Block Toeplitz determinants, constrained KP and Gelfand-Dickey hierarchies

We propose a method for computing any Gelfand-Dickey tau function living in Segal-Wilson Grassmannian as the asymptotics of block Toeplitz determinant associated to a certain class of symbols. Also truncated block Toeplitz determinants associated to the same symbols are shown to be tau function for rational reductions of KP. Connection with Riemann-Hilbert problems is investigated both from the point of view of integrable systems and block Toeplitz operator theory. Examples of applications to algebro-geometric solutions are given.Comment: 35 pages. Typos corrected, some changes in the introductio

Changing trends of ocular trauma in the time of COVID-19 pandemic

To reduce the spread of the novel coronavirus (2019-nCoV), countries have promoted a range of unprecedented public health responses. These measures aim at reducing the final size of the epidemic as well as its peak in order to decrease the acute pressure on the health-care system [1]. In Italy, the government ordered people to stay home, restricting movements with the exception of work, urgent matters and health reasons. Furthermore, all commercial and productive activities, except those providing essential services, were obligated to remain closed [2]. Ocular trauma represents a serious public health problem and leading cause of visual impairment [3, 4]. The COVID-19 social distancing measures might have a significant impact on the risk of ocular trauma. In this study, we retrospectively reviewed the charts of all patients presenting to an Italian ophthalmological emergency department (the Ophthalmology Unit of the S.Orsola-Malpighi University Hospital in Bologna) to identify all eye injuries. Data were analysed from 10th March 2020 (i.e. the day in which the quarantine measures were applied in our city) to 10th April 2020, and confronted with those of the same period of the previous year (from 10th March 2019 to 10th April 2019). In the 2019 study period, there were 354 eye injuries (15.6% of all patients presenting to the emergency department). In the 2020 study period, eye injuries decreased to 112 (19.9% of all patients). The characteristics of eye injuries in the two study periods are reported in Table 1. During quarantine, the proportion of children and adolescents with eye injuries decreased (from 14.7% to 8.0%, Fig. 1a), while the proportion of males increased (from 66.7% to 75.0%, Fig. 1b). Regarding the mechanisms of injury, the percentage of falls and sport injuries had the highest decrease (respectively, from 6.5% to 0.9% and from 5.9% to 2.7%), while injuries during home activities and injuries with plants had the highest increase (respectively, from 12.4% to 17.0% and from 8.5% to 10.7%, Fig. 1c). The percentage of minor injuries with low risk of vision loss increased (from 93.2% to 94.6%), while major injuries requiring monitoring decreased (from 6.8% to 5.4%, Fig. 1d). There was a striking 68.4% decrease in the number of eye injuries seen in our Unit during the last month. Behavioural changes during the quarantine could be associated with lower risk of trauma. The decreases of sport injuries and of injuries in children during school closure seem to support this hypothesis. However, the drop of patients seeking emergency care affected all injuries, including serious ones potentially associated with vision loss. We believe that some patients may intentionally avoid urgent care rather than risking coronavirus exposure at hospitals. Anecdotal reports suggest that this is also happening for life-threatening medical emergencies such as myocardial infarction and stroke [5, 6]. Since ocular trauma is a major cause of vision loss, the importance of not delaying or avoiding treatment should be stressed to all patients to prevent ocular morbidities

Efficacy of the combined intrastromal injection of voriconazole and amphotericin B in recalcitrant fungal keratitis

This study aims to report the efficacy of a combined intrastromal injection in optimizing the outcome of severe mycotic keratitis. Herein, we report a case series of 20 consecutive patients with positive fungal cultures not responding to topical antifungal treatment. Patients received cycles of intrastromal injections of voriconazole (50 μg/0.1 mL) and amphotericin B (2.5 μg/0.1 mL); all patients continued their topical antifungal therapy. The organisms isolated were Fusarium (n = 5), Aspergillus (n = 4), Candida (n = 4), Rhodotorula (n = 2), Penicillium (n = 2), Alternaria (n = 1), Bipolaris (n = 1), and Curvularia (n = 1). The size of the infiltrate varied from 6.5 to 1.5 mm. At presentation, the best corrected visual acuity (BCVA, namely, the best visual acuity achieved with glasses, if needed) was less than 20/400 in all patients, improving to better than 20/400 in eleven patients. Seven patients required surgical intervention; four of them underwent penetrating keratoplasty (PK) à chaud one month after the first intrastromal injection. Patients who underwent surgery achieved a BCVA of 20/40 or better. Combined intrastromal injections before therapeutic penetrating keratoplasty (TPK) effectively reduced ulcer size and graft diameter, preventing infection recurrence. Our results highlight the efficacy of combined intrastromal injections in optimizing outcomes for severe mycotic keratitis undergoing TPK

Role of deep sponge grounds in the Mediterranean Sea: a case study in southern Italy

The Mediterranean spongofauna is relatively well-known for habitats shallower than 100 m, but, differently from oceanic basins, information upon diversity and functional role of sponge grounds inhabiting deep environments is much more fragmentary. Aims of this article are to characterize through ROV image analysis the population structure of the sponge assemblages found in two deep habitats of the Mediterranean Sea and to test their structuring role, mainly focusing on the demosponges Pachastrella monilifera Schmidt, 1868 and Poecillastra compressa (Bowerbank, 1866). In both study sites, the two target sponge species constitute a mixed assemblage. In the Amendolara Bank (Ionian Sea), where P. compressa is the most abundant species, sponges extend on a peculiar tabular bedrock between 120 and 180 m depth with an average total abundance of 7.3 +/- 1.1 specimens m(-2) (approximately 230 gWW m(-2) of biomass). In contrast, the deeper assemblage of Bari Canyon (average total abundance 10.0 +/- 0.7 specimens m(-2), approximately 315 gWW m(-2) of biomass), located in the southwestern Adriatic Sea between 380 and 500 m depth, is dominated by P. monilifera mixed with living colonies of the scleractinian Madrepora oculata Linnaeus, 1758, the latter showing a total biomass comparable to that of sponges (386 gWW m(-2)). Due to their erect growth habit, these sponges contribute to create complex three-dimensional habitats in otherwise homogenous environments exposed to high sedimentation rates and attract numerous species of mobile invertebrates (mainly echinoderms) and fish. Sponges themselves may represent a secondary substrate for a specialized associated fauna, such zoanthids. As demonstrated in oceanic environments sponge beds support also in the Mediterranean Sea locally rich biodiversity levels. Sponges emerge also as important elements of benthic-pelagic coupling in these deep habitats. In fact, while exploiting the suspended organic matter, about 20% of the Bari sponge assemblage is also severely affected by cidarid sea urchin grazing, responsible to cause visible damages to the sponge tissues (an average of 12.1 +/- 1.8 gWW of individual biomass removed by grazing). Hence, in deep-sea ecosystems, not only the coral habitats, but also the grounds of massive sponges represent important biodiversity reservoirs and contribute to the trophic recycling of organic matter

The CAESAR project for the ASI space weather infrastructure

This paper presents the project Comprehensive spAce wEather Studies for the ASPIS prototype Realization (CAESAR), which aims to tackle the relevant aspects of Space Weather (SWE) science and develop a prototype of the scientific data centre for Space Weather of the Italian Space Agency (ASI) called ASPIS (ASI SPace Weather InfraStructure). To this end, CAESAR involves the majority of the SWE Italian community, bringing together 10 Italian institutions as partners, and a total of 92 researchers. The CAESAR approach encompasses the whole chain of phenomena from the Sun to Earth up to planetary environments in a multidisciplinary, comprehensive, and unprecedented way. Detailed and integrated studies are being performed on a number of well-observed “target SWE events”, which exhibit noticeable SWE characteristics from several SWE perspectives. CAESAR investigations synergistically exploit a great variety of different products (datasets, codes, models), both long-standing and novel, that will be made available in the ASPIS prototype: this will consist of a relational database (DB), an interface, and a wiki-like documentation structure. The DB will be accessed through both a Web graphical interface and the ASPIS.py module, i.e., a library of functions in Python, which will be available for download and installation. The ASPIS prototype will unify multiple SWE resources through a flexible and adaptable architecture, and will integrate currently available international SWE assets to foster scientific studies and advance forecasting capabilities

A silicified Early Triassic marine assemblage from Svalbard

peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=tjsp2

Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 2: The Physics Program for DUNE at LBNF

The Physics Program for the Deep Underground Neutrino Experiment (DUNE) at the Fermilab Long-Baseline Neutrino Facility (LBNF) is described

Ornamento a graffito delle facciate. La rappresentazione dell’Architettura sull’Architettura / Graffiti ornament of the façades. The representation of Architecture on Architecture.

La completa schedatura dei paramenti ornamentali a graffito dei palazzi di Pienza è stata preceduta dalla ricerca specifica degli elementi di valutazione e catalogazione necessari. Il rilievo diretto e il ridisegno hanno poi condotto a una tesi di laurea magistrale già discussa e a pubblicazioni in corso di editazione sulla terminata e completa schedatura delle facciate della città. In questo paper si rende conto degli studi preliminari condotti. Da letteratura e documentazione si evince quanto nella Toscana del Rinascimento le facciate affrescate fossero meno apprezzate di quelle graffite, anche a fronte di una maggiore padronanza della tecnica da parte degli esecutori, della durabilità nel tempo e della rapidità di realizzazione. In seguito, spesso e inspiegabilmente considerate semplici strati di protezione, anziché vere e proprie opere d’arte e d’architettura, queste superfici sono state spesso trascurate nella manutenzione o addirittura ricoperte da intonaco uniforme. Pressoché ignorate dalla storiografia, la perdita di molte fra esse si è verificata prima che un corretto processo di documentazione e salvaguardia fosse definito, con la sola sensibilità dei proprietari degli immobili a portare con sé responsabilità e onere di tutela. L’auspicio ultimo della schedatura dei palazzi pientini, nel tentativo di ricondurre il tema della facciata a graffito alla possibilità di una lettura critica, è riportare il tema a dignità di argomento di studio, mai esplicitamente negata, ma certo sminuita, in secoli di disattenzione