Testing for equivalence: an intersection-union permutation solution

The notion of testing for equivalence of two treatments is widely used in clinical trials, pharmaceutical experiments,bioequivalence and quality control. It is essentially approached within the intersection-union (IU) principle. According to this principle the null hypothesis is stated as the set of effects lying outside a suitably established interval and the alternative as the set of effects lying inside that interval. The solutions provided in the literature are mostly based on likelihood techniques, which in turn are rather difficult to handle, except for cases lying within the regular exponential family and the invariance principle. The main goal of present paper is to go beyond most of the limitations of likelihood based methods, i.e. to work in a nonparametric setting within the permutation frame. To obtain practical solutions, a new IU permutation test is presented and discussed. A simple simulation study for evaluating its main properties, and three application examples are also presented.Comment: 21 pages, 2 figure

Biomonitoring survey of the hydrographical network in a MAB UNESCO Biosphere Reserve

The knowledge of microbial biodiversity (bacteria and protists) in aquatic ecosystems is far from complete. This is mainly due to the inadequacy of conventional taxonomic identifications, which are based on the discrimination of diacritical morphological traits. Further, investigations are mainly focused on specific lake and river typologies that are usually also of interest for economic exploitation, often disregarding the small and/or ephemeral water bodies. Nevertheless, due to their physiographical complexity and temporal dynamics, these neglected hydrographical elements can host a vast microbial diversity. In order to fill the gap in the biodiversity estimates in the Alpine region, we carried out a survey using high throughput sequencing (HTS) of 16S and 18S rDNA markers from water and sediments collected in the MAB UNESCO Alpi Ledrensi and Judicaria Biosphere Reserve (Project Acqua Viva). The study sites are located between Lake Garda and the Brenta Dolomites, and include natural environments in a semi- anthropized Alpine context with agricultural and tourist vocation. The survey was carried out during the summer 2019, covering 20 sites of different sizes and characteristics, including lakes, alpine pasture ponds and wetlands. The results allowed disclosing a high number of amplicon sequence variants (ASVs) belonging to a wide variety of bacterial and protists groups, and significant differences linked to lake and sample typologies. Despite a wide presence of potentially toxigenic cyanobacteria, microcystins and anatoxin-a were detected only in a few water bodies, including Lake Ledro, which showed the presence of both Planktothrix rubescens and Tychonema bourrellyi in the pelagic samples

A comparison of efficient permutation tests for unbalanced ANOVA in two by two designs--and their behavior under heteroscedasticity

We compare different permutation tests and some parametric counterparts that are applicable to unbalanced designs in two by two designs. First the different approaches are shortly summarized. Then we investigate the behavior of the tests in a simulation study. A special focus is on the behavior of the tests under heteroscedastic variances.Comment: 20 pages, 9 figures, Working Paper of the Department of Management And Enigineering of the University of Padov

Expansion of cyanobacteria outbreaks in the Alpine region: first report of an intense Microcystis bloom in Lake Serraia

Lake Serraia is a small eutrophic dimictic lake located in the town of Baselga di Pinè, in the Province of Trento. The lake has an average depth of 7 m and a maximum depth of 18 m and is mainly used for recreational activities. During the last decade, summer blooms of non-toxigenic populations of Dolichospermum spp. were documented over the entire lake. Conversely, at the end of August 2023, an intense toxigenic bloom of Microcystis aeruginosa developed over several weeks, resulting in a bathing ban by the local authorities. Besides the usual monitoring for the control of bathing waters, a few opportunistic samples were collected for microscopical examinations, toxins analyses using LC-MS techniques, and strain isolation and cultivation. In the areas where the surface scums developed, the MC-LR and MC-RR congeners of microcystins showed concentrations of 200 μg L-1 and 42 μg L-1, respectively. The bloom episodes documented in Lake Serraia are part of a more general increasing trend of cyanobacterial outbreaks actively documented in the southern Alpine region. Besides persisting high trophic status, as in Lake Serraia, the causes were also connected to the general increasing temperature trends at the global and local levels

Active shape correction of a thin glass/plastic X-ray mirror

Optics for future X-ray telescopes will be characterized by very large aperture and focal length, and will be made of lightweight materials like glass or plastic in order to keep the total mass within acceptable limits. Optics based on thin slumped glass foils are currently in use in the NuSTAR telescope and are being developed at various institutes like INAF/OAB, aiming at improving the angular resolution to a few arcsec HEW. Another possibility would be the use of thin plastic foils, being developed at SAO and the Palermo University. Even if relevant progresses in the achieved angular resolution were recently made, a viable possibility to further improve the mirror figure would be the application of piezoelectric actuators onto the non-optical side of the mirrors. In fact, thin mirrors are prone to deform, so they require a careful integration to avoid deformations and even correct forming errors. This however offers the possibility to actively correct the residual deformation. Even if other groups are already at work on this idea, we are pursuing the concept of active integration of thin glass or plastic foils with piezoelectric patches, fed by voltages driven by the feedback provided by X-rays, in intra-focal setup at the XACT facility at INAF/OAPA. In this work, we show the preliminary simulations and the first steps taken in this project

Design and advancement status of the Beam Expander Testing X-ray facility (BEaTriX)

The BEaTriX (Beam Expander Testing X-ray facility) project is an X-ray apparatus under construction at INAF/OAB to generate a broad (200 x 60 mm2), uniform and low-divergent X-ray beam within a small lab (6 x 15 m2). BEaTriX will consist of an X-ray source in the focus a grazing incidence paraboloidal mirror to obtain a parallel beam, followed by a crystal monochromation system and by an asymmetrically-cut diffracting crystal to perform the beam expansion to the desired size. Once completed, BEaTriX will be used to directly perform the quality control of focusing modules of large X-ray optics such as those for the ATHENA X-ray observatory, based on either Silicon Pore Optics (baseline) or Slumped Glass Optics (alternative), and will thereby enable a direct quality control of angular resolution and effective area on a number of mirror modules in a short time, in full X-ray illumination and without being affected by the finite distance of the X-ray source. However, since the individual mirror modules for ATHENA will have an optical quality of 3-4 arcsec HEW or better, BEaTriX is required to produce a broad beam with divergence below 1-2 arcsec, and sufficient flux to quickly characterize the PSF of the module without being significantly affected by statistical uncertainties. Therefore, the optical components of BEaTriX have to be selected and/or manufactured with excellent optical properties in order to guarantee the final performance of the system. In this paper we report the final design of the facility and a detailed performance simulation.Comment: Accepted paper, pre-print version. The finally published manuscript can be downloaded from http://dx.doi.org/10.1117/12.223895

Soft Tissue Reconstruction of the Posterior Trunk after Tumor Excision: A Surgical Algorithm

Background: The posterior trunk has been considered a challenging area to reconstruct following soft tissue tumor excision because of the shortage of local donor sites. The advent of innovative procedures such as perforator flaps has radically changed this perspective and offered a new approach to the problem. Methods: Upon a review of the literature and the personal experiences of the senior author, an algorithm is developed according to the most updated procedure, combined with more conventional options that maintain a role in decision-making. Results: The upper back latissimus dorsi and trapezium flap are still the most reliable approaches, while perforator flaps based either on the circumflex scapular arteries or the transverse cervical artery represent a more refined option. In the middle third, few indications remain for the reverse latissimus dorsi, while the gold standard is represented by local perforator flaps based on the posterior intercostal system. In the lower back, conventional VY advancement flaps are still a safe and effective option in the sacral area, and perforator flaps based on posterior intercostal arteries, lumbar arteries and superior gluteal arteries are the first choice in most cases. Conclusions: Using perforator flaps significantly improved soft tissue reconstruction in the posterior trunk