The cone of curves of Fano varieties of coindex four

We classify the cones of curves of Fano varieties of dimension greater or equal than five and (pseudo)index dim X -3, describing the number and type of their extremal rays.Comment: 27 pages; changed the numbering of Theorems, Definitions, Propositions, etc. in accordance with the published version to avoid incorrect reference

New study of the 1755 earthquake source based on multi-channel seismic survey data and tsunami modeling

International audienceIn the last years, large effort has been done to carry out multi-channel seismic reflection surveys (MCS) in SW Iberia to locate the active tectonic structures that could be related to the generation of the 1755 Lisbon earthquake and the tsunami. The outcome of these researches led to the identification of a large, compressive tectonic structure, named Marques de Pombal thrust that, alone can account for only half the seismic energy released by the 1755 event. However, these investigations have shown the presence of additional tectonic structures active along the continental margin of SW Iberia that are here evaluated to model the tsunami waves observed along the coasts of Iberia, Morocco and Central Atlantic. In this paper we present a new reappraisal of the 1755 source, proposing a possible composite source, including the Marques de Pombal thrust fault and the Guadalquivir Bank. The test of the source is achieved through numerical modelling of the tsunami all over the North Atlantic area. The results presented now incorporate data from the geophysical cruises and the historical observation along the European coasts and also from the Western Indies. The results of this study will, hopefully, improve the seismic risk assessment and evaluation in the Portuguese territory, Spain, Morocco and Central/North Atlantic

INVESTIGATION ON THE BLUE PHENOTYPE IN PSEUDOMONAS SPECIES INVOLVED IN BLUE DISCOLORATION DEFECT OF FRESH CHEESE

La presenza di macchie di colore blu su Mozzarella \ue8 una problematica attuale per le industrie produttrici di questa tipologia di formaggio fresco. In particolare dal 2010 sono stati segnalati diversi casi in Italia con grande risalto nei notiziari nazionali ed europei, causando anche una segnalazione da parte del sistema di allerta RASFF. La causa della formazione del colore blu \ue8 stata identificata nella contaminazione di ceppi appartenenti al genere Pseudomonas. Per questo lavoro di tesi di dottorato \ue8 stata costituita una collezione di 69 isolati appartenenti al genere Pseudomonas (elencati nel capito Appendix 1): di questi, 59 sono stati isolati da campioni di Mozzarella con difetto blu e identificati mediante sequenziamento della regione 16S rRNA. La produzione del pigmento blu \ue8 stata confermata incubando gli isolati nel liquido di governo di Mozzarella, precedentemente centrifugato e sterilizzato per filtrazione 0.22 \ub5m (PF), a 4\ub0C. Trenta campioni diventarono blu dopo 7 giorni (33.7% degli isolati). Su tutti gli 89 ceppi \ue8 stata fatta la restrizione del genoma usando l\u2019enzima SpeI seguita dalla corsa elettroforetica in campo pulsato (PFGE) per valutare un\u2019eventuale correlazione genetica tra gli isolati produttori del pigmento blu. Dai profili ottenuti i 30 isolati presentati il fenotipo blu sono stati raggruppati in 12 genotipi. Per ogni genotipo \ue8 stato scelto un ceppo rappresentativo su cui \ue8 stata fatta una tipizzazione attraverso il sequenziamento di 7 loci conservati (MultiLocus Sequence Typing) per confermare l\u2019esistenza di una relazione filogenetica comune ai ceppi produttori del blu. Per 3 ceppi produttori del blu (200188/6, UMB247, UMB248) \ue8 stato sequenziato l\u2019intero genoma. Le sequenze dei genomi ottenuti sono state confrontate con quelle di altri 2 ceppi produttori del blu (PS77 e PS22) e di 5 ceppi non presentanti la formazione del pigmento blu (PS40, PS20, Pf01, A506, SBW25). Da questa analisi di comparazione dei genomi \ue8 stata individuata una regione di circa 10 kbp presente unicamente nei genomi dei ceppi produttori del blu, composta da 13 CDS, la maggior parte delle quali (53.7%) codificante per proteine costitutive di batteriofagi. Per indagare la relazione tra la presenza di profagi integrati nel genoma dei ceppi produttori del blu e lo sviluppo di questo particolare fenotipo, i 30 isolati produttori del blu sono stati sottoposti a induzione con due diversi antibiotici (norfloxacina e ciprofloxacina). La presenza di batteriofagi indotti dal trattamento con gli antibiotici \ue8 stata verificata misurando un\u2019eventuale attivit\ue0 inibente sulla crescita di ceppi produttori del blu di Pseudomonas spp., seguita dalla conferma mediante spot test e isolamento con la formazione di placche di lisi in doppio strato di agar. Alcuni campioni che hanno causato una zona di lisi negli spot test sono stati fotografati con microscopio elettronico a trasmissione. Attraverso le immagini sono state individuate due tipologie di particelle virali esclusivamente nei campioni indotti con ciporfloxacina. Non \ue8 stato per\uf2 possibile procedere all\u2019isolamento dei batteriofagi in quanto non sono state ottenute singole placche di lisi. L\u2019altra tematica affrontata durante questo progetto di dottorato \ue8 stata l\u2019identificazione della/e molecola/e blu e del suo ruolo nell\u2019ambiente. Per determinare i requisiti necessari per la produzione del pigmento blu sono state allestite delle prove fenotipiche in liquido di governo a tre diverse temperature (4\ub0C, 14\ub0C e 30\ub0C) e in terreno minimo M9 a diversi pH (5.7, 6.3, 7.2) addizionato con (a) differenti fonti di carbonio (lattosio, glucosio, galattosio, acido lattico e acido succinico), (b) diversi metalli (Mo, Cu, Zn, Ca, Mg, Bo, Co, Mn, Fe) e (c) 18 diversi amminoacidi. La produzione del pigmento blu \ue8 stata osservata solo quando i campioni sono stati incubati a temperature di refrigerazione (al di sotto dei 14\ub0C) in liquido di governo o nel terreno minimo a pH 5.7. La presenza di Cobalto e di alcuni amminoacidi, ad esempio la lisina, hanno avuto un effetto inibente sulla produzione del pigmento blu, mentre l\u2019aggiunta di prolina ne ha aumentato l\u2019intensit\ue0. L\u2019analisi UPLC/MS dei campioni 200188/6, UMB247 e UMB248 in liquido di governo e dei campioni in M9 + prolina non ha portato all\u2019identificazione univoca della/e molecola/e che danno la colorazione blu. Per comprendere la funzione del pigmento blu sono state verificate una possibile correlazione con i segnali di quorum sensing e un possibile ruolo come batteriocina. I segnali di quorum sensing non sono risultati legati alla produzione del blu, mentre per quanto riguarda l\u2019attivit\ue0 batteriostatica \ue8 risultato che, al contrario delle aspettative, il pigmento blu possiede un effetto positivo sulla crescita dei ceppi blu di Pseudomonas spp..In 2010 the occurrence of blue spots on Mozzarella cheese was reported from several consumers in Italy and highlighted by local and international media and by RASFF alert system (RASFF Annual Report 2010). P. fluorescens spp. was identified as the causing agent of this blue pigmentation. In this phD thesis work a collection of about 69 Pseudomonas spp. isolates (listed in Appendix 1) was used: from these 59 were isolated from spoiled samples of Mozzarella cheese presenting the blue coloration defect and identified by 16S rDNA sequencing. The production of the blue pigment was confirmed by incubation of the isolates in Mozzarella Preserving Fluid (PF) centrifuged and sterilized by filtration 0.22 \ub5m; incubation was made at 4\ub0C. The medium turned blue after 7 days in 30 samples (33.7% of the isolates). To investigate the genetic relationship between blue pigment-producing and blue pigment not-producing isolates, genome restriction was performed using SpeI enzyme, coupled with pulsed gel field electrophoresis (PFGE). From bands profile it was seen that the 30 blue producing isolates were grouped in 12 genotypes. From each genotype one representative strain was chosen for MultiLocus Sequence Typing analysis (MLST) to confirm a phylogenetic relationship among the blue pigment-producing strains. For 3 blue pigment-producing strains (200188/6, UMB247 and UMB248) the whole genome was sequenced and compared with 2 further blue pigment-producing strains genome (PS77 and PS20) and with the genomes of 5 blue pigment not-producing strains (PS40, PS20, Pf01, A506, SBW25). From this comparison a unique region of about 10kbp present in the blue pigment-producing strains and not shared by the blue pigment not-producing strains was found. This region is composed by 15 CDS, most of them (53.7%) coding for phage related elements. To investigate the relationship between the presence of prophages and the development of the blue phenotype the 30 blue pigment-producing isolates were induced by two different antibiotics (norfloxacin and ciprofloxacin). The presence of induced bacteriophages was assayed by measuring an inhibitory effect on the growing curves of blue pigment-producing Pseudomonas spp., by spot test assay and by plaques formation on double layer agar. For samples with a positive result from spot test, TEM photographs were made, showing two phage morphologies from a sample induced by ciprofloxacin. It was not possible to isolate these phages because they were not plaque producing. The other main topic of this job was the identification of the blue pigment and of its role in the ecology of P. fluorescens. To determinate the environmental requirement for its production several assays were made incubating the blue strains in PF at different temperature (4\ub0C, 14\ub0C and 30\ub0C) and in M9 minimal medium at different pH (5.7, 6.3, 7.2) with (a) different carbon source (glucose, galactose, succinic acid, lactic acid), (b) different metals (Mo, Cu, Zn, Ca, Mg, Bo, Co, Mn, Fe) and (c) 18 different amino acids. From these phenotypic tests it resulted that the blue production occurred only at refrigeration temperature (lower than 14\ub0C) in medium with pH 5.7. The presence of Cobalt or lysine inhibited the blue synthesis, while it was increased when proline was present. The individuation of the blue molecule/s from blue samples of PF and M9+proline incubated with strains 200188/6, UMB248 and UMB254 was made by UPLC/MS without leading to a definitive result. Trying to identify the function of the blue molecule/s, its possible connection with quorum sensing signals and its role as bacteriocine were investigated. Quorum sensing signals were found not to be related with blue production; as for the bacterial growth inhibiting effect it was noticed that the presence of the blue molecule/s, contrary of what expected, was able to promote the growing of Pseudomonas spp

Multiple Parton Interactions, top--antitop and W+4j production at the LHC

The expected rate for Multiple Parton Interactions (MPI) at the LHC is large. This requires an estimate of their impact on all measurement foreseen at the LHC while opening unprecendented opportunities for a detailed study of these phenomena. In this paper we examine the MPI background to top-antitop production, in the semileptonic channel, in the early phase of data taking when the full power of $b$--tagging will not be available. The MPI background turns out to be small but non negligible, of the order of 20% of the background provided by W+4j production through a Single Parton Interaction. We then analyze the possibility of studying Multiple Parton Interactions in the W+4j channel, a far more complicated setting than the reactions examined at lower energies. The MPI contribution turns out to be dominated by final states with two energetic jets which balance in transverse momentum, and it appears possible, thanks to the good angular resolution of ATLAS and CMS, to separate the Multiple Parton Interactions contribution from Single Parton Interaction processes. The large cross section for two jet production suggests that also Triple Parton Interactions (TPI) could provide a non negligible contribution. Our preliminary analysis suggests that it might be indeed possible to investigate TPI at the LHC.Comment: Typos fixed. Published in JHE

Hybrid manufacturing of steel construction parts via arc welding of LPBF-produced and hot-rolled stainless steels

The demand for free-form steel structures having improved performances, reducing labour and resource usage is increasing in the construction sector. Structural nodes are some of the most critical regions for steel structures characterised often by large dimensions. These nodes can exploit the geometrical freedom of metal additive manufacturing (MAM) processes. Laser powder bed fusion (LPBF) is arguably the most developed MAM process, which has limitations regarding the size of the parts to be produced. A way to overcome the size limits of LPBF for producing structural nodes while still exploiting its geometrical capacity is producing hybrid components by welding them to traditionally manufactured beams. Such hybrid joints would constitute a complex system from a mechanical design perspective requiring a systematic analysis in order to be certified for structural use. Accordingly, this work studies the mechanical behaviour of hybrid steel components generated by welding LPBF plates and quarto plates made of AISI 316L stainless steel. The work was guided by a case study based on a large steel node, which helped defining the requirements to fill the gap of the international standards. The mechanical characterisation of LPBF-produced plates and quarto plates, as well as the welded hybrid components revealed a maximum of 10% difference between the properties of the differently manufactured plates. Through the digital image correlation (DIC) analyses, the anisotropic deformation behaviour along the LPBF, weld seam, and quarto plate regions have been identified, and the properties after welding did not show relevant modifications. The tests allowed to define that the failure behaviour is mainly governed by interlayer bounds, and a 0.9 safety reduction parameter for considering the reduction of ductility induced by arc welding to LPBF. Finally, design and production suggestions have been provided for a correct evaluation of gross and effective sections of the designed nodes

Variability in pH, fCO2, oxygen and flux of CO2 in the surface water along a transect in the Atlantic sector of the Southern Ocean

Underway sampling and measurements of pH, fCO2, oxygen and Chlorophyll a (Chl a) were performed in the surface waters from Cape Town (South Africa) to Queen Maud Land (Antarctica) in the Atlantic sector of the Southern Ocean during the austral summer 1997/1998. From direct measurements of these parameters and from calculated fCO2 the oceanic carbon dioxide system was studied and related to hydrological and biological parameters. fCO2 was in general undersaturated relative to the atmosphere and showed a large variability with values ranging from 313 to 377 μatm with a mean value of 346±13 μatm. The undersaturation was more pronounced in areas associated with fronts where high Chl a and high pH in situ values were observed. Using shipboard wind speed data, estimates of the CO2 flux were made along the transect and during three mesoscale surveys on the northward return transect in the area of the Spring Ice Edge (SIE), the Winter Ice Edge (WIE) and in the Antarctic Polar Front (APF). The undersaturation observed during the transect caused the ocean to act as a sink for CO2 with a mean sea–air flux for the entire transect of −3±5 mmol m−2 d−1 with a large variability between −20 mmol m−2 d−1 (oceanic uptake) to 1.3 mmol m−2 d−1 (oceanic source). The lowest fCO2 values (largest oceanic uptake of CO2) were found at the southern boundary of the APF at 53°S, which coincided with a supersaturation in oxygen and high pH values. Oxygen concentrations were measured from 50°S to 63°S and varied between 324 and 359 μmol kg−1 with a mean value of 347±9 μmol kg−1. In general only small deviations from equilibrium oxygen saturation were observed (mean value=99±2%). However, in the SIE oxygen was clearly undersaturated, probably an effect of upwelling of oxygen poor deep water which had not yet been compensated for by biological production. Three weeks later, the ice edge had retreated in the SIE region and the Chl a concentration had increased three-fold, suggesting the start of a phytoplankton bloom. This was also seen in the oxygen concentration which had increased and showed supersaturation. This coincided with an increased oceanic uptake of CO2 in the SIE during the mesoscale survey

The Threat of Plant Toxins and Bioterrorism: A Review

The intentional use of highly pathogenic microorganisms, such as bacteria, viruses or their toxins, to spread mass-scale diseases that destabilize populations (with motivations of religious or ideological belief, monetary implications, or political decisions) is defined as bioterrorism. Although the success of a bioterrorism attack is not very realistic due to technical constraints, it is not unlikely and the threat of such an attack is higher than ever before. It is now a fact that the capability to create panic has allured terrorists for the use of biological agents (BAs) to cause terror attacks. In the era of biotechnology and nanotechnology, accessibility in terms of price and availability has spread fast, with new sophisticated BAs often being produced and used. Moreover, there are some BAs that are becoming increasingly important, such as toxins produced by bacteria (e.g., Botulinum toxin, BTX), or Enterotoxyn type B, also known as Staphylococcal Enterotoxin B (SEB)) and extractions from plants. The most increasing records are with regards to the extraction / production of ricin, abrin, modeccin, viscumin and volkensin, which are the most lethal plant toxins known to humans, even in low amounts. Moreover, ricin was also developed as an aerosol biological warfare agent (BWA) by the US and its allies during World War II, but was never used. Nowadays, there are increasing records that show how easy it can be to extract plant toxins and transform them into biological weapon agents (BWAs), regardless of the scale of the group of individuals

Hybrid manufacturing of steel construction parts via arc welding of LPBF-produced and hot-rolled stainless steels

The demand for free-form steel structures having improved performances, reducing labour and resource usage is increasing in the construction sector. Structural nodes are some of the most critical regions for steel structures characterised often by large dimensions. These nodes can exploit the geometrical freedom of metal additive manufacturing (MAM) processes. Laser powder bed fusion (LPBF) is arguably the most developed MAM process, which has limitations regarding the size of the parts to be produced. A way to overcome the size limits of LPBF for producing structural nodes while still exploiting its geometrical capacity is producing hybrid components by welding them to traditionally manufactured beams. Such hybrid joints would constitute a complex system from a mechanical design perspective requiring a systematic analysis in order to be certified for structural use. Accordingly, this work studies the mechanical behaviour of hybrid steel components generated by welding LPBF plates and quarto plates made of AISI 316L stainless steel. The work was guided by a case study based on a large steel node, which helped defining the requirements to fill the gap of the international standards. The mechanical characterisation of LPBF-produced plates and quarto plates, as well as the welded hybrid components revealed a maximum of 10% difference between the properties of the differently manufactured plates. Through the digital image correlation (DIC) analyses, the anisotropic deformation behaviour along the LPBF, weld seam, and quarto plate regions have been identified, and the properties after welding did not show relevant modifications. The tests allowed to define that the failure behaviour is mainly governed by interlayer bounds, and a 0.9 safety reduction parameter for considering the reduction of ductility induced by arc welding to LPBF. Finally, design and production suggestions have been provided for a correct evaluation of gross and effective sections of the designed nodes

Effects of ionizing radiation on flora ten years after the Fukushima Dai-ichi disaster

: The aim of this work is to analyze the effects of ionizing radiation and radionuclides (like 137Cs) in several higher plants located around the Fukushima Dai-ichi Nuclear Power Plant (FNPP), evaluating both their adaptive processes and evolution. After the FNPP accident in March 2011 much attention was focused to the biological consequences of ionizing radiation and radionuclides released in the area surrounding the nuclear plant. This unexpected mishap led to the emission of radionuclides in aerosol and gaseous forms from the power plant, which contaminated a large area, including wild forest, cities, farmlands, mountains, and the sea, causing serious problems. Large quantities of 131I, 137Cs, and 134Cs were detected in the fallout. People were evacuated but the flora continued to be affected by the radiation exposure and by the radioactive dusts' fallout. The response of biota to FNPP irradiation was a complex interaction among radiation dose, dose rate, temporal and spatial variation, varying radiation sensitivities of the different plants' species, and indirect effects from other events. The repeated ionizing radiations, acute or chronic, guarantee an adaptation of the plant species, demonstrating a radio-resistance. Consequently, ionizing radiation affects the genetic structure, especially during chronic irradiation, reducing genetic variability. This reduction is associated with the different susceptibility of plant species to chronic stress. This would confirm the adaptive theory associated with this phenomenon. The effects that ionizing radiation has on different life forms are examined in this review using the FNPP disaster as a case study focusing the attention ten years after the accident

Fatigue analysis of hybrid steel construction parts using LPBF on hot-rolled steel

Metal additive manufacturing presents significant opportunities in the construction industry by enabling the creation of innovative components and seamless integration with conventional steel parts to form hybrid structures. However, ensuring the long-term performance of such structures, particularly under cyclic loading, requires a comprehensive investigation into the behavior of individual materials and their interfaces. Unfortunately, current European fatigue design standards do not adequately address the unique considerations of metal additive manufacturing. This paper provides a thorough analysis of high-cycle fatigue in butt-joint connections of arc-welded hybrid additive manufactured joints. The study specifically concentrates on the use of arc welding to join an AISI316L plate produced through the Laser Powder Bed Fusion (LPBF) technique with a quarto plate. Experimental tests incorporate engineering stress control and utilize three distinct stress steps to establish S–N curves. The findings highlight the substantial influence of internal defects and their geometric characteristics on stress concentrations and fatigue life. These insights provide valuable understanding regarding the fatigue performance of hybrid additive manufactured joints compared to conventional steel, opening avenues for further research on the integration of metal additive manufacturing components with traditional steel structures