In this paper, the recent progress of synaptic electronics is reviewed. The basics of biological synaptic plasticity and learning are described. The material properties and electrical switching ...characteristics of a variety of synaptic devices are discussed, with a focus on the use of synaptic devices for neuromorphic or brain-inspired computing. Performance metrics desirable for large-scale implementations of synaptic devices are illustrated. A review of recent work on targeted computing applications with synaptic devices is presented.
The insights contained in Gordon Moore's now famous 1965 and 1975 papers have broadly guided the development of semiconductor electronics for over 50 years. However, the field-effect transistor is ...approaching some physical limits to further miniaturization, and the associated rising costs and reduced return on investment appear to be slowing the pace of development. Far from signaling an end to progress, this gradual "end of Moore's law" will open a new era in information technology as the focus of research and development shifts from miniaturization of long-established technologies to the coordinated introduction of new devices, new integration technologies, and new architectures for computing.
Background
Deep versus surface knowledge is widely discussed by educational practitioners. A corresponding construct, levels of processing, has received extensive theoretical and empirical attention ...in learning science and psychology. In both arenas, lower levels of information and shallower levels of processing are predicted and generally empirically demonstrated to limit knowledge learners gain, curtail what they can do with newly acquired knowledge, and shorten the life span of recently acquired knowledge.
Purpose
I recapitulate major accounts of levels or depth of information and information processing to set a stage for conceptualizing, first, self‐regulated learning (SRL) from this perspective and, second, how a “levels‐sensitive” approach might be implemented in research about SRL.
Method
I merge the levels construct into a model of SRL (Winne, 2011, Handbook of self‐regulation of learning and performance (pp. 15–32), New York: Routledge; Winne, 2017b, Handbook of self‐regulation of learning and performance (2nd ed.), New York: Routledge; Winne & Hadwin, 1998, Metacognition in educational theory and practice (pp. 277–304). Mahwah, NJ: Lawrence Erlbaum) conceptually and with respect to operationally defining the levels construct in the context of SRL in relation to each of the model's four phases – surveying task conditions, setting goals and planning, engaging the task, and composing major adaptations for future tasks. Select illustrations are provided for each phase of SRL. Regarding phase 3, a software system called nStudy is introduced as state‐of‐the‐art instrumentation for gathering fine‐grained, time‐stamped trace data about information learners select for processing and operations they use to process that information.
Conclusions
Self‐regulated learning can be viewed through a lens of the levels construct, and operational definitions can be designed to research SRL with respect to levels. While information can be organized arbitrarily deeply, the levels construct may not be particularly useful for distinguishing among processes except in a sense that, because processes in SRL operate on information with depth, they epiphenomenally acquire characteristics of levels. Thus, SRL per se is not a deeper kind of processing. Instead, it is processing more complex – deeper – information about a different topic, namely processes for learning.
Context:
The epidemiology of primary hyperparathyroidism (PHPT) has generally been studied in Caucasian populations.
Objective:
The aim was to examine the incidence and prevalence of PHPT within a ...racially mixed population.
Design:
A descriptive epidemiologic study was performed.
Patients/Setting:
The study population included 3.5 million enrollees within Kaiser Permanente Southern California.
Methods:
All patients with at least one elevated serum calcium level (>10.5 mg/dL, 2.6 mmol/L) between 1995 and 2010 were included. Cases of PHPT were identified by electronic query of laboratory values using biochemical criteria, after exclusion of secondary or renal and tertiary hyperparathyroidism cases. The incidence and prevalence rates of PHPT were calculated according to sex, race, age group by decade, and year.
Results:
Initial case finding identified 15,234 patients with chronic hypercalcemia, 13,327 (87%) of which had PHPT as defined by elevated or inappropriately normal parathyroid hormone levels. The incidence of PHPT fluctuated from 34 to 120 per 100 000 person-years (mean 66) among women, and from 13 to 36 (mean 25) among men. With advancing age, incidence increased and sex differences became pronounced (incidence 12–24 per 100 000 for both sexes younger than 50 y; 80 and 36 per 100 000 for women and men aged 50–59 y, respectively; and 196 and 95 for women and men aged 70–79 y, respectively). The incidence of PHPT was highest among blacks (92 women; 46 men, P < .0001), followed by whites (81 women; 29 men), with rates for Asians (52 women, 28 men), Hispanics (49 women, 17 men), and other races (25 women, 6 men) being lower than that for whites (P < .0001). The prevalence of PHPT tripled during the study period, increasing from 76 to 233 per 100 000 women and from 30 to 85 per 100 000 men. Racial differences in prevalence mirrored those found in incidence.
Conclusions:
PHPT is the predominant cause of hypercalcemia and is increasingly prevalent. Substantial differences are found in the incidence and prevalence of PHPT between races.
This article analyzes the concept of validity to set out key factors bearing on claims about validity in general and particularly regarding learning analytics. Because uses of trace data in learning ...analytics are increasing rapidly, specific consideration is given to reliability of trace data and their role in claiming validity for interpretations grounded on trace data. This analysis reveals the essential and inescapable role of theory in deciding what trace data should be gathered and how trace data can contribute to recommendations for improving learning, one main goal for generating and using learning analytics.
•Trace data are increasingly useful in developing learning analytics.•“Raw” data are biased by the theory that recommends observing those data.•Self-regulating learners acting as agents complicate reliability of trace data.•Reliability of trace data concerns dynamic events, not static aspects of a measure.•Generalizability over facets of data sets limits on reliability and validity.
The priority of synaptic device researches has been given to prove the device potential for the emulation of synaptic dynamics and not to functionalize further synaptic devices for more complex ...learning. Here, we demonstrate an optic-neural synaptic device by implementing synaptic and optical-sensing functions together on h-BN/WSe
heterostructure. This device mimics the colored and color-mixed pattern recognition capabilities of the human vision system when arranged in an optic-neural network. Our synaptic device demonstrates a close to linear weight update trajectory while providing a large number of stable conduction states with less than 1% variation per state. The device operates with low voltage spikes of 0.3 V and consumes only 66 fJ per spike. This consequently facilitates the demonstration of accurate and energy efficient colored and color-mixed pattern recognition. The work will be an important step toward neural networks that comprise neural sensing and training functions for more complex pattern recognition.
Neuromorphic visual systems have considerable potential to emulate basic functions of the human visual system even beyond the visible light region. However, the complex circuitry of artificial visual ...systems based on conventional image sensors, memory and processing units presents serious challenges in terms of device integration and power consumption. Here we show simple two-terminal optoelectronic resistive random access memory (ORRAM) synaptic devices for an efficient neuromorphic visual system that exhibit non-volatile optical resistive switching and light-tunable synaptic behaviours. The ORRAM arrays enable image sensing and memory functions as well as neuromorphic visual pre-processing with an improved processing efficiency and image recognition rate in the subsequent processing tasks. The proof-of-concept device provides the potential to simplify the circuitry of a neuromorphic visual system and contribute to the development of applications in edge computing and the internet of things.
Selenium species, particularly the oxyanions selenite (SeO3 (2-)) and selenate (SeO4 (2-)), are significant pollutants in the environment that leach from rocks and are released by anthropogenic ...activities. Selenium is also an essential micronutrient for organisms across the tree of life, including microorganisms and human beings, particularly because of its presence in the 21st genetically encoded amino acid, selenocysteine. Environmental microorganisms are known to be capable of a range of transformations of selenium species, including reduction, methylation, oxidation, and demethylation. Assimilatory reduction of selenium species is necessary for the synthesis of selenoproteins. Dissimilatory reduction of selenate is known to support the anaerobic respiration of a number of microorganisms, and the dissimilatory reduction of soluble selenate and selenite to nanoparticulate elemental selenium greatly reduces the toxicity and bioavailability of selenium and has a major role in bioremediation and potentially in the production of selenium nanospheres for technological applications. Also, microbial methylation after reduction of Se oxyanions is another potentially effective detoxification process if limitations with low reaction rates and capture of the volatile methylated selenium species can be overcome. This review discusses microbial transformations of different forms of Se in an environmental context, with special emphasis on bioremediation of Se pollution.
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