A derivation of a microscopic entropy and time irreversibility from the discreteness of time

All of the basic microsopic physical laws are time reversible. In contrast, the second law of thermodynamics, which is a macroscopic physical representation of the world, is able to describe irreversible processes in an isolated system through the change of entropy S larger than 0. It is the attempt of the present manuscript to bridge the microscopic physical world with its macrosocpic one with an alternative approach than the statistical mechanics theory of Gibbs and Boltzmann. It is proposed that time is discrete with constant step size. Its consequence is the presence of time irreversibility at the microscopic level if the present force is of complex nature (i.e. not const). In order to compare this discrete time irreversible mechamics (for simplicity a classical, single particle in a one dimensional space is selected) with its classical Newton analog, time reversibility is reintroduced by scaling the time steps for any given time step n by the variable sn leading to the Nose-Hoover Lagrangian. The corresponding Nose-Hoover Hamiltonian comprises a term Ndf *kB*T*ln(sn) (with kB the Boltzmann constant, T the temperature, and Ndf the number of degrees of freedom) which is defined as the microscopic entropy Sn at time point n multiplied by T. Upon ensemble averaging this microscopic entropy Sn in equilibrium for a system which does not have fast changing forces approximates its macroscopic counterpart known from thermodynamics. The presented derivation with the resulting analogy between the ensemble averaged microscopic entropy and its thermodynamic analog suggests that the original description of the entropy by Boltzmann and Gibbs is just an ensemble averaging of the time scaling variable sn which is in equilibrium close to 1, but that the entropy term itself has its root not in statistical mechanics but rather in the discreteness of time

Healthcare Robotics

Robots have the potential to be a game changer in healthcare: improving health and well-being, filling care gaps, supporting care givers, and aiding health care workers. However, before robots are able to be widely deployed, it is crucial that both the research and industrial communities work together to establish a strong evidence-base for healthcare robotics, and surmount likely adoption barriers. This article presents a broad contextualization of robots in healthcare by identifying key stakeholders, care settings, and tasks; reviewing recent advances in healthcare robotics; and outlining major challenges and opportunities to their adoption.Comment: 8 pages, Communications of the ACM, 201

Building Community and Fostering Excellence through the Writing Process

The purpose of this article is to share a successful model for incorporating community building and academic achievement into an honors program by creating a public forum for honors students to display their work. According to what Roger McCain has described as a fundamental humanistic view of a university honors education, each student possesses a hierarchy of needs, which includes the need for individual value to be “recognized and confirmed, so that the individual [student] develops a sense of his or her own unique identity” (2). I suggest that honors writing courses, in particular, can foster what McCain contends is the “central objective” of an honors program: “the academic challenge needed by students of excellent academic ability and motivation, and concurrently the recognition of their success in meeting that challenge” (McCain, my emphasis). Creating an academically challenging curriculum to meet the needs of university honors students is the charge of honors programs, but beyond good grades assigned to student work and the honors designation conferred upon graduation, how do we acknowledge student success in those programs? The following briefly outlines the symposia that our Honors Writing Program, which includes a core faculty of seven and a student population of approximately 150 first-year students, developed to recognize just such student success beyond the classroom. These symposia serve not only to expand our concept of the “writing process” but simultaneously redefine our Honors Program community and meet the specific humanistic needs of our honors students

Renormalization of a gapless Hartree-Fock approximation to a theory with spontaneously broken O(N)-symmetry

The renormalization of a gapless Phi-derivable Hartree--Fock approximation to the O(N)-symmetric lambda*phi^4 theory is considered in the spontaneously broken phase. This kind of approach was proposed by three of us in a previous paper in order to preserve all the desirable features of Phi-derivable Dyson-Schwinger resummation schemes (i.e., validity of conservation laws and thermodynamic consistency) while simultaneously restoring the Nambu--Goldstone theorem in the broken phase. It is shown that unlike for the conventional Hartree--Fock approximation this approach allows for a scale-independent renormalization in the vacuum. However, the scale dependence still persists at finite temperatures. Various branches of the solution are studied. The occurrence of a limiting temperature inherent in the renormalized Hartree--Fock approximation at fixed renormalization scale mu is discussed.Comment: 11 pages, 14 figures / Version accepted by Phys. Rev. D: title and one reference change

Editorial

Sustainable Development Goals implementation in the context of South Suda

Simple Tools with Nontrivial Implications for Assessment of Hypothesis-Evidence Relationships: The Interrogator’s Fallacy

This paper takes a mathematical analysis technique derived from the Interrogator’s Fallacy (in a legal context), expands upon it to identify a set of three interrelated probabilistic tools with wide applicability, and demonstrates their ability to assess hypothesis-evidence relationships associated with important problem

Fossil insects from the Middle Ecca (Lower permian) of southern Africa

Main articleThree insects are recorded from carbonaceous shales of Middle Ecca age from Hammanskraal, near Pretoria. Thaumalophora pranotalis gen. et sp. nov., is an aquatic nymph of the Paraplecoptera showing lateral abdominal gills. Sysciophlebia kovacsae sp. nov. is a tegmen of a spiloblattinid cockroach. The third specimen is a small protopsyllidiid nymph. Only three insects of greater age are known from southern Africa.Non

Screening for broad mite susceptibility in Rhododendron simsii hybrids

Broad mite Polyphagotarsonemus latus, is a key pest of pot azalea (Rhododendron simsii Planch hybrids). No information on variation in susceptibility or potential tolerance within these plants is available to date. We evaluated a selection of 32 Rhododendron cultivars, mainly Rhododendron simsii hybrids, for susceptibility to broad mite. The plants were artificially infested in a greenhouse by surrounding each azalea with four broad mite-infested English ivy plants (Hedera helix). Broad mite infestation was evaluated by counting the number of broad mites per shoot tip and assigning a damage rate. Results indicated a comparable infestation rate expressed as the number of mites on all cultivars at the initial stage of the experiments. Correlations between the average damage rate and the number of broad mites per shoot tip on all cultivars at different time intervals were significantly positive, although low, in each experiment, with R-2-values of 0.14 and 0.61. At the end of the experiments significant differences in susceptibility between the evaluated cultivars were observed. The cultivars, 'Emil De Coninck' and 'Mont Blanc' were rated as the most susceptible, whereas 'Mistral' and its bud sport 'Elien' were tolerant towards the broad mite, because damage rates were low and very few broad mites were found

A FOSSIL INSECT FROM THE DWYKA SERIES OF RHODESIA

Hadenlomoides dwykensis, gen. et sp. nov. (Paraplecoptera: Hadentomidael is the oldest recorded insect in the southern hemisphere. It is similar to Hadenlomum americanum from the Upper Carboniferous of North America. The close relationship between these two species tends to support the view that at least part of the Dwyka Series extends below the Permian into the Upper Carboniferous