curves and the band gaps between them are evaluated numerically in the reduced Brillouin zone. Five kinds of typical gradient profiles and two limited cases are considered. At last, the influence of the graded medium with different gradient profiles upon dispersive curves and the band gaps are discussed based on the numerical results.
Optical scattering and electric field enhancement from core–shell plasmonic nanostructures
Authors: Mejdoubi A. , Malki M. , Essone Mezeme M. , Sekkat Z. , Bousmina M. , Brosseau C.
Published: November 2011

Three-dimensional finite-difference time-domain simulations are used to study the near- and far-field properties of plasmonic core–shell (CS) nanostructures of reduced symmetry. Special attention is given to silica core and gold shell nanoparticles by changing their geometry. For the simulated range of wavelengths (300–2100 nm) our calculations of the scattering and absorption efficiencies imply strong polarization sensitivity and are highly dependent on the size and geometry of the CS nanostructures. Strong enhancements of the exciting electric field associated with the excitations of nanoparticle plasmons are observed. The wavelength dependence of the scattering spectra and concentration of electromagnetic field in subwavelength volumes have a potential for biosensing and bioimaging.
Gentle cold welding between gold nano objects driven by electrical field and atomic rearrangement
Authors: Ishida Tadashi , Kakushima Kuniyuki , Fujita Hiroyuki
Published: November 2011

The combination of a top-down and a bottom-up fabrication approach will be a key technology to overcome the minimum size limit of the top-down approach. Gentle cold welding is a promising method to connect nano objects without appreciable damages to the nano device in a bottom-up approach. We developed the gentle cold welding method using the combination of an electrical field and an atomic rearrangement. The formulated process was visualized between gold tips using a transmission electron microscope. The initial connection mechanism was divided into three modes depending on a bias voltage between tips; (1) physical contact, (2) atom extraction, and (3) field evaporation, depending on the electrical fields. All the nano connections grew by the atomic rearrangement driven by gold surface self-diffusion. The grown connections were single crystalline structures. These results suggested that this welding will be a useful method to build up future nano devices and systems.
Markov processes and generalized Schrödinger equations
Authors: Andrisani Andrea , Petroni Nicola Cufaro
Published: November 2011

Starting from the forward and backward infinitesimal generators of bilateral, time-homogeneous Markov processes, the self-adjoint Hamiltonians of the generalized Schrödinger equations are first introduced by means of suitable Doob transformations. Then, by broadening with the aid of the Dirichlet forms, the results of the Nelson stochastic mechanics, we prove that it is possible to associate bilateral, and time-homogeneous Markov processes to the wave functions stationary solutions of our generalized Schrödinger equations. Particular attention is then paid to the special case of the Lévy-Schrödinger (LS) equations and to their associated Lévy-type Markov processes, and to a few examples of Cauchy background noise.
Third harmonic generation by a low intensity laser pulse in a corrugated discharge capillary
Authors: Katzir Y. , Ferber Y. , Megidish E. , Zigler A. , Milchberg H. M.
Published: November 2011

Quasi phase matching and increase of laser interaction length were promoted by periodically modulated plasma guide formed by a discharge current ablating the inner capillary walls. The phenomenon was demonstrated through the use of third harmonics. For Ti:Sapphire laser pulses propagating through 1 cm long corrugated discharge capillaries, with an axial corrugation period of 200 μm, the third harmonic was generated at intensities as low as ∼109 W/cm2.
Ethics and Australian mammalogy: reflections on 15 years (1991 - 2006) on an Animal Ethics Committee
Authors: Lunney Daniel
Published: November 2011

This essay on field mammalogy and research ethics presents my reflections on 15 years as a researcher sitting on an Animal Ethics Committee in New South Wales. It outlines the community debate on animal welfare and the ethics of research on animals, how government has responded, and how wildlife researchers can move forward in this arena. Three schools are identified within the animal protection movement: ‘animal welfare’ holds that it is legitimate to use animals as a resource, so long as that use is ‘necessary’ and the animal’s suffering ‘minimised’; ‘animal liberationists’ are likely to oppose most animal research; the ‘animal rights’ position is firmly abolitionist. The instruments that regulate research involving animals are examined, in particular the New South Wales Animal Research Act 1985, the Australian code of practice for the care and use of animals for scientific purposes, and Animal Ethics Committees. Examples of ethical dilemmas involving both native and non-native animals are discussed. The debate over animals in research will continue, and it is clear that far more can be gained by engaging in the debate than avoiding it. It is in researchers’ interests to publicly defend the essential role of science in conserving our native fauna, and to conduct our work within a well managed welfare framework.
Distribution and status of the red-tailed phascogale (Phascogale calura)
Authors: Short Jeff , Hide Andrew
Published: November 2011

The red-tailed phascogale once extended widely across semiarid and arid Australia, but is now entirely confined to the southern wheatbelt of Western Australia, occupying less than 1% of its former range. Here it occurs in a portion of the Avon Wheatbelt, Jarrah Forest, Mallee, and Esperance Plains biogeographical regions. The species persists only in areas that have been extensively cleared for agriculture and where the remaining bushland is highly fragmented. It does not appear to extend into unfragmented habitat in either the Jarrah Forest to the west or Mallee region to the east. It occurs primarily in woodland habitat with old-growth hollow-producing eucalypts, primarily wandoo (Eucalyptus wandoo) or York Gum (E. loxophleba), but records from the periphery of its current range appear to come from a broader range of habitats, including shrublands and various mosaics of woodland, shrubland, and scrub-heath.
Key factors limiting persistence are likely to be fragmentation of habitat that is likely to greatly increase the risks associated with dispersal, a shortage of suitable nesting hollows in many vegetation associations, and predation by feral and domestic cats and by foxes. These factors, particularly fragmentation and lack of suitable nesting hollows, suggest that the species’ long-term persistence in areas beyond the wandoo belt is far from assured.
Detecting karrikinolide responses in seeds of the Poaceae
Authors: Long Rowena L. , Stevens Jason C. , Griffiths Erin M. , Adamek Markus , Powles Stephen B. , Merritt David J.
Published: November 2011

The smoke-derived chemical karrikinolide commonly triggers seeds in the Brassicaceae, Solanaceae and Asteraceae families to germinate, yet species in the Poaceae – another major understorey and weed family – have responded to the chemical with mixed results. This study aimed to understand why some grass species respond to karrikinolide while others do not. Using a field-based seed-burial trial, dose-response experiment, and stratification experiment, we investigated whether karrikinolide could alleviate dormancy and trigger seeds to germinate for seven global agronomic weeds: Avena fatua L., Lolium rigidum Gaudin, Eragrostis curvula (Schrad.) Nees, Phalaris minor Retz., Hordeum glaucum Steud., Ehrharta calycina Sm. and Bromus diandrus Roth. Seeds of A. fatua were consistently stimulated to germinate with karrikinolide in all experiments, whether seeds were freshly collected or dormancy had been partially alleviated. In contrast, seeds of L. rigidum failed to respond to karrikinolide when the seeds were fresh, after-ripened in the laboratory, and even during natural dormancy loss in the field. Interestingly, although karrikinolide did not stimulate freshly collected E. curvula seeds to germinate, it hastened dormancy loss when applied during stratification. These findings are helpful for understanding the responses of grass species following fire. They also contribute to a growing body of research aimed at using karrikinolide as a tool for triggering uniform germination of seeds for enhancing restoration efforts and depleting the weed seed bank.
The impact of harvesting native forests on vegetation and soil C stocks, and soil CO2, N2O and CH4 fluxes
Authors: Page K. L. , Dalal R. C. , Raison R. J.
Published: November 2011

Australia’s harvested native forests are extremely diverse in terms of species-mix, disturbance history and ecology, forest productivity and C storage. Our understanding of the effects of harvesting on C storage and greenhouse gas (GHG) emissions from these systems is incomplete, and this paper consolidates current Australian knowledge, places this in a global context, and identifies areas requiring further study. The uptake of CO2 and the re-accumulation of forest C stocks after harvesting or other disturbance is largely dependent on forest primary production. However, in Australian native forests, knowledge of rates of primary production for the diverse range of species and management practices present is poor. Soil respiration rates following harvest have also been largely unquantified for Australian systems. It is essential that both these parameters are quantified if estimates of net ecosystem production (NEP) are to be made. It is generally acknowledged that harvested forests have a negative NEP, and thus are sources of C, immediately following harvest, but attain a positive NEP as the forest regrows and photosynthetic capacity increases. The magnitude and time course of these changes are largely unknown for most Australian forest systems. In addition, little data are available to quantify the effect on soil C storage, and where estimates have been made these are often subject to methodological uncertainty and are thus highly contentious. Following harvest, the changes that occur to soil structure, moisture content, and N cycling may also influence CH4 and N2O flux, although these fluxes also remain largely unquantified in harvested Australian forests. Given the significant changes to NEP, CH4 and N2O fluxes observed after forest harvest in international studies, it is expected that GHG fluxes would typically increase from Australian native forests following harvest, and then slowly decrease over time as biomass accumulates, and N2O and CH4 fluxes return to background levels. However, it is currently difficult to quantify the magnitude and time course of these changes due to a lack of both gas flux and primary production measurements. Clearly, further research effort to quantify these parameters throughout Australia is required in order to obtain a more reliable picture of the effects of harvesting and other disturbances on forest GHG balance.
Cytotoxicity of essential oils from two species of Heterothalamus (Asteraceae)
Authors: Schmidt-Silva Valeri , Pawlowski Ângela , Kaltchuk dos Santos Eliane , Zini Cláudia Alcaraz , Soares Geraldo L. G.
Published: November 2011

Essential oils are widely found in plant species. They can be involved in a variety of ecological interactions and may act as inhibitors of germination, suppressing root apical-meristem growth in some species. The present study aimed to determine the potential cytotoxicity of essential oils from leaves of Heterothalamus psiadioides Less. and H. alienus (Sprengel) O.Kuntze on root tips of lettuce (Lactuca sativa L.) and onion (Allium cepa L.). Lettuce seeds germinated with essential oils from H. psiadioides and H. alienus had a reduced mitotic index (MI) for all treatments. Onion seedlings treated with H. psiadioides oil showed a decrease in MI, and seedlings treated with H. alienus oil showed a decrease in MI of 89% in the most concentrated treatment. Analysis of the results showed chromosomal abnormalities, including stickiness, c-mitosis, micronuclei and anaphase bridges in lettuce and onion root tips exposed to essential oils of Heterothalamus.
Long-term memory prepares neural activity for perception
Authors: Stokes Mark G. , Atherton Kathryn , Patai Eva Zita , Nobre Anna Christina
Published: November 2011

Past experience provides a rich source of predictive information about the world that could be used to guide and optimize ongoing perception. However, the neural mechanisms that integrate information coded in long-term memory (LTM) with ongoing perceptual processing remain unknown. Here, we explore how the contents of LTM optimize perception by modulating anticipatory brain states. By using a paradigm that integrates LTM and attentional orienting, we first demonstrate that the contents of LTM sharpen perceptual sensitivity for targets presented at memory-predicted spatial locations. Next, we examine oscillations in EEG to show that memory-guided attention is associated with spatially specific desynchronization of alpha-band activity over visual cortex. Additionally, we use functional MRI to confirm that target-predictive spatial information stored in LTM triggers spatiotopic modulation of preparatory activity in extrastriate visual cortex. Finally, functional MRI results also implicate an integrated cortical network, including the hippocampus and a dorsal frontoparietal circuit, as a likely candidate for organizing preparatory states in visual cortex according to the contents of LTM.