Spatial surface-pattern analyses and boundary detection techniques applied in forest ecology

[EN] We review methods for uni- and multivariate surface pattern analysis and boundary detection used in forest ecology. A continuous surface pattern is defined as the locations of points (trees) in the space and the associated variable or variables. We illustrate useful methods to describe spatial patterns and infer the generating processes. We show the statistical basis and applied examples of univariate methods for binary (join counts) and quantitative variables (Moran and Geary correlograms, semivariograms, fractal dimension). We explain the calculus and interpretation of multivariate methods to describe surface patterns (Mantel test and correlogram) and their relationships with ordination methods. Finally, we show examples of techniques for boundary detection. Most analysed patterns corresponded to Pinus uncinata forests from the upper altitudinal limit in the Pyrenees or from a relict population. We discuss the advantages and disadvantages of each methodology and their applications in forest ecology.[ES] En este trabajo se revisan los métodos de análisis univariable y multivariable de los patrones de superficies y de detección de fronteras más utilizados en ecología forestal. El patrón de superficies es un patrón espacial continuo definido por las posiciones de los puntos (árboles) en el espacio y una o varias variables asociadas a cada punto. Se ilustran métodos útiles para describir patrones espaciales e inferir los procesos que los generaron. Se muestra el fundamento estadístico y ejemplos aplicados de métodos de análisis univariables para variables binarias (conteo contiguo) y cuantitativas (correlogramas de Moran y Geary, semivariogramas, dimensión fractal). Se detalla el cálculo e interpretación de métodos multivariables para la descripción de patrones de superficies (correlograma y test de Mantel) y su relación con los métodos de ordenación. Finalmente, se muestran ejemplos de métodos para la detección de fronteras. La mayor parte de los patrones reales analizados provienen de bosques de Pinus uncinata del límite altitudinal superior en los Pirineos o bien de una población relíctica. Se discuten las ventajas y desventajas de cada metodología y sus aplicaciones en ecología forestal.Los datos de Vinuesa se obtuvieron en el proyecto AMB95-0160 (CICyT).Peer reviewe

Design and analysis of cross vaults along history

The history of cross vaults began almost 2,000 years ago with a widespread use during the Middle Ages and Renaissance, becoming nowadays one of the most diffused and fascinating structural typologies of the European building cultural heritage. However, conversely to the undeniable excellence achieved by the ancient masons, the structural behavior of these elements is still at the center of the scientific debate. In this regard, with the aim of reviewing the knowledge on this subject as a concise and valuable support for researchers involved in conservation of historical buildings, with a focus on design rules and structural analysis, the present study firstly introduces the cross vaults from a historical perspective, by describing the evolution of the main geometrical shapes together with basic practical rules used to size them. Then, the article deals with the subsequent advancements in structural analysis methods of vaults, until the development of modern limit analysis.This work was partially carried out under the program "Dipartimento di Protezione Civile - Consorzio RELUIS", signed on 2013-12-27.info:eu-repo/semantics/publishedVersio

The Swiss bryophyte collection of Paul Frédéric Culmann (1860 –1936) in Zurich

The Swiss bryophyte collection of Paul Culmann in the herbarium Zurich (acronym: Z) has been digitalised and the data are now stored in a relational database. The collection contains 12,536 specimens with detailed information on locality, altitude, collecting date, and ecology. The specimens were collected between 1876 and 1923. They belong to 756 taxa, which is 69 % of the taxa known today from Switzerland. From a systematic point of view they well represent the Swiss bryophyte flora, as nearly all families are covered and there is no bias on either liverworts or mosses. Geographically, the data are less even distributed, because Paul Culmann collected preferentially in two regions: the canton of Zurich and the “Berner Oberland” (southern, alpine part of the canton of Bern). Therefore, many of his specimens are from higher altitudes, whereas lower regions are underrepresented. Despite the uneven geographical distribution, the data are a most valuable source for analysis of changes in the bryophyte flora of Switzerland

Revision of encapsulated blebs after trabeculectomy: Long-term comparison of standard bleb needling and modified needling procedure combined with transconjunctival scleral flap sutures.

To compare two surgical approaches for treating encapsulated blebs after trabeculectomy with mitomycin C, in terms of the development of intraocular pressure and progression of glaucoma in a long-term follow up: 1. bleb needling alone vs. 2. a combined approach of needling with additional transconjunctival scleral flap sutures, to prevent early ocular hypotony.Forty-six patients with failing blebs after trabeculectomy with mitomycin C were enrolled in this study. Patients received either needling revision alone (group 1; n = 23) or a combined needling with additional transconjuctival flap sutures, if intraoperatively the intraocular pressure was estimated to be low (group 2; n = 23). Intraocular pressure (IOP), visual acuity, visual fields, and optic nerve head configuration by means of Heidelberg Retina Tomograph (HRT®) were analysed over time. Results from both groups were compared using Mann-Whitney U-test for single timepoints.IOP did not differ significantly between the two groups during follow-up at three months (P = 0.13), six months (P = 0.12), one year (P = 0.92) and two years (P = 0.57) after surgery. Furthermore, there was no significant difference in the course of glaucoma concerning the optic nerve anatomy between the two groups (Rim Area Change in the Moorfields Regression Analysis of HRT®) till two years after surgery (P = 0.289). No functional impairment in visual acuity and visual fields was found in the groups of the study.Single needling procedure is a standard successful method for restoring the function of encapsulated blebs. Postoperative hypotony represents a possible hazard, which can be minimized by additional transconjunctival flap sutures. Long-term results suggest that this modification is equally effective in lowering the IOP and preventing the progression of glaucoma as the standard needling procedure. To our knowledge this is the first study to investigate the long-term effect of tranconjunctival sutures for the prevention of hypotony

Differentiation between active and chronic Crohn's disease using MRI small-bowel motility examinations — Initial experience

AIM: To evaluate the influence of locally active Crohn's disease on systemic small-bowel motility in patients with chronic Crohn's disease compared to healthy individuals. MATERIAL AND METHODS: Fifteen healthy individuals (11 men, four women; mean age 37 years) and 20 patients with histopathologically proven active (n = 15; 10 women, 5 men; mean age 45 years) or chronic (n = 5; four women, one man; mean age 48 years) Crohn's disease were included in this institutional review board-approved, retrospective study. Magnetic resonance imaging (MRI; 1.5 T) was performed after standardized preparation. Two-dimensional (2D) cine sequences for motility acquisition were performed in apnoea (27 s). Motility assessment was performed using dedicated software in three randomly chosen areas of the small-bowel outside known Crohn's disease-affected hotspots. The main quantitative characteristics (frequency, amplitude, occlusion rate) were compared using Student's t-test and one-way analysis of variance (ANOVA). RESULTS: Three randomly chosen segments were analysed in each participant. Patients with active Crohn's disease had significantly (p < 0.05) reduced contraction frequencies (active Crohn's disease: 2.86/min; chronic: 4.14/min; healthy: 4.53/min) and luminal occlusion rates (active: 0.43; chronic: 0.70; healthy: 0.73) compared to healthy individuals and patients with chronic Crohn's disease. Contraction amplitudes were significantly reduced during active Crohn's disease (6.71 mm) compared to healthy participants (10.14 mm), but this only reached borderline significance in comparison to chronic Crohn's disease (8.87 mm). Mean bowel lumen diameter was significantly (p = 0.04) higher in patients with active Crohn's disease (16.91 mm) compared to healthy participants (14.79 mm) but not in comparison to patients with chronic Crohn's disease (13.68). CONCLUSION: The findings of the present study suggest that local inflammatory activity of small-bowel segments in patients with active Crohn's disease alters small-bowel motility in distant, non-affected segments. The motility patterns revealed reduced contraction-wave frequencies, amplitudes, and decreased luminal occlusion rates. Thus evaluation of these characteristics potentially helps to differentiate between chronic and active Crohn's disease

Courses of the intraocular pressure (A), visual acuity (B), mean deviation (C) and pattern standard deviation (D) for two years after the bleb revision in both study groups.

<p>The group, which received single needle procedure, is shown in blue, while the group, which received a combined procedure of needling with transconjunctival scleral flap sutures, is shown in red.</p

Intraocular pressure (A), visual acuity (B), mean deviation (C) and pattern standard deviation (D) in the visual fields examination before bleb revision and at specific time points within the following two years in both study groups.

<p>Results are presented as means with standard deviation. P values for the comparison between the study groups are also shown.</p