bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of loss of perennial lake ice on mixing and phytoplankton dynamics: insights from High Arctic Canada
Authors: Veillette Julie , Martineau Marie-Josée , Antoniades Dermot , Sarrazin Denis , Vincent Warwick F.
Published: June 2011

Perennially ice-covered lakes are well known from Antarctica and also occur in the extreme High Arctic. Climate change has many implications for these lakes, including the thinning and disappearance of their perennial ice cover. The goal of this study was to consider the effects of transition to seasonal ice cover by way of limnological observations on a series of meromictic lakes along the northern coastline of Ellesmere Island, Nunavut, Canada. Conductivity-temperature profiles during a rare period of ice-free conditions (August 2008) in these lakes suggested effects of wind-induced mixing of their surface freshwater layers and the onset of entrainment of water at the halocline. Sampling of the mixed layer of one of these meromictic lakes in May and August 2008 revealed a pronounced vertical structure in phytoplankton pigments and species composition, with dominance by cyanobacteria, green algae, chrysophytes, cryptophytes and dinoflagellates, and a conspicuous absence of diatoms. The loss of ice cover resulted in an 80-fold increase in water column irradiance and apparent mixing of the upper water column during a period of higher wind speeds. Zeaxanthin, a pigment found in cyanobacteria, was entirely restricted to the <3μm cell fraction at all depths and increased by a factor of 2–17, with the greatest increases in the upper halocline region subject to mixing. Consistent with the pigment data, picocyanobacterial populations increased by a factor of 3, with the highest concentration (1.65 × 108 cells L−1) in the upper halocline. Chlorophyll a concentrations and the relative importance of phytoplankton groups differed among the four lakes during the open-water period, implying lake-specific differences in phytoplankton community structure under ice-free conditions.
Modelling the impacts of a nitrogen pollution event on the biogeochemistry of an Arctic glacier
Authors: Roberts Tjarda J. , Hodson Andy , Evans Chris D. , Holmén Kim
Published: June 2011

A highly polluted rain event deposited ammonium and nitrate on Midtre Lovénbreen, Svalbard, European High Arctic, during the melt season in June 1999. Quasi-daily sampling of glacial runoff showed elevated ion concentrations of both ammonium (NH4+) and nitrate (NO3−), collectively dissolved inorganic nitrogen (DIN) in the two supraglacial meltwater flows, but only elevated NO3− in the subglacial outburst. Time-series analysis and flow-chemistry modelling showed that supra- and subglacial assimilation of NH4+ were major impacts of this deposition event. Supraglacial assimilation likely occurred while the pollution-event DIN resided within a/the supraglacial slush layer (estimated DIN half-life 40–50 hours, with the lifetime of NO3− exceeding that of NH4+ by 30%). Potentially, such processes could affect preservation of DIN in melt-influenced ice cores. Subglacial routing of event DIN and its multi-day storage beneath the glacier also enabled significant assimilation of NH4+ to occur here (60% of input), which may have been either released as particulate N later during the melt season, or stored until the following year. Our results complement existing mass-balance approaches to the study of glacial biogeochemistry, show how modelling can enable time-resolved interpretation of process dynamics within the biologically active melt season, and highlight the importance of episodic polluted precipitation events as DIN inputs to Arctic glacial ecosystems.
Organic matter content and quality in supraglacial debris across the ablation zone of the Greenland ice sheet
Authors: Stibal Marek , Lawson Emily C. , Lis Grzegorz P. , Mak Ka Man , Wadham Jemma L. , Anesio Alexandre M.
Published: June 2011

Quantifying the biogeochemical cycling of carbon in glacial ecosystems is of great significance for regional, and potentially global, carbon flow estimations. The concentration and quality of organic carbon (OC) is an important indicator of biogeochemical and physical processes that prevail in an ice-sheet ecosystem. Here we determine the content and quality of OC in debris from the surface of the Greenland ice sheet (GrIS) using microscopic, chromatographic, spectrophotometric and high-temperature combustion techniques. The total OC content in the debris increased with distance from the edge of the ice sheet, from virtually zero to >6% dry weight at 50 km inland, and there was a peak in the carbohydrate proportion and the microbial abundance at ∼6km inland. The highest (galactose + mannose)/(arabinose + xylose) ratios, indicating maximum autochthonous microbial production, were found at >10km inland. We propose that three key processes influence the carbon cycling on the GrIS: aeolian input of microbial inoculum and nutrients, in situ biological C transformation and the wash-away of supraglacial debris by meltwaters. We show that all these processes have significant spatial variability. While the total OC content of the debris on the ice sheet is probably controlled by the physical processes of wind transport and wash-away by meltwater, the microbial abundance and the quantity of the labile cell-contained OC within the debris is likely to be driven by the balance between the wash-away and the microbial productivity.
Detecting biogeochemical activity in basal ice using fluorescence spectroscopy
Authors: Barker J.D. , Klassen J.L. , Sharp M.J. , Fitzsimons S.J. , Turner R.J.
Published: June 2011

Dissolved organic matter (DOM) is an important component of aquatic carbon and nutrient budgets and is a metabolic substrate for organisms at the base of aquatic food chains. Active microbial communities in glaciers affect the abundance and characteristics of organic matter (OM) that is exported to downstream ecosystems. However, how OM is biogeochemically altered in glaciers remains unknown and studies documenting active microbial activity by detecting in situ biogeochemical modifications of OM are lacking due to difficulties characterizing OM and the low concentrations of DOM typical of glacier environments. To address this issue, we measure the abundance and fluorescence characteristics of DOM in basal ice at Victoria Upper Glacier (VUG), McMurdo Dry Valleys, Antarctica. We compare these observations with the results of microbial incubations from the same basal ice samples to determine whether the occurrence of fluorophores indicative of recent microbial activity is linked to the presence of culturable microbial communities containing organisms that could have produced them. Psychrotolerant bacteria were isolated from basal ice samples and were associated with marine humic-like fluorescence. This is interpreted as being indicative of in situ microbial degradation of OM within basal ice at VUG. Marine humic-like material is a recalcitrant form of OM, and its biogeochemical transformation from a relatively labile form of OM in glacier ice may function as a carbon sink.
Basal ice microbiology at the margin of the Greenland ice sheet
Authors: Yde Jacob C. , Finster Kai W. , Raiswell Rob , Steffensen Jørgen P. , Heinemeier Jan , Olsen Jesper , Gunnlaugsson Haraldur P. , Nielsen Ole B.
Published: June 2011

Basal ice at the margin of the Greenland ice sheet was studied with respect to its physical characteristics and microbiological community. The basal ice contained high concentrations of dissolved ferrous Fe and must therefore be anoxic. Oxygen consumption experiments indicate that 50% of the oxidation was due to biological activity while the rest could be attributed to chemical processes, most likely weathering reactions with ferrous Fe. At least six different Fe-containing mineral sources were detected in basal ice together with potential bioavailable Fe nanoparticles. An active denitrifier population was identified due to formation of 30N-dinitrogen gas after amendment of anoxic sediment slurries with 15N-NO3−. Sulfate reduction could not be detected. The solid ice facies contained an abundant (∼108 cells cm−3) and complex microbial community that harbored representatives of at least eight major phyla within the domain Bacteria. The clone library was dominated by members of the β-subdivision of proteobacteria of which the largest proportion was affiliated to the genus Rhodoferax that comprises facultative aerobic iron reducers. The second most abundant phylum was Bacteroidetes. The solid ice facies had many physical similarities with the overlying debris-rich banded ice facies, indicating that they formed by similar subglacial processes and harbor similar microbial communities. This study extends our knowledge of life in subglacial environments such as beneath ice sheets. GenBank accession numbers: HM439882-HM439950; HQ144215-HQ144221.
The cryoconite ecosystem on the Greenland ice sheet
Authors: Hodson Andy , Bøggild Carl , Hanna Edward , Huybrechts Phillipe , Langford Harry , Cameron Karen , Houldsworth Alexandra
Published: June 2011

This paper presents an assessment of biological activity associated with ice surface debris (cryoconite) at the ice-sheet scale. Estimates of the mass distribution of cryoconite over the Greenland ice sheet (GIS) and the biological activity associated with it are presented and then coupled with a surface mass-balance model to estimate total carbon fluxes due to respiration and photosynthesis. We find an average loading of 66gm−2 at Kangerlussuaq, southwest Greenland, which compares well with recent estimates from Kronprins Christians Land (17–440 gm−2: Bøggild and others, 2010) in northeast Greenland. We also report a significant microbial biomass in cryoconite at both these places (103–104 cells mg−1) and carbon fluxes of the order of 1–3 μM C g−1d−1 for both respiration and photosynthesis. The modelling indicates that total respiration and photosynthesis fluxes are likely to be ∼101–102 GgCa−1 and thus far from trivial. However, estimation of the net ecosystem impact across the entire ice sheet on atmospheric CO2 concentrations is problematic because photosynthesis rates were almost certainly low during our field campaign. Therefore, like its water balance, the carbon balance of the GIS is now known to be important, but its accurate quantification will remain elusive until more data are forthcoming.
Laser-induced fluorescence emission (LIFE) from Lake Fryxell (Antarctica) cryoconites
Authors: Sattler Birgit , Storrie-Lombardi Michael C. , Foreman Christine M. , Tilg Markus , Psenner Roland
Published: June 2011

Laser-induced fluorescence emission (LIFE) images were obtained in situ from a 27 cm long ice core at Lake Fryxell, Antarctica. The excitation was accomplished with a simple 532 nm green laser pen light, and the fluorescence images were captured with a small compact digital camera. The targets for the experiment were mm-scale cryoconite assemblages found in the ice covers of this perennially frozen Antarctic lake. The fluorescence response originates from photo-pigments in cyanobacteria-dominated cryoconite assemblages with phycoerythrin (PE) exhibiting the optimal target cross section. This inexpensive, low-mass, low-energy method avoids manipulation of the in situ habitat and individual target organisms and does not disturb the microbial community or the surrounding ice matrix. We establish the correlation between fluorescence intensity and PE concentration. We show that cryoconite fluorescence response does not appear to decrease with depth in the ice cover, in agreement with similar findings at Lake Untersee, a perennially ice-covered lake in Dronning Maud Land, Antarctica. Optical reflection and refraction events at the air/ice interface can complicate quantitative estimates of total pigment concentrations. Laser targeting of a single mm-scale cryoconite can result in multiple neighboring excitation events secondary to reflection and refraction phenomena in the multiple air/ice interface of the bubbles surrounding the primary target.
Structure and formation process of cryoconite granules on Ürümqi glacier No. 1 , Tien Shan, China
Authors: Takeuchi Nozomu , Nishiyama Hiromu , Li Zhongqin
Published: June 2011

Cryoconite granules are dark-colored spherical aggregates of organic and inorganic material on glacier ice, and are commonly observed on glaciers the world over. The structure of cryoconite granules on Ürümqi glacier No. 1, Tien Shan, China, was analyzed. Granules were distributed over the entire ice surface of the ablation area, and ranged in size from 0.26 to 3.5 mm (mean 1.1 mm). The granule surface was densely covered with filamentous cyanobacteria. Microscopy of a thin section revealed various inner structures. Most granules had concentric layers of dense organic matter, which are probably derived from annual growth of the granules by the activity of cyanobacteria. The number of layers averaged 3.5 and ranged up to 7, which is likely to indicate their mean and maximum growth ages, respectively. Some granules contained two or more subgranules, showing that small granules had combined and enlarged. Such structures suggest that granule formation was mainly due to the activity of filamentous cyanobacteria, and that the granules repeatedly grew and disintegrated over a cycle of several years on the glacier.
The mass–area relationship within cryoconite holes and its implications for primary production
Authors: Cook J. , Hodson A. , Telling J. , Anesio A. , Irvine-Fynn T. , Bellas C.
Published: June 2011

Linear relationships between the mass of sediment present in a cryoconite hole and the hole area are described for a range of glacier and ice-sheet surfaces. The strong relationships found indicate that some mechanism regulates the thickness of the layer of sediment occupying the ‘floor’ of the hole. We find that this regulation process responds immediately to the addition of new debris to a hole and infer that it is caused by lateral thermal conduction from the debris to the hole wall. This causes hole widening by melt, and a redistribution of the debris within then takes place, usually resulting in 0.04–0.20 gcm−2 of debris in a layer of single cryoconite grains. The thinning of the debris layer during hole widening also reduces self-shading and thus maximizes the exposure of cryoconite to solar radiation. We explore the implications of the hole widening for biological production. Net photosynthesis (CO2 fixation) is shown to be favoured by thin debris layers, whilst net heterotrophy (CO2 respiration) occurs when debris layers are in excess of 2–4 mm. We conclude that the carbon balance of cryoconite holes is sensitive to the thickness of the debris and that the thermodynamic equilibration of the debris thickness helps the ecosystem to maximize primary production during the summer.
Measuring rates of gross photosynthesis and net community production in cryoconite holes: a comparison of field methods
Authors: Telling J. , Anesio A.M. , Hawkings J. , Tranter M. , Wadham J.L. , Hodson A.J. , Irvine-Fynn T. , Yallop M.L.
Published: June 2011

Photosynthesis by microbes on the surfaces of glaciers and ice sheets has the potential to fix carbon, alter the albedo of ice surfaces via the production of organic matter and so enhance ice melt. It could also be important for supplying labile organic matter and nutrients to in situ and downstream ecosystems. This study compares in situ 24 hour incubation methods for measuring rates of gross photosynthesis, respiration and net community production (NCP) in cryoconite holes on three Svalbard valley glaciers. Rates of gross photosynthesis and respiration measured by the ΔCO2 method were closely balanced, resulting in rates of NCP close to the detection limit (mean of –1.3 μg C g−1 d–1) consistent with previous measurements in Arctic cryoconite holes. This suggests that organic matter within cryoconite holes may be derived largely from allochthonous sources. The molar ratio of ΔO2 to ΔCO2 in incubations gave mean respiratory and photosynthetic quotients of 0.80 ± 0.17 (1 × SD) and 1.24 ± 0.20 (1 × SD), respectively. The 14C method typically underestimated rates of gross photosynthesis (ΔCO2 method) by more than one order of magnitude and measured a rate closer to NCP.
In-stream uptake and retention of C, N and P in a supraglacial stream
Authors: Scott Durelle , Hood Eran , Nassry Michael
Published: June 2011

Supraglacial streams form annually during the melt season, transporting dissolved solutes from the melting ice and snowpack to subglacial flow paths and the glacier terminus. Although nutrient and carbon processing has been documented in other supraglacial environments (cryoconite holes, snowpack), little work has examined the potential for in-stream nutrient retention in supraglacial streams. Here we carried out a solute nutrient injection experiment to quantify NH3+, PO43− and labile dissolved organic carbon (DOC) retention in a supraglacial stream. The experiment was performed on a 100 m stream reach on Mendenhall Glacier, an outlet glacier on the Juneau Icefield, southeastern Alaska, USA. The study stream contained two distinct reaches of equal length. The first reach had a lower velocity (0.04 ms−1) and contained abundant gravel sediment lining the ice–water interface, while the second reach was devoid of bedload sediment and had an order-of-magnitude higher velocity. At the end of the second reach, the stream emptied into a moulin, which is typical of supraglacial streams on this and other temperate glaciers. We found that N and P were transported largely conservatively, although NO3− increased along the reach, suggestive of nitrification. Labile DOC was retained slightly within the stream, although rates were low relative to the travel times observed within the supraglacial stream. Although our findings show that these streams have low processing rates, measurable in-stream nitrification and dissolved organic matter uptake within this biologically unfavorable environment suggests that supraglacial streams with longer residence times and abundant fine substrate have the potential to modify and retain nutrients during transport to the glacier terminus.
Recent hydrologic change in a Colorado alpine basin: an indicator of permafrost thaw?
Authors: Caine Nel
Published: June 2011

Hydrologic and hydrochemical studies have been conducted in Green Lakes Valley, Colorado Front Range, USA, above 3550 m since 1982. They show a classic seasonal hydrograph dominated by snowmelt and an earlier date for the start of spring flow and for peak flow over the period of record. This is consistent with patterns found at lower elevations in Colorado and throughout western North America. They also show an increasing trend in flows in September and October of 2.6 ±0.7 mm a−1 which is not found elsewhere and cannot be accounted for by increased autumn precipitation and the melting of surface ice. Because this late-season increase is not found at the highest elevations or in basins in which there is no evidence of permafrost, it seems best explained by the thawing of alpine permafrost at intermediate elevations. This is corroborated by an increase in the concentration of base cations and silica, and particularly in Ca2+ and SO4–, in the stream discharge starting in 2000. As with the physical hydrology, the geochemical signals have not been detected at the higher elevations in the basin, though they have previously been associated with streamflow from a small rock glacier in the valley. The combined evidence suggests the degradation of ice-rich permafrost on the north-facing slopes of the valley below 3700 m, where it has been detected at 3 m depth by geophysical surveys.
The microstructure and biogeochemistry of Arctic cryoconite granules
Authors: Langford Harry , Hodson Andy , Banwart Steve , Bøggild Carl
Published: June 2011

A cryoconite granule is a biologically active aggregation of microorganisms, mineral particles and organic matter found on glacier surfaces, often within shallow pools or cryoconite holes. Observations of the microstructure of a range of cryoconite granules from locations in Svalbard and Greenland reveal their structure and composition. Whereas bulk analyses show that the mineralogy and geochemistry of these granules are broadly similar, analyses of their microstructure, using optical, epifluorescence and confocal microscopy, indicate differences in the location and quantity of photosynthetic microorganisms, heterotrophic bacteria and organic matter. Using these findings, a hypothesis on the aggregation of cryoconite is presented, centred upon multilevel aggregation by bioflocculation and filamentous binding.
Carbon fluxes through bacterial communities on glacier surfaces
Authors: Anesio Alexandre M. , Sattler Birgit , Foreman Christine , Telling Jon , Hodson Andy , Tranter Martyn , Psenner Roland
Published: June 2011

There is very little information about the activity of microbial communities on the surface of glaciers, though there is an increasing body of evidence to show that they strongly influence the biogeochemistry of these habitats. We measured bacterial abundance and production in cryoconite holes on Arctic, Antarctic and Alpine glaciers in order to estimate the role of heterotrophic bacteria within the carbon budget of glacial ecosystems. Our results demonstrate an active bacterial community on the surface of glaciers with doubling times that vary from a few hours to hundreds of days depending on the glacier and position (water or sediments) within the cryoconite hole. However, bacterial production is only ∼2–3% of the published literature values of community respiration from similar habitats, indicating that other types of microbes (e.g. eukaryotic organisms) may also play a role in the C cycle of glaciers. We estimate that only up to 7% of the organic C in cryoconite sediments is utilized by the heterotrophic bacterial community annually, suggesting that the surface of glaciers can accumulate organic carbon, and that this C may be important for biogeochemical activity downstream to adjacent ecosystems.
Prediction of Countershock Success in Patients Using the Autoregressive Spectral Estimation
Authors: Neurauter A. , Wieser L. , Wenzel V. , Abella B. , Myklebust H. , Steen P. A. , Strohmenger H.-U. , Nowak C. N.
Published: June 2011

Objectives: Ventricular fibrillation (VF) is a life-threatening cardiac arrhythmia and within of minutes of its occurrence, optimal timing of countershock therapy is highly warranted to improve the chance of survival. This study was designed to investigate whether the autoregressive (AR) estimation technique was capable to reliably predict countershock success in VF cardiac arrest patients.

Methods: ECG data of 1077 countershocks applied to 197 cardiac arrest patients with out-of-hospital and in-hospital cardiac arrest between March 2002 and July 2004 were retrospectively analyzed. The ECG from the 2.5 s interval of the precountershock VF ECG was used for computing the AR based features Spectral Pole Power (SPP) and Spectral Pole Power with Dominant Frequency weighing (SPPDF) and Centroid Frequency (CF) and Amplitude Spectrum Area (AMSA) based on Fast Fourier Transformation (FFT).

Results: With ROC AUC values up to 84.1 % and diagnostic odds ratio up to 19.12 AR based features SPP and SPPDF have better prediction power than the FFT based features CF (80.5 %; 6.56) and AMSA (82.1 %; 8.79).

Conclusions: AR estimation based features are promising alternatives to FFT based features for countershock outcome when analyzing human data.
Determination of object position, vortex shedding frequency and flow velocity using artificial lateral line canals
Authors: Klein Adrian , Bleckmann Horst
Published: June 2011

The lateral line system of fish consists of superficial neuromasts, and neuromasts embedded in lateral line canals. Lateral line neuromasts allow fish to sense both minute water motions and pressure gradients, thereby enabling them to detect predators and prey or to recognize and discriminate stationary objects while passing them. With the aid of the lateral line, fish can also sense vortices caused by an upstream object or by undulatory swimming movements of fish. We show here that artificial lateral line canals equipped with optical flow sensors can be used to detect the water motions generated by a stationary vibrating sphere, the vortices caused by an upstream cylinder or the water (air) movements caused by a passing object. The hydrodynamic information retrieved from optical flow sensors can be used to calculate bulk flow velocity and thus the size of the cylinder that shed the vortices. Even a bilateral sensor platform equipped with only one artificial lateral line canal on each side is sufficient to determine the position of an upstream cylinder.
Single enantiomer synthesis of α-(trifluoromethyl)-β-lactam
Authors: Jurčík Václav , Slawin Alexandra M Z , O'Hagan David
Published: June 2011

The first synthesis of α-(trifluoromethyl)-β-lactam ((S)-1) is reported. The route starts from α-(trifluoromethyl)acrylic acid (2). Conjugate addition of α-(p-methoxyphenyl)ethylamine ((S)-3b), generated an addition adduct 4b which was cyclised to β-lactam 5b. Separation of the diastereoisomers by chromatography gave ((αS,3S)-5b). N-Debenzylation afforded the desired α-(trifluoromethyl)-β-lactam ((S)-1). The absolute stereochemistry of diastereoisomers 5 was determined by X-ray crystallographic determination of a close structural analogue, (αS,3S)-5c, and then 1H and 19F NMR correlation to the individual diastereoisomers of 5a and 5b.
Early Outcomes and the Virological Effect of Delayed Treatment Switching to Second-Line Therapy in An Antiretroviral Roll-Out Programme in South Africa
Authors: Levison Julie H , Orrell Catherine , Losina Elena , Lu Zhigang , Freedberg Kenneth A , Wood Robin
Published: June 2011

Background

More patients in resource-limited settings are starting second-line antiretroviral treatment (ART) following first-line ART failure. We aimed to describe predictors of lack of virological suppression in HIV-infected patients on second-line ART in a roll-out programme in South Africa.

Methods

A retrospective analysis was performed on an adult HIV treatment cohort who started second-line ART (lopinavir/ritonavir, didanosine and zidovudine) after virological failure of first-line ART (two consecutive HIV RNA>1,000 copies/ml). Predictors of week 24 lack of suppression (HIV RNA>400 copies/ml) on second-line ART were determined by bivariate analysis where missing equals failure. A multivariable model that adjusted for gender, age and time to ART switch was used. We tested these findings in sensitivity analyses defining lack of suppression at week 24 as HIV RNA>1,000 and >5,000 copies/ml.

Results

Of 6,339 patients on ART, 202 started second-line ART. At week 24, an estimated 41% (95% CI 34–47) did not achieve virological suppression. Female sex (adjusted OR 2.25, 95% CI 1.03–4.88) and time to ART switch (adjusted OR 1.07, 95% CI 1.01–1.14 for each additional month) increased the risk of lack of virological suppression. Age, CD4+ T-cell count and HIV RNA at second-line ART initiation did not predict this outcome. In multivariate models, these findings were insensitive to the definition of lack of virological suppression.

Conclusions

A substantial number of HIV-infected patients do not achieve virological suppression by week 24 of second-line ART. Women and patients with delayed start of second-line ART after first-line ART failure were at an increased risk of lack of virological suppression.
Le genre : de la politique à la clinique
Authors: Linhares Andréa
Published: June 2011

À partir de l’histoire de la notion de genre en politique, cet article entend apporter un éclairage sur le débat concernant la pertinence du genre en psychanalyse. En effet, les réticences vis-à-vis du « genre » dans le monde psychanalytique français semblent souvent résulter d’un amalgame entre deux perspectives différentes : celle de Stoller et celle des sciences sociales. Une théorisation proprement psychanalytique du genre, comme celle proposé par Laplanche, articulé à des apports des sciences sociales, laisse soupçonner la possibilité d’un champ clinique étendu, allant au-delà des troubles de l’identité sexuelle.
Des gender studies aux disability studies : repenser les catégories
Authors: Korff-Sausse Simone
Published: June 2011

L’auteure fait l’hypothèse qu’il y a une analogie entre les gender studies et les disability studies , car il y a un point de convergence entre ces études sur l’identité sexuée et la construction identitaire de la personne en situation de handicap, qui se trouve comme les intersexes avec un statut non déterminé. Les disability studies remettent en question l’opposition binaire entre le normal et la pathologique, tout comme les gender studies le font entre masculin et féminin. Chaque catégorie –homme/femme ; valide/handicapé – constitue désormais une figure parmi les figures multiples, hétérogènes, fluctuantes qui se proposent à l’individu contemporain pour définir une identité qui sera de plus en plus métisse.
Pour une nouvelle cartographie du désir : genre et subjectivité chez Judith Butler
Authors: Arán Marcia , Augusto Peixoto Júnior Carlos
Published: June 2011

C’est sur une suggestion de Judith Butler que le genre est devenu une norme, c’est-à-dire, une construction sociale historique et contingente. Le travail ci-dessous cherche à faire une analyse critique des concepts d’identification et sexuation dans la psychanalyse, issus d’une conception structuraliste du sujet et de la différence sexuelle. Partant du principe que si l’on comprend la loi comme une structure antérieure et transcendante aux manifestations sociales, politiques et obligatoirement historiques, le symbolique sera présenté comme une force qui ne pourra pas être modifiée et subvertie sans la menace de la psychose ou de la perversion. Au contraire, si l’on comprend la loi comme quelque chose qui est vécu et constamment réitéré de façon immanente aux relations de pouvoir, les possibilités de modification et aussi de subversion du symbolique , ne signifieront pas nécessairement une menace à la culture et à la civilisation. Il faut ainsi une certaine déstabilisation de ces frontières excessivement rigides et fixes de l’identification et du désir pour que d’autres formes de construction du genre puissent habiter le monde viable de la sexuation et sortir du spectre de l’abjection.
Sexologie et féminisme au début du XXe siècle
Authors: Chaperon Sylvie
Published: June 2011

Ce texte rappelle les principales caractéristiques de la sexologie, ses incidences conscientes et inconscientes sur le genre, en France au début du XXe siècle où elle a beaucoup moins d’éclat qu’en Angleterre ou en Allemagne parce que la sexualité féminine y est conçue comme problématique. Les femmes, victimes sociales du genre, font très peu entendre leur voix dans ce concert de médecins, de psychologues ou de militants masculins. Quelques néo-malthusiennes ou féministes font exception : Jeanne Humbert, Madeleine Vernet et Madeleine Pelletier notamment, mais elles s’abstiennent d’aborder les pratiques sexuelles.
Un autre genre d'amour ? De quelques mouvements du désir dans la poésie grecque et romaine
Authors: Boehringer Sandra
Published: June 2011

Dans les sociétés grecque et romaine, l’identité de sexe n’était pas le premier critère distinctif pour penser les identités personnelles et les rapports de domination. De même, les Anciens ne concevait pas l’identité de sexe comme un élément définissant différentes formes de désir ou d’amour. Une étude du vocabulaire antique de la sexualité et des types de relations érotiques dans le monde grec et romain dresse un panorama de ces sociétés d’« avant la sexualité ». Une étude d’un poème de Sappho et d’un extrait des Métamorphoses d’Ovide, avec l’outil contemporain du genre, permet d’historiciser les catégories de sexe et de sexualité et, par effet de conséquence, d’interroger les constructions contemporaines des identités.
Comment penser la clinique de l'intersexuation ?
Authors: Jacquot Mélanie
Published: June 2011

À partir d’éléments cliniques recueillis dans le cadre d’une recherche pluridisciplinaire menée auprès de 17 sujets adultes présentant une intersexuation à la naissance, ayant un caryotype XY, opérés et élevés en tant que fille, et par le biais d’entretien de recherche et des épreuves projectives, l’auteure interroge la pertinence du recours au modèle théorique freudien pour penser la clinique de l’intersexuation. Il apparaît en effet que ce référentiel épistémologique, par la référence fondamentale qu’il fait à la différence anatomique des sexes, oriente rapidement les interprétations de la clinique vers une dérive naturaliste qui décale de l’objet de la psychanalyse. L’auteure propose alors le recours à la théorie laplanchienne de l’assignation du genre. Une relecture des premiers éléments cliniques au travers du prisme de ce référentiel épistémologique révèle la pertinence de cette proposition pour penser les spécificités de cette clinique des plus originales.
Homosexualités, mauvais genre ?
Authors: de Baecque Benoit
Published: June 2011

À partir de sa clinique issue d’entretiens individuels avec des jeunes homosexuels victimes d’homophobie, l’auteur développe l’hypothèse que la haine d’un désir non-conforme au paradigme hétérosexuel repose sur des représentations figées du genre. La polarité masculin/féminin serait le pivot de l’« ordre » qui définit par le rejet l’idéal groupal de la famille classique, et que menace l’aveu de l’homosexualité. Pour maintenir sa place dans le groupe, le sujet serait alors contraint à des sacrifices qui mettent en jeu son identité et son intégrité spéculaire.
Mémoire, genre, identité et lien social : le cri d'Antigone
Authors: Estellon Vincent
Published: June 2011

À partir de l’histoire du personnage littéraire d’Antigone qui révèle que ses désirs les plus profonds sont conditionnés par la configuration complexe de ses liens de parenté et par les mots qui l’ont entouré, l’auteur ouvre un questionnement sur ce qui fait tenir la notion même de genre : une polarité, une aspiration profonde, un tropisme, une attraction contre laquelle nulle loi publique ne peut lutter. Figure politique toujours actuelle, symbole de l’espoir en l’humain, Antigone promeut cette idée selon laquelle toute violence à l’égard des faibles, des étrangers ou des morts est violence commise à l’égard des vivants.
Sexes et genres de mort en deuil : Louise Bourgeois
Authors: Desprats-Péquignot Catherine
Published: June 2011

Louise Bourgeois explore dans son œuvre, de sexe en genre qu’elle mélange et métamorphose, des désirs et fantasmes infantiles dont la psychanalyse a montré toute l’importance avec les questions de la castration et du rapport au phallus. L’auteure propose de considérer, d’une part que ce sont des révélateurs de la distribution sociale, culturelle, de sexe et de genre et, d’autre part, que pourrait s’en expliquer le succès mondial de ses sculptures d’araignées, animal qui symbolise la « mère phallique », et en particulier de celle que Louise Bourgeois nomme Maman .
À la mémoire de Claude Olievenstein
Authors: Nizzoli Umberto
Published: June 2011

Résumé Par une synthèse des multiples contributions de Claude Olievenstein, l’auteur tente de mettre en évidence ce que lui doivent les professionnels du secteur des dépendances formés en Italie au début des années 1980. Sa maestria était importante. Il a transmis des bases professionnelles pour comprendre les défis de l’actualité de notre action et pour éviter les erreurs de la contemporanéité.
Claude Olievenstein et « le système de soins français »
Authors: Hautefeuille Michel
Published: June 2011

Résumé À l’occasion d’une table ronde, onze intervenants en toxicomanie témoignent de ce qu’ils ont retenu du travail et des réflexions du Pr. Olievenstein. Ces propos font le tour de cinq thèmes : le système de soins français, la clinique et la théorie du Pr. Olievenstein, la substitution, la critique de l’action d’Olievenstein, bilan et héritage.
Du non-dit au non-verbal
Authors: Poloméni Pierre , Lascaux Muriel , Levy Joy , Levêque Juliette
Published: June 2011

Résumé Dans son livre Le non-dit des émotions , Claude Olievenstein porte un regard sensible et lucide sur l’impossible de l’aveu de soi à soi, et sur ses implications dans la relation entre un toxicomane et un thérapeute. Il étaye une analyse à la fois émouvante, voire poétique, du (non-)discours de l’usager, et une critique du modèle thérapeutique. Sa lecture nous a troublés et elle alimente notre pratique quotidienne. Nous avons orienté nos réflexions dans plusieurs directions, faisant le choix d’un travail de groupe, réagissant sur les thèmes qui nous paraissaient les plus en lien avec notre pratique et nos questionnements. Nous avons par exemple interrogé les conditions de l’émergence d’un soignant vers les informations non verbales qu’aurait, peut-être, à nous transmettre l’usager (comment et pourquoi percevoir plutôt qu’entendre ?). D’autre part, nous avons pris en compte et réévalué l’analyse de C. Olievenstein, quasi prémonitoire, d’une dérive du soin qui ne prendrait en compte que les aspects neurobiologiques de l’homme.
Olievenstein au miroir de Lacan
Authors: Chassaing Jean-Louis
Published: June 2011

Résumé Il était surprenant d’entendre le Professeur Olievenstein, lors de la journée du 30 e anniversaire de Marmottan, encenser la psychanalyse comme méthode, « la meilleure » avait-il dit, pour comprendre « aujourd’hui » la psychopathologie. Il avait si souvent raillé les analystes, ferraillé contre eux et leur manque d’intérêt pour les toxicomanies, pour le politique. Toujours cependant avec un clin d’œil et un humour, un sourire en coin ; mais c’était dit. Une relation ambivalente à la psychanalyse. Cet aspect du personnage, c’était un personnage, « Olive », touchant et déroutant, force à livrer, avec respect et discrétion, quelques anecdotes, simples et pour moi marquantes. D’autres ont certainement beaucoup plus de souvenirs. Le rapport qu’il entretenait avec la théorie donnait à penser qu’il tenait plutôt à trouver des mots adéquats aux effets des drogues, et aux personnalités des toxicomanes, que de véritablement installer un corpus. Cependant, il parlait de « ses élèves », et cherchait dans les sciences des explications, des modélisations. Ainsi a-t-il abordé Lacan à travers ce qu’il a, lui, appelé « le stade du miroir brisé ». Nous pensons qu’il s’est appuyé – un peu – essentiellement sur un seul texte de Lacan, ne poursuivant pas le trajet et l’élaboration de ce dernier, mais il essayait de rendre compte de la rencontre d’une personnalité avec les effets des drogues. Nous tentons ici de donner notre avis sur cette « rencontre » d’Olievenstein et de Lacan.
La création d'une atmosphère
Authors: Bortino Raffaella
Published: June 2011

Résumé L’auteur met en lumière l’influence de la pensée de Claude Olievenstein sur sa pratique clinique et sur la vie institutionnelle de sa communauté thérapeutique, à Turin, en Italie, dans les années 1980 et 1990. Le professeur y était régulièrement convié afin d’effectuer un travail de supervision avec toute l’équipe.
Pour démédicaliser la médecine des addictions
Authors: Jacques Jean-Pierre
Published: June 2011

Résumé Cette contribution s’emploie à jauger la médicalisation du traitement des addictions, à en souligner autant les mérites que les impasses, dans une analyse d’une subjectivité toute assumée. Nous commencerons par une mise en perspective historique aussi brève qu’ironique.
Evidencias de un recubrimiento de magnetita artificial en el armamento íbero
Authors: García L. , Criado A. Javier , Criado Antonio J. , Chamón J. , Penco F. , Alonso J. , Arévalo R. , Martínez J. A. , Dietz C.
Published: June 2011

Se presenta un estudio metalográficos de dos armas prerromanas afectadas por un proceso de cremación. Las armas poseen un recubrimiento exterior de magnetita que las confieren unas altas propiedades de protección frente a la corrosión. Esta capa es extraordinariamente tenaz y posee un espesor muy homogéneo, indicando que son producto de un proceso de fabricación intencionado más que una formación accidental durante los varios ciclos de calentamiento/ enfriamiento que han sufrido los objetos. Hasta la fecha, la producción intencional de este tipo de recubrimientos ha sido atribuida a un proceso de soldadura de tres láminas metálicas diferentes. En este trabajo se propone un modelo alternativo de formación, el cual permite una simulación en el laboratorio en la que se forma exclusivamente una capa de magnetita.
Obtención de recubrimientos de hidroxiapatita sobre titanio mediante el método biomimético
Authors: Paz A. , Martín Y. , Pazos L. M. , Parodi M. B. , Ybarra G. O. , González J. E.
Published: June 2011

En el presente trabajo se realizó un estudio de la deposición de hidroxiapatita sobre un sustrato de titanio mediante el método biomimético. Para ello se empleó una disolución con elevado contenido de calcio y fósforo (SCS). Además, se realizó la activación del titanio a partir de la aplicación de procesos de oxidación con peróxido de hidrógeno y ácido clorhídrico con un posterior tratamiento térmico. La caracterización de los materiales empleados, así como de los recubrimientos obtenidos, se realizó mediante Espectroscopia Infrarroja (FT-IR), Difracción de Rayos X (DRX), Microscopia Electrónica de Barrido (MEB) y Espectroscopia de Energía Dispersiva de Rayos X (EDX). Como resultado del proceso de activación se formó un óxido de titanio hidratado. Sobre la superficie activada se logró obtener un recubrimiento de hidroxiapatita en un período de 24 h, caracterizado por su elevada densidad y cristalinidad y por presentar un espesor entre 2-4 μm.
Tecnologías de membranas líquidas soportadas en la eliminación de metales de efluentes líquidos
Authors: De Agreda D. , Garcia-Diaz I. , López F. A. , Alguacil F. J.
Published: June 2011

La generación, por parte de las industrias, de efluentes líquidos conteniendo sustancias orgánicas e inorgánicas, es un peligro potencial tanto para los humanos como para el medio ambiente, siendo necesaria la eliminación de estos elementos tóxicos de las disoluciones que los contienen. Para conseguir este fin, se están aplicando diversas técnicas y entre ellas las tecnologías de membranas líquidas soportadas, están demostrando sus aptitudes para la eliminación de metales contenidos en efluentes líquidos. Las membranas líquidas soportadas, resultan de la unión de las membranas poliméricas y de la tecnología de extracción líquido-líquido. Este tipo de membranas se pueden utilizar en diversas configuraciones: plana, módulo en fibra hueca y módulo en espiral y para aumentar su efectividad se están desarrollando las llamadas operaciones avanzadas: extracción no dispersiva, extracción no dispersiva con dispersión de la fase de reextracción y empleo del módulo de fibra hueca, con renovación de la membrana líquida. En este trabajo se revisan estas operaciones de membranas líquidas soportadas y algunas de las aplicaciones de las mismas, en el tratamiento de efluentes líquidos conteniendo metales.
T Cell Lineage Commitment: Identity and Renunciation
Authors: Rothenberg Ellen V.
Published: June 2011

Precursors undertaking T cell development shed their access to other pathways in a sequential process that begins before entry into the thymus and continues through many cell cycles afterward. This process involves three levels of regulatory change, in which the cells’ intrinsic transcriptional regulatory factors, expression of signaling receptors (e.g., Notch1), and expression of distinct homing receptors separately contribute to confirmation of T cell identity. Each alternative potential has a different underlying molecular basis that is neutralized and then permanently silenced through different mechanisms in early T cell precursors. This regulatory mosaic has notable implications for the hierarchy of relationships linking T lymphocytes to other hematopoietic fates.
Serum 1,3-βD-Glucan Assay in the Diagnosis of Invasive Fungal Disease in Neonates
Authors: Mackay Cheryl , Ballot Daynia , Perovic Olga
Published: June 2011

Invasive fungal disease is a significant cause of morbidity and mortality in the neonate. The current study aims to assess the 1, 3-βD-Glucan (BG) assay in a prospective analysis in neonates with suspected fungaemia. A multicentre, prospective cohort study was conducted in Johannesburg, South Africa. The study included 72 neonates with clinically suspected late onset sepsis who were at high risk of fungaemia. A BG assay was performed on each patient and correlated with a sepsis classification based on the full blood count, C-reactive protein and blood culture results as no fungaemia, possible fungaemia, probable fungaemia or definite fungaemia. Sensitivity and specificity of the BG assay at levels of 60pg/ml are 73.2% and 71.0% respectively and at levels of 80pg/ml are 70.7% and 77.4% respectively. Positive and negative predictive values at 60pg/ml are 76.9% and 66.7% respectively and at 80pg/ml are 80.6% and 66.7% respectively. The area under the receiver operating curve is 0.753. The BG assay is a useful adjunct to the diagnosis of invasive fungal disease in neonates. It does, however, need to be considered in the context of the clinical picture and supplementary laboratory investigations.
Merkel cell carcinoma of skin-current controversies and recommendations
Authors: Assouline Avi , Tai Patricia , Joseph Kurian , Lian Ji Dong , Krzisch Claude , Yu Edward
Published: June 2011

The review covers the current recommendations for Merkel cell carcinoma (MCC), with detailed discussion of many controversies. The 2010 AJCC staging system is more in-line with other skin malignancies although more complicated to use. The changes in staging system over time make comparison of studies difficult. A wide excision with margins of 2.5–3 cm is generally recommended. Even for primary </= 1 cm, there is a significant risk of nodal and distant metastases and hence sentinel node biopsy should be done if possible; otherwise adjuvant radiotherapy to the primary and nodal region should be given. Difficulties of setting up trials owing to the rarity of the disease and the mean age of the patient population result in infrequent reports of adjuvant or concurrent chemotherapy in the literature. The benefit, if any, is not great from published studies so far. However, there may be a subgroup of patients with high-risk features, e.g. node-positive and excellent performance status, for whom adjuvant or concurrent chemotherapy may be considered. Since local recurrence and metastases generally occur within 2 years of the initial diagnosis, patients should be followed more frequently in the first 2 years. However delayed recurrence can still occur in a small proportion of patients and long-term follow-up by a specialist is recommended provided that the general condition of the patient allows it. In summary, physician judgment in individual cases of MCC is advisable, to balance the risk of recurrence versus the complications of treatment.