Doubts on the efficacy of outliers correction methods

While the utilisation of different methods of outliers correction has been shown to counteract the inferential error produced by the presence of contaminating data not belonging to the studied population; the effects produced by their utilisation when samples do not contain contaminating outliers are less clear. Here a simulation approach shows that the most popular methods of outliers correction (2 Sigma, 3 Sigma, MAD, IQR, Grubbs and winsorizing) worsen the inferential evaluation of the studied population in this condition, in particular producing an inflation of Type I error and increasing the error committed in estimating the population mean and STD. We show that those methods that have the highest efficacy in counteract the inflation of Type I and Type II errors in the presence of contaminating outliers also produce the stronger increase of false positive results in their absence, suggesting that the systematic utilisation of methods for outliers correction risk to produce more harmful than beneficial effect on statistical inference. We finally propose that the safest way to deal with the presence of outliers for statistical comparisons is the utilisation of non-parametric test

Numerical studies of a negative ion beam and of a tomographic beam diagnostic

ITER is the first reactor-scale scientific experiment that aims to demonstrate the scientific and the technological feasibility of fusion energy. It is based on the tokamak concept of magnetic confinement, in which the fuel, a mixture of deuterium and tritium heated to temperatures in excess of 150 million degrees Celsius, is contained in a toroidal vacuum chamber. Among the systems used to reach such high temperature range, a fundamental role is played by the injection of intense beams of neutral particles into the plasma, which is consequently heated by collisions. This process is realized by means of two Neutral Beam Injectors (NBIs), capable of delivering to the plasma a power of 16.7 MW each. These devices are mainly composed of a negative deuterium ion source, an electrostatic accelerator where a 40 A beam of negative deuterons will be accelerated to 1 MV and a neutralizer which converts part of the beam into high energy neutrals able to penetrate the high magnetic field confining the ITER plasma. The ITER requirements for these devices have never been simultaneously achieved so far in a full scale, full performance device and therefore a neutral beam test facility is being constructed at Consorzio RFX in Padova. The research activity presented in this thesis work is in the framework of the development of the negative ion source (SPIDER) and full injector (MITICA) prototypes for the ITER neutral beam. In particular, it is focused on two main topics: particle transport studies inside the MITICA accelerator and the development of a tomographic beam diagnostic. A proper modeling of the particle transport inside the MITICA accelerator, considering the main processes that generate secondary particles relevant for the evaluation of the heat loads on the accelerator grids is essential for the thermo-mechanical analysis and the mechanical design of the accelerator. For this reason an upgrade of the relativistic particle tracking code called EAMCC has been undertaken and the simulations performed for evaluating the thermal power deposited on the MITICA accelerator grids are presented in the first part of the present thesis work. For the first time, an entire source called NIO1 installed at RFX and made of nine beamlets has been simulated in EAMCC considering multi-beamlet effects which were neglected earlier and discarding the axis-symmetry hypothesis of the electric fields imposed by the original version of the code. Results obtained, also presented in the first part, will be used for benchmarking the modifications introduced in the code. The second part of the thesis is dedicated to beam tomography, an important diagnostic for the assessment of the density profile of the beam. A tomography code based on algebraic reconstruction techniques has been developed and numerically tested. Beam emissivity profiles considered for testing the code are calculated by the upgraded version of EAMCC. The tomography code has been developed with the aim of realizing a versatile instrument, applicable to linear accelerators as well as to a tokamak and without adding any hypotheses about the beam characteristics or the emissivity in a particular region of the tomography plane, not to limit the capability of the code of detecting irregularities in the beam profiles. The effects of the instrumental noise on tomography reconstructions have also been studied and, in order to reduce its impact, different filtering techniques have been considered both in the frequency and in the spatial domain, demonstrating the feasibility to filter out the effect of the noise by post-processing the reconstructed image of the bea

Short length-scale variability of hybrid event beds and its applied significance

Hybrid event beds (HEBs) are a type of deep-water sediment gravity flow deposit that generally comprise a basal clean sandstone overlain by a variety of muddier and less-permeable sandy facies. They are thought to be emplaced by combinations of turbidity currents, transitional flows and debris flows, all as part of the same transport event. To date, a number of studies have highlighted the common presence of HEBs mainly in the outer and marginal parts of deep-water systems where they replace beds composed dominantly of clean sand up-dip and/or axially over scales of km to 10s km. In addition to these broad patterns, important yet poorly understood short-length facies changes (over metres to 100s m) occur, modifying the overall texture and reservoir characteristics at or beneath typical spacing of production wells. The nature and origin of the short length-scale transitions is here addressed in four well-exposed HEB-prone outcrops: the Cretaceous-Paleocene Gottero Sandstone and the Miocene Cilento Flysch, both in Italy, the Carboniferous Mam Tor Sandstone in northern England, and the Carboniferous basal Ross Sandstone Formation, Western Ireland. A series of detailed correlation panels show marked lateral variations in internal bed make-up for most of the hybrid event beds studied. This variability typically involves lateral changes in the proportions of the cleaner basal sandstone and the overlying muddy sandstone division that occur without substantial change in the overall event bed thickness. The variability is inferred to reflect the complex fingering between the up-dip sandstone-dominated part of the event bed and the down-dip linked debrite due to internal erosion (ploughing) of the debrite into the basal clean sand. Where the upper part of the bed is dominated by large mudstone rafts, these may have foundered into liquefied sand and been injected and partly fragmented by the sand intrusions. The variable thickness and continuity of the basal clean sandstones have important implications for reservoir characterisation; significant variability in bed character at interwell scale can be anticipated. Rugose contacts between the intra-bed facies divisions may impact on drainage and sweep efficiency during hydrocarbon production

Mandatos y consejos en la filosofía práctica moderna

This paper addresses the traditional distinction between commands and advices in modern practical philosophy as doctrine of duties. The distinction plays an essential role in Christian Thomasius' thought for his differentiation between distinct spheres of practical life, iustum, honestum and decorum, i. e. the spheres of law (iustum), proper ethics (honestum) and incoercible external behaviour – with ethical meaning –, including good manners (decorum). In Kant's practical philosophy, the distinction between commands and counsels corresponds to the distinction between morality and prudence as pursuit of happiness. Moral life is ruled by moral law and by the idea of duty, that organizes in its own perspective the other aspects of practical activity and the different kinds of duties. As time passed, Kant is more and more interested to the historical realization of morality as Moralisierung through promotion of its external conditions such as pacific coexistence through the juridical law and improvement of intersubjective relations through Zivilisierung and good manners. Kant's and eighteenth century's doctrine of duties leave no space for a morality beyond duty as supererogation, a concept that has received a new attention in contemporary moral debate and can still be discussed in a Kantian perspective.Este artículo trata de la distinción entre órdenes y consejos en la filosofía práctica moderna como doctrina de deberes. La distinción juega un papel esencial en el pensamiento cristiano de Thomasius por su diferenciación entre las distintas esferas de la vida práctica, iustum, honestum y decorum, por ejemplo, las esferas de la ley (iustum), ética correcta (honestum) e incoercible comportamiento externo —con significado ético—, incluyendo las buenas maneras (decorum). En la filosofía práctica de Kant, la distinción entre mandatos y consejos corresponde a la distinción entre moralidad y prudencia como búsqueda de la felicidad. La vida moral está regida por la ley moral y por la idea del deber, que organiza en su propia perspectiva los otros aspectos de la actividad práctica y los diferentes tipos de deberes. Según pasó el tiempo, Kant estaba cada vez más interesado en la realización histórica de la moralidad como Moralisierung a través de la promoción de sus condiciones externas como la coexistencia pacífica a través de la ley jurídica y el desarrollo de las relaciones intersubjetivas a través de Zivilisierung y buenas maneras. La doctrina de los deberes de Kant y del siglo dieciocho no deja espacio para una moralidad más allá del deber como supererogation, un concepto que ha recibido una nueva atención en el debate contemporáneo moral y puede seguir siendo discutido en una perspectiva kantiana

Effetti della siccità sull'abbondanza e distribuzione dei macroinvertebrati

The role of disturbance on structuring animal communities is a central subject in the ecological research. In particular in the intermittent systems river, the drought event seems to determine the macroinvertebrate community structure. In such context, we analysed the macrobenthos of a Sardinia intermittent stream (Rio Pula, Cagliari). The study was carried out on 16 sites in 3 years (from 2000 to 2002) with seasonal samplings (spring and autumn) of the macroinvertebrate community. The results have shown a temporal stability of community and a spatial change of community structure along the river basin determined by drought frequency. Finally, patterns of spatial change in the guild composition seem to be partly in contrast with the River Continuum concept

Hybrid Event Beds Generated By Local Substrate Delamination On A Confined-Basin Floor

The outer parts of deep-water fans, and the basin plains into which they pass, are often described as areas where erosion is negligible and turbidite systems have net aggradation. Nevertheless sedimentological and stratigraphic analysis of outer fan lobe and confined basin plain deposits in Cretaceous-Paleocene Gottero Sandstone (NW of Italy) has revealed extensive but cryptic bedding-parallel substrate-delamination features at the base of many sheet-like event beds. These comprise a variety of shallow but wide scour structures showing evidence of lateral expansion by sand-injection. The scours commonly occur at the base of beds made up of a basal clean sandstone overlain by argillaceous sandstone containing abundant mudstone clasts and locally large substrate rafts (up to 20 meters long). These strata are interpreted as a type of hybrid event bed. Field observations suggest that mud-clast entrainment occurred by delamination at the base of dense sandy flows. The large rafts, in some cases only partly detached, were incorporated in the flows locally and then carried for short distances (100s m to a few km) before partly disaggregating and undergoing deformation due to internal shearing. The development of such features may be common in flat and/or confined basin settings where high-volume flows interact with a cohesive and well layered substrate (e.g. muddy outer fans or confined or ponded basins with thick mudstone caps). Delamination is therefore suggested as an alternative mechanism leading to the formation of hybrid event beds following local substrate entrainment on the basin floor as opposed to on more remote slopes and at channel-lobe transition zones

Facies and architecture of a sand-rich turbidite system in an evolving collisional-trench basin: a case history from the upper Cretaceous-Palaeocene Gottero system (Nw apennines)

This study documents the main depositional elements of a dynamically-controlled sand-rich deep-water turbidite system (Upper Cretaceous\u2013Palaeocene Gottero system, north-west Italy). The large exposures and the wide range of facies and deep-water sub-environments recognised, ranging from proximal channels, unconfined proximal and distal lobes and confined basin plain deposits make this an instructive case study to investigate the spatial-temporal relationships between fan features (channels and lobes) and confined to ponded basin-plain deposits developed in a trench-fill basin. The study focus on stratigraphic and palaeo-environmental reconstruction of the Gottero system in the western sector of the basin. Bed types, facies associations and depositional sub-environments are described in main outcrop locations and used to feed a comprehensive bed-scale database. A coherent stratigraphic framework of the system is proposed for the first time, linking its stratigraphic evolution with the collisional-trench context of the Ligurian units during the Upper Cretaceous-Palaeocene. It includes a first stage in which the Gottero was a prograding extensive basin-floor fan developed in a relatively unconfined setting (Gottero 1 and 2), and a second stage in which the system deepens and got progressively confined and segmented in multiple distal depocentres, dominated by sheet-like high magnitude events, meanwhile the proximal area forms a series of fan elements which display an overall retrograding trend (Gottero 3). The basin fill terminates with the deposition of the Giaiette mass-transport complex interepreted to represent the final collapse of the growing Ligurian accrectionary wedge

The preparation of the Shutdown Dose Rate experiment for the next JET Deuterium-Tritium campaign

The assessment of the Shutdown Dose Rate (SDR) due to neutron activation is a major safety issue for fusion devices and in the last decade several benchmark experiments have been conducted at JET during Deuterium-Deuterium experiments for the validation of the numerical tools used in ITER nuclear analyses. The future Deuterium-Tritium campaign at JET (DTE2) will provide a unique opportunity to validate the codes under ITER-relevant conditions through the comparison between numerical predictions and measured quantities (C/E). For this purpose, a novel SDR experiment, described in the present work, is in preparation in the frame of the WPJET3-NEXP subproject within EUROfusion Consortium. The experimental setup has been accurately designed to reduce measurement uncertainties; spherical air-vented ionization chambers (ICs) will be used for on-line ex-vessel decay gamma dose measurements during JET shutdown following DT operations and activation foils have been selected for measuring the neutron fluence near ICs during operations. Active dosimeters (based on ICs) have been calibrated over a broad energy range (from about 30 keV to 1.3 MeV) with X and gamma reference beam qualities. Neutron irradiation tests confirmed the capability of active dosimeters of performing on-line decay gamma dose rate measurements, to follow gamma dose decay at the end of neutron irradiation as well as insignificant activation of the ICs