Mirror Symmetry and smoothing Gorenstein toric affine 3-folds

We state two conjectures that together allow one to describe the set of smoothing components of a Gorenstein toric affine 3-fold in terms of a combinatorially defined and easily studied set of Laurent polynomials called 0-mutable polynomials. We explain the origin of the conjectures in mirror symmetry and present some of the evidence.Comment: 23 pages, 6 figures. The paper has been submitted to "Facets of Algebraic Geometry: A Volume in Honour of William Fulton's 80th Birthday

Impact of Percutaneous Transluminal Intervention on Vascular Hypoxia and the Role of Micro-calcifications on Atherosclerotic Plaque Rupture

Atherosclerotic disease is initiated by cholesterol build-up beneath the endothelium, which evolves into a fibroatheroma, a lipid-rich plaque covered by a fibrous cap. Many of these plaques are considered as vulnerable, as they grow to occlude the luminal section of the artery (chronically stenotic) or become mechanically unstable with a higher chance of rupturing (rupture-prone). On one hand, chronically stenotic vulnerable plaques are symptomatic lesions that are often treated with Percutaneous Transluminal Intervention (PTI). Unfortunately, approximately 10% of PTI procedures are followed by severe Neointima Hyperplasia (NH), which causes a new occlusion and failure of the implant. A significant precursor of NH appears to be PTI-induced vascular hypoxia, but the reason for this drop in oxygen tension remains unclear. On the other hand, rupture-prone vulnerable plaques are predominantly asymptomatic and remain silent until the fibrous cap ruptures under the action of blood pressure, triggering a sudden, severe clinical event such as myocardial infarction or stroke. The stability of the fibrous cap is crucial to assess the vulnerability of a plaque, but a thorough characterization of the factors that compromise its mechanical integrity has yet to be defined. In this dissertation, we first explored Vasa Vasorum (VV) compression after PTI as the root cause of vascular hypoxia and then analysed the effect of micro-calcifications (µCalcs) as a high-risk indicator of plaque vulnerability. To achieve this, we combined numerical simulations on idealized and ex-vivo human coronary arteries, high-resolution imaging modalities, the development of a micro-material tensile machine, characterization of arterial tissues mimicking materials, and mechanical testing of fibrous caps laboratory models. Overall, we found that PTI significantly deforms the VV network that perfuses the artery, with levels of compressions that depend on the location of the branches and the degree of stent expansion. The VV that are squeezed the most experience major fold-increases in hydraulic resistance, which could lead to vascular hypoxia, followed by NH. We demonstrated that the presence of one spherical µCalc in the cap tissue is the most influential factor of plaque vulnerability together with the cap thickness. The µCalc-induced stress amplification at the particle tensile poles can transform a stable human coronary atheroma into a rupture-prone lesion. The same effect is also observed in fibrous cap laboratory models containing hard solid micro-beads (µBeads). When the µBeads -to-cap model size ratio reaches a critical point, the material starts experiencing early rupture, with a reduction in ultimate strength that is positively correlated with the µBeads diameter. Additionally, closely spaced µBeads further compromise the mechanical stability of the fibrous cap phantoms, validating previous analytical and numerical studies that showed an exponential increase in stresses between close pairs of µCalcs

A metrological characterization of the Kinect V2 time-of-flight camera

A metrological characterization process for time-of-flight (TOF) cameras is proposed in this paper and applied to the Microsoft Kinect V2. Based on the Guide to the Expression of Uncertainty in Measurement (GUM), the uncertainty of a three-dimensional (3D) scene reconstruction is analysed. In particular, the random and the systematic components of the uncertainty are evaluated for the single sensor pixel and for the complete depth camera. The manufacturer declares an uncertainty in the measurement of the central pixel of the sensor of about few millimetres (Kinect for Windows Features, 2015), which is considerably better than the first version of the Microsoft Kinect (Chow et al., 2012 [1]). This work points out that performances are highly influenced by measuring conditions and environmental parameters of the scene; actually the 3D point reconstruction uncertainty can vary from 1.5 to tens of millimetres

Scaling collaborative policymaking: how to leverage on digital co-creation to engage citizens

n recent years, new methods to engage citizens in deliberative processes of governments and institutions have been studied. Such methodologies have become a necessity to assure the efficacy and sustainability of policies. Several tools and solutions have been proposed while trying to achieve such a goal. The dual problem to citizen engagement is how to provide policymakers with useful and actionable insights and data stemming from those processes. The following paper has the aim to share with the audience of the Data for Policy Conference 2021 an innovative tool based on the concept of participatory policymaking with the scope of collecting feedback and comments to enhance the consistency and the usefulness of the tool. We propose research featuring a method and implementation of a crowdsourcing and co-creation technique that can provide value to both citizens and policymakers engaged in the policy-making process. Thanks to our methodology, policymakers can design challenges for citizens to take part, cooperate and provide their input to policymakers. We also propose a web-based tool that allows citizens to participate and produce content to support the policymaking processes through a gamified interface that focuses on emotional and vision-oriented content

Small and large scale segmental motion in polymers: Estimating cooperativity length by ordinary relaxation experiments

We derive a suitable expression for estimating the size of the cooperatively rearranging regions (CRRs) in supercooled polymer melts by fitting data worked out by ordinary relaxation experiments carried out in isothermal conditions. As an example, the average CRR size in poly(n-butyl methacrylate) in proximity to the glass transition temperature is derived from a stress relaxation experiment performed by means of an atomic force microscopy setup. Good agreement is found with results in the literature derived from measurements of temperature fluctuations (the so-called Donth method). The temperature dependence of the CRR size is explored for poly(butadiene); in this case the segmental relaxation function is derived through a novel method for the analysis of the efficiency with which free induction decay echoes are refocused in 1H NMR experiments. It is found that the CRR size increases upon cooling. The results derived from the analysis of the NMR data are found to be in satisfactory agreement with those worked out from broadband dielectric spectroscopy data in the literatur

Nylon 6 and nylon 6,6 micro- and nanoplastics: a first example of their accurate quantification, along with polyester (PET), in wastewater treatment plant sludges

A novel procedure for nylon 6 and nylon 6,6 polyamide (PAs) microplastics (MPs) quantification is described for the first time. The overall procedure, including quantification of poly(ethylene terephthalate) (PET), was tested on wastewater treatment plant (WWTP) sludges. The three polymers account for the largest global share of synthetic textile microfibers, being possibly the most common MPs released upon laundering in urban wastewaters. Therefore, measuring their content in WWTP sludges may provide an accurate picture of the potential risks associated with both the inflow of these MPs in natural water bodies and the practice of using WWTP sludges as agricultural soil amendment. The novel procedure involves PAs depolymerization by acid hydrolysis followed by derivatization of the monomers 6-aminohexanoic acid (AHA) and hexamethylene diamine (HMDA) with a fluorophore. Reversed-phase HPLC analysis with fluorescence detection results in high sensitivities for both AHA (LOD = 8.85·10–4 mg/L, LOQ = 3.73·10–3 mg/L) and HMDA (LOD = 2.12·10–4, LOQ = 7.04·10–4 mg/L). PET quantification involves depolymerization, in this case by alkaline hydrolysis, followed by HPLC analysis of its comonomer terephthalic acid. Eight sludge samples from four WWTPs in Italy showed contamination in the 29.3–215.3 ppm and 10.6–134.6 ppm range for nylon 6 and nylon 6,6, respectively, and in the 520–1470 ppm range for PET

Fault architecture in the Main Ethiopian Rift and comparison with experimental models: Implications for rift evolution and Nubia-Somalia kinematics

The Main Ethiopian Rift (MER) offers a complete record of the time–space evolution of a continental rift. We have characterized the brittle deformation in different rift sectors through the statistical analysis of a new database of faults obtained from the integration between satellite images and digital elevation models, and implemented with field controls. This analysis has been compared with the results of lithospheric-scale analogue models reproducing the kinematical conditions of orthogonal and oblique rifting. Integration of these approaches suggests substantial differences in fault architecture in the different rift sectors that in turn reflect an along-axis variation of the rift development and southward decrease in rift evolution. The northernmost MER sector is in a mature stage of incipient continental rupture, with deformation localised within the rift floor along discrete tectono-magmatic segments and almost inactive boundary faults. The central MER sector records a transitional stage in which migration of deformation from boundary faults to faults internal to the rift valley is in an incipient phase. The southernmost MER sector is instead in an early continental stage, with the largest part of deformation being accommodated by boundary faults and almost absent internal faults. The MER thus records along its axis the typical evolution of continental rifting, from fault-dominated rift morphology in the early stages of extension toward magma-dominated extension during break-up. The extrapolation of modelling results suggests that a variable rift obliquity contributes to the observed along-axis variations in rift architecture and evolutionary stage, being oblique rifting conditions controlling the MER evolution since its birth in the Late Miocene in relation to a constant post ca. 11 Ma ~ N100°E Nubia–Somalia motion.Published479-4923.2. Tettonica attiva3.3. Geodinamica e struttura dell'interno della TerraJCR Journalreserve

Carbon Dioxide Removal and Capture for Landfill Gas Up-grading

Abstract Within the frame of an EC financially supported project - LIFE05 ENV/IT/000874 GHERL (Greenhouse Effect Reduction from Landfill)–a pilot plant was set up in order to demonstrate the feasibility of applying chemical absorption to remove carbon dioxide from landfill gas. After proper upgrading - basically removal of carbon dioxide, hydrogen sulphide, ammonia and other trace gas compound–the gas might be fed into the distribution grid for natural gas or used as vehicle fuel, replacing a fossil fuel thus saving natural resources and carbon dioxide emissions. Several experiences in Europe have been carried out concerning the landfill gas - and biogas from anaerobic digestion - quality up-grading through CO 2 removal, but in all of them carbon dioxide was vented to the atmosphere after separation, without any direct benefit in terms of greenhouse gases reduction. With respect to those previous experiences, in this work the attention was focused on CO 2 removal from landfill gas with an effective capture process, capable of removing carbon dioxide from atmosphere, through a globally carbon negative process. In particular, processes capable of producing final solid products were investigated, with the aim of obtaining as output solid compounds which can be either used in the chemical industry or disposed off. The adopted absorption process is based on using aqueous solutions of potassium hydroxide, with the final aim of producing potassium carbonate. Potassium carbonate is a product which has several applications in the chemical industry if obtained with adequate quality. It can be sold as a pulverised solid, or in aqueous solution. Several tests were carried out at the pilot plant, which was located at a landfill site, in order to feed it with a fraction of the on-site collected landfill gas. The results of the experimental campaign are reported, explained and commented in the paper. Also a discussion on economic issues is presented