References of "2012"
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See detailImproved Finite Element Solvers for the Helmholtz Equation at High Frequencies
Geuzaine, Christophe ULg

Scientific conference (2012, March 29)

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See detailComment peut-on parler des littératures francophones. À propos de Vies et mort de la francophonie
Provenzano, François ULg

Conference given outside the academic context (2012)

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See detailThe Characteristics of Low-Input Grasslands
Bogdan, Anca Dorina; Pacurar, Florin; Albus, Amalia et al

in ProEnvironment (2012), 5

Several studies show that the global interest in health and human nutrition is continually growing. A continuous change includes also the food production systems. There are more and more papers that ... [more ▼]

Several studies show that the global interest in health and human nutrition is continually growing. A continuous change includes also the food production systems. There are more and more papers that connect the value of agricultural production and food production system, papers that show a particular interes on the high value of products that are produced in low input agricultural systems./ On grassland canopy, these systems have a high diversity of floristic species. At European level, this concept has been extrapolated also to the farms, being a major concern regarding the quantification of inputs, aspect pursued along this paper. [less ▲]

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See detailChirality in nonlinear-optical response of planar G-shaped nanostructures
Mamonov, E.A.; Murzina, T.V.; Kolmychek, I.A. et al

in Optics Express (2012), 20(8), 8518

Chirality effects in optical second harmonic generation (SHG) are studied in periodic planar arrays of gold G-shaped nanostructures. We show that G-shaped structures of different handedness demonstrate ... [more ▼]

Chirality effects in optical second harmonic generation (SHG) are studied in periodic planar arrays of gold G-shaped nanostructures. We show that G-shaped structures of different handedness demonstrate different SHG efficiency for the left and right circular polarizations, as well as the opposite directions of the SHG polarization plane rotation. The observed effects are interpreted as the appearance of chirality in the SHG response which allows clear distinguishing of two enantiomers. [less ▲]

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See detailStriptease em raio-x: algumas interrelações artístico-científicas no domínio visual.
Sturnack, Lionel ULg

Conference (2012, March 28)

O striptease que propomos analisar é na verdade o título de uma obra que pertence à produção da artista italiana Benedetta Bonichi. Trata-se de uma composição mista, a meio caminho entre os raios-x e a ... [more ▼]

O striptease que propomos analisar é na verdade o título de uma obra que pertence à produção da artista italiana Benedetta Bonichi. Trata-se de uma composição mista, a meio caminho entre os raios-x e a fotografia. “Striptease” constitui uma base analítica interessante para várias razões. Com certeza, por seu caráter surpreendente, sendo uma cena erótica e ao mesmo tempo uma radiografia. Mas também e sobretudo por sua estética particular em relação aos outros artistas que desenvolvem uma técnica similar. Uma parte do nosso estudo consistirá na abordagem indispensável mesmo que breve das realizações de quatro outros artistas que trabalham com os raios-x. O propósito de nossos passos é levar em consideração o lugar da obra estudada no espaço de realizações em raio-x artístico, numa perspectiva semiótica. Pretendemos desta maneira chegar à descrição fina de “Striptease”, ou seja, conseguir por um lado estabelecer os critérios sobre os quais se correlacionam e se diferenciam os raios-x artísticos vistos e, por outro lado e graças à primeira etapa, dar conta da riqueza da obra da italiana. Desenvolveremos o estudo segundo três etapas gerais. Com a primeira, efetuaremos uma descrição de “Striptease” segundo os três eixos da leitura plástica padrão, tal como foram trabalhados por Jean-Marie Floch: cromático, eidético e topológico. Na segunda etapa, adotaremos o mesmo ponto de vista para a descrição plástica de cinco obras de quatro outros artistas: Nick Veasey, a agência Butter, Wim Delvoye e Claudio Mubarac. O interesse da segunda parte consiste em mostrar que o tipo de descrição estabelecido para “Striptease” vale nos outros casos e como se atualizam as unidades plásticas em cada realização particular, a fim de observar as suas possíveis convergências. Na última etapa, poderemos considerar a estética de cada obra à luz das atualizações plásticas e das integrações entre elas com outros patamares temáticos. Conseguiremos, finalmente, entender a pertinência e a particularidade de “Striptease” como metalinguagem crítica por meio destas considerações temáticas e plásticas. [less ▲]

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See detailLes pédagogues de l'austérité : éditorialistes et économistes médiatiques face à la crise
Geuens, Geoffrey ULg

Conference given outside the academic context (2012)

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See detailPréjugés et maladie d'Alzheimer
Adam, Stéphane ULg

Conference given outside the academic context (2012)

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See detailOrigine et effet de la myéloperoxydase lors de la congélation du sperme d'étalon
Ponthier, Jérôme ULg

Doctoral thesis (2012)

Semen freezing allows worldwide commercialization of equine genetic. Despite improvement of techniques, semen of 20% of stallions remains unfreezable. Currently, post-thaw semen quality is only determined ... [more ▼]

Semen freezing allows worldwide commercialization of equine genetic. Despite improvement of techniques, semen of 20% of stallions remains unfreezable. Currently, post-thaw semen quality is only determined by progressive motility, but its definition is not standardised. Spermatozoa are highly differentiated cells and freezing lesions can occur on DNA, membrane, mitochondria or acrosome. Current research focuses on prediction of freezability, improvement of freezing extenders and prevention of Reactive Oxygen Species (ROS) effects. Under its O2 form, oxygen is inactive and oxidase or oxygenase enzymes are required to produce ROS. Two pathways of ROS production in semen are described: the intrinsic pathway reflecting ROS escaping from the spermatozoon mitochondria and the extrinsic pathway corresponding to ROS produced by inflammatory cells. ROS induce DNA fragmentation, lipid peroxidation, apoptosis and decreased motility of spermatozoa. Myeloperoxidase (MPO) is a pro-oxidant enzyme contained in and released by neutrophils during degranulation or after lysis. It is responsible for formation of hypochlorous acid, a strong oxidant, which could damage spermatozoa. However, MPO presence and effects have never been investigated in equine semen. The first aim was to assay presence of MPO in equine thawed semen and to determine a relation between MPO concentration and post-thaw semen parameters. 35 straws from different stallions were analyzed. Post-thaw spermatozoa and MPO concentrations, viability, morphology, progressive and total motility were determined. Our study showed that thawed semen contains large amounts of free MPO. High MPO concentration samples showed lower total and progressive motility. Higher proportion of acrosome reaction was observed in late examinations of the high MPO concentration group. As MPO was present in frozen semen and did interfere with its quality, timing and origin of its release was determined during the freezing process. Forty ejaculates were frozen with a classical procedure. MPO ELISA and MPO immunocytochemistries (ICC) were assayed in raw semen, centrifugation supernatant, and after cooling down to 4°C. Post-thaw MPO concentration and spermogram parameters were determined. MPO concentration increased after cooling and thawing when compared to fresh semen. As temperature decreased, MPO was higher in post-thaw poor quality samples. Non-sperm cells (NSC) showed various degrees of MPO-ICC, and were mostly epithelial cells with nuclear picnosis. Elastase, another neutrophil pro-inflammatory enzyme, was also assayed in post-thaw semen. In twenty ejaculates, NSC concentration was determined in fresh semen. Post-thaw motilities were determined by CASA; MPO and elastase concentrations were assayed by ELISA. Post-thaw elastase concentrations were low and there was no difference according to semen quality. NSC or MPO concentrations were not correlated to elastase concentration. NSC concentration was higher in unfreezable semen and correlated to post-thaw MPO concentration. To confirm MPO release by NSC during freezing, the effect of washing semen with density gradient centrifugation (DGC) was then assayed on NSC and MPO concentrations. NSC and MPO concentrations were assessed at each step and MPO localization was performed by ICC. DGC washing decreased NSC and MPO concentrations in post-thaw semen and NSC were mainly remaining in DGC supernatant. MPO concentration was correlated with NSC concentration in the upper layer of the DGC supernatant and in post-thaw semen. NSC were epithelial cells showing MPO-ICC staining. Fresh semen MPO concentration had no effect on fresh or post-thaw semen quality, while post-thaw semen concentrations were correlated with decreased motility. To understand these findings, concentration, activity and structure of MPO present in seminal plasma, sperm-rich pellet and post-thaw semen were assayed. Factor inducing MPO release was determined by adding or not glycerol in samples stored at 4°C or 20°C. Total MPO was high in seminal plasma and thawed semen and low in sperm-rich pellet. Active MPO was high in sperm-rich pellet and low in seminal plasma and post-thaw semen. MPO concentrations were correlated in post-thaw and in semen cooled at 4°C with or without glycerol. Active MPO in sperm-rich pellet and post-thaw progressive motility were highly negatively correlated. MPO present in fresh semen is mainly the native inactive enzyme subunit. To confirm our previous findings, effect of active MPO and fresh or frozen-thawed NSC was assayed on purified spermatozoa motility, mitochondrial potential, membrane and acrosome integrity. Highest MPO concentration tested (50ng/ml) decreased motility. However, highest MPO concentration did not affect mitochondrial potential, membrane or acrosome integrity. Thawed NSC did decrease motility and mitochondrial potential when compared to fresh NSC, suggesting a synergic effect between MPO and other products released by NSC after thawing. Temperature decrease during freezing process increases MPO concentration and post-thaw concentration is negatively associated to post-thaw motilities. ICC slides have shown MPO presence on epithelial keratinized and pycnotic cells while neutrophils were rarely observed. Semen washing with DGC decreases MPO and NSC concentrations in post-thaw semen as NSC and MPO concentrations were positively correlated. MPO present in seminal plasma is native and inactive form while MPO present in sperm-rich pellet is active and negatively correlated to the post-thaw progressive motility. Addition of active MPO in semen decreased motility but had no effect on acrosome integrity, despite what had previously been suggested. Thawed NSC addition to spermatozoa decreased mitochondrial potential, suggesting a synergic effect between MPO and other factors released by NSC. Further studies should investigate the origin of high inactive MPO concentrations in fresh semen. Other studies should be conduced about the origin of epithelial keratinized pyknotic NSC in fresh semen and the pathophysiological mechanism leading to their MPO release during freezing. Large scale studies should be conducted to confirm the use of NSC concentration in fresh semen or active MPO concentration in sperm rich pellet as freezability prognosis. Further studies should also investigate effect of MPO specific inhibitors. [less ▲]

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See detailIntraocular Lenses with Functionalized Surfaces by Biomolecules in Relation with Lens Epithelial Cell Adhesion
Huang, Yi-Shiang ULg

Conference (2012, March 27)

A cataract is pathology opacity of the lens or capsule of the eye, causing impairment of vision or even blindness. In 1998, it was estimated that worldwide 19.4 million people were bilaterally blind from ... [more ▼]

A cataract is pathology opacity of the lens or capsule of the eye, causing impairment of vision or even blindness. In 1998, it was estimated that worldwide 19.4 million people were bilaterally blind from age-related cataract. Surgery, with lens extraction and intraocular lens implantation, is still the only currently available treatment. More than 1.3 million cataract operations were performed in the USA in 1998 at a cost of $3.5 billion. The most common complication after implantation of intraocular lenses (IOLs) is the posterior capsular opacification (PCO) or secondary cataract. This is the result of lens epithelial cells (LECs) proliferation and their transition to mesenchymal cells. In 1997, a Sandwich theory was proposed to elucidate the developmental process of PCO. According to this model, an IOL with higher affinity to LECs will induce a less PCO. In our research, the pHEMA (Poly(2-hydroxyethyl methacrylate)) based acrylic hydrophilic polymer is subjected to the surface modification by conjugating with the bioactive peptides. The RGD sequence, known for its excellent biocompatibility, is designed to stimulate the biointegration between the LECs and the polymer implant. Our research program will focus on the evaluation of the physical, mechanical and biological properties of the lens before and after peptide grafting. These diverse tests include contact angle measurements, Atomic Force Microscopy (AFM), x-ray photoelectron spectroscopy (XPS), FTIR/ATR, Scanning Electron Microscopy (SEM), and the MTS cytotoxicity assay. [less ▲]

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See detailL'accord institutionnel d'octobre 2011 et sa mise en oeuvre constitutionnelle et législative
Behrendt, Christian ULg

Conference given outside the academic context (2012)

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See detailRegard du G1000 sur les propositions de réformes de l'État belge d'écolo j et Jong Groen
Dodeigne, Jérémy ULg

Conference given outside the academic context (2012)

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See detailAbundance estimates of southern right whales (Eubalaena australis) in Bahía San Antonio, Patagonia, Argentina
Vermeulen, Els ULg; Cammareri, Alejandro

Poster (2012, March 27)

Aerial surveys were conducted to estimate the abundance of southern right whales in Bahía San Antonio, a bay located in the north-western region of the San Matías Gulf (40°50¿S 64°50¿W), Rio Negro ... [more ▼]

Aerial surveys were conducted to estimate the abundance of southern right whales in Bahía San Antonio, a bay located in the north-western region of the San Matías Gulf (40°50¿S 64°50¿W), Rio Negro, Patagonia Argentina. The transect for the realization of aerial surveys was designed using the program DISTANCE 6.0 and consisted out of 14 North-South (up to S 40.9°) parallel transect lines with a 2.5km separation, covering a total surface of 418km² (mean coverage probability=0.78). Transect length was chosen according to the safety restrictions of the pilot. Surveys were conducted in good weather conditions and calm sea state (Beaufort 3 or less) using a high-wing Cessna 152 with a flat window. Due to the small size of the aircraft, only one person could fly besides the pilot; observations where therefore made from one side only. Average speed and height of the aircraft was kept constant over the surveys at 90kn (166km/h) and 700ft (213m) respectively. When a group of southern right whales was sighted, data were taken on location (using a Garmin GPSmap 60csx), time and group size. The downward angle to the group perpendicular to the aircraft¿s track was then measured using a hand-held clinometer (Suunto PM5/360PC). Perpendicular distances were calculated by the means of trigonometry using the aircraft¿s altitude and the declination angle to the sighting. Due the flat windows of the aircraft a left truncation distance was set at 150m. Perpendicular distances were also right-truncated at 10% of the observations. The uniform cosine model was chosen in the view of the minimum AIC to model the detection function of southern right whales in the study area. The estimates of g(0)=(s+t)/(s+d) resulted in a correction factor of 0.392 ± 0.456 In total, 7 aerial surveys were conducted in the beginning of August and September 2009, September, October and November 2010, and August, September 2011, resulting in a total flight time effort of 12.4h. In total, 200 whales were seen in 119 whale groups, equally distributed over the entire bay. Group sizes ranged between 1-5 animals with a mean group size of 1.7 animals (SD=0.83). Results show a peak of averagely 136 ± 63 whales in the bay during the month of September, with less than half the amount of whales present in adjacent months. September being the peak month for right whale presence accords to data from other regions in the country. The aerial surveys resulted in the first estimates of southern right whale abundance in this north Patagonian bay and indicate a marked peak during September. Nevertheless, data obtained over the other months remain scarce. More aerial surveys should be conducted to accurately determine the evolution of southern right whale abundance in the study area. [less ▲]

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See detailMercury in blood of free-ranging seals Phoca vitulina from the North Sea: Time-trend and association with environmental factors
Das, Krishna ULg; Brochoire, Charlène ULg; Chambosse, Mélanie et al

Conference (2012, March 27)

The harbour seal (Phoca vitulina) population from the North Sea has experienced various fluctuations these last decades due to habitat loss, prey fluctuation and pollution of the marine environment ... [more ▼]

The harbour seal (Phoca vitulina) population from the North Sea has experienced various fluctuations these last decades due to habitat loss, prey fluctuation and pollution of the marine environment. Recently, development of monitoring programs and non-invasive sampling techniques, including seal catches allowed blood sampling on a regular basis together with measurements of blubber thickness, body mass, sex and body length. Concentrations of total mercury (T-Hg) and other trace elements (Cd, Pb, Zn, Cu, Fe) as well as ∂13C and ∂15N values were determined by mass spectrometry in blood of 75 wild harbour seals caught in the German Wadden Sea between 1997 and 2011. ∂13C and ∂15N mean values (-17.5‰ and 18.1 ‰ respectively) were strongly similar to that measured previously in the muscle of stranded harbour seals from the Wadden Sea. In contrast, ∂15N mean value was strikingly higher than that recorded in grey seals (Halichoerus grypus) from Scotland (14.1 ‰ respectively; Habran et al. submitted.) while ∂13C values remained similar between the two seal species. These values confirmed the high trophic position of the harbour seal in the North Sea. In contrast to Cd and Pb, T-Hg in blood harbour seals reached concentrations as high as 2.1 μg.g-1 dry weight (10 times higher than the 0.21 μg.g-1 dry weight recorded for grey seals from Scotland) but depended on several factors including ∂15N values, age group and the body mass. T-Hg was detected in juveniles confirming maternal transfer to offspring and time-trend revealed no decrease of T-Hg in blood of harbour seals these last 15 years. [less ▲]

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See detailEnergie et climat : historique et perspectives
Ozer, Pierre ULg

in La ville : air, eau, terre, feu. Éléments pour un Plan Régional de Développement Durable économe en ressources (2012)

On le sait, la Conférence de Copenhague a été un échec. En effet, quelques chefs d'Etat –à savoir les européens et américains pour le monde industrialisé– et la Chine, l'Inde, le Brésil et l'Afrique du ... [more ▼]

On le sait, la Conférence de Copenhague a été un échec. En effet, quelques chefs d'Etat –à savoir les européens et américains pour le monde industrialisé– et la Chine, l'Inde, le Brésil et l'Afrique du Sud pour les pays émergents ont doublé le processus de négociations des Nations Unies (dans l'obscurantisme le plus total et sans concertation avec les pays en développement) pour arriver à une note qui tient sur deux pages. Ce texte ne comporte plus de trace d'engagement de réduction de GES pour 2020 ou 2050, pas même volontaire. Une aide financière sera dégagée pour aider les pays pauvres à faire face aux conséquences du changement climatique. Quel sera le montant de cette aide ? Sera-t-elle additionnelle ou détournée des fonds d'aide au développement ? De qui viendra-t-elle et à qui profitera-t-elle ? Et pour quoi faire ? Nul ne le sait. Quant à la réduction de la déforestation et aux contraintes d'émissions de GES pour les secteurs aérien et maritime (annoncés comme des conditions sine qua non d'accord par les européens), pas un mot... Autant dire que le résultat final de ce grand rendez-vous n'est guère étincelant... Directement après ladite Conférence, j’écrivais dans une carte blanche « A quoi sert la science, si le politique se borne à cultiver, pour des raisons économiques dans le court terme, la science de l'inconscience ? » (Ozer 2010). Arriverons-nous à trouver un accord dans les mois ou les années à venir ? Ou devrons-nous subir brutalement les conséquences de ce changement climatique ? Car on peut négocier à l’infini entre délégations, mais on ne négociera jamais avec la physique de l’atmosphère. [less ▲]

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