Dark matter search and neutrino physics in Liquid Argon

Several astrophysical observations, both on a galactic and cosmological scales, showing that there’s a “missing mass” in the observable Universe, can be explained assuming a non-luminous kind of matter, hence called “dark matter”. One of the most promising candidates is the Weakly Interacting Massive Particle (WIMP), a non-relativistic massive particle, gravitationally and weakly interacting with baryonic matter. The present work is specifically focused on the physics potential besides WIMP search of dark matter detectors filled with Liquid argon, like DarkSide and DEAP-3600. Liquid argon is an optimal target thanks to its high scintillation and ionization yields. DEAP-3600 is a single-phase detector, exploiting the scintillation channel only, while DarkSide-20k and Argo, future tonne scale experiments from the DarkSide program, are dual-phase Time Projection Chambers (TPCs), looking at both scintillation and ionization signals. The large mass (3.3 tons) of the DEAP-3600 target has allowed me to perform an analysis to search for Multi Interacting Massive Particles (MIMPs), a dark matter candidate alternative to WIMPs, at masses above 10^{ 16} GeV and with argon-dark matter spin-independent cross-section of about 10^{ −22 }cm^{ 2} , fully setting up the upcoming unblinding of three years of data taking. Going from the present to the future dark matter detectors, DarkSide-20k and Argo will be characterized by an extraordinary sensitivity at low energy recoils. This is mainly consequence of the high energy resolution of the chosen photodetectors, Silicon Photomultipliers (SiPMs). Custom SiPMs have been designed for the dark matter search in DarkSide-20k; hence, SiPMs have been here characterized, with a focus on their correlated noises, namely afterpulses and optical crosstalks. The same sensitivity at low energy brings also to a strong potential in detecting supernova neutrinos via coherent elastic neutrino-nucleus scattering (CEvNS) in argon by exploiting the ionization signal. The related sensitivity study is here performed showing that the neutrino emission will be detected for any galactic supernova, with a good accuracy in reconstructing the main parameters of the burst, namely the total energy of neutrinos and their average energy

Models and algorithms for the empty container repositioning and its integration with routing problems

The introduction of containers has fostered intermodal freight transportation. A definition of intermodality was provided by the European Commission as “a characteristic of a transport system whereby at least two different modes are used in an integrated manner in order to complete a door-to-door transport sequence”. The intermodal container transportation leads to several benefits, such as higher productivity during handling phases and advantages in terms of security, losses and damages. However, the distribution of containers comes with a drawback: due to directional imbalances in freight flows, some areas tend to accumulate unnecessary empty containers, while others face container shortages. Several planning models were developed for carriers in order to manage both loaded and empty containers profitably. However, they were built to operate under normal circumstances, neglecting the fact that networks are increasingly affected by both uncertainty and vulnerability, which may result in disruptions. The thesis aims to survey whether the impact of uncertainty can be mitigated by a stochastic programming approach, in which disruptions and normal operations are both foreseen as possible futures or scenarios. This approach is carried out by a multi-scenario optimization model in which scenarios are linked by non-anticipativity conditions. The empty container repositioning becomes even more challenging and difficult when integrated with routing problems. In fact, carriers often face problems in which they must determine simultaneously how many empty containers are carried by a fleet of vehicles and which routes must be followed by these vehicles. These problems typically arise in inland networks, in which one must plan the distribution by trucks of loaded and empty containers to customers. The thesis addresses this type of vehicle routing problems, which are motivated by a real case study occurred during the collaboration with a carrier that operates in the Mediterranean Sea in door-to-door modality. The carrier manages a fleet of trucks based at the port. Trucks and containers are used to service two types of transportation requests, the delivery of container loads from the port to import customers, and the shipment of container loads from export customers to the port. The thesis addresses two problems which differ in the composition of the fleet of trucks. The first problem involves a heterogeneous fleet of trucks that can carry one or two containers. We present a Vehicle Routing Problem with backhauls, load splits into multiple visits, and the impossibility to separate trucks and containers during customer service. Then, we formalize the problem by an Integer Linear Programming formulation and propose an efficient meta-heuristic algorithm able to solve it. The meta-heuristic determines the initial solution by a variant of the Clarkeand-Wright algorithm, and improves it by several local search phases, in which both node movements and truck swaps are implemented. The second problem involves a homogeneous fleet of trucks that can carry more than a container. As a consequence, the identification of routes can be more difficult. We present and formalize the associated Vehicle Routing Problem by an Integer Linear Programming formulation. Then we propose an efficient adaptive guidance meta-heuristic algorithm able to solve it. The meta-heuristic determines an initial feasible solution by a Tabu Search step, and next improves this solution by appropriate adaptive guidance mechanisms

Metabolic syndrome and cardiovascular risk after liver transplantation: a single-center experience.

Excessive weight gain, hypertension, hyperlipidemia, and diabetes are frequently observed among orthotopic liver transplantation (OLT) patients. These alterations, which are probably multifactorial in origin, contribute to posttransplantation metabolic syndrome (PTMS), which increases the risk of cardiovascular events. We assessed the prevalence of PTMS (diagnosed according to modified NCEP Adult Treatment Panel III criteria) in 156 OLT patients undergoing regular follow-up after transplantation (median 68 months; range, 6 to 234 months). Several pre- and post-OLT data were collected to identify the factors associated with the presence of PTMS which was found in 28% of cases. The only independent predictive factors for PTMS were diabetes mellitus and patients who were overweight or obese before-OLT. The prevalence of PTSM was lower among patients on tacrolimus immunosuppression. In our population, 21% of patients showed a high cardiovascular risk score with a 4% incidence of cardiovascular events, which was higher among subjects with PTMS. Close follow-up is mandatory to prevent the development of PTMS mainly among overweight and diabetic patients before transplantation

Melatonin ultrastructural localization in mitochondria of human salivary glands

The hormone melatonin was initially believed to be synthesized exclusively by the pineal gland and the enterochromaffin cells, but nowadays its production and distribution were observed in several other tissues and organs. Among others, the ultrastructural localization of melatonin and its receptors has been reported in human salivary glands. In these glands, the fine localization of melatonin in intracellular organelles, above all in mitochondria, remains to be explored comprehensively. Bioptic samples of parotid and submandibular glands were treated to search for melatonin using the immunogold staining method by transmission electron microscopy. Morphometric analysis was applied to micrographs. The results indicated that, both in parotid and submandibular glands mitochondria, a certain melatonin positivity was present. Within glandular cells, melatonin was less retrieved in mitochondria than in secretory granules; however, its presence in this organelle was clearly evident. Inside striated duct cells, melatonin staining in mitochondria was more prominent than in glandular cells. Our data provide an ultrastructural report on the presence of melatonin in mitochondria of human major salivary glands and represent a fundamental prerequisite for a better understanding of the melatonin role in this organelle

An adaptive guidance meta-heuristic for the vehicle routing problem with splits and clustered backhauls

This paper presents the case study of an Italian carrier, Grendi Trasporti Marittimi, which provides freight transportation services by trucks and containers. Its trucks deliver container loads from a port to import customers and collect container loads from export customers to the same port. In this case study, all import customers in a route must be serviced before all export customers, each customer can be visited more than once and containers are never unloaded or reloaded from the truck chassis along any route. We model the problem using an Integer Linear Programming formulation and propose an Adaptive Guidance metaheuristic. Our extensive computational experiments show that the adaptive guidance algorithm is capable of determining good-quality solutions in many instances of practical or potential interest for the carrier within 10 min of computing time, whereas the mathematical formulation often fails to provide the first feasible solution within 3 h of computing time

Male and Female Mitochondria Respond Differently after Exercising in Acute Hypoxia

The use of hypoxic devices among athletes who train in normobaric hypoxia has become increasingly popular; however, the acute effects on heart and brain metabolism are not yet fully understood. This study aimed to investigate the mitochondrial bioenergetics in trained male and female Wistar rats after acute hypoxia training. The experimental plan included exercising for 30 min on a treadmill in a Plexiglas cage connected to a hypoxic generator set at 12.5% O2 or in normoxia. After the exercise, the rats were sacrificed, and their mitochondria were isolated from their brains and hearts. The bioenergetics for each complex of the electron transport chain was tested using a Clarktype electrode. The results showed that following hypoxia training, females experienced impaired oxidative phosphorylation through complex II in heart subsarcolemmal mitochondria, while males had an altered ADP/O in heart interfibrillar mitochondria, without any change in oxidative capacity. No differences from controls were evident in the brain, but an increased electron transport system efficiency was observed with complex I and IV substrates in males. Therefore, the study’s findings suggest that hypoxia training affects the heart mitochondria of females more than males. This raises a cautionary flag for female athletes who use hypoxic devices

Psychological and behavioral disease during developmental age: the importance of the alliance with parents

The aim of the study is to analyze the clinician’s alliance with parents during the diagnostic process in relation to therapeutic compliance and clinical evolution of individuals aged 0–11 years. The sample was formed by 84 individuals aged 0 to 11 years (18 < 6 years, 66 aged 6 to 11 years; 62 males and 22 females) who came to the Neuropsychiatric Unit for Children and Adolescents for a consultation regarding psychorelational and behavioral problems. Neuropsychiatric consultation took place in five diagnostic interviews with child and parents, separately. The last session was devoted to communication of psychiatric diagnosis (according to ICD 10) and therapeutic suggestions, if any. The clinician’s relationship with parents and patients’ participation were evaluated in terms of collaboration and quality of interaction, on the basis of pre-established criteria. Data about patients’ therapeutic compliance and clinical outcome were collected during a follow-up visit eight months after the last session. Results suggest that the better the alliance between parents and clinician, the higher the therapeutic compliance and the likelihood of a positive outcome for patients. Our data suggest that good communication with parents benefits child patients, both in terms of response to the parents’ need to report their children’s worrying behavior and as a response to the discomfort expressed by children when they come in for consultation