195 research outputs found

    Sandpile probabilities on triangular and hexagonal lattices

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    We consider the Abelian sandpile model on triangular and hexagonal lattices. We compute several height probabilities on the full plane and on half-planes, and discuss some properties of the universality of the model.Comment: 26 pages, 12 figures. v2 and v3: minor correction

    Multipoint correlators in the Abelian sandpile model

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    We revisit the calculation of height correlations in the two-dimensional Abelian sandpile model by taking advantage of a technique developed recently by Kenyon and Wilson. The formalism requires to equip the usual graph Laplacian, ubiquitous in the context of cycle-rooted spanning forests, with a complex connection. In the case at hand, the connection is constant and localized along a semi-infinite defect line (zipper). In the appropriate limit of a trivial connection, it allows one to count spanning forests whose components contain prescribed sites, which are of direct relevance for height correlations in the sandpile model. Using this technique, we first rederive known 1- and 2-site lattice correlators on the plane and upper half-plane, more efficiently than what has been done so far. We also compute explicitly the (new) next-to-leading order in the distances (r−4r^{-4} for 1-site on the upper half-plane, r−6r^{-6} for 2-site on the plane). We extend these results by computing new correlators involving one arbitrary height and a few heights 1 on the plane and upper half-plane, for the open and closed boundary conditions. We examine our lattice results from the conformal point of view, and confirm the full consistency with the specific features currently conjectured to be present in the associated logarithmic conformal field theory.Comment: 60 pages, 21 figures. v2: reformulation of the grove theorem, minor correction

    A New Marker on Chicken Hematopoietic Cells is Defined by a Monoclonal Antibody Raised Against a V ß Chain of the Human TCR

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    In this paper, we show that a mouse monoclonal antibody, 111-427, specific for the V ß 5.3 chain of the human T-cell receptor (TCR) for antigen, also reacts with chicken hematopoietic cells. Our data indicate that the majority of 111-427 positive cells among peripheral blood leucocytes (PBL) are thrombocytes. This antibody also recognizes two in vitro cell lines, III-C5, an IL-2-dependent T-cell-line and HD11, a macrophage cell line. In addition, erythrocytes and a minor subpopulation of thymus and spleen cells are also stained by the monoclonal antibody (mAb). No specific immunoprecipitation could be detected from 125I radiolabeled cell lysates. By Western blotting techniques, the 111- 427 mAb identifies a single band of apparent molecular weight 91 kD, unaffected by reduction, from III-C5 and HD11 cell lysates. This band is absent in negative cell control lysates. On thrombocytes, the apparent molecular weight of the band is shifted to 87 kD. These results indicate that the mAb does not recognize the chicken T-cell receptor for antigen, but a cell surface marker shared primarily between thrombocytes and erythrocytes. This new chicken cell marker is compared to other cell surface markers in avian or mammalian species that present some analogies in their tissue distribution

    Modeling recent uplift caused by decreased groundwater extraction and revealed by geodetic InSAR measurements in the Brussels area

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    peer reviewedRadar interferometry (InSAR) measurements have provided recent evidence of ground movements, particularly a slight uplift in north-western areas near the center of Brussels in response to changes in groundwater pumping and drainage. A 3D transient groundwater model is developed and calibrated to simulate the historical potentiometric head changes between 1970 and 2020. The corresponding water pressures are then transmitted to 1D vertical models coupling the vertical flow (and subsequent water pressure variations) with geomechanical swelling/consolidation calculations. The discretization of the 1D model is refined in the most compressible layers to obtain an accurate transient propagation of the water pressure changes and thus a better estimation of the swelling/consolidation values. The total uplift (or subsidence) is compared to the estimations obtained from the InSAR data processing. A detailed interpretation of such a comparison is not straightforward. Many factors and uncertainties can also play an important role in the estimated values from processing the InSAR measurements, as in the calculated values from the coupled hydrogeological-geotechnical models.LASUGEO: monitoring LAnd SUbsidence caused by Groundwater exploitation through gEOdetic measurements9. Industry, innovation and infrastructur

    A necessary step forward for proper non-energetic abiotic resource use consideration in life cycle assessment: The functional dissipation approach using dynamic material flow analysis data

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    The impact of non-energetic abiotic resource use in life cycle as- sessment (LCA) has been receiving much attention in the last decades, and even more so since the resource efficiency and circular economy have become prominent subjects of discussion in public and private sectors all around the world. As LCA has proven to be the most solid holistic tool to integrate environmental impacts in sustainability as- sessments of product systems, it should be able to integrate current concerns about non-energetic abiotic resource use into its methodology and therefore provide exploitable results for every LCA user. However, to this day no consensus has been reached on which approach for characterizing impacts due to the use of these resources should be used (Drielsma et al., 2016; Sonderegger et al., 2017). This seems to be at- tributable to the fact that no method is recognized as both solid on the methodological level while answering at the same time the true con- cerns for abiotic natural resource uses in LCA: the need to retain and therefore maximize their functional value in the technosphere after their extraction in order to fulfill the needs of current and future gen- erations, while minimizing the losses to the ecosphere. Indeed, abiotic resources are not always consumedBRGM ADEM

    Geomechanical modeling of the recent post-industrial uplift in Brussels and comparison with geodetic InSAR measurements

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    Radar interferometry (InSAR) measurements have provided recent evidence of ground movements, particularly a slight uplift in north-western areas near the center of Brussels in response to changes in groundwater pumping and drainage linked to decreased industrial activities within the city. Historical potentiometric head changes between 1970 and 2020 are translated in water pressures transmitted to 1D vertical models coupling the vertical flow (and subsequent water pressure variations) with geomechanical swelling/consolidation calculations. The discretization of the 1D model is refined in the most compressible layers to obtain an accurate transient propagation of the water pressure changes and thus a better estimation of the swelling/consolidation values. The total uplift (or subsidence) is compared to the estimations obtained from the InSAR data processing. A detailed interpretation of such a comparison is not straightforward. Many factors and uncertainties can also play an important role in the estimated values from the processing of the InSAR measurements, as in the calculated values from the coupled hydrogeological-geotechnical models.LASUGEO project—monitoring LAnd SUbsidence caused by Groundwater exploitation through gEOdetic measurements11. Sustainable cities and communitie

    The Ross procedure in young adults: over 20 years of experience in our Institution†

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    OBJECTIVES: The aim of this study was to evaluate the long-term outcomes following the Ross procedure in young adults in our institution. METHODS: All adult patients who received a Ross operation between 1991 and 2014 were included in the study. Survival analysis and regression analysis were performed. Survival of the Ross cohort was compared with the age-, gender- and calendar year-matched general population. RESULTS: Three hundred-and-six patients (mean age: 41.7 ± 9.7, male: 74.8%, bicuspid aortic valve: 58.5%, valve stenosis: 68%) were included in the analysis. There were 7 perioperative deaths (2.3%). Nine patients were lost to follow-up from hospital and completeness of the follow-up was 94%. The median follow-up of the remaining 290 patients was 10.6 years. There were 21 late deaths of which only 3 were valve-related. The overall survival at 15 years since surgery is 88 ± 3% that is comparable with the matched population. Freedom from valve-related deaths was 96.8 ± 2% at 16 years. Freedom from autograft and pulmonary homograft reoperation was 74.5 ± 4.3% at 16 years. Preoperative aortic regurgitation was the only significant predictor of autograft failure over time. Freedom from the combined end point of bleeding/thromboembolism/endocarditis/reoperation was 69.2 ± 4% at 16 years. Perioperative mortality following reoperation was 2.6% and the autograft could be spared in 72% of reinterventions. CONCLUSIONS: The Ross operation in young adults is associated with an excellent survival in the long term that is comparable with the general population. Although there is a risk of reoperation, incidence of other valve-related events is very low. The use of pulmonary autograft should be considered in any young adult patient requiring aortic valve replacement

    The role of annular dimension and annuloplasty in tricuspid aortic valve repair†

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    OBJECTIVES: Valve sparing reimplantation can improve the durability of bicuspid aortic valve repair compared with subcommissural annuloplasty, especially in patients with a large basal ring. This study analyses the effect of basal ring size and annuloplasty on valve repair in the setting of a tricuspid aortic valve. METHODS: From 1995 to 2013, 382 patients underwent elective tricuspid aortic valve repair. We included only those undergoing subcommissural annuloplasty, valve sparing reimplantation or no annuloplasty and in whom intraoperative transoesophageal echocardiography images were available for retrospective pre- and post-repair basal ring measurements (n = 323, subcommissural annuloplasty: 146, valve sparing reimplantation: 154, no annuloplasty: 23). In a subgroup of patients with available echocardiographic images, basal ring was retrospectively measured at the latest follow-up or prior to reoperation. subcommissural annuloplasty and valve sparing reimplantation were compared after matching for degree of aortic regurgitation and root size. RESULTS: All three groups differed significantly for most of preoperative characteristics. Hospital mortality was 0.9%. The median follow-up was 4.7 years. At 8 years, overall survival was 80 ± 5%. Freedom from reoperation and freedom from aortic regurgitation >1+ were 92 ± 5% and 71 ± 8%, respectively. In multivariate analysis, predictors of aortic regurgitation >1+ were left ventricular end-diastolic diameter (P = 0.003), cusp repair (P = 0.006), body surface area (P = 0.01) and subcommissural annuloplasty (P = 0.05). In subcommissural annuloplasty, freedom from aortic regurgitation >1+ was lower for patients with basal ring ≥28 mm compared with patients with basal ring 1+ was independent of basal ring size (P = 0.38). In matched comparison between subcommissural annuloplasty and valve sparing reimplantation, freedom from aortic regurgitation >1+ was not significantly different (P = 0.06), but in patients with basal ring ≥28 mm, valve sparing reimplantation was superior to subcommissural annuloplasty (P = 0.04). Despite similar intraoperative reduction in basal ring size in subcommissural annuloplasty and valve sparing reimplantation, patients with subcommissural annuloplasty exhibited greater increase in basal ring size during the follow-up compared with the valve sparing reimplantation group (P < 0.001). CONCLUSIONS: As with a bicuspid aortic valve, a large basal ring predicts recurrence of aortic regurgitation in patients with tricuspid aortic valve undergoing repair with the subcommissural annuloplasty technique. This recurrence is caused by basal ring dilatation over time after subcommissural annuloplasty. With the valve sparing reimplantation technique, large basal ring did not predict aortic regurgitation recurrence, as prosthetic-based circumferential annuloplasty displayed better stability over time. Stable circumferential annuloplasty is recommended in tricuspid aortic valve repair whenever the basal ring size is ≥28 mm

    Long-term Cross-reactivity Against Nonvaccine Human Papillomavirus Types 31 and 45 After 2- or 3-Dose Schedules of the AS04-Adjuvanted Human HPV-16/18 Vaccine

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    This analysis focused on long-term cross-reactive immunogenicity against nonvaccine human papillomavirus (HPV) types 31 and 45 following 2 doses of AS04-adjuvanted HPV-16/18 vaccine in girls aged 9-14 years or following 3 doses in women aged 15-25 years, for up to 3 years (HPV-070 study) and up to 5 years (HPV-048 study) after the first vaccination. Both schedules elicited antibodies against HPV-31 and HPV-45 up to 5 years after first dose. The antibody concentration was similar in young girls as compared to women. Specific CD4+ T-cell and B-cell responses to HPV-31 and HPV-45 at month 36 were similar across groups. Clinical trials registration: NCT01381575 and NCT00541970
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