bluuebunny/crossref_metadata_2025 huggingface dataset:
Liver Resection and Transplantation in the Management of Iatrogenic Biliary Injury
Authors: Thomson B. N. J. , Parks R. W. , Madhavan K. K. , Garden O. J.
Published: October 2007

Background

Biliary injury during cholecystectomy can be managed successfully by biliary reconstruction in the majority of patients; however, a proportion of patients may require hepatic resection or even liver transplantation.

Methods

Data on all patients referred with biliary injuries were recorded prospectively. The details of patients who required hepatic resection or transplantation were analyzed and compared to those patients managed with biliary reconstruction alone.

Results

From November 1984 until November 2003 there were 119 patients referred with Strasberg grade E injuries to the biliary tree, 14 of whom (9 women, 5 men) required hepatic resection or transplantation. The median age of these 14 patients was 48 (range: 30–81) years. Nine patients were considered for hepatic resection, and of these six underwent right hepatectomy, two had a left lateral sectionectomy, and one patient was deemed unfit for surgery and underwent metal stenting of the right hepatic duct. All patients are alive and remain well. Five patients developed hepatic failure and were considered for liver transplantation. Two patients who were unfit for transplantation died, and another died while on the waiting list for transplantation. The remaining two patients underwent liver transplantation, and one of them died from overwhelming sepsis. Concomitant vascular injury was demonstrated in 8 of the 14 patients (57%), and in 3 of the 4 (75%) patients that died.

Conclusions

Hepatic atrophy or sepsis after biliary injury can be managed successfully with hepatic resection. Liver transplantation is required occasionally for patients with secondary biliary cirrhosis, but is rarely successful for early hepatic failure following iatrogenic biliary injury.
School Climate and Implementation of a Preventive Intervention
Authors: Gregory Anne , Henry David B. , Schoeny Michael E. ,   The Metropolitan Area Child Study Research Group
Published: October 2007

Although there has been wide dissemination of research‐based psychosocial prevention programs, a similarly strong research base to guide program implementation has been lacking. Program implementation has been particularly difficult for schools, due partly to insufficient understanding of how school ecologies interact with these programs. This study examined the effects of multiple dimensions of school climate on level and rate of change in implementation of a violence prevention intervention across three school years. Using multi‐level modeling, the study found that teacher‐reported support between staff and among teachers and students predicted higher average levels of implementation. Teacher‐reported administrative leadership predicted greater growth in implementation across 3 years. Findings offer implications for an ecological model of program implementation that considers school‐level contextual effects on adoption and sustainability of new programs in schools.
Osteoma of the calvaria in l‐2‐hydroxyglutaric aciduria
Authors: Larnaout A. , Amouri R. , Neji S. , Zouari M. , Kaabachi N. , Hentati F.
Published: October 2007

l‐2‐Hydroxyglutaric aciduria (l‐2‐OHGA) is a rare autosomal recessive neurometabolic disease linked to chromosome 14q21.1 and is caused by mutations in the gene that most likely encodes l‐2‐hydroxyglutarate dehydrogenase, which normally catalyses l‐2‐hydroxyglutarate to α‐ketoglutarate. It is characterized by progressive mental deterioration, pyramidal and cerebellar syndromes, macrocephaly and marked polycystic white‐matter degeneration mainly involving frontal lobes. Brain tumours of variable nature have frequently been observed in l‐2‐OHGA. We report a patient affected by this disease who at the age of 20 years developed a bone tumour involving the right frontal region of the calvaria. He had first presented at the age of 10 years with psychomotor delay, clumsy gait and moderate mental impairment. Examination showed macrocephaly, cerebellar ataxia and quadripyramidal syndrome. Brain MRI showed low signal intensities on T1‐weighted images and high signal intensities on T2‐weighted images in cerebral subcortical white matter. Serum and urinary amino acid assay was normal. Urinary 2‐hydroxyglutaric acid was 1418 mmol/mol creatinine (controls <25). Analysis of the l‐2‐hydroxyglutarate dehydrogenase gene revealed a homozygous mutation in exon 2 (A320G). At the age of 20 years, an osteoma of the right frontal bone was diagnosed. This finding reinforces the opinion concerning the association of l‐2‐OHGA and tumorigenesis and prompted us to verify the possible responsibility of some overproduced substances in this disease for the development of tumours and to look for any correlation between the type of mutation in the l‐2‐OHGA gene and the tumorigenic potential observed in some patients affected by this disease.
Molecular differences in the mitochondrial cytochrome oxidase I (mtCOI) gene and development of a species-specific marker for onion thrips, Thrips tabaci Lindeman, and melon thrips, T. palmi Karny (Thysanoptera: Thripidae), vectors of tospoviruses (Bunyaviridae)
Authors: Asokan R. , Krishna Kumar N.K. , Kumar Vikas , Ranganath H.R.
Published: October 2007

A quick and developmental-stage non-limiting method of the identification of vectors of tospoviruses, such as Thrips tabaci and T. palmi, is important in the study of vector transmission, insecticide resistance, biological control, etc. Morphological identification of these thrips vectors is often a stumbling block in the absence of a specialist and limited by polymorphism, sex, stage of development, etc. Molecular identification, on the other hand, is not hampered by the above factors and can easily be followed by a non-specialist with a little training. The mitochondrial cytochrome oxidase I (mtCOI) exhibits reliable inter-species variations as compared to the other markers. In this communication, we present the differences in the mtCOI partial sequence of morphologically identified specimens of T. tabaci and T. palmi collected from onion and watermelon, respectively. Species-specific markers, identified in this study, could successfully determine T. tabaci and T. palmi, which corroborated the morphological identification. Phylogenetic analyses showed that both T. tabaci and T. palmi formed different clades as compared to the other NCBI accessions. The implication of these variations in vector efficiency has to be investigated further. The result of this investigation is useful in the quick identification of T. tabaci and T. palmi, a critical factor in understanding the epidemiology of the tospoviruses, their management and also in quarantine.
Differential electroantennogram response of females and males of two parasitoid species to host-related green leaf volatiles and inducible compounds
Authors: Chen L. , Fadamiro H.Y.
Published: October 2007

Parasitoids employ different types of host-related volatile signals for foraging and host-location. Host-related volatile signals can be plant-based, originate from the herbivore host or produced from an interaction between herbivores and their plant host. In order to investigate potential sex- and species-related differences in the antennal response of parasitoids to different host-related volatiles, we compared the electroantennogram (EAG) responses of both sexes of the specialist parasitoid, Microplitis croceipes (Cresson), and the generalist, Cotesia marginiventris (Cresson), to varying doses of selected plant-based host-related volatiles: two green leaf volatiles (cis-3-hexenol and hexanal) and three inducible compounds (cis-3-hexenyl acetate, linalool, and (E,E)-α-farnesene). Mating had no significant effect on EAG response. Females of both species showed significantly greater EAG responses than conspecific males to green leaf volatiles, which are released immediately after initiation of herbivore feeding damage. In contrast, males showed greater responses than conspecific females to inducible compounds released much later after initial damage. Cotesia marginiventris females and males showed greater EAG responses than counterpart M. croceipes to the tested compounds at various doses, suggesting that the generalist parasitoid shows greater antennal sensitivity than the specialist to the tested host-plant volatiles. These results are discussed in relation to the possible roles of green leaf volatiles and inducible compounds in the ecology of female and male parasitoids.
How can alien species inventories and interception data help us prevent insect invasions?
Authors: Kenis M. , Rabitsch W. , Auger-Rozenberg M.-A. , Roques A.
Published: October 2007

Information relevant to invasion processes and invasive alien insect species management in Central Europe was extracted from two databases: a compilation of two inventories of alien insects in Austria and Switzerland, and a list of interceptions of non-indigenous plant pests in Europe gathered by the European and Mediterranean Plant Protection Organisation (EPPO) for the period 1995–2004. For one-third of the insects established in Switzerland and Austria, the region of origin is unclear. Others come mainly from North America, Asia and the Mediterranean region. Among the intercepted insects, 40% were associated with commodities from Asia, 32% from Europe and only 2% from North America. Sternorrhyncha, Coleoptera and Psocoptera were particularly well represented in the alien fauna compared to the native fauna. In the interception database, Sternorrhyncha were also well represented but Diptera accounted for the highest number of records. Sap feeders and detritivores were the dominant feeding niches in the alien insect fauna. In contrast, external defoliators, stem borers, gall makers, root feeders, predators and parasitoids were underrepresented. Nearly 40% of the alien insects in Switzerland and Austria live only indoors. Another 15% live outdoors but exclusively or predominantly on exotic plants. Less than 20% are found mainly in ‘natural’ environments. The majority of introductions of alien insects in Europe are associated with the international trade in ornamental plants. An economic impact was found for 40% of the alien insects in Switzerland and Austria, whereas none is known to have an ecological impact. The implications of these observations for further studies and the management of alien species in Europe are discussed.
Early season natural control of the brown planthopper, Nilaparvata lugens: the contribution and interaction of two spider species and a predatory bug
Authors: Sigsgaard L.
Published: October 2007

Nilaparvata lugens Stål, the Brown Planthopper (BPH), is a major pest in rice. The lycosid Pardosa pseudoannulata (Bösenberg & Strand) and the linyphiid Atypena formosana (Oi) are the early dominant predators in irrigated rice. Later, predatory bugs, including the mirid Cyrtorhinus lividipennis Reuter, become dominant. In unsprayed rice, BPH numbers normally remain low. While P. pseudoannulata is known to be a key natural enemy of BPH, the contribution to BPH reduction by the smaller A. formosana is less well known. Due to the size difference, A. formosana may also be an intraguild prey of P. pseudoannulata. To investigate predation on BPH by the two spider species alone, together and in combination with C. lividipennis, two cage experiments were conducted, the first with adult spiders, the second with immature/unmated spiders. In the latter, spiders were introduced with a delay to allow a better establishment of C. lividipennis. In both experiments, BPH numbers were lowest in treatments with more than one predator species present. Intermediate BPH reduction was obtained with P. pseudoannulata followed by A. formosana and C. lividipennis. While P. pseudoannulata can prey upon large nymphs and adult BPH, A. formosana favour early instar BPH, leading to a more even control across instars in treatments with both spider species. Pardosa pseudoannulata numbers increased more with A. formosana or A. formosana and C. lividipennis present. In contrast, P. pseudoannulata reduced A. formosana and C. lividipennis numbers. The presence of C. lividipennis apparently lessened intraguild predation on A. formosana and may be an intraguild prey of A. formosana. Competition for prey may have added to the antagonistic interactions found. From a biological control perspective, the presence of both spiders in early rice is an advantage for the biological control of BPH in rice. In early rice, results show that A. formosana is an important predator of BPH and, like C. lividipennis, can complement control by P. pseudoannulata and serve as intraguild prey for the latter species.
Parameter rigid actions of the Heisenberg groups
Authors: DOS SANTOS NATHAN M.
Published: October 2007

A locally free action of a Lie group is parameter rigid if for each other action with the same orbit foliation there exists a $C^\infty $ orbit-preserving diffeomorphism which conjugates the action to a reparametrization of the other by an automorphism of the Lie group. We show that for actions of the Heisenberg groups, if the first leafwise cohomology group of the orbit foliation is isomorphic to the first cohomology of the Lie algebra of the group, then the action is parameter rigid. Using this, we give examples of parameter rigid actions for all of the Heisenberg groups.
Introduction: The Class Politics of Privatization: Global Perspectives on the Privatization of Public Workers, Land, and Services
Authors: Klein Jennifer
Published: October 2007

Surveying countries in all continents, a recent international report sponsored by The Club of Rome declared privatization to be “one of the defining features of our era.” Any major phenomenon of our time must have historical roots. The purpose of this volume is to address privatization as an issue of globalization, to give it a history apart from the totalizing notion ofneoliberalismand the prescriptive models of economic theory. The consensus among social theorists and observers is that this global process of privatization is a result of neoliberalism, a practice and ideology whose central tenet is the primacy of markets. Certainly, the rhetoric and policies of neoliberalism have been spreading rapidly throughout the globe, but the blanket use of this concept has not enabled us to get inside the real social and political transformations that marked the last decades of the twentieth century. The writers in this volume introduce the particularities of social and labor histories and locate privatization in narratives of class politics and struggle. Bringing social and labor history into the analyses of privatization, at the same time, these essays put labor history, often monographically focused, into larger discussions of the state and capitalism. These essays make the class agenda of privatization explicit, viewing it not just as the “opening of markets,” but as clear assaults on the working classes and on the public claims that workers and citizens are able to make on the economy's resources and productivity.
Workforce Responses to the Creeping Privatization of the UK National Health Service
Authors: Givan Rebecca Kolins , Bach Stephen
Published: October 2007

When the British National Health Service was founded in 1948, professional employees and support staff, with the exception of family doctors, worked directly for the state. Since the 1980s, private employment in the National Health Service (NHS) has steadily grown. Beginning with the outsourcing of support services, the number of privately-employed workers in the National Health Service has gradually increased. This paper argues that marketization in the health sector has increased dramatically under the New Labour government. As policymakers have moved from ideological to pragmatic justifications for marketization, union opposition has similarly become more pragmatic and less ideological. With unions unable to stop these reforms, they have turned to the practical concerns of their members in partially-privatized workplaces under complex employment arrangements. This article shows that while ideologically opposing marketization, unions and employees have been forced into a more pragmatic position. Research at two privately-funded public hospitals shows that unions in the workplace have used their resources to protect their members, as thwarting the involvement of the private sector is nearly impossible.
“Blame the System, Not the Victim!” Organizing the Unemployed in New Zealand, 1983–1992
Authors: Locke Cybèle
Published: October 2007

The restructuring of capital and the transformation of the workforce in the late twentieth century has produced a newly-shaped working class; one that encompasses those in insecure work and unemployed workers. With this repositioning has come new political organizations of unemployed workers, of which Te Roopu Rawakore o Aotearoa, the national New Zealand organization for unemployed workers, is an example. This organization of unemployed was not only significant for its existence in the face of poverty, status disintegration, and a perceived sense of social worthlessness, but also for the tripartite ideology its members employed. Unemployed workers in New Zealand combined the identity politics of race and gender with a class-based critique of society to demand “the right to work and a living wage for all.”
Racism in a “Raceless” Society: The Soviet Press and Representations of American Racial Violence at Stalingrad in 1930
Authors: Roman Meredith
Published: October 2007

In late August 1930, two white American workers from the Ford Motor Company in Detroit were tried for attacking a black American laborer at one of the Soviet Union's prized giants of socialist industry, the Stalingrad Traktorostroi. Soviet trade-union authorities and all-union editors used the near month-long campaign to bring the two assailants to “proletarian justice,” in order to cultivate the image that workers in the USSR valued American technical and industrial knowledge in the construction of the new socialist society, but vehemently rejected American racism. They reinforced this image in publications by juxtaposing visual depictions of Soviet citizens' acceptance of black Americans as equals against those which portrayed the lynching of black workers in the United States.
Projections of the nucleus of the basal optic root in pigeons (Columba livia): A comparison of the morphology and distribution of neurons with different efferent projections
Authors: WYLIE DOUGLAS R.W. , PAKAN JANELLE M.P. , ELLIOTT CAMERON A. , GRAHAM DAVID J. , IWANIUK ANDREW N.
Published: October 2007

The avian nucleus of the basal optic root (nBOR) is a visual structure involved in the optokinetic response. nBOR consists of several morphologically distinct cell types, and in the present study, we sought to determine if these different cell types had differential projections. Using retrograde tracers, we examined the morphology and distribution of nBOR neurons projecting to the vestibulocerebellum (VbC), inferior olive (IO), dorsal thalamus, the pretectal nucleus lentiformis mesencephali (LM), the contralateral nBOR, the oculomotor complex (OMC) and a group of structures along the midline of the mesencephalon. The retrogradely labeled neurons fell into two broad categories: large neurons, most of which were multipolar rather than fusiform and small neurons, which were either fusiform or multipolar. From injections into the IO, LM, contralateral nBOR, and structures along the midline-mesencephalon small nBOR neurons were labeled. Although there were no differences with respect to the size of the labeled neurons from these injections, there were some differences with the respect to the distribution of labeled neurons and the proportion of multipolar vs. fusiform neurons. From injections into the VbC, the large multipolar cells were labeled throughout nBOR. The only other cases in which these large neurons were labeled were contralateral OMC injections. To investigate if single neurons project to multiple targets we used paired injections of red and green fluorescent retrograde tracers into different targets. Double-labeled neurons were never observed indicating that nBOR neurons do not project to multiple targets. We conclude that individual nBOR neurons have unique projections, which may have differential roles in processing optic flow and controlling the optokinetic response.
Cytoskeleton alteration correlates with gross structural plasticity in the cat lateral geniculate nucleus
Authors: KUTCHER MATTHEW R. , DUFFY KEVIN R.
Published: October 2007

Monocular deprivation during early development causes rearrangement of neural connections within the visual cortex that produces a shift in ocular dominance favoring the non-deprived eye. This alteration is manifested anatomically within deprived layers of the lateral geniculate nucleus (LGN) where neurons have smaller somata and reduced geniculocortical terminal fields compared to non-deprived counterparts. Experiments using monocular deprivation have demonstrated a spatial correlation between cytoskeleton alteration and morphological change within the cat LGN, raising the possibility that subcellular events mediating deprivation-related structural rearrangement include modification to the neuronal cytoskeleton. In the current study we compared the spatial and temporal relationships between cytoskeleton alteration and morphological change in the cat LGN. Cross-sectional soma area and neurofilament labeling were examined in the LGN of kittens monocularly deprived at the peak of the critical period for durations that ranged from 1 day to 7 months. After 4 days of deprivation, neuron somata within deprived layers of the LGN were significantly smaller than those within non-deprived layers. This structural change was accompanied by a spatially coincident reduction in neurofilament immunopositive neurons that was likewise significant after 4 days of deprivation. Both anatomical effects reached close to their maximum by 10 days of deprivation. Results from this study demonstrate that alteration to the neuronal cytoskeleton is both spatially and temporally linked to the gross structural changes induced by monocular deprivation.
SYMPOSIUM: WHAT WAS THE HISTORY OF THE BOOK? INTRODUCTION
Authors: BELL BILL
Published: October 2007

“‘Histoire du livre’”, remarked Robert Darnton in a much celebrated essay from 1982, “‘Geschichte des Buchwesens’…‘history of books’ or ‘of the book’ in English-speaking countries—its name varies from place to place, but everywhere it is being recognized as an important new discipline”. In the twenty-five years since Darnton's original observation book history has if anything continued to flourish. With a number of multi-volume national histories of the book now at various stages of completion, an international infrastructure of research centres, teaching programmes and publishers’ lists, quite clearly something has been happening.
THE ORDER OF BOOKS REVISITED
Authors: CHARTIER ROGER
Published: October 2007

The Order of Books was published in France in 1992 and translated into English in 1994. I have to confess that I had not reread it since, and perhaps I would have never read it again had I not been invited to do so for this exercise. The central aim of that book was to try to understand something of how in the period between the fourteenth and the eighteenth century the written word was classified, organized, and perceived by all the actors involved within the trajectory of the text, from authors to publishers and printers, from the printing shop to the library. I will begin by recounting some of the factors in my own intellectual life that I believe led up to that book, and go on to reflect on the arguments that I posited in 1992, in the hope of giving some account of the ways in which that earlier work might today be supplemented.
A SOCIAL HISTORY OF KNOWLEDGE REVISITED
Authors: BURKE PETER
Published: October 2007

In contributing to this symposium on book history, I was asked to reflect on my A Social History of Knowledge (hereafter SHK), which was published in 2000, describing how I came to write it and what has happened to the field since, and considering the question of whether I might write my essay differently if I were beginning it today. Following this, I shall devote the remainder of the article to a sketch for a future project on the history of knowledge.
WHAT ARE ENLIGHTENMENTS?
Authors: MCMAHON DARRIN M.
Published: October 2007

Jonathan Israel, Radical Enlightenment: Philosophy and the Making of Modernity 1650–1750 (Oxford: Oxford University Press, 2001)

Jonathan Israel, Enlightenment Contested: Philosophy, Modernity, and the Emancipation of Man 1670–1750 (Oxford: Oxford University Press, 2006)

“A public can only attain enlightenment slowly,” Kant famously observed. His use of the term “public” (Publikum), of course, is notoriously slippery, and even now, after decades of academic discussion of Öffenlichkeit and l'opinion publique, it regularly trips up the unsuspecting undergraduate intent on answering Kant's central question: What is enlightenment? And yet it is clear that whatever else he meant, Kant envisioned a central role for the scholar (Gelehrter) in constituting the public, and furthering enlightenment. And so we might say, in a Kantian gloss, that scholars attain enlightenment, and knowledge of the Enlightenment, only slowly.
ORIENTALISM REVERSED: RUSSIAN LITERATURE IN THE TIMES OF EMPIRES
Authors: ETKIND ALEXANDER
Published: October 2007

Susan Layton, Russian Literature and Empire: Conquest of the Caucasus from Pushkin to Tolstoy (Cambridge: Cambridge University Press, paperback version 2005; first edition 1994)

Harsha Ram, The Imperial Sublime: A Russian Poetics of Empire (Madison: University of Wisconsin Press, 2003)

In the last decades of the Russian Empire, Edward Gibbon's Decline and Fall of the Roman Empire made for favorite reading among the intelligentsia. Today imperial themes have become increasingly important in American academia; historians and literary scholars who study Russia are no exception. The two studies under review explore the spirit and the letter of the Russian Empire in the moment of boom and glory preceding its collapse. Published in 1994, Susan Layton's Russian Literature and Empire was the pioneering study of the subject. Published in 2003, Harsha Ram's The Imperial Sublime is so different from Layton's book that the differences, rooted in the American rather than the Russian imperial experience, deserve reflection in their own right. While Layton looked at the world through the emancipatory optic of postcolonialist and feminist movements, Ram manifests a different kind of sensibility, one which is alert to the scale and beauty of the victorious power. In a sad but understandable way, Susan Layton's ethical concerns give way to Harsha Ram's aesthetic ones.
“LIKE BUT UNALIKE”: ERIC SUNDQUIST AND LITERARY HISTORICISM
Authors: POSNOCK ROSS
Published: October 2007

Eric Sundquist, Strangers in the Land: Blacks, Jews, Post-Holocaust America (Cambridge, MA: Harvard University Press, 2005)

As measured by that deadly but inescapable phrase “quantity and quality,” Eric Sundquist is perhaps the most productive American literature scholar of his generation. Since 1979, when he was still in his twenties, he has authored half a dozen books while editing another half-dozen. All have made an impact and many of these have been highly influential—his first book, Home as Found: Authority and Genealogy in Nineteenth-Century American Literature, was among the very first to read canonical American works through the lens of contemporary literary and psychoanalytic theory; his edited collection American Realism: New Essays (1982) proved pivotal in reviving the critical energy in a major but long-dormant literary and historical period. To Wake the Nations: Race in the Making of American Literature (1993) was by implicit design and to powerful effect nothing less than a rewriting of the foundational work of American literary history and criticism—F. O. Matthiessen's monumental American Renaissance: Art and Expression in the Age of Emerson and Whitman (1941). I will spend some time describing To Wake the Nations not only because of the book's exceptional importance but because its eloquent introduction provides the closest thing to a critical credo that Sundquist has written. His description there of his critical ideals—particularly of “justice,” boundary-crossing and “verification”—will help orient our approach to Strangers in the Land, which remains loyal to these ideals as it extends his interest in race and ethnicity, black and white, to the tormented subject of blacks and Jews, united by a “bond of alienation.” (52).
Atmospheric total precipitable water from AIRS and ECMWF during Antarctic summer
Authors: Ye Hengchun , Fetzer Eric J. , Bromwich David H. , Fishbein Evan F. , Olsen Edward T. , Granger Stephanie L. , Lee Sung‐Yung , Chen Luke , Lambrigtsen Bjorn H.
Published: October 2007

This study compares the atmospheric total precipitable water (PWV) obtained by Atmospheric Infrared Sounder (AIRS) with radiosondes and the European Centre for Medium‐range Weather Forecasts (ECMWF) operational analysis products during December 2003 and January 2004. We find that PWV from AIRS Level 3 (daily gridded) data is about 9% drier while ECMWF is 14% moister than sondes at the two grid points closest to the Dome C radiosonde site on the Antarctic Plateau at 3233 m elevation. The largest ECMWF moist biases occur on warmer days at Dome C. When AIRS Level 3 data are compared with ECMWF over the entire Antarctic continent, AIRS and ECMWF PWV have similar variability (correlation coefficients are predominantly 0.8 or higher), but with AIRS drier over most of the Antarctic by a consistent offset of about 0.1–0.2 mm. Because of this constant difference, the largest percentage differences are found over the highland areas of about 2500 meters and above, where absolute water vapor amounts are smallest.
Fault gouge evolution and its dependence on normal stress and rock strength—Results of discrete element simulations: Gouge zone properties
Authors: Guo Yonggui , Morgan Julia K.
Published: October 2007

In order to study the process of gouge zone evolution, and its dependence on normal stress, σn, and uniaxial compressive strength, σucs, we simulate the breakdown of fault blocks and growth of fault gouge zones using the distinct element method (DEM) in two dimensions. Breakable elastic bonds were added between adjacent, closely packed particles to generate the fault blocks with a given σucs ranging from 100 to 260 MPa. DEM experiments were conducted by shearing the fault blocks along an initially flat surface for a range of σn from 10 to 100 MPa. The simulated fault gouge zones experience two distinct stages of evolution, i.e., fast growth and slow growth, distinguished by a switch in deformation mechanism from dominantly wear of the fault blocks to dominantly shearing of existing fault gouge. The rate of the gouge zone thickening decreases exponentially during the fast growth stage (to about 20% shear strain, i.e., 7.4 mm shear displacement) and then reaches a relatively constant value, marking the beginning of the slow growth stage. The thickening rate increases with increasing σn and decreasing σucs during the fast growth stage, but the dependency reverses during the slow growth stage. The mean grain size of the gouge shows a first‐order dependence on shear displacement, and varies less significantly with σn and σucs. In our simulated shear zones that undergo both surface wear and grain comminution, gouge grains develop power law size distributions characterized by a two‐dimensional fractal dimension D ranging from 0.6 to 2.4.
Lithospheric modification during crustal extension in the Main Ethiopian Rift
Authors: Rooney Tyrone , Furman Tanya , Bastow Ian , Ayalew Dereje , Yirgu Gezahegn
Published: October 2007

Quaternary lavas erupted in zones of tectonomagmatic extension within the Main Ethiopian Rift (MER) preserve details of lithospheric structure in the East African Rift System. Despite observed source heterogeneity, basalts, trachybasalts, and basaltic trachyandesites erupted in the Wonjii Fault Belt (WFB) and the Silti‐Debre Zeyit Fault Zone (SDFZ) form coherent fractionation paths dominated by variable removal of observed phenocryst phases. Crustal assimilation is not widespread, though it is observed at the southern end of the WFB where both fault belts merge; farther north, assimilation of cumulate phases related to fractional crystallization of previous magmas is identified. Shallow fractionation conditions (∼1 kbar) within the WFB do not change from north to south. In contrast, lavas erupted within the contemporaneous SDFZ fractionate at various crustal depths. These results indicate a better developed magmatic system beneath the WFB where magmas rose quickly before undergoing more significant fractionation at near surface levels and a less developed system beneath the SDFZ. The distribution of magmatism and extant geophysical data indicate thinned crust and a single rift‐centered zone of magmatic activity northeast of 8°30′N, consistent with a transitional lithosphere between continental and oceanic settings. Southwest of 8°30′N, thicker crust and rift‐marginal axes of extension suggest lithosphere with continental affinities. The WFB is propagating southward in response to extension within the Red Sea Rift; the northward propagating SDFZ is related to rifting within the East African Rift System. This region records the unification of two rift systems, requiring care in interpreting the MER as simply transitional between continental and oceanic environments.
Determination of water and alkaline extractable atmospheric humic‐like substances with the TU Vienna HULIS analyzer in samples from six background sites in Europe
Authors: Feczko T. , Puxbaum H. , Kasper‐Giebl A. , Handler M. , Limbeck A. , Gelencsér A. , Pio C. , Preunkert S. , Legrand M.
Published: October 2007

With a newly developed method based on the combination of two separation steps (by polarity and by acidity) with a universal detector for organic carbon, efficient isolation of humic‐like substances (HULIS) from the matrix and quantitative determination of the isolated organic carbon is achieved. This new method was applied to determine the water extractable (HULISWS) and, in sequence, the 0.1 M NaOH alkaline extractable HULIS (HULISAS) fractions in aerosol from six sites situated at a transect from west to east across Europe. The sum of the two HULIS fractions is here defined as total HULIS (HULIST). The lowest 12‐month average concentrations of HULIST ranged from 0.075 μgC/m3 the Azores (Portugal) to 1.7 μgC/m3 at the continental background site K‐puszta (Hungary). On the continent, the HULIST concentration decreases exponentially with elevation. The relative amounts of water extractable and alkaline soluble HULIS were relatively similar at the six sites. Dramatic differences were observed for the seasonal variations of the HULIS fractions at the different sites. At the Azores, as well as at the higher mountain sites (1450 and 3100 m), a summer maximum of the HULIST concentration was observed, while at the continental low‐level sites (Aveiro and K‐puszta), winter maxima dominated the seasonal variation. The summer/winter ratio of the HULIST concentration varied from 7.1 at Sonnblick to 0.36 at Aveiro. The seasonal variation at the two continental lower‐level sites with winter maxima might be explained by overlapping of a weaker summer source and a stronger winter source.
Description of a simple hydrochemical indicator to estimate groundwater residence time in carbonate aquifers
Authors: Lalbat F. , Blavoux B. , Banton O.
Published: October 2007

Some chemical and/or isotope indicators are required to interpret radiocarbon data in terms of groundwater residence time. Among the simplest indicators, the Mg:Ca ratio is commonly used in carbonate aquifers. However, this ratio only accounts for the dissolution/precipitation reaction of calcite and dolomite, whereas other dissolution reactions and ion exchanges can greatly influence the chemistry of groundwater. The aim of this study was thus to describe how the Mg:Ca ratio can be modified by the hydrogeochemical setting to define a new indicator based on the major elements in a molasse basin in southeastern France. The new indicator was computed and the results were compared with radiocarbon activity. The study showed the new indicator correlated well with radiocarbon activity. The new indicator is more useful than the Mg:Ca ratio for long residence times and in the sectors where gypsum dissolution occurs.
Cassini observations of the variation of Saturn's ring current parameters with system size
Authors: Bunce E. J. , Cowley S. W. H. , Alexeev I. I. , Arridge C. S. , Dougherty M. K. , Nichols J. D. , Russell C. T.
Published: October 2007

We have examined residual magnetic field vectors observed in Saturn's magnetosphere during the first 2 years of the Cassini mission and have fit them to a simple axisymmetric model of the ring current in the middle magnetosphere. We then examine the variations of the ring current parameters with size of the magnetosphere. In addition, we obtain secondary parameters, including the value of the axial field at the center of the ring (equivalently Saturn's Dst) Bz0, the total current IT flowing in the modeled ring current region, and the ratio of the ring current magnetic moment relative to the magnetic moment of Saturn's dipole field, kRC. Results show that the derived parameters increase significantly with system size, due principally to the increasing radius of the outer edge of the ring. We consider the implications of the response of the magnetic moment of the ring current to changing magnetospheric size, by theoretical consideration of the magnetic moment of individual particles in the ring current. The strong positive correlation of the ring current magnetic moment with system size suggests a system in which the ring current is dominated by inertia currents, rather than by thermal effects as in the case of the Earth, with magnetosphere‐ionosphere coupling maintaining the angular velocity of the plasma. The variations of Saturn's ring current parameters with system size found in this study are shown to be closely compatible with the size variations in response to the solar wind dynamic pressure recently determined from Cassini data.
Hybrid simulations of debris‐ambient ion interactions in astrophysical explosions
Authors: Winske Dan , Gary S. Peter
Published: October 2007

Hybrid simulations (particle ions, massless fluid electrons) have been carried out to study the super‐Alfvenic expansion of a dense, hot debris plasma against a relatively tenuous, relatively cool magnetized ambient plasma for the purpose of modeling the physics relevant to the early phase of explosions in astrophysical environments (supernovae, solar flares). We examine the stopping of the debris ions, the spatial distribution of the stopped ions, and their penetration across the compressed ambient magnetic field, using simulations run in a two‐dimensional geometry. The simulations show that the expanding debris excludes the ambient magnetic field to form a diamagnetic cavity. The stopping distance of the debris is consistent with that determined from the debris ions overrunning an equivalent mass of ambient ions. The distribution of the stopped debris ions is strongly dependent on the debris gyroradius based on the initial directed velocity ρd, being highly peaked at the debris‐magnetic field interface when ρd is large. The distance that debris ions penetrate into and mix with the excluded magnetic field is measured and shown to increase linearly with ρd.
Experimental evidence of D region heating by lightning‐induced electromagnetic pulses on MF radio links
Authors: Farges Thomas , Blanc Elisabeth , Tanguy Michel
Published: October 2007

Broadband medium frequency (MF) measurements are used to study perturbations of the lower ionosphere related to lightning activity. A station measuring the vertical electric field in the MF band (500–1500 kHz) was set up in France in 2004. Just after the lightning return stroke, a strong attenuation is very frequently observed in the MF waves of radio transmissions. This perturbation effect is studied in each case of about 4000 return strokes and at nine radio frequencies. The main characteristics of the perturbation are a mean peak attenuation of 12 dB, an onset time of less than 1 ms, and a duration varying from 3 to 10 ms. Peak attenuations and durations are roughly proportional to the lightning‐induced peak current. Perturbations are characterized by a circular structure with a radius reaching 250 km, which is centered on the return stroke location. The recovery time of the electromagnetic pulse (EMP) induced electron density is too long compared with the duration of the observed perturbation. However, we show that the origin of these MF wave perturbations, on timescales involved in the heating produced, can be explained by a lightning‐induced electric field at 90 km altitude. The observed attenuation is compatible with a heating of 4–14 eV of the lower ionospheric electrons produced by the lightning electric field. These perturbations are then the MF radio signature of an EMP effect on the lower ionosphere, in the same way as elves correspond to their optical signature.
Ammonia oxidation and ammonia-oxidizing bacteria and archaea from estuaries with differing histories of hypoxia
Authors: Caffrey Jane M , Bano Nasreen , Kalanetra Karen , Hollibaugh James T
Published: October 2007

Nitrification, the oxidation of NH4+ to NO2− and subsequently to NO3−, plays a central role in the nitrogen cycle and is often a critical first step in nitrogen removal from estuarine and coastal environments. The first and rate-limiting step in nitrification is catalyzed by the enzyme ammonia monooxygenase (AmoA). We evaluate the relationships between the abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) amoA genes; potential nitrification rates and environmental variables to identify factors influencing AOA abundance and nitrifier activity in estuarine sediments. Our results showed that potential nitrification rates increased as abundance of AOA amoA increased. In contrast, there was no relationship between potential nitrification rates and AOB amoA abundance. This suggests that AOA are significant in estuarine nitrogen cycling. Surprisingly, more of the variability in potential nitrification rates was predicted by salinity and pore water sulfide than by dissolved oxygen history.
Primary producing prokaryotic communities of brine, interface and seawater above the halocline of deep anoxic lake L'Atalante, Eastern Mediterranean Sea
Authors: Yakimov Michail M , La Cono Violetta , Denaro Renata , D'Auria Giuseppe , Decembrini Franco , Timmis Kenneth N , Golyshin Peter N , Giuliano Laura
Published: October 2007

Meso- and bathypelagic ecosystems represent the most common marine ecological niche on Earth and contain complex communities of microorganisms that are for the most part ecophysiologically poorly characterized. Gradients of physico-chemical factors (for example, depth-related gradients of light, temperature, salinity, nutrients and pressure) constitute major forces shaping ecosystems at activity ‘hot spots’ on the ocean floor, such as hydrothermal vents, cold seepages and mud volcanoes and hypersaline lakes, though the relationships between community composition, activities and environmental parameters remain largely elusive. We report here results of a detailed study of primary producing microbial communities in the deep Eastern Mediterranean Sea. The brine column of the deep anoxic hypersaline brine lake, L'Atalante, the overlying water column and the brine-seawater interface, were characterized physico- and geochemically, and microbiologically, in terms of their microbial community compositions, functional gene distributions and [14C]bicarbonate assimilation activities. The depth distribution of genes encoding the crenarchaeal ammonia monooxygenase α subunit (amoA), and the bacterial ribulose-1,5-biphosphate carboxylase/oxygenase large subunit (RuBisCO), was found to coincide with two different types of chemoautotrophy. Meso- and bathypelagic microbial communities were enriched in ammonia-oxidizing Crenarchaeota, whereas the autotrophic community at the oxic/anoxic interface of L'Atalante lake was dominated by Epsilonproteobacteria and sulfur-oxidizing Gammaproteobacteria. These autotrophic microbes are thus the basis of the food webs populating these deep-sea ecosystems.
Differences in the gene expression profile of human monocytic cells activated by high and low affinity Fc-gamma-receptors.
Authors: Manikandan Jayapal , Reghunathan Renji , Melendez Alirio Jose , Pushparaj Peter Natesan
Published: October 2007

Receptors for the constant (Fc) region of immunoglobulin G, play an important role in linking the humoral and cellular arms of immune response. Three different classes of receptors have been defined, FcγRI (CD64), FcγRII (CD 32), and FcγRIII (CD16). We have previously shown that in a human monocyte model (IFNγ-primed U937 cells), FcγRI and FcγRII stimulation trigger two very distinct intracellular signalling pathways. Here we show for the first time, the use of oligonucleotide microarrays to investigate the overall gene-expression profile of human monocytes triggered with FcγRI or FcγRII. Our data indicate that several interesting genes are differentially expressed in response to the different receptors, pointing out to a complete different genetic response of human monocytes regulated by the different signal transduction cascade triggered by FcγRI or FcγRIIa. Thus, providing new insights into the different mechanisms utilized by the different IgG receptors to effect their functions.
Activation of TRF3 Transcription Factor by Small Interfering RNAs
Authors: Persengiev Stephan
Published: October 2007

RNA interference (RNAi) is a conserved biological response to double-stranded RNAs that results in posttranscriptional silencing of target gene expression. Double-stranded processed RNAs of 21-23 nt were found to affect in a non-specific manner a number of signaling and transcription pathways, including interferon and PKR cascades. We report here that siRNAs induce the expression of general transcription factor TRF3, which can trigger an interferon response in mammalian cells.
Removal forces and adhesion properties of Saccharomyces cerevisiae on glass substrates probed by optical tweezer
Authors: Castelain Mickaël , Pignon Frédéric , Piau Jean-Michel , Magnin Albert , Mercier-Bonin Muriel , Schmitz Philippe
Published: October 2007

In agroindustry, the hygiene of solid surfaces is of primary importance in order to ensure that products are safe for consumers. To improve safety, one of the major ways consists in identifying and understanding the mechanisms of microbial cell adhesion to nonporous solid surfaces or filtration membranes. In this paper we investigate the adhesion of the yeast cell Saccharomyces cerevisiae (about 5μm in diameter) to a model solid surface, using well-defined hydrophilic glass substrates. An optical tweezer device developed by Piau [J. Non-Newtonian Fluid Mech. 144, 1 (2007)] was applied to yeast cells in contact with well-characterized glass surfaces. Two planes of observation were used to obtain quantitative measurements of removal forces and to characterize the corresponding mechanisms at a micrometer length scale. The results highlight various adhesion mechanisms, depending on the ionic strength, contact time, and type of yeast. The study has allowed to show a considerable increase of adhering cells with the ionic strength and has provided a quantitative measurement of the detachment forces of cultured yeast cells. Force levels are found to grow with ionic strength and differences in mobility are highlighted. The results clearly underline that a microrheological approach is essential for analyzing the adhesion mechanisms of biological systems at the relevant local scales.