171 research outputs found
Differential equations for real-structured defectivity measures.
No full textLet be a real matrix with all distinct eigenvalues. We propose a new method for the computation of the distance of the matrix from the set of real defective matrices, i.e., the set of those real matrices with at least one multiple eigenvalue with algebraic multiplicity larger than its geometric multiplicity.
For 0 < \eps \le w_\R(A), this problem is closely related to the computation of the most ill-conditioned \eps-pseudoeigenvalues of , that is points in the \eps-pseudospectrum of characterized by the highest condition number.
The method we propose couples a system of differential equations on a low rank manifold which determines the \eps-pseudoeigenvalue closest to coalesce, with a fast Newton-like iteration aiming to determine the minimal value \eps such that an \eps-pseudoeigenvalue becomes defective.
The method has a local behaviour; this means that in general we find upper bounds for . However, they usually provide good approximations, in those (simple) cases where we can check this.
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The methodology can be extended to a structured matrix, where it is required that the distance is computed within some manifold defining the structure of the matrix. In this paper we extensively examine the case of real matrices. As far as we know, there do not exist methods in the literature able to compute such distance
Architecture and Decoration of the Propylon at Seuthopolis
No full textThe architectural and decorative dataset concerning Seuthopolis, the royal capital of the Odrysian Kingdom in the Tundzha Valley (today Bulgaria), remains notably limited, hindering a full appreciation of its original grandeur. This article addresses this gap by presenting newly (re)discovered findings related to the propylon of the royal palace (basileion) within the fortified citadel at the northeastern corner of the city. This represents the first attempt to reconstruct the architectural and decorative features of this significant structure based on material evidence. We also explore a potential connection between Seuthopolis and Samothrace, specifically the influence of the cult of the Great Gods, suggesting that decorative elements of Samothrace may have been replicated at Seuthopolis. In a broader context, this analysis of architectural marbles paves the way for a reassessment of the debated locations of both the royal palace and the temple of the Great Gods in the city. Our study also aims to shed light on the political dynamics between the Odrysian and Macedonian royal families, particularly in the aftermath of Macedonian expansion into Thrace during the 4th century BC. Ultimately, the findings contribute to a deeper understanding of the Macedonian role in the dissemination of North Aegean religious practices and architectural styles in the region
Clinical markers predictive of primary inefficacy: a "real life" retrospective study in psoriatic patients treated with etanercept.
No full textInfluence of body mass index and weight on etanercept efficacy in patients with psoriasis: A retrospective study
No full textAim To investigate the role of body mass index (BMI) and weight in the long-term efficacy of etanercept in patients with psoriasis. Methods Medical records were retrospectively analysed. Extracted data included weight, BMI, comorbidities and psoriasis area severity index (PASI). Patients were stratified by weight (<80kg or 80kg) and BMI (healthy, BMI 22 - 24.99kg/m(2); overweight, BMI 25 - 29.99kg/m(2); obese, BMI 30kg/m(2)). Results The study included 66 patients. Body weight had no effect on etanercept efficacy. There was a significant reduction in etanercept efficacy in obese patients (n=12) compared with healthy weight (n=33) or overweight (n=21) patients. Conclusion Obesity has a negative effect on the efficacy of etanercept in psoriasis
Updating the water budget of the Gran Sasso carbonate fractured/karstified aquifer (Central Italy) for a sustainable management of groundwater resources
No full textKarst aquifers are fundamental in the water supply of European countries, where outcrops of carbonate rocks are very common, providing abundant groundwater resources. The Gran Sasso karst aquifer, selected as representative study area for Italy in the EU-funded KARMA project, is characterized by both high percentage of withdrawals for drinking purposes and significant interaction between groundwater and underground works. The recharge evaluation of the aquifer has been carried out considering the 2001–2020 monitoring period, comparing three different methods: the Turc and APLIS methods, on annual scale, and the Thornthwaite method, on monthly scale, territorially distributed by 100 x 100 m cells on GIS basis. The total recharge considers not only rainfall but also the contribution of snow melting on infiltration. The results show similar mean recharge values in 2001–2020 for all methods, corresponding to 19.9, 18.5, and 19.4 m3/s, respectively, from Turc, Thornthwaite, and APLIS methods. A significant contribution to recharge from snowmelt has been confirmed (3.2 m3/s included in the above-mentioned values). These values can be considered reliable with respect to real discharge of the regional aquifer. The obtained results can be used to provide updated information to the drinking water companies for a suitable management of the available resource
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