Computer used to program numerically controlled milling machine

Computer program automatically directs a numerically controlled milling machine through a series of cutting and trimming actions. It accepts engineering data points, passes smooth curve segments through the points, breaks the resulting curves into a series of closely spaced points, and transforms these points into the form required by the mechanism

The neural basis of centre-surround interactions in visual motion processing

Perception of a moving visual stimulus can be suppressed or enhanced by surrounding context in adjacent parts of the visual field. We studied the neural processes underlying such contextual modulation with fMRI. We selected motion selective regions of interest (ROI) in the occipital and parietal lobes with sufficiently well defined topography to preclude direct activation by the surround. BOLD signal in the ROIs was suppressed when surround motion direction matched central stimulus direction, and increased when it was opposite. With the exception of hMT+/V5, inserting a gap between the stimulus and the surround abolished surround modulation. This dissociation between hMT+/V5 and other motion selective regions prompted us to ask whether motion perception is closely linked to processing in hMT+/V5, or reflects the net activity across all motion selective cortex. The motion aftereffect (MAE) provided a measure of motion perception, and the same stimulus configurations that were used in the fMRI experiments served as adapters. Using a linear model, we found that the MAE was predicted more accurately by the BOLD signal in hMT+/V5 than it was by the BOLD signal in other motion selective regions. However, a substantial improvement in prediction accuracy could be achieved by using the net activity across all motion selective cortex as a predictor, suggesting the overall conclusion that visual motion perception depends upon the integration of activity across different areas of visual cortex

Hardware-accelerated interactive data visualization for neuroscience in Python.

Large datasets are becoming more and more common in science, particularly in neuroscience where experimental techniques are rapidly evolving. Obtaining interpretable results from raw data can sometimes be done automatically; however, there are numerous situations where there is a need, at all processing stages, to visualize the data in an interactive way. This enables the scientist to gain intuition, discover unexpected patterns, and find guidance about subsequent analysis steps. Existing visualization tools mostly focus on static publication-quality figures and do not support interactive visualization of large datasets. While working on Python software for visualization of neurophysiological data, we developed techniques to leverage the computational power of modern graphics cards for high-performance interactive data visualization. We were able to achieve very high performance despite the interpreted and dynamic nature of Python, by using state-of-the-art, fast libraries such as NumPy, PyOpenGL, and PyTables. We present applications of these methods to visualization of neurophysiological data. We believe our tools will be useful in a broad range of domains, in neuroscience and beyond, where there is an increasing need for scalable and fast interactive visualization

Bond Length - Bond Valence Relationships for Carbon - Carbon and Carbon - Oxygen Bonds

In the present study, relationships are developed for determining bond orders (also referred to as bond valences or bond numbers) from published bond lengths for carbon-carbon (C-C) and carbon-oxygen (C-O) bonds. The relationships are based on Pauling’s empirical formula s = exp((Ro-R)/b)), where s is the bond order, R is the corresponding bond length, Ro is the unit valence bond length, and b is a fitting parameter. We use a recently derived relationship for the b parameter in terms of the bonding atoms’ published atomic orbital exponents. The resulting equations were checked against published x-ray diffraction (XRD) data for 176 carbon systems with 540 published C-C bond lengths, and 50 oxygen systems having 72 published C-O bond lengths. The C-C and C-O bond length-valence relationships are shown to have sufficient applicability and accuracy for use in any bonding environment, regardless of physical state or oxidation number

Branching Brownian Motion with catalytic branching at the origin

We consider a branching Brownian motion in which binary fission takes place only when particles are at the origin at a rate \beta > 0 on the local time scale. We obtain results regarding the asymptotic behaviour of the number of particles above \lambda t at time t, for \lambda > 0. As a corollary, we establish the almost sure asymptotic speed of the rightmost particle. We also prove a Strong Law of Large Numbers for this catalytic branching Brownian motion.Comment: 25 page

The Trichoptera of Panama XIV. New species of microcaddisflies (Trichoptera: Hydroptilidae) from Omar Torrijos Herrera National Park

Abstract. In 2017, a new project was begun to assess the biodiversity of national parks and forest reserves in the Republic of Panama. Designated “Proyecto Sistema de Producción Sostenible Conservación de la Biodiversidad (PSPSCB)”, this project is managed by Panama’s Ministerio de Ambiente. The first park sampled in 2017 was Omar Torrijos Herrera National Park (OTHNP). Trichoptera (Insecta) were collected at four locations using both Malaise traps and UV light traps. The rugged terrain and lack of access in this remote park limited the sampled area. Sampling included streams in both the Caribbean and Pacific drainages. Seven new species of microcaddis­flies (Hydroptilidae: Alistotrichia coclensis Armitage and Harris, Cerasmatrichia akanthos Armitage and Harris, Metrichia corazones Armitage and Harris, Neotrichia espinosa Armitage and Harris, Neotrichia michaeli Armit­age and Harris, Neotrichia pierpointorum Armitage and Harris, and Neotrichia yayas Armitage and Harris) and one new country record, Metrichia macrophallata Flint, were identified from this preliminary survey and are re­ported herein. Other recently described species are reported here for the first time outside of their type localities. Based on other areas more extensively sampled compared to this modest survey, many more new species and new country records await discovery in OTHNP as are reported herein. There are now 439 species distributed among 15 families and 55 genera known from Panama. Resumen. En 2017, se inició un nuevo proyecto para evaluar la biodiversidad de parques nacionales y reservas forestales en la República de Panamá. Designado “Proyecto Sistema de Producción Sostenible Conservación de la Biodiversidad (PSPSCB)”, este proyecto es administrado por el Ministerio de Ambiente de Panamá. El primer parque muestreado en 2017 fue el Parque Nacional Omar Torrijos Herrera (OTHNP). Se recogieron Trichoptera en cuatro ubicaciones utilizando trampas Malaise y trampas de luz UV. El terreno accidentado y la falta de acceso en este parque remoto limitaron el área muestreada. El muestreo incluyó corrientes en los drenajes del Caribe y del Pacífico. Siete nuevas especies de micro-Trichoptera (Hydroptilidae: Alistotrichia coclensis Armitage and Harris, Cerasmatrichia akanthos Armitage and Harris, Metrichia corazones Armitage and Harris, Neotrichia es­pinosa Armitage and Harris, Neotrichia michaeli Armitage and Harris, Neotrichia pierpointorum Armitage and Harris, and Neotrichia yayas Armitage and Harris) y un nuevo registro de país, Metrichia macrophallata Flint, se identificaron a partir de esta encuesta preliminar y se informan aquí. Otras especies recientemente descritas se registran aquí por primera vez fuera de sus localidades tipo. Con base en otras áreas más extensamente mues­treadas, en comparación con esta modesta investigación, muchas más especies nuevas y nuevos registros para el país esperan ser descubiertos en el OTHNP como se informa aquí. Ahora en Panamá, hay 439 especies conocidas de Trichoptera distribuidas entre 15 familias y 55 géneros