bluuebunny/crossref_metadata_2025 huggingface dataset:
Classical Algebraic Geometry
Authors: Dolgachev Igor V.
Published: September 2012

Algebraic geometry has benefited enormously from the powerful general machinery developed in the latter half of the twentieth century. The cost has been that much of the research of previous generations is in a language unintelligible to modern workers, in particular, the rich legacy of classical algebraic geometry, such as plane algebraic curves of low degree, special algebraic surfaces, theta functions, Cremona transformations, the theory of apolarity and the geometry of lines in projective spaces. The author's contemporary approach makes this legacy accessible to modern algebraic geometers and to others who are interested in applying classical results. The vast bibliography of over 600 references is complemented by an array of exercises that extend or exemplify results given in the book.
Human Adaptation in the Asian Palaeolithic
Authors: Rabett Ryan J.
Published: September 2012

This book examines the first human colonization of Asia and particularly the tropical environments of Southeast Asia during the Upper Pleistocene. In studying the unique character of the Asian archaeological record, it reassesses long-accepted propositions about the development of human 'modernity.' Ryan J. Rabett reveals an evolutionary relationship between colonization, the challenges encountered during this process – especially in relation to climatic and environmental change – and the forms of behaviour that emerged. This book argues that human modernity is not something achieved in the remote past in one part of the world, but rather is a diverse, flexible, responsive and ongoing process of adaptation.
Mapping the Chinese and Islamic Worlds
Authors: Park Hyunhee
Published: September 2012

Long before Vasco da Gama rounded the Cape of Good Hope en route to India, the peoples of Africa, the Middle East, and Asia engaged in vigorous cross-cultural exchanges across the Indian Ocean. This book focuses on the years 700 to 1500, a period when powerful dynasties governed both regions, to document the relationship between the Islamic and Chinese worlds before the arrival of the Europeans. Through a close analysis of the maps, geographic accounts, and travelogues compiled by both Chinese and Islamic writers, the book traces the development of major contacts between people in China and the Islamic world and explores their interactions on matters as varied as diplomacy, commerce, mutual understanding, world geography, navigation, shipbuilding, and scientific exploration. When the Mongols ruled both China and Iran in the thirteenth and fourteenth centuries, their geographic understanding of each other's society increased markedly. This rich, engaging, and pioneering study offers glimpses into the worlds of Asian geographers and mapmakers, whose accumulated wisdom underpinned the celebrated voyages of European explorers like Vasco da Gama.
Works of Thomas Hill Green
Authors: Green Thomas Hill
Published: September 2012

Thomas Hill Green (1836–82) was one of the most influential English thinkers of his time, and he made significant contributions to the development of political liberalism. Much of his career was spent at Balliol College, Oxford: having begun as a student of Jowett, he later acted effectively as his second-in-command at the college. Interested for his whole career in social questions, Green supported the temperance movement, the extension of the franchise, and the admission of women to university education. He became Whyte's professor of moral philosophy at Oxford in 1878, and his lectures had a lasting influence on a generation of students. Much of Volume 1, edited by Green's pupil R. L. Nettleship and published in 1885, consists of Green's work on David Hume (1711–76). In his essay, 'Introductions to Hume's Treatise of Human Nature' (originally published in 1874), Green gives a detailed critique of Hume's metaphysical thought.
Social Rights and Duties
Authors: Stephen Leslie
Published: September 2012

Sir Leslie Stephen (1832–1904), the founding editor of the Dictionary of National Biography, and a writer on philosophy, ethics, and literature, was educated at Eton, King's College London and Trinity College, Cambridge, where he remained as a fellow and a tutor for a number of years. Though a sickly child, he later became a keen and successful mountaineer, taking part in first ascents of nine peaks in the Alps. In 1871 he became editor of the Cornhill Magazine. During his eleven-year tenure, he wrote two successful books on ethics, including The Science of Ethics in 1892, which was widely adopted as a standard textbook. This two-volume work, which was first published in 1896, brings together the lectures he gave to various ethical societies, mostly in London. In Volume 1, he considers the role of ethical societies and discusses a range of questions in politics, social equality and morality.
A Ride through Asia Minor and Armenia
Authors: Barkley Henry C.
Published: September 2012

Henry C. Barkley (c.1825–c.1895) was a civil engineer and author. His travel books included Between the Danube and the Black Sea (1876), which covers the five years in which he was working on the construction of a railway line linking the Danube and the Black Sea, and Bulgaria before the War (1877), written at the time of the Russo-Turkish war. (He also wrote a guide to rat-catching for public-school boys, and My Boyhood (1877), a collection of tales from his own childhood.) Published in 1891, this work recounts the author's adventures on a journey that took him in 1878 from Bucharest, through Istanbul, across Asia Minor and back to Trebizond (now Trabzon) on the Black Sea coast, a distance of 1400 miles, completed in 96 days. He describes with zest and humour the habits and customs of Christian and Muslim communities that he encounters on the way.
Autobiography and Correspondence of Mary Granville, Mrs Delany
Authors: Delany Mary
Published: September 2012

Mary Delany (née Granville, 1700–88) is best known for her cut-paper illustrations of plants - she completed nearly 1,000 of these botanical pictures. Widowed after an unhappy first marriage, she lived in London, attended court, and was a favourite of George III and Queen Charlotte. After being widowed for a second time, and at the age of 74, she began her plant illustrations: failing eyesight caused her to abandon the work in 1784. Delany knew many of the leading cultural figures of the eighteenth century, including Handel and Swift. An enthusiastic correspondent, she wrote and received hundreds of letters, which were edited by her great-great-niece, Lady Llanover (1802–96). Published in 1861–2, they tell the life story of this remarkable woman, while also providing a fascinating glimpse into the world of Georgian England. Volume 6 covers the final years of Delany's life, and includes a copy of her will.
A Treatise on the Science of Music
Authors: Reeves Daniel M. G. S.
Published: September 2012

First published by the house of Novello in 1853, and later reprinted, this was one of the earliest treatises to take a scientific as well as a practical approach to the discussion of music. Written before Wagner had begun work on Tristan, this work can be seen as a response to the growing interest from the amateur in the 'science' of music. Little is known about the author, Daniel Reeves, who declares that that 'the idea of music comprises both an art and a science: the art consisting in the power of performing … ; the science, in an acquaintance with the system on which the constituent sounds … depend'. Using numerous examples, Reeves explains the basics of musical notation, and includes a lengthy mathematical analysis of the ratios of tones and intervals, underlining his belief that an understanding of music should be 'a necessary branch of every gentleman's education'.
Melville and the Idea of Blackness
Authors: Freeburg Christopher
Published: September 2012

By examining the unique problems that 'blackness' signifies in Moby-Dick, Pierre, 'Benito Cereno' and 'The Encantadas', Christopher Freeburg analyzes how Herman Melville grapples with the social realities of racial difference in nineteenth-century America. Where Melville's critics typically read blackness as either a metaphor for the haunting power of slavery or an allegory of moral evil, Freeburg asserts that blackness functions as the site where Melville correlates the sociopolitical challenges of transatlantic slavery and US colonial expansion with philosophical concerns about mastery. By focusing on Melville's iconic interracial encounters, Freeburg reveals the important role blackness plays in Melville's portrayal of characters' arduous attempts to seize their own destiny, amass scientific knowledge and perfect themselves. A valuable resource for scholars and graduate students in American literature, this text will also appeal to those working in American, African American and postcolonial studies.
The Calendar in Revolutionary France
Authors: Perovic Sanja
Published: September 2012

One of the most unusual decisions of the leaders of the French Revolution - and one that had immense practical as well as symbolic impact - was to abandon customarily-accepted ways of calculating date and time to create a Revolutionary calendar. The experiment lasted from 1793 to 1805, and prompted all sorts of questions about the nature of time, ways of measuring it and its relationship to individual, community, communication and creative life. This study traces the course of the Revolutionary Calendar, from its cultural origins to its decline and fall. Tracing the parallel stories of the calendar and the literary genius of its creator, Sylvain Maréchal, from the Enlightenment to the Napoleonic era, Sanja Perovic reconsiders the status of the French Revolution as the purported 'origin' of modernity, the modern experience of time, and the relationship between the imagination and political action.
The WTO Dispute Settlement Procedures
Authors: WTO Secretariat
Published: September 2012

The third edition of The WTO Dispute Settlement Procedures collects together the treaty texts, decisions and agreed practices relating to the procedures that apply in the settlement of WTO disputes. It affords ready answers to technical questions relating to matters such as: how disputes are initiated and conducted, including at the appellate stage; what deadlines apply and how to calculate them; what rules of conduct bind individuals involved in WTO dispute settlement; and what rules of procedure apply to meetings of the Dispute Settlement Body. This highly practical work, which includes cross-references and a subject index, will prove invaluable to anyone working in WTO dispute settlement, including lawyers, civil servants working in the field of trade, economists, academics and students. This edition has been fully updated to take account of revised rules and procedures.
Superstring Theory
Authors: Green Michael B. , Schwarz John H. , Witten Edward
Published: September 2012

Twenty-five years ago, Michael Green, John Schwarz, and Edward Witten wrote two volumes on string theory. Published during a period of rapid progress in this subject, these volumes were highly influential for a generation of students and researchers. Despite the immense progress that has been made in the field since then, the systematic exposition of the foundations of superstring theory presented in these volumes is just as relevant today as when first published. A self-contained introduction to superstrings, Volume 1 begins with an elementary treatment of the bosonic string, before describing the incorporation of additional degrees of freedom: fermionic degrees of freedom leading to supersymmetry and internal quantum numbers leading to gauge interactions. A detailed discussion of the evaluation of tree-approximation scattering amplitudes is also given. Featuring a new preface setting the work in context in light of recent advances, this book is invaluable for graduate students and researchers in general relativity and elementary particle theory.
‘Hearing the Country’: Reflexivity as an Intimate Journey into Epistemological Liminalities
Authors: Bradley John
Published: September 2012

In this article I discuss the way Problem-Based Learning (PBL) and reflexivity is employed in a university environment to address the question of how we can most successfully transfer knowledge about the presumed Other into our own cultural space without reducing, fragmenting, and exoticising complex knowledge systems. My goal is to stimulate in students an awareness of, and empathic engagement with, Indigenous epistemologies and Indigenous perspectives on environment, other species, moral ecology and cultural and commercial activities undertaken on Country. In this article I focus on one particular course in which I use ethnographic scenarios as learning triggers for weekly workshops to provide a multi-sensorial and experiential style of learning. Topics range from the construction of ethnoclassificatory systems to the construction of kinship as an expression of moral ontological frameworks. The process draws on over 30 years experience working with the Yanyuwa families of the southwest Gulf of Carpentaria in the Northern Territory. Central to the success of the course are the li-Yanyuwa li-Wirdiwalangu (Yanyuwa knowledge holders), a core group of senior men and women who play an active daily role in the maintenance and dissemination of Yanyuwa knowledge systems, increasingly a site of their own empowerment. In consultation with Bradley, they have selected and annotated core ethnographic information which I have then developed into PBL triggers for the course.
Dietary patterns obtained through principal components analysis: the effect of input variable quantification
Authors: Smith Andrew D. A. C. , Emmett Pauline M. , Newby P. K. , Northstone Kate
Published: September 2012

Principal components analysis (PCA) is a popular method for deriving dietary patterns. A number of decisions must be made throughout the analytic process, including how to quantify the input variables of the PCA. The present study aims to compare the effect of using different input variables on the patterns extracted using PCA on 3-d diet diary data collected from 7473 children, aged 10 years, in the Avon Longitudinal Study of Parents and Children. Four options were examined: weight consumed of each food group (g/d), energy-adjusted weight, percentage contribution to energy of each food group and binary intake (consumed/not consumed). Four separate PCA were performed, one for each intake measurement. Three or four dietary patterns were obtained from each analysis, with at least one component that described ‘more healthy’ and ‘less healthy’ diets and one component that described a diet with high consumption of meat, potatoes and vegetables. There were no obvious differences between the patterns derived using percentage energy as a measurement and adjusting weight for total energy intake, compared to those derived using gram weights. Using binary input variables yielded a component that loaded positively on reduced fat and reduced sugar foods. The present results suggest that food intakes quantified by gram weights or as binary variables both resulted in meaningful dietary patterns and each method has distinct advantages: weight takes into account the amount of each food consumed and binary intake appears to describe general food preferences, which are potentially easier to modify and useful in public health settings.
Philosophy, Hellenicity, Law: Porphyry on Origen, Again
Authors: Johnson Aaron P.
Published: September 2012

Porphyry's criticism of Origen (in c.Christ. fr. 39 Harnack) is usually interpreted as expressive of the ‘double apostasy’ accusation: Christians had not only abandoned their pagan religious traditions (‘Hellenism’) but also their new religious host, Judaism, whose texts they misappropriated for themselves. Reading key elements of the fragment within Porphyry's broader philosophical thought prompts suspicion of this cultural interpretation of the fragment, and instead points to a serious Platonic reaction to Christianity.
Pseudo-Skylax and the Natural Philosophers
Authors: Shipley D. Graham J.
Published: September 2012

This paper seeks to establish an intellectual context for the periplous of Pseudo-Skylax (probably written in or near Athens in 338 to ca. 337 BC). The unknown author is aware of the work of contemporary natural philosophers, including those in the post-Platonic Academy and those who were to form the Peripatos, especially Aristotle, Theophrastos and Dikaiarchos. Among known writers, Dikaiarchos is most likely to have written the periplous; but the case remains unproven. Doubts are also raised as to the validity of the so-called periplographic genre.
Local structure of self-affine sets
Authors: BANDT CHRISTOPH , KÄENMÄKI ANTTI
Published: September 2012

The structure of a self-similar set with the open set condition does not change under magnification. For self-affine sets, the situation is completely different. We consider self-affine Cantor sets $E\subset \mathbb {R}^2$ of the type studied by Bedford, McMullen, Gatzouras and Lalley, for which the projection onto the horizontal axis is an interval. We show that in small square $\varepsilon $-neighborhoods $N$ of almost each point $x$ in $E,$ with respect to many Bernoulli measures on the address space, $E\cap N$ is well approximated by product sets $[0,1]\times C$, where $C$ is a Cantor set. Even though $E$ is totally disconnected, all tangent sets have a product structure with interval fibers, reminiscent of the view of attractors of chaotic differentiable dynamical systems. We also prove that $E$has uniformly scaling scenery in the sense of Furstenberg, Gavish and Hochman: the family of tangent sets is the same at almost all points$x.$
The House that Built Holmes
Authors: Snyder Brad
Published: September 2012

Justice Oliver Wendell Holmes Jr. is one of the few modern judges whose reputations have survived the twentieth century's culture wars relatively intact. Among his contemporaries Louis Brandeis, Benjamin Cardozo, and Learned Hand, Holmes was the first to become a judicial and cultural icon. Although Holmes's judicial reputation has fluctuated wildly since his death, his canonical status is unquestioned. His opinions, like those of Brandeis, are often quoted in high-profile Supreme Court decisions. Popular historians continue to be fascinated with his life story.
Convergence of error-driven ranking algorithms
Authors: Magri Giorgio
Published: September 2012

According to the OT error-driven ranking model of language acquisition, the learner performs a sequence of slight re-rankings triggered by mistakes on the incoming stream of data, until it converges to a ranking that makes no more mistakes. Two classical examples are Tesar & Smolensky's (1998) Error-Driven Constraint Demotion (EDCD) and Boersma's (1998) Gradual Learning Algorithm (GLA). Yet EDCD only performs constraint demotion, and is thus shown to predict a ranking dynamics which is too simple from a modelling perspective. The GLA performs constraint promotion too, but has been shown not to converge. This paper develops a complete theory of convergence of error-driven ranking algorithms that perform both constraint demotion and promotion. In particular, it shows that convergent constraint promotion can be achieved (with an error-bound that compares well to that of EDCD) through a proper calibration of the amount by which constraints are promoted.
Algorithmic thermodynamics
Authors: BAEZ JOHN , STAY MIKE
Published: September 2012

Algorithmic entropy can be viewed as a special case of the entropy studied in statistical mechanics. This viewpoint allows us to apply many techniques developed for use in thermodynamics to the subject of algorithmic information theory. In particular, suppose we fix a universal prefix-free Turing machine and letXbe the set of programs that halt for this machine. Then we can regardXas a set of ‘microstates’, and treat any function onXas an ‘observable’. For any collection of observables, we can study the Gibbs ensemble that maximises entropy subject to constraints on the expected values of these observables. We illustrate this by taking the log runtime, length and output of a program as observables analogous to the energyE, volumeVand number of moleculesNin a container of gas. The conjugate variables of these observables allow us to define quantities we call the ‘algorithmic temperature’T, ‘algorithmic pressure’Pand ‘algorithmic potential’ μ, since they are analogous to the temperature, pressure and chemical potential. We derive an analogue of the fundamental thermodynamic relationdE=TdS−PdV+μdN, and use it to study thermodynamic cycles analogous to those for heat engines. We also investigate the values ofT,Pand μ for which the partition function converges. At some points on the boundary of this domain of convergence, the partition function becomes uncomputable – indeed, at these points the partition function itself has non-trivial algorithmic entropy.
Incomputability in Physics and Biology
Authors: LONGO GIUSEPPE
Published: September 2012

Computability has its origins in Logic within the framework formed along the original path laid down by the founding fathers of the modern foundational analysis for Mathematics (Frege and Hilbert). This theoretical itinerary, which was largely focused on Logic and Arithmetic, departed in principle from the renewed relations between Geometry and Physics occurring at the time. In particular, the key issue of physical measurement, as our only access to ‘reality’, played no part in its theoretical framework. This is in stark contrast to the position in Physics, where the role of measurement has been a core theoretical and epistemological issue since Poincaré, Planck and Einstein. Furthermore, measurement is intimately related to unpredictability, (in-)determinism and the relationship with physical space–time. Computability, despite having exact access to its own discrete data type, provides a unique tool for the investigation of ‘unpredictability’ in both Physics and Biology through its fine-grained analysis of undecidability – note that unpredictability coincides with physical randomness in both classical and quantum frames. Moreover, it now turns out that an understanding of randomness in Physics and Biology is a key component of the intelligibility of Nature. In this paper, we will discuss a few results following along this line of thought.
The Rescripting of Pain Images
Authors: Philips Clare , Samson Debbie
Published: September 2012

Background: The majority of pain sufferers experience images when in pain. The most distressing of these images (the Index image) provokes intense emotional reactions, appraisal shifts, and increases in pain. The ability of pain sufferers to rescript their Index images, and the consequences of doing so, remain to be determined. Aims: To assess the effects upon emotions, appraisals and pain experience of rescripting Index images in pain sufferers. Method: The Index images of a group of 55 pain sufferers were assessed using a voluntary image induction procedure (VIE) to obtain basal levels of pain, appraisal and emotion. Participants were than randomly allocated to one of two groups: Rescripted Image repetition or Index Image repetition. The two groups were compared on their responses to their Index and Rescripted images respectively. Results: The participants found it easy to rescript their distressing Index images. During rescripting, they reported dramatic reductions in emotion, negative appraisals, and pain. The clinically and statistically significant decrements in pain were found independent of reductions in emotion. The pain levels during rescripting were significantly below their basal levels, with 49% reporting no pain at all while viewing a rescripted image. These changes were not a function of image repetition. Conclusion: Index images of pain sufferers can be easily elicited and rescripted. Rescripting leads to remarkable reductions in emotion, cognitions and pain levels that are not attributable to image repetition. The significant reductions in pain were independent of reductions in emotion. The implications of these results for CBT approaches to pain management are considered.
Effluent charge reform for controlling water pollution in the Malaysian crude palm oil industry
Authors: Hojat Amir Hossein Montazer , Rahim Khalid Abdul
Published: September 2012

This study analyzes the costs borne by Malaysian palm oil mills (POMs) in order to reach standard levels. A number of studies have been conducted on Malaysian palm oil mills; however, none has obtained the marginal abatement cost (MAC) through an estimated total cost function. More particularly, as far as inflation is concerned, the effluent-related fee and effluent charge specified have not been revised within the past two decades. In addition, to our knowledge, there has not been any study comparing MAC to the mills of the two different methods of disposal, namely watercourse and on land. Our results show that, to force POMs to meet the standard, the effluent charge must be set higher, equaling the MAC. While the results show the existence of economies of scale in abatement activity, setting the effluent-related fee equal to the MAC may encourage mills to further abate their water pollution.
Gender-specific abnormalities in the serotonin transporter system in panic disorder
Authors: Cannon Dara M. , Klaver Jacqueline M. , Klug Summer A. , Carlson Paul J. , Luckenbaugh David A. , Ichise Masanori , Drevets Wayne C.
Published: September 2012

The central serotonergic system has been implicated in the pathophysiology of panic disorder (PD) by evidence of abnormally elevated serotonin-turnover, reduced pre- and post-synaptic 5-HT1A−receptor sensitivity and binding and clinical improvement during administration of agents that enhance serotonergic transmission. Polymorphisms in genes that putatively influence serotonergic neurotransmission increase the vulnerability for developing PD specifically in males. We tested the hypotheses that serotonin transporter (5-HTT) binding is elevated in PD subjects vs. healthy controls in regions where in vivo evidence exists for both elevated 5-HTT and 5-HT1A receptor levels in PD and investigated whether the extent of this difference depends upon gender. Volunteers were out-patients with current PD (n=24) and healthy controls (n=24). The non-displaceable component of 5-HTT binding-potential (BPND) was measured using positron emission tomography and the 5-HTT selective radioligand, [11C]DASB. PD severity was assessed using the PD Severity Scale. The 5-HTT-BPND was increased in males with PD relative to male controls in the anterior cingulate cortex (F=8.96, pFDR=0.01) and midbrain (F=5.09, pFDR=0.03). In contrast, BPND did not differ between females with PD and female controls in any region examined. The finding that 5-HTT-binding is elevated in males but not in females with PD converges with other evidence suggesting that dysfunction within the central serotonergic system exists in PD, and also indicates that such abnormalities are influenced by gender. These findings conceivably may reflect a sexual dimorphism that underlies the greater efficacy of serotonin reuptake inhibitor treatment in females vs. males with PD.
Pre-pregnancy maternal overweight and obesity increase the risk for affective disorders in offspring
Authors: Robinson M. , Zubrick S. R. , Pennell C. E. , Van Lieshout R. J. , Jacoby P. , Beilin L. J. , Mori T. A. , Stanley F. J. , Newnham J. P. , Oddy W. H.
Published: September 2012

Maternal pre-pregnancy obesity has been linked with an increased risk for negative emotionality and inattentiveness in offspring in early childhood. The aim of this study was to examine the association between maternal pre-pregnancy body mass index (BMI) and the development of affective problems (dysthymic disorder, major depressive disorder) throughout childhood and adolescence. In the Western Australian Pregnancy Cohort (Raine) Study, 2900 women provided data on their pre-pregnancy weight, and height measurements were taken at 18 weeks of gestation. BMI was calculated and categorized using standardized methods. Live-born children (n= 2868) were followed up at ages 5, 8, 10, 14 and 17 years using the Diagnostic and Statistical Manual of Mental Disorders-oriented scales of the Child Behavior Checklist (CBCL/4–18). Longitudinal models were applied to assess the relationships between maternal pre-pregnancy BMI and affective problems from age 5 through 17. There was a higher risk of affective problems between the ages of 5 and 17 years among children of women who were overweight and obese compared with the offspring of women in the healthy pre-pregnancy weight range (BMI 18.5–24.99) after adjustment for confounders, including paternal BMI. Maternal pre-pregnancy overweight and obesity may be implicated in the development of affective problems, including depression, in their offspring later in life.
Fallbericht: Dementia Pugilistica (D.P.) bzw. chronisch traumatische Encephalopathie
Authors: Wentzlaff Sascha , Knauss Janet , Mohr Silke
Published: September 2012

In diesem Artikel wird ein möglicher Fall einer Dementia Pugilistica beschrieben. Interessant wird dieser Fall nicht nur durch die Seltenheit einer solchen Diagnose, sondern vielmehr durch die Fragestellung an den Neuropsychologen. Es geht darum, ob die neuropsychologischen Defizite des Probanden ursächlich durch eine alkoholtoxische Genese oder den jahrzehntelangen Boxsport zu erklären sind. Die Ergebnisse präsentieren als Hauptsymptomatik eine deutliche Verlangsamung der Reiz-Reaktionsfähigkeit, die höheren kognitiven Funktionen präsentieren sich besser intakt, gleichwohl auch systematische Beeinträchtigungen in den exekutiven und mnestischen Funktionen zu erheben sind. Die Ausprägung und das Profil der Symptomatik deuten auf das Vorliegen einer Dementia Pugilistica, wobei eine alkoholtoxische Genese nicht auszuschließen ist. Erst die Zusammenschau der neuropsychologischen, radiologischen und anamnestischen Daten führt zu der Diagnose Dementia Pugilistica.
Assessing offsets between the δ13C of sedimentary components and the global exogenic carbon pool across early Paleogene carbon cycle perturbations
Authors: Sluijs Appy , Dickens Gerald R.
Published: September 2012

Negative stable carbon isotope excursions (CIEs) across the Paleocene–Eocene thermal maximum (PETM; ∼56 Ma) range between 2‰ and 7‰, even after discounting sections with truncated records. Individual carbon isotope records differ in shape and magnitude from variations in the global exogenic carbon cycle through changes in (1) the relative abundance of mixed components with different δ13C within a measured substrate, (2) isotope fractionation through physiological change, and (3) the isotope composition of the carbon source. All three factors likely influence many early Paleogene δ13C records, especially across the PETM and other hyperthermal events. We apply these concepts to late Paleocene–early Eocene (∼58–52 Ma) records from Lomonosov Ridge, Arctic Ocean. Linear regression analyses show correlations between the δ13C of total organic carbon (TOC) and two proxies for the relative contribution of terrestrial organic components to sediment TOC: the branched and isoprenoid tetraether index and palynomorphs. We use these correlations to subtract the terrestrial component from δ13CTOC and calculate marine organic matter δ13C. The results show that the magnitude of the CIE in δ13CTOC across the PETM is exaggerated relative to the magnitude of the CIE in δ13CMOM by ∼3‰ due to increased contributions of terrestrial organic carbon during the event. Collectively, all carbon isotope records across the PETM and other major climate–carbon cycle perturbations in Earth's history are potentially biased through one or more of the above factors. Indeed, it is highly unlikely that any δ13C record shows the true shape and magnitude of the CIE for the global exogenic carbon cycle. For the PETM, we conclude that CIE in the exogenic carbon cycle is likely <4‰, but it will take additional analyses and modeling to obtain an accurate value for this CIE.
The detection of energetic electrons with the Cassini Langmuir probe at Saturn
Authors: Garnier P. , Wahlund J.‐E. , Holmberg M. K. G. , Morooka M. , Grimald S. , Eriksson A. , Schippers P. , Gurnett D. A. , Krimigis S. M. , Krupp N. , Coates A. , Crary F. , Gustafsson G.
Published: September 2012

The Cassini Langmuir probe, part of the Radio and Plasma Wave Science (RPWS) instrument, has provided a wealth of information about the cold and dense plasma in the Saturnian system. The analysis of the ion side current (current for negative potentials) measured by the probe from 2005 to 2008 reveals also a strong sensitivity to energetic electrons (250–450 eV). These electrons impact the surface of the probe, and generate a detectable current of secondary electrons. A broad secondary electrons current region is inferred from the observations in the dipole L Shell range of ∼6–10, with a peak full width at half maximum (FWHM) at L = 6.4–9.4 (near the Dione and Rhea magnetic dipole LShell values). This magnetospheric flux tube region, which displays a large day/night asymmetry, is related to the similar structure in the energetic electron fluxes as the one measured by the onboard Electron Spectrometer (ELS) of the Cassini Plasma Spectrometer (CAPS). It corresponds spatially to both the outer electron radiation belt observed by the Magnetosphere Imaging Instrument (MIMI) at high energies and to the low‐energy peak which has been observed since the Voyager era. Finally, a case study suggests that the mapping of the current measured by the Langmuir probe for negative potentials can allow to identify the plasmapause‐like boundary recently identified at Saturn, and thus potentially identify the separation between the closed and open magnetic field lines regions.
First‐principles physics of cusp/polar cap thermospheric disturbances
Authors: Carlson Herbert C. , Spain Timothy , Aruliah Anasuya , Skjaeveland Asmund , Moen Joran
Published: September 2012

This first‐principles examination of physics driving the cusp/polar upper thermosphere response to significant input energy impulses discloses previously unappreciated factors essential to thermospheric input‐response relationships. The physics essential to coupling of cusp input‐response processes is detailed, to make previously unexplained up‐to‐doubling of air density and drag near 400 km not only understandable but expected, if not inevitable. Presented as a common natural consequence of magnetic reconnection near the magnetopause, this energy‐coupling from sun to upper atmosphere is through familiar processes, but by inadequately appreciated linkages. The underlying physics applies more broadly than this. We trace a logic path that should clarify the input‐response, and lay out a path which if followed should enable most existing time‐dependent 3‐D global thermospheric models to significantly improve the realism of their representation and prediction of cusp/polar thermosphere disturbances to transient energy sources. We illustrate the concept with a sample model‐run incorporating representative data.
Spatial and temporal variability of global ocean mixing inferred from Argo profiles
Authors: Whalen C. B. , Talley L. D. , MacKinnon J. A.
Published: September 2012

The influence of turbulent ocean mixing transcends its inherently small scales to affect large scale ocean processes including water‐mass transformation, stratification maintenance, and the overturning circulation. However, the distribution of ocean mixing is not well described by sparse ship‐based observations since this mixing is both spatially patchy and temporally intermittent. We use strain information from Argo float profiles in the upper 2,000 m of the ocean to generate over 400,000 estimates of the energy dissipation rate, indicative of ocean mixing. These estimates rely on numerous assumptions, and do not take the place of direct measurement methods. Temporally averaged estimates reveal clear spatial patterns in the parameterized dissipation rate and diffusivity distribution across all the oceans. They corroborate previous observations linking elevated dissipation rates to regions of rough topography. We also observe heightened estimated dissipation rates in areas of high eddy kinetic energy, as well as heightened diffusivity in high latitudes where stratification is weak. The seasonal dependence of mixing is observed in the Northwest Pacific, suggesting a wind‐forced response in the upper ocean.
LLNL‐G3Dv3: Global P wave tomography model for improved regional and teleseismic travel time prediction
Authors: Simmons N. A. , Myers S. C. , Johannesson G. , Matzel E.
Published: September 2012

We develop a global‐scale P wave velocity model (LLNL‐G3Dv3) designed to accurately predict seismic travel times at regional and teleseismic distances simultaneously. The model provides a new image of Earth's interior, but the underlying practical purpose of the model is to provide enhanced seismic event location capabilities. The LLNL‐G3Dv3 model is based on ∼2.8 millionP and Pnarrivals that are re‐processed using our global multiple‐event locator called Bayesloc. We construct LLNL‐G3Dv3 within a spherical tessellation based framework, allowing for explicit representation of undulating and discontinuous layers including the crust and transition zone layers. Using a multiscale inversion technique, regional trends as well as fine details are captured where the data allow. LLNL‐G3Dv3 exhibits large‐scale structures including cratons and superplumes as well numerous complex details in the upper mantle including within the transition zone. Particularly, the model reveals new details of a vast network of subducted slabs trapped within the transition beneath much of Eurasia, including beneath the Tibetan Plateau. We demonstrate the impact of Bayesloc multiple‐event location on the resulting tomographic images through comparison with images produced without the benefit of multiple‐event constraints (single‐event locations). We find that the multiple‐event locations allow for better reconciliation of the large set of direct P phases recorded at 0–97° distance and yield a smoother and more continuous image relative to the single‐event locations. Travel times predicted from a 3‐D model are also found to be strongly influenced by the initial locations of the input data, even when an iterative inversion/relocation technique is employed.
The HDO/H2O relationship in tropospheric water vapor in an idealized “last‐saturation” model
Authors: Sherwood S. C. , Risi C.
Published: September 2012

Previous model studies have shown that the isotopic composition of tropospheric water vapor is sensitive to atmospheric water transport processes, but compositional information is difficult to interpret due to the complexity of the models. Here an attempt is made to clarify the sensitivity by computing the relationship between tropospheric HDO (via δD) and H2O (via specific humidity q) in an idealized model atmosphere based on a “last‐saturation” framework that includes convection coupled to a steady large‐scale circulation with prescribed horizontal mixing. Multiple physical representations of convection and mixing allow key structural as well as parametric uncertainties to be explored. This model has previously been shown to reproduce the essential aspects of the humidity distribution. Variations ofδD or qindividually are dominated by local dynamics, but their relationship is preserved advectively, thus revealing conditions in regions of convection. The model qualitatively agrees with satellite observations, and reproduces some parametric sensitivities seen in previous GCM experiments. Sensitivity to model assumptions is greatest in the upper troposphere, apparently because in‐situ evaporation and condensation processes in convective regions are more dominant in the budget there. In general, vapor recycling analogous to that in continental interiors emerges as the crucial element in explaining whyδD exceeds that predicted by a simple Rayleigh process; such recycling involves coexistent condensation sinks and convective moisture sources, induced respectively by (for example) waves and small‐scale convective mixing. The relative humidity distribution is much less sensitive to such recycling.
Streamflow variability and optimal capacity of run‐of‐river hydropower plants
Authors: Basso S. , Botter G.
Published: September 2012

The identification of the capacity of a run‐of‐river plant which allows for the optimal utilization of the available water resources is a challenging task, mainly because of the inherent temporal variability of river flows. This paper proposes an analytical framework to describe the energy production and the economic profitability of small run‐of‐river power plants on the basis of the underlying streamflow regime. We provide analytical expressions for the capacity which maximize the produced energy as a function of the underlying flow duration curve and minimum environmental flow requirements downstream of the plant intake. Similar analytical expressions are derived for the capacity which maximize the economic return deriving from construction and operation of a new plant. The analytical approach is applied to a minihydro plant recently proposed in a small Alpine catchment in northeastern Italy, evidencing the potential of the method as a flexible and simple design tool for practical application. The analytical model provides useful insight on the major hydrologic and economic controls (e.g., streamflow variability, energy price, costs) on the optimal plant capacity and helps in identifying policy strategies to reduce the current gap between the economic and energy optimizations of run‐of‐river plants.
Improved snowmelt simulations with a canopy model forced with photo‐derived direct beam canopy transmissivity
Authors: Musselman Keith N. , Molotch Noah P. , Margulis Steven A. , Lehning Michael , Gustafsson David
Published: September 2012

The predictive capacity of a physically based snow model to simulate point‐scale, subcanopy snowmelt dynamics is evaluated in a mixed conifer forest, southern Sierra Nevada, California. Three model scenarios each providing varying levels of canopy structure detail were tested. Simulations of three water years initialized at locations of 24 ultrasonic snow depth sensors were evaluated against observations of snow water equivalent (SWE), snow disappearance date, and volumetric soil water content. When canopy model parameters canopy openness and effective leaf area index were obtained from satellite and literature‐based sources, respectively, the model was unable to resolve the variable subcanopy snowmelt dynamics. When canopy parameters were obtained from hemispherical photos, the improvements were not statistically significant. However, when the model was modified to accept photo‐derived time‐varying direct beam canopy transmissivity, the error in the snow disappearance date was reduced by as much as one week and positive and negative biases in melt‐season SWE and snow cover duration were significantly reduced. Errors in the timing of soil meltwater fluxes were reduced by 11 days on average. The optimum aggregated temporal model resolution of direct beam canopy transmissivity was determined to be 30 min; hourly averages performed no better than the bulk canopy scenarios and finer time steps did not increase overall model accuracy. The improvements illustrate the important contribution of direct shortwave radiation to subcanopy snowmelt and confirm the known nonlinear melt behavior of snow cover.
Coarse-graining MARTINI model for molecular-dynamics simulations of the wetting properties of graphitic surfaces with non-ionic, long-chain, and T-shaped surfactants
Authors: Sergi Danilo , Scocchi Giulio , Ortona Alberto
Published: September 2012

We report on a molecular dynamics investigation of the wetting properties of graphitic surfaces by various solutions at concentrations 1–8 wt. % of commercially available non-ionic surfactants with long hydrophilic chains, linear or T-shaped. These are surfactants of length up to 160 Å. It turns out that molecular dynamics simulations of such systems ask for a number of solvent particles that can be reached without seriously compromising computational efficiency only by employing a coarse-grained model. The MARTINI force field with polarizable water offers a framework particularly suited for the parameterization of our systems. In general, its advantages over other coarse-grained models are the possibility to explore faster long time scales and the wider range of applicability. Although the accuracy is sometimes put under question, the results for the wetting properties by pure water are in good agreement with those for the corresponding atomistic systems and theoretical predictions. On the other hand, the bulk properties of various aqueous surfactant solutions indicate that the micellar formation process is too strong. For this reason, a typical experimental configuration is better approached by preparing the droplets with the surfactants arranged in the initial state in the vicinity of contact line. Cross-comparisons are possible and illuminating, but equilibrium contact angles as obtained from simulations overestimate the experimental results. Nevertheless, our findings can provide guidelines for the preliminary assessment and screening of surfactants. Most importantly, it is found that the wetting properties mainly depend on the length and apolarity of the hydrophobic tail, for linear surfactants, and the length of the hydrophilic headgroup for T-shaped surfactants. Moreover, the T-shaped topology appears to favor the adsorption of surfactants onto the graphitic surface and faster spreading.
Extended diffusion in a double well potential: Transition from classical to quantum regime
Authors: Blaise Paul , Kalmykov Yuri P. , Velcescu Adina A.
Published: September 2012

The transition between the classical and quantum regimes in the diffusion of a particle in a 2–4 double-well potential is treated via the strong collision model in the high-temperature limit. Both the classical and semiclassical position correlation functions, their spectra, and correlation times are evaluated using the memory function formalism. It is shown that even in the high temperature limit, marked classical-quantum transition effects appear in the observables when collisions are rare.
EBT2 dosimetry of x-rays produced by the electron beam from a Plasma Focus for medical applications
Authors: Ceccolini E. , Rocchi F. , Mostacci D. , Sumini M. , Tartari A. , Mariotti F.
Published: September 2012

The electron beam emitted from the back of Plasma Focus devices is being studied as a radiation source for intraoperative radiation therapy applications. A Plasma Focus device is being developed to this aim, to be utilized as an x-ray source. The electron beam is driven to impinge on 50 μm brass foil, where conversion x-rays are generated. Measurements with gafchromic film are performed to analyse the attenuation of the x-rays beam and to predict the dose given to the culture cell in radiobiological experiments to follow.
A compact and miniaturized high resolution capacitance dilatometer for measuring thermal expansion and magnetostriction
Authors: Küchler R. , Bauer T. , Brando M. , Steglich F.
Published: September 2012

We describe the design, construction, calibration, and two different applications of a miniature capacitance dilatometer. The device is suitable for thermal expansion and magnetostriction measurements from 300 K down to about 25 mK, with a resolution of 0.02 Å at low temperatures. The main body of the dilatometer is fabricated from a single block of a Be-Cu alloy by electrical discharge milling. This creates an extremely compact high-resolution measuring cell. We have successfully tested and operated dilatometers of this new type with the commonly used physical property measurement system by quantum design, as well as with several other cryogenic refrigeration systems down to 25 mK and in magnetic fields up to 20 T. Here, the capacitance is measured with a commercially available capacitance bridge. Using a piezoelectric rotator from Attocube Systems, the cell can be rotated at T = 25 mK inside of an inner vacuum chamber of 40 mm diameter. The miniaturized design for the one-axis rotation setup allows a rotation of 360°.