Studies on generalized Yule models

We present a generalization of the Yule model for macroevolution in which, for the appearance of genera, we consider point processes with the order statistics property, while for the growth of species we use nonlinear time-fractional pure birth processes or a critical birth-death process. Further, in specific cases we derive the explicit form of the distribution of the number of species of a genus chosen uniformly at random for each time. Besides, we introduce a time-changed mixed Poisson process with the same marginal distribution as that of the time-fractional Poisson process.Comment: Published at https://doi.org/10.15559/18-VMSTA125 in the Modern Stochastics: Theory and Applications (https://vmsta.org/) by VTeX (http://www.vtex.lt/

Environmental proactivity and firms' performance: Mediation effect of competitive advantages in Spanish wineries

The main aim of this paper is to show the extent to which environmental proactivity is able to generate competitive advantages in a firm in order to improve their economic-financial performance by introducing the role of managerial perception into the analysis. This study focuses on Spanish wineries and their environmental practices and covers a total of 4598 wineries with a sample of 142 valid responses during the month of November 2015. The results can be summarized as follows. Firstly, there is positive environmental proactivity in terms of obtaining both cost-based and differentiation-based competitive advantages. Likewise, this proactivity has a positive impact on the manager’s perception of performance. Secondly, obtaining differentiation-based competitive advantages has a positive impact on the manager’s perception of performance although a negative impact on performance itself. There is, however, no significant evidence of the impact of cost-based competitive advantages on financial performance nor on the perception of performance itself, nor the impact of environmental proactivity on financial performance

Chemical Stabilization of Perovskite Solar Cells with Functional Fulleropyrrolidines.

While perovskite solar cells have invigorated the photovoltaic research community due to their excellent power conversion efficiencies (PCEs), these devices notably suffer from poor stability. To address this crucial issue, a solution-processable organic chemical inhibition layer (OCIL) was integrated into perovskite solar cells, resulting in improved device stability and a maximum PCE of 16.3%. Photoenhanced self-doping of the fulleropyrrolidine mixture in the interlayers afforded devices that were advantageously insensitive to OCIL thickness, ranging from 4 to 190 nm. X-ray photoelectron spectroscopy (XPS) indicated that the fulleropyrrolidine mixture improved device stability by stabilizing the metal electrode and trapping ionic defects (i.e., I-) that originate from the perovskite active layer. Moreover, degraded devices were rejuvenated by repeatedly peeling away and replacing the OCIL/Ag electrode, and this repeel and replace process resulted in further improvement to device stability with minimal variation of device efficiency

Content and Meaning Constitutive Inferences

A priori theories of justification of logic based on meaning often lead to trouble, in particular to issues concerning circularity. First, I present Boghossian’s a prioriview. Boghossian maintains the rule-circular justifications from a conceptual role semantics. However, rule-circular justifications are problematic. Recently, Boghossian (Boghossian, 2015) has claimed that rules should be thought of as contents and contents as abstract objects. In this paper, I discuss Boghossian’s view. My argumentation consists of three main parts. First, I analyse several arguments to show that in fact, Boghossian’s inferentialist solution is not fully satisfying. Second, I discuss the matter further, if one accepts that basic logical rules are constitutive of meaning, that is, they constitute the logical concepts and the content of a rule is an abstract object, then abstract objects — like, for example, rules — could be constitutive of meaning. The question is whether conceptual priority is in the judgment or in the object and what theory of content is pursued. Grasping content as a matter of knowing how a word or concept behaves in inferences is not completely explicative. Finally, I contend that rules come to exist as a result of certain kinds of mental action. These actions function as constitutive norms. Logical rules are not abstract objects but ideal. What one construes as norms or rules of content may involve idealization, but this is because we share a language

High Scale Boundary Conditions in Models with Two Higgs Doublets

We investigate high scale boundary conditions on the quartic Higgs-couplings and their $\beta$-functions in the Type-II Two Higgs Doublet Model and the Inert Doublet Model. These conditions are associated with two possible UV physics scenarios: the Multiple Point Principle, in which the potential exhibits a second minimum at $M_{Pl}$, and Asymptotic Safety, where the scalar couplings run towards an interacting UV fixed point at high scales. We employ renormalisation group running at two-loops and apply theoretical and experimental constraints to their parameter spaces. We find neither model can simultaneously accommodate the MPP whilst also providing realistic masses for both the Higgs and the top quark. However, we do find regions of parameter space compatible with Asymptotic Safety.Comment: 25 pages, 13 figures (25 plots); v3: version accepted for publicatio