The problem of artificial precision in theories of vagueness: a note on the role of maximal consistency

The problem of artificial precision is a major objection to any theory of vagueness based on real numbers as degrees of truth. Suppose you are willing to admit that, under sufficiently specified circumstances, a predication of "is red" receives a unique, exact number from the real unit interval [0,1]. You should then be committed to explain what is it that determines that value, settling for instance that my coat is red to degree 0.322 rather than 0.321. In this note I revisit the problem in the important case of {\L}ukasiewicz infinite-valued propositional logic that brings to the foreground the role of maximally consistent theories. I argue that the problem of artificial precision, as commonly conceived of in the literature, actually conflates two distinct problems of a very different nature.Comment: 11 pages, 2 table

Coupling dark energy to dark matter inhomogeneities

We propose that dark energy in the form of a scalar field could effectively couple to dark matter inhomogeneities. Through this coupling energy could be transferred to/from the scalar field, which could possibly enter an accelerated regime. Though phenomenological, this scenario is interesting as it provides a natural trigger for the onset of the acceleration of the universe, since dark energy starts driving the expansion of the universe when matter inhomogeneities become sufficiently strong. Here we study a possible realization of this idea by coupling dark energy to dark matter via the linear growth function of matter perturbations. The numerical results show that it is indeed possible to obtain a viable cosmology with the expected series of radiation, matter and dark-energy dominated eras. In particular, the current density of dark energy is given by the value of the coupling parameters rather than by very special initial conditions for the scalar field. In other words, this model - unlike standard models of cosmic late acceleration - does not suffer from the so-called "coincidence problem" and its related fine tuning of initial conditions.Comment: 12 pages, 2 figures; revised and expanded discussion of proposed interaction and figures; matches version accepted for publication in Physics of the Dark Univers

Astrophysicists and physicists as creators of ArXiv-based commenting resources for their research communities. An initial survey

This paper conveys the outcomes of what results to be the first, though initial, overview of commenting platforms and related 2.0 resources born within and for the astrophysical community (from 2004 to 2016). Experiences were added, mainly in the physics domain, for a total of 22 major items, including four epijournals, and four supplementary resources, thus casting some light onto an unexpected richness and consonance of endeavours. These experiences rest almost entirely on the contents of the database ArXiv, which adds to its merits that of potentially setting the grounds for web 2.0 resources, and research behaviours, to be explored. Most of the experiences retrieved are UK and US based, but the resulting picture is international, as various European countries, China and Australia have been actively involved. Final remarks about creation patterns and outcome of these resources are outlined. The results integrate the previous studies according to which the web 2.0 is presently of limited use for communication in astrophysics and vouch for a role of researchers in the shaping of their own professional communication tools that is greater than expected. Collaterally, some aspects of ArXiv s recent pathway towards partial inclusion of web 2.0 features are touched upon. Further investigation is hoped for.Comment: Journal article 16 page

Delegation, Knowledge Integration, and Cooperation: How to Solve Problems of Coordination in Structural Fund Programs. Findings From Comparative Case Studies in the South of Italy

European cohesion policies are increasingly relying on grassroots networks tapping into tacit knowledge and participatory decision-making processes. Regional governments delegate their decision making power to local institutions with the assumption that local agents possess both contextual knowledge and political legitimacy to integrate different policy measures in a cooperative fashion. Delegation of decision making power is therefore presumed to minimize the unintended or conflicting outcomes emerging, for instance, when environmental protection and infrastructure building are not designed consistently to local contextual needs nor are these pursued through a cooperative effort of local networks of actors. Different agents, including resource users and government agencies try to work together to resolve shared dilemmas of coordination, as an increasingly common alternative to centralized institutions. Coordination consists of managing interdependencies among multiple individuals or organizations involved in the overall program or project management. Several studies classify different types of coordination mechanisms, including standards, hierarchy, targets or plans, slack resources, vertical information systems, direct contact, liaison roles, task forces, and integrating roles. Other ways of classifying coordination include formal impersonal, formal interpersonal, and informal interpersonal; non-coordination, standards, schedules and plans, mutual adjustment, and teams; task-task, task-resource, and resource-resource coordination; vertical and horizontal coordination; coordination by programming and by feedback; and coordination by standards, plans, and mutual adjustment. Building upon a current field research in four regions of the South of Italy, this paper examines how coordination occurs across local development programs, which are embedded within multilevel governance structures and relations. The paper presents a number of cases of local collaborations in which large numbers of local actors representing a wide range of contending groups have, with the help of mediating institutions, worked out agreements for integrating development programs. In some circumstances, specific coordination mechanisms encouraged consensus building offering all relevant groups the knowledge and skills needed to participate in these negotiations. In other circumstances, though, delegation of decision making power opened the door for opportunistic participation, lacking vision and trust for mutual cooperation.

Exact spherically-symmetric inhomogeneous model with n perfect fluids

We present the exact equations governing the dynamics of a spherically-symmetric inhomogeneous model with n decoupled and non-comoving perfect fluids. Thanks to the use of physically meaningful quantities we write the set of 3+2n equations in a concise and transparent way. The n perfect fluids can have general equations of state, thus making the model extremely flexible to study a large variety of cosmological and astrophysical problems. As applications we consider a model sourced by two non-comoving dust components and a cosmological constant, and a model featuring dust and a dark energy component with negligible speed of sound.Comment: 31 pages, 11 figures; matches version accepted for publication in JCAP; added application to clustering dark energy, comparison with previous work on exact solutions, and other minor improvements/reference