On the use of photobleaching to reduce fluorescence background in Raman spectroscopy to improve the reliability of pigment identification on painted textiles

Subjecting a specimen of red lead watercolour paint on silk to photobleaching was demonstrated to be a simple means by which to engineer a reduction in the magnitude of the fluorescent background that was approximately exponential with time, with a corresponding improvement in the signal to noise ratio of the Raman spectrum, thus rendering the characteristic peaks more easily visible and allowing more confident identification of the pigment. However, relative heights of the Raman peaks obtained from the sample were seen to alter progressively as a result of irradiation, indicating that some component of the sample was undergoing degradation that may result in longer-term damage to a fragile historic artefact. It was also shown that crystals of the lead monoxide pigment massicot were present in the samples ofred lead on a painted silk artefact dating from 1750. It is concluded that this was either due to deliberate mixing of pigments by the artist, contrary to historic records, or as a result of the roasting techniques used to create red lead pigments at the time and not due to thermal degradation of the pigment during Raman analysis

The Effect of a Refractory Period on the Power Spectrum of Neuronal Discharge

The interspike intervals in steady-state neuron firing are assumed to be independently and identically distributed random variables. In the simplest model discussed, each interval is assumed to be the sum of a random neuron refractory period and a statistically independent interval due to a stationary external process, whose statistics are assumed known. The power spectral density (hence the autocorrelation) of the composite neuron-firing renewal process is derived from the known spectrum of the external process and from the unknown spectrum of the neuron-refraction process. The results are applied to spike trains recorded in a previous study [2] of single neurons in the visual cortex of an awake monkey. Two models are demonstrated that may produce peaks in the power spectrum near 40 Hz

Temporal Precision of Spike Trains in Extrastriate Cortex of the Behaving Macaque Monkey

How reliably do action potentials in cortical neurons encode information about a visual stimulus? Most physiological studies do not weigh the occurrences of particular action potentials as significant but treat them only as reflections of average neuronal excitation. We report that single neurons recorded in a previous study by Newsome et al. (1989; see also Britten et al. 1992) from cortical area MT in the behaving monkey respond to dynamic and unpredictable motion stimuli with a markedly reproducible temporal modulation that is precise to a few milliseconds. This temporal modulation is stimulus dependent, being present for highly dynamic random motion but absent when the stimulus translates rigidly

Grounding action in visuo-haptic space using experience networks

Traditional approaches to the use of machine learning algorithms do not provide a method to learn multiple tasks in one-shot on an embodied robot. It is proposed that grounding actions within the sensory space leads to the development of action-state relationships which can be re-used despite a change in task. A novel approach called an Experience Network is developed and assessed on a real-world robot required to perform three separate tasks. After grounded representations were developed in the initial task, only minimal further learning was required to perform the second and third task

Robot Navigation in Unseen Spaces using an Abstract Map

Human navigation in built environments depends on symbolic spatial information which has unrealised potential to enhance robot navigation capabilities. Information sources such as labels, signs, maps, planners, spoken directions, and navigational gestures communicate a wealth of spatial information to the navigators of built environments; a wealth of information that robots typically ignore. We present a robot navigation system that uses the same symbolic spatial information employed by humans to purposefully navigate in unseen built environments with a level of performance comparable to humans. The navigation system uses a novel data structure called the abstract map to imagine malleable spatial models for unseen spaces from spatial symbols. Sensorimotor perceptions from a robot are then employed to provide purposeful navigation to symbolic goal locations in the unseen environment. We show how a dynamic system can be used to create malleable spatial models for the abstract map, and provide an open source implementation to encourage future work in the area of symbolic navigation. Symbolic navigation performance of humans and a robot is evaluated in a real-world built environment. The paper concludes with a qualitative analysis of human navigation strategies, providing further insights into how the symbolic navigation capabilities of robots in unseen built environments can be improved in the future.Comment: 15 pages, published in IEEE Transactions on Cognitive and Developmental Systems (http://doi.org/10.1109/TCDS.2020.2993855), see https://btalb.github.io/abstract_map/ for access to softwar

Ernst von Wildenbruch: his sense of justice

Thesis (M.A.)--Boston University, 1935. This item was digitized by the Internet Archive

Constructing realities

This document is the written component accompanying the Constructing Realities art exhibition. The five interactive digital art installations encourage participants to investigate various fundamental elements of photography. By exploring these component parts, a greater overall understanding of the power of photography over our perceived realities can be gained. This document describes the artist\u27s creative intention. Major historic and contemporary philosophic and artistic influences are identified and analyzed. Included are postmodern theories related to reality and contemporary interactive artists, in order to place and explain the exhibition\u27s relevance. The themes and processes that were employed to create this exhibition are explained and documented. The artwork examines the impact elements of photography have on our understanding of reality

Spatiotemporal patterns in water yield from the humid puna: a case study in the agrarian district of Zurite, Perú

The humid puna is a seasonally dry alpine grass- and shrub-land biome that exists at the altitudinal limits of plant survival, hosts peat-forming wetlands known as bofedales, and yields water to streams used by small and large communities throughout the central and southern Peruvian Andes. Despite the importance of the humid puna in supplying water resources, particularly to perennial streams, few studies have quantified water yield and no studies have explored relationships between the structure of puna landscapes and spatial patterns in water yield. Zurite (population: 3,640, elevation: 3,011 m.a.s.l., annual precipitation: 855 mm) is an agrarian district in the department of Cusco, Perú that derives water resources from the Upper Ramuschaka Watershed (URW, area: 2.12 km2, mean elevation: 4,332 m.a.s.l.), a humid puna headwater catchment with 11.5% coverage of seasonally saturated bofedales. The URW provides an opportunity to explore the hydrology of the Andean puna, and to present baseline water resources data to the community of Zurite to guide sustainable water management and resiliency to a changing climate. Our study sought to: a) Determine the total, wet, and dry season water yield and derive annual water balances from in-situ measurements in the URW; b) Explore the temporal phases of the URW annual water balance; c) Identify relationships between spatiotemporal patterns in water yield and the presence of bofedales; and d) Estimate seasonal dynamic water storage contributions to dry season runoff from bofedales in the URW. We monitored precipitation inputs, seasonal dynamics in subsurface moisture, groundwater, and streamflow for two years, and took distributed discharge measurements at 18 subbasins nested throughout the Central and Eastern tributaries of the URW from June 2019 - January 2021. Over the course of four field campaigns spanning wet and dry seasons, we flew an unmanned aerial vehicle (UAV) to generate a 1-m resolution digital elevation model (DEM) for topographic analyses, and measured material and hydrologic properties in bofedales via direct measurements and downhole nuclear magnetic resonance (NMR). The URW received 749 mm annual precipitation in WY2019 and 825 mm in WY2020. Annual runoff ranged from 62% to 80% of the annual water balance, with dry season runoff accounting for between 11% and 19% of annual runoff. Spatiotemporal analysis of water yield throughout the URW revealed that subbasins with a greater proportion of bofedal land cover yielded greater unit runoff and that this relationship strengthened through the dry season. We estimated seasonal dynamic water storage across all bofedales of the URW to account for 50 - 60 mm of streamflow contributions, or approximately one half of dry season runoff. Collectively, these results suggest: a) water yield from headwater humid puna catchments can represent 60-80% of annual precipitation, and b) bofedales integrate groundwater resources from upslope contributing areas 4 – 12 times their area, store water primarily in high porosity peat, and release water through low conductivity clay rich deposits, sustaining baseflow. Regional research and management efforts should design monitoring programs to improve baseline bofedal hydrology data sets and specifically incorporate bofedales in conservation initiatives due to their role in sustaining dry season streamflow in the puna

Ictal crying

PURPOSE: The purpose of this study was to describe a series of patients with ictal crying to estimate its occurrence and characterize the clinical features and the underlying etiology. METHODS: We retrospectively reviewed all the long-term video-EEG reports from Jefferson Comprehensive Epilepsy Center over a 12-year period (2004-2015) for the occurrence of the terms cry or sob or weep in the text body. All the extracted reports were reviewed, and patients with at least one episode of documented ictal crying at the epilepsy monitoring unit (EMU) were included in the study. RESULTS: During the study period, 5133 patients were investigated at our EMU. Thirty-two patients (0.6%) had at least one documented seizure accompanied by crying. Twenty-seven patients (26 women and one man) had psychogenic nonepileptic seizures (PNES), and five patients (0.1%) had epilepsy. Among patients with epileptic ictal crying, four patients had focal epilepsy (two had definite, and two had probable frontal lobe epilepsy), while one patient had Lennox-Gastaut syndrome. CONCLUSION: Ictal crying is a rare finding among patients evaluated at the EMUs. The most common underlying etiology for ictal crying is PNES. However, ictal crying is not a specific sign for PNES. Epileptic ictal crying is often a rare type of partial seizure in patients with focal epilepsy. Dacrystic seizures do not provide clinical value in predicting localization of the epileptogenic zone