Fundamental Properties of Intensity, Form, and Motion Perception in the Visual Nervous Systems of Calliphora phaenicia and Musca domestica

Several classes of interneurons in the optic lobes and brain of the insects, Musca domestica and Calliphora phaenicia, have been studied in detail. Visual stimuli have been categorized on the basis of the properties of intensity, form, and motion. Response characteristics of the classes of neural units are described with respect to these three classes of visual stimuli. While those units that detect motion in select directions have a tonic response, form detection units have a phasic response only. Through correlation of the responses of these classes with visual stimuli, it is shown that these units integrate the responses of other units which have very small visual fields. The small-field units are presumed to integrate the output of a small group of adjacent retinula cells and to respond differentially to intensity, form, and motion. It is shown that the response of both form and motion detection units is independent of the direction of pattern intensity gradation. As a consequence of this independence, it is further shown that failure to detect motion properly must start at a spatial wavelength four times the effective sampling station spacing rather than twice as has been predicted previously

Atmospheric Influences on Cave Meteorology, Jinapsan Cave, Guam: A Drip Rate Analysis

Temperature, pressure, and relative humidity within Jinapsan Cave on Guam were compiled and analyzed over a five-month period to gain a better understanding of this environment. Temperatures within the cave hover around ~26°C with no apparent influences except the mean annual temperature, with humidity values over 90%. There is high fidelity between outside and internal air pressures indicating no pressure differential exists and pressure changes are a result of kinematic wave flow. A mild correlation exists between a cave speleothem’s drip rate and outside pressure. The cave’s tidal pool compared to oceanic tides show a lag of 1-2 hours and amplitude dampening. The tidal pool’s temperature is 25.7°C, signifying no mass transfer of water occurs. Tropical cave studies are rare, but are important for paleoclimate research using cave speleothems as proxies. This study determined cave meteorological factors that affect speleothem development to allow for more accurate paleoclimate studies

Postcard: Kansas City Commercial Club

This black and white photographic postcard features a group of people standing outside with a sign to the right of them. The sign states that this group is the Kansas City Commercial Club. Written text is to the right side of the image. Handwriting is on the back of the card.https://scholars.fhsu.edu/tj_postcards/1986/thumbnail.jp

Gate-tunable bandgap in bilayer graphene

The tight-binding model of bilayer graphene is used to find the gap between the conduction and valence bands, as a function of both the gate voltage and as the doping by donors or acceptors. The total Hartree energy is minimized and the equation for the gap is obtained. This equation for the ratio of the gap to the chemical potential is determined only by the screening constant. Thus the gap is strictly proportional to the gate voltage or the carrier concentration in the absence of donors or acceptors. In the opposite case, where the donors or acceptors are present, the gap demonstrates the asymmetrical behavior on the electron and hole sides of the gate bias. A comparison with experimental data obtained by Kuzmenko et al demonstrates the good agreement.Comment: 6 pages, 5 figure

Ultracold, radiative charge transfer in hybrid Yb ion - Rb atom traps

Ultracold hybrid ion-atom traps offer the possibility of microscopic manipulation of quantum coherences in the gas using the ion as a probe. However, inelastic processes, particularly charge transfer can be a significant process of ion loss and has been measured experimentally for the Yb$^{+}$ ion immersed in a Rb vapour. We use first-principles quantum chemistry codes to obtain the potential energy curves and dipole moments for the lowest-lying energy states of this complex. Calculations for the radiative decay processes cross sections and rate coefficients are presented for the total decay processes. Comparing the semi-classical Langevin approximation with the quantum approach, we find it provides a very good estimate of the background at higher energies. The results demonstrate that radiative decay mechanisms are important over the energy and temperature region considered. In fact, the Langevin process of ion-atom collisions dominates cold ion-atom collisions. For spin dependent processes \cite{kohl13} the anisotropic magnetic dipole-dipole interaction and the second-order spin-orbit coupling can play important roles, inducing couplingbetween the spin and the orbital motion. They measured the spin-relaxing collision rate to be approximately 5 orders of magnitude higher than the charge-exchange collision rate \cite{kohl13}. Regarding the measured radiative charge transfer collision rate, we find that our calculation is in very good agreement with experiment and with previous calculations. Nonetheless, we find no broad resonances features that might underly a strong isotope effect. In conclusion, we find, in agreement with previous theory that the isotope anomaly observed in experiment remains an open question.Comment: 7 figures, 1 table accepted for publication in J. Phys. B: At. Mol. Opt. Phys. arXiv admin note: text overlap with arXiv:1107.114

Conceptualisation and experiences of engaged citizenship as critical consciousness, transformative education and mutual joy: An autoethnography

In recent years, higher education institutions globally and in South Africa have begun to focus more on the educational potential of community-university engagement. As a result, many institutions of higher learning have been reimagining and debating the terms used to describe the engagement between students, academic staff and their community partners. At Rhodes University in Makhanda, there has been an active change in terminology, with previous “volunteerism” programmes renamed “engaged citizenship” opportunities. This article’s authors are current staff members and previous students at Rhodes University, whose university experiences were shaped by their involvement in the Rhodes University Community Engagement (RUCE) Division. Using an autoethnographic style, they reflect on their experiences as volunteers/engaged citizens. These stories and reflections serve to highlight how the term engaged citizenship better encapsulates the nature of the involvement of students who are actively involved in their communities: where these community engagement spaces provide mutual benefit and mutual joy, deep learning and platforms for individuals to direct their agency to socially just ends. Ultimately, these narratives aim to illustrate the deeply personal ways in which the practice of engaged citizenship has shaped the authors’ own growth and generated the holistic and transformative educational experience for which higher education institutions strive

Einstein's cosmic model of 1931 revisited: an analysis and translation of a forgotten model of the universe

We present a translation and analysis of a cosmic model published by Einstein in 1931. The paper, which is not widely known, features a model of a universe that undergoes an expansion followed by a contraction, quite different to his static model of 1917 or the monotonic Einstein-de Sitter model of 1932. The paper offers many insights into the cosmology of Albert Einstein in the light of the first evidence for an expanding universe, and we discuss his views of issues such as the curvature of space, the cosmological constant, the singularity and the timespan of the expansion. We argue that retrospective descriptions of this model as cyclic or periodic are not historically or mathematically accurate. We find that calculations in the paper of the matter density and radius of the universe contain a numerical error, a finding that is supported by writing on a blackboard used by Einstein during a lecture at Oxford University in May 1931. Our article concludes with a general discussion of his philosophy of cosmology.Comment: Accepted for publication in the European Physical Journal (H). The article includes a first English translation of Einstein's 1931 SAW paper and the discovery of an error in Einstein's calculation of the matter density of the universe. 30 pages, 2 figure