1,721,136 research outputs found
Frontiers in hemodialysis: Solutions and implications of mathematical models for bicarbonate restoring
No full textAcid–base correction is one main goal of hemodialysis therapy, some aspects of which are not yet well understood. This work considers a novel mathematical model of the patients’ response to the rapid addition of base, providing closed-form analytical expressions for the bicarbonate concentration in the patient blood versus the time on dialysis, in function of the main physiological/clinical parameters. A signal processing model of the dialysis is proposed, in which the metabolic processes are represented by a combination of first-order linear systems with input step-signals that correspond to the external stimuli. The model sheds a light on important features of the therapy, highlighting the main medical implications, and revealing new challenges. With current dialysis protocols, it is shown that the base added actually decreases during the last two-thirds of the therapy, and the net amount of bicarbonate in the patient blood does not reach a steady-state value. Elaborating on the mathematical model, more sophisticated clinical protocols are suggested to counteract the potentially maladaptive patient response to treatment
Capital gains from player transfers as a value creation tool: some evidence from European listed football clubs
Full text linkPurposeThis article explores the value creation process from player sales in football to understand if the related capital gains correspond to significant increases in the stock value of selling companies. In addition, it aims to detect any potential drivers for higher (or slower) abnormal stock returns.Design/methodology/approachThe authors analyze all the capital gains of the Italian and Portuguese listed football companies (the only ones for which, based on their annual reports, it was possible to trace the net book value for each player sold and, consequently, if any, the related capital gain) from 2012 to 2020 and use event study analysis to calculate the abnormal returns of the football companies' stocks. Moreover, the authors use a multiple linear regression model to identify the factors affecting investors' reactions and value creation process intensity.FindingsThe results show that, on average, the capital gains from player transfers in football are positive income components and produce statistically significant higher abnormal returns. In addition, the authors identified some relevant drivers related to their intensity which could guide the choices of corporate executives regarding future disposals of the multi-year performance rights of players in the roster.Research limitations/implicationsThis study considers only Italian and Portuguese football listed companies. It would be helpful to consider some of the companies from other countries which are also outstanding from the sports perspective, but, in practice, it was not possible due to the impossibility to trace the net book value of the single footballers sold in those clubs' public financial disclosure.Practical implicationsThe value relevance of the capital gains from player trading activities should increase their importance, creating cascade effects on several activities generating value for football clubs (youth sector management, player scouting, technical improvement of the players). In addition, financial data show that the capital gains from player transfers are a basic income of European football clubs nowadays. Their executives consider these operations recurrent and continually search for more valuable transfers. Hence, it is reasonable to think that they (will) choose the players to sell considering both sports and financial aspects.Originality/valueTo the best of the authors' knowledge, this is the first study exploring the effects of capital gains from player trading activities on professional football clubs' stock value. The results obtained are even more relevant if one considers the importance these income components have in the profit formula of professional football clubs nowadays, also because of the negative repercussions caused by the recent COVID-19 pandemic
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Progetto per l'ampliamento della casa di riposo 'Vittorio Emanuele II' a Trani -I e II fase-. Menzione speciale della giuria
No full textBest Simultaneous Monotone Approximants in Orlicz Spaces
Full text linkLet f = (f1, , fm ), where fj belongs to the Orlicz space [0, 1], and let w = (w1, , wm ) be an m-tuple of m positive weights. If ⊂ [0, 1] is the class of nondecreasing functions, we denote by ,w(f, ) the set of best simultaneous monotone approximants to f, that is, all the elements g ∈ minimizing m j=1 1 0 (|fj − g |)wj, where is a convex function, (t) > 0 for t > 0, and (0) = 0. In this work, we show an explicit formula to calculate the maximum and minimum elements in ,w(f, ). In addition, we study the continuity of the best simultaneous monotone approximants.Fil: Levis, Fabián Eduardo. Universidad Nacional de Rio Cuarto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marano, M.. Universidad de Jaén; Españ
A New Approach to Bicarbonate Addition during Hemodialysis: Testing Model Predictions in a Patient Cohort
No full textIn this study, we present a new protocol for kidney replacement therapy (hemodialysis), based on an explicitly solvable mathematical model. With current protocols, the high and constant level of bath bicarbonate (HCO3-) used to prevent metabolic acidosis leads to very rapid delivery of HCO3- into the patient during the first part of the therapy. This rapid alkalinization elicits a robust buffer response that, paradoxically, consumes more HCO3- than is added during the remainder of the treatment. In previous studies, we developed an analytical model that allows one to quantify these events and tested alternative protocols manipulating the rate of rise in blood bicarbonate concentration (HCO3-). The protocol tested in this paper enforces a more gradual increase in blood HCO3-, by means of a model-based staircase adjustment of bath HCO3-. Model equations predict a reduction of buffer response and rate of organic acid production. These predictions are tested in 20 stable outpatients receiving hemodialysis. We find that the proposed protocol achieves the desired profile of blood HCO3- with good accuracy and reduces the total buffer response by 1/3 and the rate of lactic acid production by at least 1/4, as compared to conventional therapy. Although more studies are needed, we believe that our work will pave the way for a more rational approach to correction of acidosis during hemodialysis. Article Highlights •Our study tests an analytic model designed to enforce a more gradual rate of bicarbonate delivery during hemodialysis.•Using our model, we show that we can reduce the excessive buffer response and lactic acid production that occur with the conventional approach.•We demonstrate that our model can provide a rational approach to bicarbonate addition during treatment
Corporate Governance of Insurance Firms After Solvency II
No full textUnder Solvency II, corporate governance requirements are a complementary, but nonetheless essential, element to build a sound regulatory framework for insurance undertakings, also to address risks not specifically mitigated by the sole solvency capital requirements. After recalling the provisions of the Second Pillar concerning the system of governance, the paper highlights the emerging regulatory trends in the corporate governance of insurance firms. Among others things, it signals the exceptional extension of the duties and responsibilities assigned to the board of directors, far beyond the traditional role of both monitoring the chief executive officer, and assessing the overall direction and strategy of the business. However, a better risk governance is not necessarily built on narrow rule-based approaches to corporate governance
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