ALBERT

Description: We present a brief overview of some key concepts in the theory of generalized complex manifolds. This new geometry interpolates, so to speak, between symplectic geometry and complex geometry. As such it provides an ideal framework to analyze thermodynamical fluctuation theory in the presence of gravitational fields. To illustrate the usefulness of generalized complex geometry, we examine a simplified version of the Unruh effect: the thermalising effect of gravitational fields on the Schroedinger wavefunction.

Description: For over 140 years, the habitat of Socorro Island in the Mexican Pacific has been altered by the presence of exotic sheep. Overgrazing, jointly with tropical storms, has caused soil erosion, and more than 2000 hectares of native vegetation have been lost. Sheep eradication was conducted from 2009 to 2012. Since then, the vegetation has begun to recover passively, modifying soil properties. The objective of our study was to verify that this island was resilient enough to be recovered and in a relatively short time scale. To confirm our hypothesis, we analyzed changes in the physical-chemical properties of the soil and vegetation cover, the last one in different times and habitats after sheep eradication. The change in vegetation cover was estimated by comparing the normalized difference vegetation index (NDVI) between 2008 and 2013. In sites altered by feral sheep, soil compaction was assessed, and soil samples were taken, analyzing pH, electrical conductivity, organic carbon, total nitrogen, phosphorus, calcium, and magnesium. After a year of total sheep eradication, clear indications in the recovery of vegetation cover and improvement of soil quality parameters were observed and confirmed, specifically compaction and nitrogen, organic carbon, phosphorus, and calcium. The results seem to support our hypothesis.

Description: Entropy, Vol. 20, Pages 247: On the Contact Geometry and the Poisson Geometry of the Ideal Gas Entropy doi: 10.3390/e20040247 Authors: J.M. Isidro P. de Córdoba We elaborate on existing notions of contact geometry and Poisson geometry as applied to the classical ideal gas. Specifically, we observe that it is possible to describe its dynamics using a 3-dimensional contact submanifold of the standard 5-dimensional contact manifold used in the literature. This reflects the fact that the internal energy of the ideal gas depends exclusively on its temperature. We also present a Poisson algebra of thermodynamic operators for a quantum-like description of the classical ideal gas. The central element of this Poisson algebra is proportional to Boltzmann’s constant. A Hilbert space of states is identified and a system of wave equations governing the wavefunction is found. Expectation values for the operators representing pressure, volume and temperature are found to satisfy the classical equations of state.

Description: Sustainability, Vol. 10, Pages 2185: Lessons for Sustainable Development: Marine Mammal Conservation Policies and Its Social and Economic Effects Sustainability doi: 10.3390/su10072185 Authors: Nahieli Manjarrez-Bringas Eugenio Alberto Aragón-Noriega Luis Felipe Beltrán-Morales Michael Victor Cordoba-Matson Alfredo Ortega-Rubio The objective of this research is to assess the main social and economic effects on local fishermen in El Golfo de Santa Clara, as a result of the severe fishing restrictions enforced to protect the marine mammal “vaquita” (Phocoena sinus). Sustainable development includes natural resources conservation and the improvement of the social and economic conditions of local inhabitants. In Mexico, the vaquita is in imminent danger of extinction. It is a marine cetacean endemic to the Upper Gulf of California. Conservation measures to save this species, such as gear-switching and transformation subsidies from fishing activities to tourist services, have caused severe social and economic impacts on the local fishermen of this region. Presently, it is estimated that there are only 30 vaquita individuals left in the wild, and none are in captivity. In this study, we conduct surveys of the human local population involved in the incidental bycatch fishing of the vaquita, and also use secondary sources to come up with recommendations, based on taking into account stakeholder needs. For this fishing community the economic and social problems have worsened because currently there are limited economic activity options in the area for the human population, and the vaquita population continues to decline. Recommendations are offered to contribute to the ecological sustainability of this species, and for economic and social sustainability of local fishermen.

Description: Entropy, Vol. 20, Pages 554: On the van der Waals Gas, Contact Geometry and the Toda Chain Entropy doi: 10.3390/e20080554 Authors: Diego Alarcón P. Fernández de Córdoba J. M. Isidro Carlos Orea A Toda–chain symmetry is shown to underlie the van der Waals gas and its close cousin, the ideal gas. Links to contact geometry are explored.

Description: A dynamical estimate is given for the Boltzmann entropy of the Universe, under the simplifying assumptions provided by Newtonian cosmology. We first model the cosmological fluid as the probability fluid of a quantum-mechanical system. Next, following current ideas about the emergence of spacetime, we regard gravitational equipotentials as isoentropic surfaces. Therefore, gravitational entropy is proportional to the vacuum expectation value of the gravitational potential in a certain quantum state describing the matter contents of the Universe. The entropy of the matter sector can also be computed. While providing values of the entropy that turn out to be somewhat higher than existing estimates, our results are in perfect compliance with the upper bound set by the holographic principle.

Description: Entropy, Vol. 20, Pages 83: On the Holographic Bound in Newtonian Cosmology Entropy doi: 10.3390/e20020083 Authors: José Isidro Pedro Fernández de Córdoba The holographic principle sets an upper bound on the total (Boltzmann) entropy content of the Universe at around 10 123 k B ( k B being Boltzmann’s constant). In this work we point out the existence of a remarkable duality between nonrelativistic quantum mechanics on the one hand, and Newtonian cosmology on the other. Specifically, nonrelativistic quantum mechanics has a quantum probability fluid that exactly mimics the behaviour of the cosmological fluid, the latter considered in the Newtonian approximation. One proves that the equations governing the cosmological fluid (the Euler equation and the continuity equation) become the very equations that govern the quantum probability fluid after applying the Madelung transformation to the Schroedinger wavefunction. Under the assumption that gravitational equipotential surfaces can be identified with isoentropic surfaces, this model allows for a simple computation of the gravitational entropy of a Newtonian Universe. In a first approximation, we model the cosmological fluid as the quantum probability fluid of free Schroedinger waves. We find that this model Universe saturates the holographic bound. As a second approximation, we include the Hubble expansion of the galaxies. The corresponding Schroedinger waves lead to a value of the entropy lying three orders of magnitude below the holographic bound. Current work on a fully relativistic extension of our present model can be expected to yield results in even better agreement with empirical estimates of the entropy of the Universe.

Description: Abies spp. in general have been shown to need a period of cold stratification to break dormancy and germinate, but this can be very time consuming. In this study, hydropriming by itself and in combination with biopriming was carried out on Abies hickelii and Abies religiosa seeds. For biopriming, three species of plant growth promoting rhizobacteria ( Pseudomonas fluorescens, P. putida and Bacillus subtilis) were tested. The purpose was to determine if germination and growth could be improved for these two endangered species. Our results demonstrated that treating A. hickelii and A. religiosa with both hydropriming and biopriming with certain strains of Plant Growth-Promoting Rhizobacteria (PGPR) could improve germination rates up to 91% for A. hickelii and up to 68% for A. religiosa. Importantly, these treatments showed no significant negative impact on the growth of A. religiosa and actually improved growth in A. hickelii. The application of both hydropriming and biopriming offer possibly an alternative methodology to improve germination, survival and preservation of these fir tree species of Mexico that are at risk of extinction.

Description: Quantum mechanics has been argued to be a coarse-graining of some underlying deterministic theory. Here we support this view by establishing a map between certain solutions of the Schroedinger equation, and the corresponding solutions of the irrotational Navier–Stokes equation for viscous fluid flow. As a physical model for the fluid itself we propose the quantum probability fluid. It turns out that the (state-dependent) viscosity of this fluid is proportional to Planck’s constant, while the volume density of entropy is proportional to Boltzmann’s constant. Stationary states have zero viscosity and a vanishing time rate of entropy density. On the other hand, the nonzero viscosity of nonstationary states provides an information-loss mechanism whereby a deterministic theory (a classical fluid governed by the Navier–Stokes equation) gives rise to an emergent theory (a quantum particle governed by the Schroedinger equation).

Description: The classical thermostatics of equilibrium processes is shown to possess a quantum mechanical dual theory with a finite dimensional Hilbert space of quantum states. Specifically, the kernel of a certain Hamiltonian operator becomes the Hilbert space of quasistatic quantum mechanics. The relation of thermostatics to topological field theory is also discussed in the context of the approach of the emergence of quantum theory, where the concept of entropy plays a key role.