Restriction categories III: colimits, partial limits, and extensivity

A restriction category is an abstract formulation for a category of partial maps, defined in terms of certain specified idempotents called the restriction idempotents. All categories of partial maps are restriction categories; conversely, a restriction category is a category of partial maps if and only if the restriction idempotents split. Restriction categories facilitate reasoning about partial maps as they have a purely algebraic formulation. In this paper we consider colimits and limits in restriction categories. As the notion of restriction category is not self-dual, we should not expect colimits and limits in restriction categories to behave in the same manner. The notion of colimit in the restriction context is quite straightforward, but limits are more delicate. The suitable notion of limit turns out to be a kind of lax limit, satisfying certain extra properties. Of particular interest is the behaviour of the coproduct both by itself and with respect to partial products. We explore various conditions under which the coproducts are ``extensive'' in the sense that the total category (of the related partial map category) becomes an extensive category. When partial limits are present, they become ordinary limits in the total category. Thus, when the coproducts are extensive we obtain as the total category a lextensive category. This provides, in particular, a description of the extensive completion of a distributive category.Comment: 39 page

Use of a glucomannan polymer to reduce the effects of mycotoxin-contaminated diets in finishing pigs

The use of feed additives with mycotoxin adsorption capacity is a common strategy for controlling negative effects of mycotoxins in swine production systems. However, adsorbents that may results very effective under experimental conditions, i.e. when feed contamination level is rather high, do not necessarily retain their efficacy when tested under field conditions feed with generally low mycotoxin contamination. In this study, the effects of diets artificially contaminated with aflatoxin B1 or ochratoxin A on fattening performance and serum chemistry of fattening pigs are investigated. Moreover, the ability of a commercial glucomannan polymer (Gm polimer) to reduce or eliminate the effects of the contaminated feeds is tested. Thirty heavy pigs (BW = 110±10.6 kg) were fed 6 diets (n = 5 pigs/diet) for 4 weeks until slaughtering. Diets were: control without toxin added (C); added with 0.02 ppm of aflatoxin B1 (AFB1); added with 0.05 ppm of ochratoxin A (OTA); other three diets as the previous but the addition of 2.0 g/kg of Gm polymer (C-GM, AFB1-GM, OTA-GM). Daily weight gain (ADG) and Feed efficiency ratio (FE) were measured every two weeks. Data were analyzed with a two-way ANOVA that included the fixed effect of diet, time and their interaction. After the first 2 weeks the ADG did not differ significantly between the diets, even if the ADG of AFB1 diet was about 20% lower than AFB1-Gm or C. In the last 2 weeks the ADG of AFB1 diet was significantly lover than the other diets (P<0.01) and was about one-half of the values reported for the same group in the first period. The contamination with ochratoxin A did not affect fattening performance of pigs during the whole experimental period. No damages were found in kidneys of all diets. Moreover, no evidence of association between observed liver damages and different diets was found. Finally, no differences between experimental diets were evidenced for the haematological parameters

Un indice per misurare la accessibilità di prossimità

IAPI (Inclusive Accessibiity by Proximity Index) misura, in ambiente GIS, l'accessibilità a servizi essenziali a partire dalle condizioni che favoriscono/sfavoriscono la pedonalità, la ciclabilità e le interazioni sociali a scala di quartiere. La sua sperimentazione in Bologna ha permesso sia di mappare la qualità dei percorsi ciclo-pedonali, sia di valutare l’accessibilità via mobilità attiva a servizi di quartiere, sia di valutare l’effetto di interventi puntuali di pedonalizzazione sulla qualità dei percorsi e degli spazi pubblici. Grazie alla facilità di calcolo, alla trasferibilità dell’approccio connessa all’uso di dati open source e alle opportunità di aggiornamento degli indicatori e dei coefficienti utilizzati, IAPI può contribuire alla costruzione di politiche multi-settore, a diverse scale

LCA study of oleaginous bioenergy chains in a Mediterranean environment

This paper reports outcomes of life cycle assessments (LCAs) of three different oleaginous bioenergy chains (oilseed rape, Ethiopian mustard and cardoon) under Southern Europe conditions. Accurate data on field practices previously collected during a three-year study at two sites were used. The vegetable oil produced by oleaginous seeds was used for power generation in medium-speed diesel engines while the crop residues were used in steam power plants. For each bioenergy chain, the environmental impact related to cultivation, transportation of agricultural products and industrial conversion for power generation was evaluated by calculating cumulative energy demand, acidification potential and global warming potential. For all three bioenergy chains, the results of the LCA study show a considerable saving of primary energy (from 70 to 86 GJ·ha−1) and greenhouse gas emissions (from 4.1 to 5.2 t CO2·ha−1) in comparison to power generation from fossil fuels, although the acidification potential of these bioenergy chains may be twice that of conventional power generation. In addition, the study highlights that land use changes due to the cultivation of the abovementioned crops reduce soil organic content and therefore worsen and increase greenhouse gas emissions for all three bioenergy chains. The study also demonstrates that the exploitation of crop residues for energy production greatly contributes to managing environmental impact of the three bioenergy chains

Un indice per misurare la accessibilità di prossimità

IAPI (Inclusive Accessibiity by Proximity Index) misura, in ambiente GIS, l'accessibilità a servizi essenziali a partire dalle condizioni che favoriscono/sfavoriscono la pedonalità, la ciclabilità e le interazioni sociali a scala di quartiere. La sua sperimentazione in Bologna ha permesso sia di mappare la qualità dei percorsi ciclo-pedonali, sia di valutare l’accessibilità via mobilità attiva a servizi di quartiere, sia di valutare l’effetto di interventi puntuali di pedonalizzazione sulla qualità dei percorsi e degli spazi pubblici. Grazie alla facilità di calcolo, alla trasferibilità dell’approccio connessa all’uso di dati open source e alle opportunità di aggiornamento degli indicatori e dei coefficienti utilizzati, IAPI può contribuire alla costruzione di politiche multi-settore, a diverse scale

Hydrogen Refueling Stations: Prevention and Scenario Management. Large Scale Experimental Investigation of Hydrogen Jet-Fires

Hydrogen is becoming an attractive alternative for energy storage and transportation, because of the elevated energy content per unit of mass and possibility to have zero carbon-emission vehicles. For these reasons, hydrogen's share in global market is expected to grow substantially in the coming years. Today, hydrogen-fueled buses and cars are already available, and several refueling stations are operating in different countries around the world. A key role of the deployment of hydrogen fueled-vehicles is the presence of a widespread network of refueling stations, especially close to residential and industrial areas. This fact poses attention to the safety aspects related to hydrogen, with particular interest to its high flammability that can lead to catastrophic consequences for personnel and equipment. As a matter of fact, hydrogen is a comparatively less safe fuel compared to conventional fuels such as gasoline and diesel. Hydrogen infrastructures are characterized by operating pressure up to 1000 bar that, in case of an unintended loss of containments, produce a highly under expanded turbulent jet. If ignited, this hydrogen jet may give rise to very severe scenarios, mainly related to high temperatures and the oriented flows. As recently suggested by Moradi and Groth (Moradi and Groth, 2019), there is a lack of experimental and on-site data for almost all of the storage and delivery technologies relevant to the hydrogen infrastructures. Experimental data is vital to support model validation, especially in the case of the very peculiar combustion process of hydrogen. In this way, a real-scale experimental campaign is proposed to investigate the main characteristic of the hydrogen jet fire resulting from its rapid fired depressurizations. Focus of the experimental campaign is evaluation of safety distance for person and device (i.e. pressurized tanks) in order to avoid critical conditions and domino effects in real refueling station. Different initial conditions, i.e., storage pressures, are exploited, and the resulting jet across specified orifice is investigated. More specifically, temperatures at various locations are measured through an arrangement of thermocouples. Values up to 1200 °C were obtained in the core of the jet. Moreover, it was found that the recorded temperatures, especially those at the outer portion of the jet, are very sensitive to the initial conditions

Geomaterials and decay forms of the coastal towers of Piscinni and Foghe, Weastern Sardinia

[EN] The distribution of Coastal Towers in Sardinia testify that foreign invasions, which occurred several times over the centuries, were particularly frequent and dangerous. The beginning of the eighth century signed an increase of the attacks from the sea. The most of Coastal Towers were built in the period of Spanish rule, from 1583 to 1720. Despite numerous restorations over the years, many of these defensive structures are in critical conditions, some also affected by structural collapse. The building materials are closely related to local geological outcrops, and consist of sedimentary, magmatic and metamorphic rocks. Study of different lithotypes allowed assessing the vulnerability of different materials in different environmental conditions. Salts, transported by aerosols and deposited inside the porous structures, are the principal cause of decay of the building materials. Chemical-physical and mineralogical-petrographic analyses, performed on some Towers allowed making some general assessments on their conservation status and restoration projects.Carcangiu, G.; Meloni, P.; Palomba, M.; Cocco, O.; Sitzia, F.; Murru, A.; Carboni, M.... (2015). Geomaterials and decay forms of the coastal towers of Piscinni and Foghe, Weastern Sardinia. En Defensive architecture of the mediterranean: XV to XVIII centuries. Vol. I. Editorial Universitat Politècnica de València. 345-352. https://doi.org/10.4995/FORTMED2015.2015.1753OCS34535

Durability of repair mortars used in restoration of a Sardinian coastal tower: assessment after ten years

[EN] This study reports the results of investigations on conservation conditions of an ancient tower, called Torre del Pozzo, located in the S-W coast of Sardinia, restored about ten years ago. The tower suffers from serious problems related to vulnerability of building materials, particularly limestone and sandstones and aerial lime mortar with poor physical-mechanical properties. Over the centuries the materials were subjected to aggressive actions (wind corrasion and salt crystallization) causing an intense erosion of the walls with consequent partial collapse of the structure. About ten years ago a restoration involved the mortars and only the replacement and integration of ashlars deteriorated. After about 10 years from this intervention, some inspections have been carried out in order to assess the effectiveness of the intervention and the state of preservation of the tower. This paper focuses on analyses and tests carried out to assess condition and durability of the repair mortars.Meloni, P.; Carcangiu, G.; Palomba, M.; Enzo, S.; Carboni, M.; Cocco, O.; Casti, M.... (2015). Durability of repair mortars used in restoration of a Sardinian coastal tower: assessment after ten years. En Defensive architecture of the mediterranean: XV to XVIII centuries. Vol. II. Editorial Universitat Politècnica de València. 397-44. https://doi.org/10.4995/FORTMED2015.2015.1761OCS3974

Current and emerging imaging techniques to evaluate bowel dysfunctions in patients with Multiple Sclerosis: a review

Multiple Sclerosis (MS) is the most common chronic disease of central nervous system (CNS). MS patients may present with a wide variety of neurologic symptoms, including fatigue, sensory and motor disturbances, depression, cognitive disorders, bladder, bowel and sexual dysfunctions (1). Pelvic floor disorders are often overlooked symptoms in patients with MS (2). With respect to the general population, constipation and/or faecal incontinence are more frequent in MS, with an estimated prevalence ranging from 52% to 68% (3). The neuro-pathophysiological mechanism of bowel dysfunction in MS remains unclear. Several factors act in concert to maintain fecal continence; among the anatomical factors the anal sphincter is crucial, interplaying with rectum and pelvic floor muscles to controll defecation. In recent decades, technological advances in diagnostic imaging have dramatically improved our knowledge favouring the assessment of anatomical and functional deficits in patients with bowel dysfunctions. We conducted a review to provide an overview on the relevance of current and emerging imaging techniques to study morphologic and functional abnormalities of anorectal region and pelvic floor of MS patients. Multimodal imaging techniques are frequently used: both static and dynamic imaging provide new insights into the complexity of global pelvic floor dysfunctions. The defecography seems to be the gold standard examination for the identification of morphological and functional disorders of the recto-anal region and pelvic floor (4). Although MRI defecography provide more accuracy in morphologic and functional assessment and allows to avoid radiation exposure, defecography is a cost-effective procedure, simple to perform, and widely available in every hospital equipped with a fluoroscopy room

Synthesis, structural characterization, and chiroptical properties of planarly and axially chiral boranils

International audience2-Amino[2.2]paracyclophane reacts with salicylaldehyde or 2-hydroxyacetophenone to yield imines that then give access to a new series of boranils (8b–d) upon complexation with BF2. These novel boron-containing compounds display both planar and axial chiralities and were examined experimentally and computationally. In particular, their photophysical and chiroptical properties were studied and compared to newly prepared, simpler boranils (9a–d) exhibiting axial chirality only. Less sophisticated chiral architectures were shown to demonstrate overall stronger circularly polarized luminescence (CPL) activity