Lifelong Learning of Spatiotemporal Representations with Dual-Memory Recurrent Self-Organization

Artificial autonomous agents and robots interacting in complex environments are required to continually acquire and fine-tune knowledge over sustained periods of time. The ability to learn from continuous streams of information is referred to as lifelong learning and represents a long-standing challenge for neural network models due to catastrophic forgetting. Computational models of lifelong learning typically alleviate catastrophic forgetting in experimental scenarios with given datasets of static images and limited complexity, thereby differing significantly from the conditions artificial agents are exposed to. In more natural settings, sequential information may become progressively available over time and access to previous experience may be restricted. In this paper, we propose a dual-memory self-organizing architecture for lifelong learning scenarios. The architecture comprises two growing recurrent networks with the complementary tasks of learning object instances (episodic memory) and categories (semantic memory). Both growing networks can expand in response to novel sensory experience: the episodic memory learns fine-grained spatiotemporal representations of object instances in an unsupervised fashion while the semantic memory uses task-relevant signals to regulate structural plasticity levels and develop more compact representations from episodic experience. For the consolidation of knowledge in the absence of external sensory input, the episodic memory periodically replays trajectories of neural reactivations. We evaluate the proposed model on the CORe50 benchmark dataset for continuous object recognition, showing that we significantly outperform current methods of lifelong learning in three different incremental learning scenario

A Study of Photosynthesis in Clear Lake, lowa

The oxygen and carbon-14 methods were used to measure photosynthesis in Clear Lake, Iowa during 1958 and 1959. Differences in the rates of photosynthesis at widely separated stations were generally small. Daily variations in the rate of photosynthesis were not greater than two-fold. The correlation between the rate of photosynthesis and the incident illumination was 0.81, and the efficiency of utilization of incident light energy was 0.72 per cent. The net gain of organic matter at the phytoplankton level during the period May 1 to November 1 was equivalent to 3480 pounds of glucose per acre

An Ontology-based Image Repository for a Biomedical Research Lab

We have developed a prototype web-based database for managing images acquired during experiments in a biomedical research lab studying the factors controlling cataract development. Based on an evolving ontology we are developing for describing the experimental data and protocols used in the lab, the image repository allows lab members to organize image data by multiple attributes. The use of an ontology for developing this and other tools will facilitate intercommunication among tools, and eventual data sharing with other researchers

Carpal tunnel syndrome associated with oral bisphosphonates. A population-based cohort study

© 2016 Carvajal et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: Bisphosphonates are widely used to prevent osteoporotic fractures. Some severe musculoskeletal reactions have been described with this medication; among them, some cases of carpal tunnel syndrome. Thus, the aim of this study was to explore whether bisphosphonates may be associated with this syndrome. Methods: A cohort study was conducted to compare exposed to unexposed women; the exposed group was that composed of women having received at least one prescription of an oral bisphosphonate. For the purpose, we used information from The Health Improvement Network (THIN) database. The outcome of interest was defined as those women diagnosed with carpal tunnel syndrome. A survival analysis was performed; the Cox proportional hazard model was used to calculate hazard ratios and 95% confidence intervals, and to adjust for identified confounding variables. Results: Out of a sample of 59,475 women older than 51 years, 19,825 were treated with bisphosphonates during the period studied. No differences in age distribution or mean follow-up time were observed between the two groups in comparison. Overall, there were 572 women diagnosed with carpal tunnel syndrome, 242 (1.2%) in the group exposed to bisphosphonates, and 330 (0.8%) in the unexposed. An adjusted hazard ratio of developing carpal tunnel syndrome of 1.38 (95%CI, 1.15-1.64) was found for women exposed to bisphosphonates; no significant changes in the hazard ratios were found when considering different levels of bisphosphonate exposure

Tailoring the frictional properties of granular media

A method of modifying the roughness of soda-lime glass spheres is presented, with the purpose of tuning inter-particle friction. The effect of chemical etching on the surface topography and the bulk frictional properties of grains is systematically investigated. The surface roughness of the grains is measured using white light interferometry and characterised by the lateral and vertical roughness length scales. The underwater angle of repose is measured to characterise the bulk frictional behaviour. We observe that the co-efficient of friction depends on the vertical roughness length scale. We also demonstrate a bulk surface roughness measurement using a carbonated soft drink.Comment: 10 pages, 17 figures, submitted to Phys. Rev.

Atmospheric Properties and Their Observable Correlations with Volatile Organic Compounds Emission Concentration at Some Gas Stations in Port Harcourt City

This study focused on atmospheric properties and their observable correlations with volatile organic compounds (VOCs). Six gas stations and the nearest residential buildings within Port Harcourt City were selected for the study. At each of the gas stations and the nearest buildings, a well calibrated handheld IGERESS VOCs detector was positioned 1.5m above the ground and in the direction of the wind to determine the levels of VOCs concentration. Atmospheric Properties (temperature and relative humidity) of the selected gas stations and the nearest buildings were determined accordingly. These were done in the morning and evening hours for a period of two weeks. The study's findings revealed gas stations emit VOCs and that the VOCs emission concentrations in the morning and evening sessions were within safe limits. But the measured mean VOCs concentration at the gas station (0.343ppm) is above the United States Environmental Protection Agency (USEPA) maximum allowable air concentration Standard of 0.20 ppm. The recorded mean value of the VOCs concentration at the gas stations (0.343ppm) shows that the average exposure limit from the gas stations for the period under study is in agreement with the permissible limits of between 0.3 ppm to 0.5ppm established by World Health Organization (WHO) and the National Institute of Occupational Safety and Health (NIOSH) respectively. The calculated correlation values between VOCs concentration and temperature at the gas stations and nearest buildings are 0.0020 (weak positive correlation) and -0.0111 (negative correlation) respectively. Similarly, VOCs concentration showed a negative correlation with the relative humidity at the gas stations and the nearest residential buildings. The calculated correlation values are -0.1952 and -0.7257, respectively. These results are in agreement with some studies. A number of studies have shown that VOCs emissions are positively correlated with temperature, but that of relative humidity has no uniform conclusions. Volatile organic compounds (VOCs) pose numerous health challenges and serious environmental concerns such as poor air quality and shift in climate. Siting of gas stations far away from residential areas and the use of fuel recovery pumps are essential for the reduction of the impacts of VOCs on humans and the environment

VAN KARNAK TOT KAKAMAS: DIE NALEEF VAN OU EGIPTE IN DIE SUID-AFRIKAANSE BOUKUNS

Die doel van hierdie artikel is om ’n oorsig te gee van die naleef of nawerking van Ou Egiptiese motiewe in die Suid-Afrikaanse argitektuur en boukuns. Watter rol het die inspirasie van Ou Egiptiese style en motiewe gespeel? Die Egyptian Revival (Curl 1994) is bekend in Europa, die Verenigde Koninkryk, Australië (Merrillees 1990 en 1995) en die VSA (Carrott 1978), maar wat is die geval in Suid-Afrika? So ’n oorsig is nog nie na behore onderneem nie

VAN DIE NYL TOT STELLENBOSCH: ANTIEKE EGIPTIESE VOORWERPE OP STELLENBOSCH

Egipte is soos Suid-Afrika deel van die kontinent van Afrika en daar is voorbeelde van hoe antieke Egiptiese motiewe in die Suid-Afrikaanse boukuns voortleef (Cornelius 2001). Afgesien van argitektoniese voorbeelde is daar ook oorspronklike antieke Egiptiese artefakte in Suid- Afrikaanse versamelings en ʼn aantal hiervan vorm tans deel van die uitstalling “Lewende Antieke” van die Dept. Antieke Studie in die SASOL-Kunsmuseum van die Universiteit van Stellenbosch. Die uitstalling bestaan uit meer as 200 voorwerpe uit die antieke wêreld en is ʼn seleksie van die Antieke versameling van Iziko Museums van Kaapstad wat kragtens ʼn leenooreenkoms tussen die Universiteit van Stellenbosch en Iziko Museums vir twee jaar op bruikleen is

Uji Total Fungi dan Organoleptik pada Jerami Padi dan Jerami Jagung yang Difermentasi dengan Isi Rumen Kerbau

The purpose of this study is to examine the effect of combined treatment (composition of rice straw and corn are different, and the addition of starter buffalo rumen contents were different) to the total test fungi and organoleptic quality. The research was conducted in May until June 2012 in the Laboratory of Animal Feed Technology and Feed Science Laboratory, Department of Nutrition and Food Animals, Faculty of Animal Husbandry and Agriculture, Diponegoro University, Semarang. The material used in this research were rice straw, corn straw, buffalo rumen contents. The tools used in the study were copper, is used to cut hay, plastic, thermometers and pH meters. This study uses a completely randomized design (CRD) 4x3 factorial with 3 replications. Factors in this treatment is the addition of cedar rumen contents and composition of hay. Factors addition of rumen contents contained 4: 0% (R0), 5% (R5), 10% (R10), 15% (R15) and R0, as the control is 0% hay fermentation. Another factor is the composition of rice straw and corn are 100% rice straw: 0% corn straw (P), 50% rice straw: 50% corn straw (PJ), 0% rice straw: 100% corn straw (J). The Research parameter were total fungi, and physical organoleptic (color, texture, smell). The data have been analyzed using a variety of test and followed by Duncan multiple test areas. The results showed no additional interaction cedar buffalo rumen contents and the combination of rice straw and corn to total fungi, total fungi most is when the addition of cedar rumen contents of 10% (R10). The cedar rumen contents were higher, causing fermentation to brown color, smooth texture and easily broken, and the sour smell caused due to the good fermentation process