bluuebunny/crossref_metadata_2025 huggingface dataset:
Hardy inequalities with non-standard remainder terms
Authors: Cianchi Andrea , Ferone Adele
Published: October 2007

Improved Hardy inequalities, involving remainder terms, are established both in the classical and in the limiting case. The relevant remainders depend on a suitable distance from the families of the “virtual” extremals.

Nous établissons des inégalités de Hardy améliorées avec reste, à la fois dans le cas classique et dans le cas limite. Ce reste dépend d'une distance à la famille des extremas « virtuels ».
The unstable spectrum of the Navier–Stokes operator in the limit of vanishing viscosity
Authors: Shvydkoy Roman , Friedlander Susan
Published: October 2007

The Navier–Stokes equations for the motion of an incompressible fluid in three dimensions are considered. A partition of the evolution operator into high frequency and low frequency parts is derived. This decomposition is used to prove that the eigenvalues of the Navier–Stokes operator in the inviscid limit converge precisely to the eigenvalues of the Euler operator beyond the essential spectrum.
F2 screen for resistance to a Bacillus thuringiensis-maize hybrid in the sugarcane borer (Lepidoptera: Crambidae)
Authors: Huang F.N. , Leonard B.R. , Andow D.A.
Published: October 2007

A novel F2 screening technique was developed for detecting resistance in sugarcane borer, Diatraea saccharalis (F.), to transgenic Bacillus thuringiensis (Bt)-maize expressing the Cry1Ab insecticidal protein. The F2 screening method involved (i) collecting larvae from maize fields; (ii) establishing two-parent families; (iii) screening F2 neonates for survival on Bt-maize leaf tissues; and (iv) confirming resistance on commercial Bt-maize plants. With the F2 screening method, 213 iso-line families of D. saccharalis were established from field collections in northeast Louisiana, USA and were screened for Bt resistance. One family was confirmed to carry a major Bt resistance allele(s). In a laboratory bioassay, larval mortality of the Bt-resistant D. saccharalis on Bt-maize leaf tissues was significantly lower than that of a Bt-susceptible strain. This Bt-resistant D. saccharalis population is the first corn stalk borer species that has completed larval development on commercial Bt-maize. The F2 screening protocol developed in this study could be modified for detecting Bt resistance alleles in other similar corn stalk borers, such as the European corn borer, Ostrinia nubilalis (Hübner), and the southwestern corn borer, D. grandiosella Dyar.
Two methods of assessing the mortality factors affecting the larvae and pupae of Cameraria ohridella in the leaves of Aesculus hippocastanum in Switzerland and Bulgaria
Authors: Girardoz S. , Tomov R. , Eschen R. , Quicke D.L.J. , Kenis M.
Published: October 2007

The horse-chestnut leaf miner, Cameraria ohridella, is an invasive alien species defoliating horse-chestnut, a popular ornamental tree in Europe. This paper presents quantitative data on mortality factors affecting larvae and pupae of the leaf miner in Switzerland and Bulgaria, both in urban and forest environments. Two sampling methods were used and compared: a cohort method, consisting of the surveying of pre-selected mines throughout their development, and a grab sampling method, consisting of single sets of leaves collected and dissected at regular intervals. The total mortality per generation varied between 14 and 99%. Mortality was caused by a variety of factors, including parasitism, host feeding, predation by birds and arthropods, plant defence reaction, leaf senescence, intra-specific competition and inter-specific competition with a fungal disease. Significant interactions were found between mortality factors and sampling methods, countries, environments and generation. No mortality factor was dominant throughout the sites, generations and methods tested. Plant defence reactions constituted the main mortality factor for the first two larval stages, whereas predation by birds and arthropods and parasitism were more important in older larvae and pupae. Mortality caused by leaf senescence was often the dominant mortality factor in the last annual generation. The cohort method detected higher mortality rates than the grab sampling method. In particular, mortality by plant defence reaction and leaf senescence were better assessed using the cohort method, which is, therefore, recommended for life table studies on leaf miners.
Exploring plant responses to aphid feeding using a fullArabidopsismicroarray reveals a small number of genes with significantly altered expression
Authors: Couldridge C. , Newbury H.J. , Ford-Lloyd B. , Bale J. , Pritchard J.
Published: October 2007

The aim of this study was to determine whichArabidopsis thaliana(L.) genes had significantly altered expression following 2–36 h of infestation by the aphidMyzus persicae(Sulzer). Six biological replicates were performed for both control and treatment at each time point, allowing rigorous statistical analysis of any changes. Only two genes showed altered expression after 2 h (one up- and one down-regulated) while two were down-regulated and twenty three were up-regulated at 36 h. The transcript annotation allowed classification of the significantly altered genes into a number of classes, including those involved in cell wall modification, carbon metabolism and signalling. Additionally, a number of genes were implicated in oxidative stress and defence against other pathogens. Five genes could not currently be assigned any function. The changes in gene expression are discussed in relation to current models of plant-insect interactions.
Copulation behaviour ofGlossina pallidipes(Diptera: Muscidae) outside and inside the female, with a discussion of genitalic evolution
Authors: Briceño R.D. , Eberhard W.G. , Robinson A.S.
Published: October 2007

If species-specific male genitalia are courtship devices under sexual selection by cryptic female choice, then species-specific aspects of the morphology and behaviour of male genitalia should often function to stimulate the female during copulation. The morphology and behaviour of the complex, species-specific male genitalia of the tsetse fly,Glossina pallidipesAusten, were determined from both direct observations and dissections of flash-frozen copulating pairs; we found that some male genitalic traits probably function to stimulate the female, while others function to restrain her. The male clamps the ventral surface of the female's abdomen tightly with his powerful cerci. Clamping does not always result in intromission. Clamping bends the female's body wall and her internal reproductive tract sharply, posteriorly and dorsally, and pinches them tightly. The male performed sustained, complex, stereotyped, rhythmic squeezing movements with his cerci that were not necessary to mechanically restrain the female and appeared instead to have a stimulatory function. Six different groups of modified setae on and near the male's genitalia rub directly against particular sites on the female during squeezing. The designs of these setae correlate with the force with which they press on the female and the probable sensitivity of the female surfaces that they contact. As expected under the hypothesis that these structures are under sexual selection by female choice, several traits suspected to have stimulatory functions have diverged inG. pallidipesand its close relative,G. longipalpis. Additional male non-genitalic behaviour during copulation, redescribed more precisely than in previous publications, is also likely to have a courtship function. The elaborate copulatory courtship behaviour and male genitalia may provide the stimuli that previous studies showed to induce female ovulation and resistance to remating.
Development of silverleaf assay, protein and nucleic acid-based diagnostic techniques for the quick and reliable detection and monitoring of biotype B of the whitefly, Bemisia tabaci (Gennadius)
Authors: Shankarappa K.S. , Rangaswamy K.T. , Aswatha Narayana D.S. , Rekha A.R. , Raghavendra N. , Lakshminarayana Reddy C.N. , Chancellor T.C.B. , Maruthi M.N.
Published: October 2007

The aim of this study was to develop and optimize silverleaf bioassay, esterase analysis and PCR-based techniques to distinguish quickly and reliably biotype B of the whitefly, Bemisia tabaci (Gennadius), from Indian indigenous biotypes. Zucchini and squash readily develop silverleaf symptoms upon feeding by the B biotype, but they are not readily available in Indian markets. A local pumpkin variety ‘Big’ was, therefore, used in silverleaf assay, which developed symptoms similar to those on zucchini and squash and can be used reliably to detect B biotype. Analysis of non-specific esterases of B and the indigenous biotypes indicated both quantitative and qualitative differences in esterase patterns. Two high molecular weight bands were unique to B biotype and they occurred in abundance. These esterases were used to develop quick and field-based novel detection methods for differentiating B from the indigenous biotypes. Development of these simple and cost-effective protocols has wider application as they can be potentially used to identify other agricultural pests. Mitochondrial cytochrome oxidase I gene sequences and randomly amplified polymorphic DNA (RAPD) polymorphisms, generated using the primer OpB11, were also found useful for detecting B. tabaci biotypes. A B biotype-specific RAPD band of 800 bp was sequenced, which was used to a develop sequence characterized amplified region (SCAR) marker. The SCAR marker involved the development of B biotype-specific primers that amplified 550 bp PCR products only from B biotype genomic DNA. Silverleaf assay, esterases, RAPDs or a SCAR marker were used in combination to analyse whitefly samples collected from selected locations in India, and it was found that any of these techniques can be used singly or in combination to detect B biotype reliably. The B biotype was found in southern parts of India but not in the north in 2004–06.
Semigroups of local homeomorphisms and interaction groups
Authors: EXEL R. , RENAULT J.
Published: October 2007

Given a semigroup of surjective local homeomorphisms on a compact space X we consider the corresponding semigroup of *-endomorphisms on C(X) and discuss the possibility of extending it to an interaction group, a concept recently introduced by the first named author. We also define a transformation groupoid whose C*-algebra turns out to be isomorphic to the crossed product algebra for the interaction group. Several examples are considered, including one which gives rise to a slightly different construction and should be interpreted as being the C*-algebra of a certain polymorphism.
Adapted metrics for dominated splittings
Authors: GOURMELON NIKOLAZ
Published: October 2007

A Riemannian metric is adapted to a hyperbolic set of a diffeomorphism if, in this metric, the expansion/contraction of the unstable/stable directions is seen after only one iteration. A dominated splitting is a notion of weak hyperbolicity where the tangent bundle of the manifold splits in invariant subbundles such that the vector expansion on one bundle is uniformly smaller than that on the next bundle. The existence of an adapted metric for a dominated splitting has been considered by Hirsch, Pugh and Shub (M. Hisch, C. Pugh and M. Shub. Invariant Manifolds(Lecture Notes in Mathematics, 583). Springer, Berlin, 1977). This paper gives a complete answer to this problem, building adapted metrics for dominated splittings and partially hyperbolic splittings in arbitrarily many subbundles of arbitrary dimensions. These results stand for diffeomorphisms and for flows.
The structure of tame minimal dynamical systems
Authors: GLASNER ELI
Published: October 2007

A dynamical version of the Bourgain–Fremlin–Talagrand dichotomy shows that the enveloping semigroup of a dynamical system is either very large and contains a topological copy of $\beta \mathbb {N}$, or it is a ‘tame’ topological space whose topology is determined by the convergence of sequences. In the latter case, the dynamical system is said to be tame. We use the structure theory of minimal dynamical systems to show that, when the acting group is Abelian, a tame metric minimal dynamical system (i) is almost automorphic (i.e. it is an almost one-to-one extension of an equicontinuous system), and (ii) admits a unique invariant probability measure such that the corresponding measure-preserving system is measure-theoretically isomorphic to the Haar measure system on the maximal equicontinuous factor.
Roots of Resistance to Urban Water Privatization in Bolivia: The “New Working Class,” the Crisis of Neoliberalism, and Public Services
Authors: Spronk Susan
Published: October 2007

This paper analyzes the roots of resistance to the privatization of public services in the context of the changes to class formation in Bolivia. Based upon two case studies of urban water privatization, it seeks to explain why the social coalitions that have emerged to protest the privatization of public water services in Bolivia have been led by territorially-based organizations composed of rural-urban and multiclass alliances rather than public-sector unions. It argues that protest against the privatization of water utilities in Bolivia must be understood within the context of neoliberal economic restructuring and the emergence of what has been termed the “new working class,” which is now primarily urban and engaged in informal forms of work.
Privatization and the Historical Trajectory of “Social Movement Unionism”: A Case Study of Municipal Workers in Johannesburg, South Africa
Authors: Barchiesi Franco
Published: October 2007

The article discusses the opposition by the South African Municipal Workers' Union (SAMWU) to the privatization of Johannesburg's municipal services under Apartheid and in the new democratic dispensation. The unionization of South African black municipal workers has been shaped by a tradition of “social-movement unionism,” which greatly contributed to the decline and fall of the racist regime. The post-1994 democratic government has adopted policies of privatization of local services and utilities, which SAMWU opposed in Johannesburg by resurrecting a social movement unionism discourse. Conditions of political democracy have, however, proven detrimental to such a strategy, whose continued validity is here questioned.
The Two Faces of Petr Arkad'evich: Land and Dispossession in Russia's Southwest, ca. 2000
Authors: Allina-Pisano Jessica
Published: October 2007

At the beginning and the end of the twentieth century, the Russian imperial and post-Soviet governments pursued large-scale projects to transform land tenure in the countryside. Based on the belief that people would work harder and more productively on land they themselves owned, both reform programs divided collectively-managed land into individual parcels. Post-Soviet land privatization, consciously modeled on the Stolypin-era reforms conducted in early twentieth-century Russia, resulted in the dispossession of much of the rural population. This article examines privatization in a district of Voronezhoblast’ in Russia's southwest, considering contemporary processes through an historical lens. It shows how successful local efforts to adapt to markets and preserve large-scale agriculture nonetheless resulted in rural dispossession.
The Hospital Employees' Union Strike and the Privatization of Medicare in British Columbia, Canada
Authors: Isitt Benjamin , Moroz Melissa
Published: October 2007

In April 2004, the Hospital Employees' Union (HEU) waged an illegal strike that mobilized sections of British Columbia's working class to the brink of a general sympathetic strike. Influenced by BC's class-polarized political culture and HEU's distinct history, the 2004 strike represents a key moment of working-class resistance to neoliberal privatization. HEU was targeted by the BC Liberal government because it represented a bastion of militant, independent unionism in a jurisdiction that appeared overripe (from the neoliberal standpoint) for a curtailment of worker rights and a retrenchment of public-sector employment. HEU also represented a direct barrier, in the language of its collective agreements and collective power of its membership, to the privatization of health services and dismantling of Medicare. The militant agency of HEU members, combined with anger generated by a constellation of social-service cutbacks, inspired rank-and-file workers and several unions to defy collective agreements and embrace sympathetic strike action. This revealed differentiation in the strategy and tactics of BC's labor leadership, and enduring sources of solidarity in labor's ranks.
The Politics of Ports: Privatization and the World's Ports
Authors: Davis Colin
Published: October 2007

The recent controversy over a foreign-owned company running a US port brought attention to the creeping privatization of work in ports worldwide. Since the 1980s, there has been a head-long rush to privatize ports. The pace can be best described as rapid and chaotic. For some economists privatization is seen as a method to increase efficiency. But the process has substantial critics. For many privatization is perceived as problematic. There is evidence that the process does not indeed lead to savings and greater efficiency. Instead, the process has been haphazard and far from uniform in its application. Even where there is an entrenched presence, savings from privatization have yet to be realized. Others have made the point that the process cannot be transferred to ports in the developing world. That is, the multiplicity of ports and transportation problems in the interior make privatization more like wishful thinking than a policy that can work.
Eye dominance and response latency in area V1 of the monkey
Authors: ROMERO MARIA C. , CASTRO ADRIAN F. , BERMUDEZ MARIA A. , PEREZ ROGELIO , GONZALEZ FRANCISCO
Published: October 2007

We measured the latency of 35 cells from V1 in two rhesus monkeys, to dynamic random dot stimuli monocular and binocularly presented. Mean latencies after non-dominant eye stimulation (97.9 ms) were longer than those for dominant eye (78.2 ms) and binocular (70.7 ms) stimulation. Differences between latencies for dominant eye and binocular stimulation were not statistically significant. For dominant eye, there was a significant statistical correlation between dominance strength and latency (R= −0.36;p= 0.03). We failed to find significant statistical differences between latencies for cells with temporal and nasal dominant receptive-field. We conclude that, in V1, the response latency is largely determined by the dominant eye, whereas interocular interactions do not seem to play a relevant role regarding response latency.
Retinal Development, edited by E. Sernagor, S. Eglen, W. Harris, and R. Wong
Authors: Sterling Peter
Published: October 2007

Retinal Development, edited by E. Sernagor, S. Eglen, W. Harris, and R. Wong. 2006. New York: Cambridge University Press.

Fairly regularly some member of my lab, finding a new feature of retinal circuitry, wonders aloud if it might “somehow relate to development.” I always reply, “We don't study development.” This partly reflects my curmudgeonly insistence that we stay focused on explaining function in the adult. But even if the discovery did relate to development, the connection would be too difficult to find—because the large territory has lacked any useful guide. Next time, however, I will hand over my copy of Retinal Development and reply more kindly, “Check it out.”
Behavioural reasoning for conditional equations
Authors: MARTINS MANUEL A. , PIGOZZI DON
Published: October 2007

Object-oriented (OO) programming techniques can be applied to equational specification logics by distinguishing visible data from hidden data (that is, by distinguishing the output of methods from the objects to which the methods apply), and then focusing on the behavioural equivalence of hidden data in the sense introduced by H. Reichel in 1984. Equational specification logics structured in this way are called hidden equational logics, HELs. The central problem is how to extend the specification of a given HEL to a specification of behavioural equivalence in a computationally effective way. S. Buss and G. Roşu showed in 2000 that this is not possible in general, but much work has been done on the partial specification of behavioural equivalence for a wide class of HELs. The OO connection suggests the use of coalgebraic methods, and J. Goguen and his collaborators have developed coinductive processes that depend on an appropriate choice of a cobasis, which is a special set of contexts that generates a subset of the behavioural equivalence relation. In this paper the theoretical aspects of coinduction are investigated, specifically its role as a supplement to standard equational logic for determining behavioural equivalence. Various forms of coinduction are explored. A simple characterisation is given of those HELs that are behaviourally specifiable. Those sets of conditional equations that constitute a complete, finite cobasis for a HEL are characterised in terms of the HEL's specification. Behavioural equivalence, in the form of logical equivalence, is also an important concept for single-sorted logics, for example, sentential logics such as the classical propositional logic. The paper is an application of the methods developed through the extensive work that has been done in this area on HELs, and to a broader class of logics that encompasses both sentential logics and HELs.
EDMUND BURKE AND THE POLITICS OF CONQUEST
Authors: BOURKE RICHARD
Published: October 2007

This article restores the context of political action to Burke's thinking about politics. It begins with the specific case of his interventions in the parliamentary debate over the Quebec Bill in 1774, and proceeds from this focal point to establish the centrality of the theme of conquest to his political motivation and understanding in general. Burke's preoccupation with conquest drove him to examine eighteenth-century British politics within a set of comparative historical frameworks. These frameworks encompassed the trajectories of both modern European and imperial politics and ancient historical development. The objective of Burke's politics of conquest was to overcome the destructive influence of the spirit of conquest. That objective involved deciding upon and justifying courses of action with reference to these comparative historical frameworks of understanding. Careful investigation shows that while Burke's approach to this task was powerfully influenced by Montesquieu, his arguments invariably entailed serious criticism of Montesquieu's conclusions. Properly understood, these criticisms show that Burke himself did not endorse the political principles that were later taken to constitute “Burkian conservatism”. The article draws the conclusion that a thorough grasp of the politics of conquest in Burke's thinking will force us to reposition him in the history of political theory.
ILLUMINATING EVIL: HANNAH ARENDT AND MORAL HISTORY
Authors: COTKIN GEORGE
Published: October 2007

Hannah Arendt's well-known examinations of the problem of evil are not contradictory and they are central to her corpus. Evil can be banal in some cases (Adolf Eichmann) and radical (the phenomenon of totalitarianism) in others. But behind all expressions of evil, in Arendt's formulations, is the imperative that it be confronted by thinking subjects and thoroughly historicized. This led her away from a view of evil as radical to one of evil as banal. Arendt's ruminations on evil are illuminated, in part, by concerns that she shared with her fellow New York intellectuals about the withering effects of mass culture upon individual volition and understanding. In confronting the challenges of evil, Arendt functioned as a “moral historian,” suggesting profitable ways that historians might look at history from a moral perspective. Indeed, her work may be viewed as anticipating a “moral turn” currently afoot in the historical profession.
WHAT WAS THE HISTORY OF THE BOOK? A RESPONSE
Authors: HALL DAVID D.
Published: October 2007

The history of the book is everywhere, so widely diffused that it merits comparison with the famously elusive Scarlet Pimpernel, whose pursuers sought him without success. Like that figure, book history passes among us in disguise, reluctant to reveal its presence even as it gains ever-greater recognition. In some quarters, it lurks within the domain of bibliography, a field of scholarship dedicated to describing the histories of printed texts and, in the service of this enterprise, concerned with the details of book-making. Elsewhere, book history installs itself within descriptions of libraries and education, sharing, with the first of these, a concern for how old books were accumulated and classified and, with the second, for the many ramifications of literacy and the fashioning of schoolbooks. Together with the history of journalism it studies how news was disseminated and ponders the significance of periodicals, be these newspapers or magazines. Political history has been another convenient site of disguise in the wake of efforts to connect the public sphere and concepts of nation with the emergence of print culture. And, of course, book history has enjoyed a long and fruitful kinship with literary history, a relationship freshly energized in recent decades as literary historians turned to describing the rise and remaking of a canon and to emphasizing the mediations that all texts undergo—the “sociology of texts,” to borrow a phrase made famous by D. F. McKenzie. To this list we can add the version of intellectual history that reconstructs the reading of a person or group and employs this data to generalize about the coming of the Enlightenment and similar formations.
THE HISTORY OF PHILOSOPHY AND THE PERSONA OF THE PHILOSOPHER
Authors: HUNTER IAN
Published: October 2007

Although history is the pre-eminent part of the gallant sciences, philosophers advise against it from fear that it might completely destroy the kingdom of darkness—that is, scholastic philosophy—which previously has been wrongly held to be a necessary instrument of theology.
Comments on Vasyliunas' and Pontius' studies of the effects of the planetary ionosphere and of the Coriolis force on the interchange instability
Authors: André N. , Ferrière K. M.
Published: October 2007

Recent Galileo and Cassini plasma and magnetic field observations indicate that the centrifugal/interchange instability plays a critical role in radial plasma transport in the rapidly rotating magnetospheres of giant planets. These observations have stimulated considerable interest in understanding the development and the properties of the instability. A complete description of the interchange instability involves an electric coupling between the magnetosphere and the planetary ionosphere. Vasyliunas (1994) pointed out that when the ionosphere is ineffective at constraining interchange motions, local magnetospheric conditions govern the plasma dynamics. In that case the Coriolis force leads to a dramatic decrease in the instability growth rate according to Pontius (1997), whereas it has a neutral influence according to Ferrière et al. (2001). The purpose of the present paper is to critically reexamine Vasyliunas' and Pontius' results and investigate the origin of their discrepancies with Ferrière et al.'s results. To that end, we consider the case of a thin plasma disk in an axisymmetric, rapidly rotating magnetosphere with no field‐aligned electric currents at equilibrium.
Long‐term changes in the cosmic ray intensity at Earth, 1428–2005
Authors: McCracken K. G. , Beer J.
Published: October 2007

The instrumental cosmic ray data recorded in the interval 1933–1965 by S. E. Forbush and H. V. Neher and cosmogenic 10Be data are merged with the neutron monitor data since 1951 to study the long‐ and short‐term variations in the galactic cosmic radiation intensity for the interval 1428–2005. It is shown that the ionization chamber data published by S. E. Forbush were deliberately detrended to remove long‐term changes. The high‐altitude ionization chambers used by H. V. Neher during this interval were well calibrated and their data exhibit a substantial decrease between 1933 and 1954 that is consistent with the long‐term trends in the cosmogenic 10Be data. Using the specific yield functions appropriate to neutron monitors, ionization chambers, and 10Be, the nonlinear relationships between these data types are determined. It is shown that the nonlinearities are large and will introduce serious errors if ignored. An intercalibrated record (the “pseudo‐Climax neutron monitor record”) is developed for the interval 1428–2005. It is used to study several features of the long‐term periodicities in the cosmic radiation, after discussion of residual effects due to meteorological effects, and the production of 10Be by solar cosmic rays. It is shown that (1) the average intensity in the neutron monitor energy range for the interval 1954–1996 is ∼16% less than the average for the period 1428–1944 and that it shows a consistency and depth of modulation that had not occurred in the previous 580 years. (2) The residual cosmic ray modulation was low throughout the Gleissberg cycle 1540–1645, considerably higher for the next two Gleissberg Cycles, and highest of all since 1944. (3) The cosmogenic data imply that solar activity was anomalously low throughout the whole interval 1428–1715, the amplitude of the solar activity during the Gleissberg cycle 1540–1645 being ∼50% of that during the following two Gleissberg cycles and ∼25% of that in the post‐1954 era. (4) It is proposed that the steadily increasing cosmic ray modulation since 1428 constitutes a quarter cycle of the previously identified 2300 year periodicity in the cosmogenic data. (5) The cosmic ray intensity decreased in two steps between 1889 and 1901 and 1944 and 1954, in broad agreement with the two‐step increase in heliomagnetic field strength determined by Schrijver et al. (2002). It is proposed that the “pseudo‐Climax neutron record” will be of benefit in the normalization of other cosmogenic records to the neutron monitor record starting in 1951.
Thermal regime of the Southeast Indian Ridge between 88°E and 140°E: Remarks on the subsidence of the ridge flanks
Authors: Géli L. , Cochran J. R. , Lee T. C. , Francheteau J. , Labails C. , Fouchet C. , Christie D.
Published: October 2007

The flanks of the Southeast Indian Ridge are characterized by anomalously low subsidence rates for the 0–25 Ma period: less than 300 m Ma−1/2 between 101°E and 120°E and less than 260 m Ma−1/2 within the Australian‐Antarctic Discordance (AAD), between 120°E and 128°E. The expected along‐axis variation in mantle temperature (∼50°C) is too small to explain this observation, even when the temperature dependence of the mantle physical properties is accounted for. We successively analyze the effect on subsidence of different factors, such as variations in crustal thickness; the dynamic contribution of an old, detached slab supposedly present within the mantle below the AAD; and depletion in ϕm, a parameter here defined as the “ubiquitously distributed melt fraction” within the asthenosphere. These effects may all contribute to the observed, anomalously low subsidence rate of the ridge flanks, with the most significant contribution being probably related to the depletion in ϕm. However, these effects have a deep‐seated origin that cannot explain the abruptness of the transition across the fracture zones that delineate the boundaries of the AAD, near 120°E and near 128°E, respectively.
A simplified approach to quantifying predictive and parametric uncertainty in artificial neural network hydrologic models
Authors: Srivastav R. K. , Sudheer K. P. , Chaubey I.
Published: October 2007

One of the principal sources of uncertainty in hydrological models is the absence of understanding of the complex physical processes of the hydrological cycle within the system. This leads to uncertainty in input selection and consequently its associated parameters, and hence evaluation of uncertainty in a model becomes important. While there has been considerable interest in developing methods for uncertainty analysis of artificial neural network (ANN) models, most of the methods are relatively complex and/or require assumption about the prior distribution of the uncertain parameters. This paper presents an effective and simple way to perform uncertainty analysis for ANN‐based hydrologic model. The method is based on the concept of bootstrap technique and is demonstrated through a case study of the Kolar River basin located in India. The method effectively quantifies uncertainty in the model output and the parameters arising from variation in input data used for calibration. In the current study, the uncertainty due to model architecture and the input vector are not directly considered; they have been minimized during the model calibration. The results from the case study suggest that the sampling variability of the training patterns as well as the initial guess of the parameters of ANN do not have significant impact on the model performance. However, despite good generalization properties for the models developed in this study, most of them fail to capture the hydrograph peak flow characteristics. The proposed method of uncertainty analysis is very efficient, can be easily applied to an ANN‐based hydrologic model, and clearly illustrates the strong and weak points of the ANN model developed.
Magnitude scaling relations from P‐waves in southern California
Authors: Tsang Louisa L. H. , Allen Richard M. , Wurman Gilead
Published: October 2007

We derive empirical magnitude scaling relationships for southern California using a dataset of 59 past earthquakes recorded in southern California by the Southern California Seismic Network (SCSN) between 1992 and 2003. The events range in magnitude from 3.0 to 7.3. We use the maximum predominant period (τpmax) and the peak displacement amplitude (Pd) measured from the first 4 seconds of P‐wave arrivals to determine period‐magnitude and amplitude‐magnitude scaling relationships respectively. Our calibration study shows that the scaling relationships are similar to those derived for northern California. The average error in magnitude estimates is 0.2 magnitude units for events with magnitudes smaller than 4.5 (M < = 4.5), 0.3 magnitude units for events with magnitudes ranging from 4.5 to 6.5 (4.5 < M < = 6.5), and 0.5 magnitude units for events with magnitudes greater than 6.5 (M > 6.5).
Rotationally driven interchange instability: Reply to André and Ferrière
Authors: Vasyliūnas Vytenis M. , Pontius Duane H.
Published: October 2007

We derive the dispersion relation for the rotationally driven interchange instability, using the same basic equations as in our previous work (Vasyliūnas, 1994; Pontius, 1997) but taking care to keep the terms we had overlooked (as pointed out by André and Ferrière (2007)), and show that inclusion of the Coriolis force does modify the dispersion relation, reducing the growth rate of the instability and adding an oscillating component. Its effect becomes negligible only in the limit of azimuthal wavelength very short in comparison to radial distance, in the limit of plasma acceleration time very short in comparison to rotation period, and in the singular case of flux tube content proportional to equatorial field strength. André and Ferière (2007) find no effect of the Coriolis force because they assume all wavelengths to be short. For plasma acceleration time longer than the rotation period, the effect of the Coriolis force can restrict the range of radial gradients that are unstable. Although not a generally valid result, neglect of the Coriolis force effects is in practice applicable as long as the fastest‐growing (hence presumably the most significant) instabilities are those with very short wavelengths.
Open Notebook Science: Perspectives from a newbie
Authors: Neylon Cameron
Published: October 2007

My group is using an electronic lab notebook based on a Blog format that is being developed in collaboration with the group of Professor Jeremy Frey. Here I discuss how this led to the adoption of an open notebook science approach in my group as well as some of the consequences, both positive and negative, of adopting such an approach.
siRNA knockdown of SPHK1 in vivo protects mice from systemic, type-I Allergy.
Authors: Manikandan Jayapal , Pushparaj Peter Natesan , Melendez Alirio Jose
Published: October 2007

Systemic anaphylaxis is considered to be a typical immediate hypersensitivity response, determined by the activation of immune cells,via antigen-induced aggregation of IgE-sensitized FcεRI cells. Perhaps most the important cells, in the immediate hypersensitivity responses, are mast cells. We have previously shown that SPHK1 plays a key role in the intracellular signaling pathways triggered by FceRI aggregation on humanmast cells. More recently, we performed a genome-wide gene expression profiling of human mast cells, sensitized with IgE alone, or stimulated by FcεRI aggregation. We found that sphingosine kinase 1 (SPHK1) was oneof genes activated at the earlier stages of mast cell activation, including during sensitization. Moreover, SPHK1 has been shown, by us and others, to be a key player in the intracellular signaling pathways triggered byseveral immune-receptors, including fMLP, C5a, and Fcg- and Fcereceptors. Here we have investigated the in vivo role of SPHK1 in allergy, using a specific siRNA to knockdown SPHK1 in vivo. Our results support a role forSPHK1 in the inflammatory responses that share clinical, immunological, and histological features of type I hypersensitivity. Thus, mice pretreated with the siRNA for SPHK1 were protected from the IgE mediated allergicreactions including: temperature changes, histamine release, cytokine production, cell-adhesion molecule expression, and immune cell infiltration into the lungs.
Transparent Exopolymer Particles (TEP): an overlooked factor in the process of biofilm formation in aquatic environments
Authors: Berman Tom , Passow Uta
Published: October 2007

We hypothesize that transparent exopolymer particles (TEP), present in high concentrations in most sea and freshwaters, are critical agents for biofilm initiation and development in many natural and anthropogenic aquatic environments. These gel-like particles appear in many forms; amorphous blobs, clouds, sheets, filaments or clumps ranging in size from ~2 to ~200 µm. TEP are mostly polysaccharide, negatively charged, very sticky and are frequently colonized by bacteria. TEP may be considered a "planktonic" subgroup of exopolymeric substances (EPS), widely studied in biofilm research. Recognition of TEP involvement in biofilm formation has important implications for a comprehensive understanding of the complexities of this process in aquatic environments and may also contribute to the considerable efforts being made in the global water industry to mitigate the harmful effects of biofouling in water treatment and desalination plants.
Through Birds' Eyes: What does vision tell us about foraging in cormorants?
Authors: Martin Graham
Published: October 2007

Great Cormorants Phalacrocorax carbo are regarded as visually-guided, pursuit-dive foragers, so it would be expected that they have excellent vision much like aerial predators, such as hawks which detect and pursue prey from a distance. However, my research shows that underwater the visual acuity of Cormorants is surprisingly poor (in fact, similar or worse than unaided humans under water) and very inferior to that of aerial predatory birds. I suggest that Cormorants are able to detect typical prey items only at close range and conclude that cormorants are not the aquatic equivalent of hawks. It seems that their efficient hunting involves the use of specialised foraging techniques which employ rapid neck extension to capture prey that cormorants flush from hiding places; much like the foraging techniques of herons. Cormorants seem to be hunting an “escaping blur”. Like herons, the eye movements and visual fields of cormorants allow visual scanning for escaping prey in a wide arc about the head. The ability of cormorants to see prey held in the mouth may help to aid its identification when it is brought to the surface before swallowing.
CiteWiz: A Tool for the Visualization of Scientific Citation Networks
Authors: Elmqvist Niklas , Tsigas Philippas
Published: October 2007

We present CiteWiz, an extensible framework for visualization of scientific citation networks. The system is based on a taxonomy of citation database usage for researchers, and provides a timeline visualization for overviews and an influence visualization for detailed views. The timeline displays the general chronology and importance of authors and articles in a citation database, whereas the influence visualization is implemented using the Growing Polygons technique, suitably modified to the context of browsing citation data. Using the latter technique, hierarchies of articles with potentially very long citation chains can be graphically represented. The visualization is augmented with mechanisms for parent–child visualization and suitable interaction techniques for interacting with the view hierarchy and the individual articles in the dataset. We also provide an interactive concept map for keywords and co-authorship using a basic force-directed graph layout scheme. A formal user study indicates that CiteWiz is significantly more efficient than traditional database interfaces for high-level analysis tasks relating to influence and overviews, and equally efficient for low-level tasks such as finding a paper and correlating bibliographical data.
Electron affinity of Li7 calculated with the inclusion of nuclear motion and relativistic corrections
Authors: Stanke Monika , Kȩdziera Dariusz , Bubin Sergiy , Adamowicz Ludwik
Published: October 2007

Explicitly correlated Gaussian functions have been used to perform very accurate variational calculations for the ground states of Li7 and Li−7. The nuclear motion has been explicitly included in the calculations (i.e., they have been done without assuming the Born-Oppenheimer (BO) approximation). An approach based on the analytical energy gradient calculated with respect to the Gaussian exponential parameters was employed. This led to a noticeable improvement of the previously determined variational upper bound to the nonrelativistic energy of Li−. The Li energy obtained in the calculations matches those of the most accurate results obtained with Hylleraas functions. The finite-mass (non-BO) wave functions were used to calculate the α2 relativistic corrections (α=1∕c). With those corrections and the α3 and α4 corrections taken from Pachucki and Komasa [J. Chem. Phys. 125, 204304 (2006)], the electron affinity (EA) of Li7 was determined. It agrees very well with the most recent experimental EA.
Aluminum diffusion and reaction in thin films of perylene-3,4,9,10-tetracarboxylic dianhydride: Depth profiles and time-dependent diffusion coefficients
Authors: Yoshida Hiroyuki , Sato Naoki
Published: October 2007

Diffusion and reaction of aluminum metal species (Al) vacuum deposited on perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) thin films were investigated using angle resolved x-ray photoemission spectroscopy. The acquired data were analyzed assuming that the diffusion of Al is described by a one-dimensional diffusion equation with a time-dependent diffusion coefficient. Depth profiles and diffusion coefficients are obtained for reacted and metallic Al separately. The results show that the metallic Al diffuses rapidly during the deposition while the metal diffusion continues at a lower rate even after the deposition at room temperature. On the other hand, the reacted Al does not diffuse further into the PTCDA layers.
The radical character of the acenes: A density matrix renormalization group study
Authors: Hachmann Johannes , Dorando Jonathan J. , Avilés Michael , Chan Garnet Kin-Lic
Published: October 2007

We present a detailed investigation of the acene series using high-level wave function theory. Our ab initio density matrix renormalization group algorithm has enabled us to carry out complete active space calculations on the acenes from napthalene to dodecacene correlating the full π-valence space. While we find that the ground state is a singlet for all chain lengths, examination of several measures of radical character, including the natural orbitals, effective number of unpaired electrons, and various correlation functions, suggests that the longer acene ground states are polyradical in nature.
Intermetallic compounds of the heaviest elements and their homologs: The electronic structure and bonding of MM′, where M=Ge, Sn, Pb, and element 114, and M′=Ni, Pd, Pt, Cu, Ag, Au, Sn, Pb, and element 114
Authors: Pershina V. , Anton J. , Fricke B.
Published: October 2007

Fully relativistic (four-component) density-functional theory calculations were performed for intermetallic dimers MM′, where M=Ge, Sn, Pb, and element 114, and M′=group 10 elements (Ni, Pd, and Pt) and group 11 elements (Cu, Ag, and Au). PbM and 114M, where M are group 14 elements, were also considered. The results have shown that trends in spectroscopic properties—atomization energies De, vibrational frequencies ωe, and bond lengths Re, as a function of M′, are similar for compounds of Ge, Sn, Pb, and element 114, except for De of PbNi and 114Ni. They were shown to be determined by trends in the energies and space distribution of the valence ns(M′) atomic orbitals (AOs). According to the results, element 114 should form the weakest bonding with Ni and Ag, while the strongest with Pt due to the largest involvement of the 5d(Pt) AOs. In turn, trends in the spectroscopic properties of MM′ as a function of M were shown to be determined by the behavior of the np1∕2(M) AOs. Overall, De of the element 114 dimers are about 1eV smaller and Re are about 0.2a.u. larger than those of the corresponding Pb compounds. Such a decrease in bonding of the element 114 dimers is caused by the large SO splitting of the 7p orbitals and a decreasing contribution of the relativistically stabilized 7p1∕2(114) AO. On the basis of the calculated De for the dimers, adsorption enthalpies of element 114 on the corresponding metal surfaces were estimated: They were shown to be about 100–150kJ∕mol smaller than those of Pb.
Two-component heterogeneous nucleation kinetics and an application to Mars
Authors: Määttänen Anni , Vehkamäki Hanna , Lauri Antti , Napari Ismo , Kulmala Markku
Published: October 2007

We develop a two-component heterogeneous nucleation model that includes exact calculation of the Stauffer-type [D. Stauffer, J. Aerosol Sci. 7, 319 (1976)] steady-state kinetic prefactor using the correct heterogeneous Zeldovich factor for a heterogeneous two-component system. The model, and a simplified version of it, is tested by comparing its predictions to experimental data for water-n-propanol nucleating on silver particles. The model is then applied to water-carbon dioxide system in Martian conditions, which has not been modeled before. Using the ideal mixture assumption, the model shows theoretical possibilities for two-component nucleation adjacent to the initial stages of one-component water nucleation, especially with small water vapor amounts. The numbers of carbon dioxide molecules in the critical cluster are small in the case of large water amounts (up to 300 ppm) in the gas phase, but larger when there is very little water vapor (1 ppm).