Can Bohmian Mechanics Be Made Background Independent?

The paper presents an inquiry into the question regarding the compatibility of Bohmian mechanics, intended as a non-local theory of moving point-like particles, with background independence. This issue is worth being investigated because, if the Bohmian framework has to be of some help in developing new physics, it has to be compatible with the most well-established traits of modern physics, background independence being one of such traits. The paper highlights the fact that the notion of background independence in the context of spacetime physics is slippery and interpretation-laden. It is then suggested that the best-matching framework developed by Julian Barbour might provide a robust enough meaning of background independence. The structure of Bohmian dynamics is evaluated against this framework, reaching some intermediate results that speak in favor of the fact that Bohmian mechanics can be made background independent.Comment: 24 pages, forthcoming in Studies in History and Philosophy of Modern Physic

General Covariance, Diffeomorphism Invariance, and Background Independence in 5 Dimensions

The paper considers the "GR-desideratum", that is, the way general relativity implements general covariance, diffeomorphism invariance, and background independence. Two cases are discussed where 5-dimensional generalizations of general relativity run into interpretational troubles when the GR-desideratum is forced upon them. It is shown how the conceptual problems dissolve when such a desideratum is relaxed. In the end, it is suggested that a similar strategy might mitigate some major issues such as the problem of time or the embedding of quantum non-locality into relativistic spacetimes

Subordinated Public Participation Loans for Financing Motorway concessions in Spain.

Budgetary constraints are prompting many governments to encourage private financing of transportation infrastructure through concession contracts. The length and complexity of such contracts often force governments to provide fiscal support in order to increase the attractiveness of concessions. This paper deals with a new public support mechanism for concession contracts, called Subordinated Public Participation Loans (SPPLs), which has been implemented in Spain during the last few years. SPPLs are subordinated loans that may be given by the government to the concessionaire if the latter requests them in the tender. SPPLs are defined in such a way that the increase in interest accrued will reflect the traffic level: the larger the traffic the larger will be the SPPL yield. SPPLs have a twofold goal. First, they increase the financial attractiveness, and hence the feasibility, of concessions contracts. And second, they set up a fairer risksharing approach between the public and the private sector. This paper analyzes the implications of SPPLs in motorway concessions by contrasting the theoretical analysis with the empirical results obtained form the tender of five motorway concessions in Spain. Overall we found that the implementation of this mechanism may be considered a success. In spite of that, we propose some measures that may contribute to improving the SPPL performance in the future

Relationalism about mechanics based on a minimalist ontology of matter

This paper elaborates on relationalism about space and time as motivated by a minimalist ontology of the physical world: there are only matter points that are individuated by the distance relations among them, with these relations changing. We assess two strategies to combine this ontology with physics, using classical mechanics as example: the Humean strategy adopts the standard, non-relationalist physical theories as they stand and interprets their formal apparatus as the means of bookkeeping of the change of the distance relations instead of committing us to additional elements of the ontology. The alternative theory strategy seeks to combine the relationalist ontology with a relationalist physical theory that reproduces the predictions of the standard theory in the domain where these are empirically tested. We show that, as things stand, this strategy cannot be accomplished without compromising a minimalist relationalist ontology

On the Prospects of a de Broglie-Bohm-Barbour-Bertotti Theory

Pure shape dynamics (PSD) is a novel implementation of the relational framework originally proposed by Julian Barbour and Bruno Bertotti. PSD represents a Leibnizian/Machian approach to physics in that it completely describes the dynamical evolution of a physical system without resorting to any structure external to the system itself. The chapter discusses how PSD effectively describes a de Broglie-Bohm N-body system and the conceptual benefits of such a relational description. The analysis will highlight the new directions in the quest for an understanding of the nature of the wave function that are opened up by a modern relationalist elaboration on de Broglie's and Bohm's original insights.Comment: 20 pages. Accepted for publication in A. Oldofredi (Ed.), "Guiding Waves in Quantum Mechanics: 100 Years of de Broglie-Bohm Pilot-Wave Theory," Oxford University Pres

How Humean is Bohumianism?

An important part of the influential Humean doctrine in philosophy is the supervenience principle (sometimes referred to as the principle of separability). This principle asserts that the complete state of the world supervenes on the intrinsic properties of its most fundamental components and their spatiotemporal relations (the so-called Humean mosaic). There are well-known arguments in the literature purporting to show that in quantum mechanics the Humean supervenience principle is violated, due to the existence of entangled states. Recently, however, arguments have been presented to the effect that the supervenience principle can be defended in Bohmian mechanics. The key element of this strategy lies in the observation that according to Bohmian mechanics the fundamental facts about particles are facts about their spatial locations, and moreover, for any proper subsystem of the world its state may non-trivially depend on the spatial configuration of the rest of the universe. Thus quantum-mechanical states of subsystems do not represent their intrinsic properties but rather characterize their relations with the environment. In this paper we point out the worry that this Bohmian strategy --known as Bohumianism-- saves the letter but not the spirit of the Humean doctrine of supervenience, since it prima facie violates another seemingly important Humean principle, which we call Strong Supervenience and whose denial implies the existence of necessary connections among distinct individuals. We argue that the best defense for Bohumians is to question the fundamental existence of complex physical systems and their states by treating any reference to them as a convenient description of the underlying collection of Bohmian particles. We consider several pros and cons of this strategy

Pharmaceutical Lipid Formulations of Amphotericin B for the Treatment of Human Leishmaniasis

The first description of a skin lesion, “Delhi button” dates back to Cunningham (1885) who reported the presence, on tissue sections, of bodies of 12.6 μm x 8.8 μm, presumably parasitic macrophages, containing "nucleoid bodies" which he believed to be spores belonging to Mycetozoa. But the first to describe the Leishmania parasite was, in 1898, a young man Russian military surgeon, named Borowsky. He investigated the cause of the "Sart button" at the military hospital in Tashkent. This paper, through the analysis of the studies carried out over the years proposes a description of the different therapeutic strategies for the treatment of leishmaniasis (advantages and criticalities of the same) and in particular an analysis detailed description of Amphotericin B, its mechanisms of action and pharmaceutical formulations, especially liposomal ones

Phytotherapeutic Strategy as a Powerful Approach for the Prevention and Therapy of Alzheimer's Disease

According to the World Health Organization and Alzheimer's Disease International there were about 35.6 million people suffering from dementia in 2010 with an estimated double increase in 2030, triple in 2050, with 7.7 million new cases. per year (1 every 4 seconds) and with an average survival, after diagnosis, of 4-8 years. Alzheimer's disease is generally associated with the elderly and with aging, which is why the symptoms of this disease are often ignored. In reality, Alzheimer's seems to affect people between the ages of 65 and 70, while more precocious and severe cases occur before the age of 65 and aging and stress can only worsen the symptoms. The sex most affected is female. It has been noted that dementia in industrialized countries affects about 8% of people over 65 and rises to over 20% after the age of eighty. This suggests that, very often, different factors such as lifestyle, stress and nutrition influence the speed and onset of this disease. To date, it is now known that the affected organ is the brain, such a complex and fascinating organ, but above all difficult to study and treat due to its complicated structure and organization. In fact, the treatment is based on pharmacological therapies, but although numerous research studies are underway to identify effective therapies in the treatment of dementia, the available interventions have not given definitive solutions to treat 6 this pathology. The therapeutic strategies available for dementias in addition to those of a pharmacological type are: psychosocial and integrated management for continuity of care and also psychotherapeutic support for families. In recent decades, however, we have focused on another aspect of this disease: how to prevent it? And this is where the use of medicinal plants comes into play to prevent and mitigate the onset of this disease. This type of approach is based on the use of medicinal plants; in particular the phytocomplex, contained in them, owes its activity to the synergy between its components. Plants produce secondary metabolites, organic compounds, which unlike the primary ones such as carbohydrates, proteins and fats, do not participate in the normal development and growth of the plant, but are developed by the plant to mediate the relationship with the external environment, carrying out important activities such as facilitate reproduction and therefore attract pollinating insects or act as a deterrent to the external environment. These compounds have very complex chemical structures that can be used as guiding compounds for the discovery of new drugs or for the development of nutraceutical or cosmeceutical remedies. In phytotherapy, medicinal plants that can be used for preventive purposes or as adjuvants in the treatment of Alzheimer's, are identified essentially starting from their antioxidant, anticholinesterase and anti-inflammatory properties, or as very often happens from all three. This paper reviews the plant species used in the prevention of Alzheimer's disease and as adjuvants in the treatment of Alzheimer's

Inversión en infraestructuras: Cuando lo público y lo privado se dan la mano

Basándonos en datos de seis economías de América Latina, así como de España, destacamos el importante papel que la inversión privada ha tenido en el crecimiento de los países estudiados. Una vez puesto de manifiesto cómo la actual crisis económica global fuerza a la austeridad presupuestaria, proponemos el desarrollo de medidas que permitan mantener un esfuerzo inversor creciente perfeccionando las fórmulas de colaboración público privada ya existentes en los países en estudio

Recomendaciones para una política de infraestructuras ante la actual coyuntura económica

En pocas coyunturas económicas como la que atraviesa España se ha hecho tan palpable una doble conjunción de factores: la necesidad de mantener un adecuado nivel de inversión en infraestructuras como motor de crecimiento económico del país, frente a la necesidad de controlar el creciente déficit de las cuentas públicas. En el presente artículo se analiza el impacto en las políticas de provisión de infraestructuras de la contención del déficit público en los Presupuestos Generales del Estado, haciendo especial hincapié en las fórmulas ofrecidas por el Plan Extraordinario de Infraestructuras