Camcorders

The author explains from an engineering standpoint, how some of the camcorder components work. He discusses the solid-state image sensor, the photodetector, scanning, the shutter frame rate, optics, the recording mechanism, the viewfinder, special effects, and automatic features. Motion detection, discrimination, and compensation are also covered. Recommendations as to which features are most useful are made     

Optimal discrimination and classification of neuronal actionpotential waveforms from multiunit, multichannel recordings usingsoftware-based linear filters

Describes advanced protocols for the discrimination and classification of neuronal spike waveforms within multichannel electrophysiological recordings. The programs are capable of detecting and classifying the spikes from multiple, simultaneously active neurons, even in situations where there is a high degree of spike waveform superposition on the recording channels. The protocols are based on the derivation of an optimal linear filter for each individual neuron. Each filter is tuned to selectively respond to the spike waveform generated by the corresponding neuron, and to attenuate noise and the spike waveforms from all other neurons. The protocol is essentially an extension of earlier work (S. Andreassen et al., 1979; W.M. Roberts and D.K. Hartline, 1975; R.B. Stein et al., 1979). However, the protocols extend the power and utility of the original implementations in two significant respects. First, a general single-pass automatic template estimation algorithm was derived and implemented. Second, the filters were implemented within a software environment providing a greatly enhanced functional organization and user interface. The utility of the analysis approach was demonstrated on samples of multiunit electrophysiological recordings from the cricket abdominal nerve cord     

Climate change gains more from nuclear substitution than from conservation

We show the massive reduction achievable, in both emissions and climate change impact, from enhanced nuclear energy use on the forecasts of future world energy use and its associated environmental impacts. A range encompassing the major scenarios for the World's energy demand have been analyzed using the latest version of the climate-modeling MAGICC/SCENGEN software (Version 4.1). We have updated and predicted the impacts of 80% substitution with CO₂-free sources (likely predominantly nuclear) for coal-fired electricity (by 2030) and for transportation fuel (by 2040). For transportation, hydrogen produced by CO₂-free sources would replace gasoline and diesel fuels. In this paper, to bracket the range of futures, we simply focus on two scenarios from the Intergovernmental Panel on Climate Change's (IPCC), one (A1FI) that is energy-profligate and one (B2) that is energy-conserving.The results show that, interestingly, projected average global temperatures for all scenarios are fairly similar until about 2035 (a further rise beyond the 1990 average temperature of +0.75 ± 0.1 K) regardless of energy usage and its sources. However, by 2050, the different IPCC scenarios diverge markedly. Understandably, A1FI is projected to have noticeably stronger effects than B2 on average global temperatures (about 0.3 K more in 2050) but the effect is much stronger over land at mid and high latitudes (up to almost 1 K more). What is most striking is that the substitution of CO₂-free sources gives projected average temperature rises in 2050 over key land areas (North America and China) that are very similar for the two energy-use scenarios—typically 1–1.5 K because A1FI's additional energy is predominantly supplied by nuclear. In contrast, projected rises with the unaltered cases are markedly different being about 2.5 K for A1FI and 1.5–2 K for B2. The projected changes in rainfall distribution show similar patterns, especially for the expected increases in higher latitudes.With the assumption of no additional policies for substitution of energy sources beyond 2040, temperature divergence between the two scenarios of relative energy profligacy or conservation grows in the latter half of the 21st century, even with substitution. However, the early substitution of nuclear energy and hydrogen appears to buy time and is not crucially dependent on severe, near-term curtailment of energy use. Near-term curtailment is too difficult to implement at a time of rapid industrialization of major emerging economies. Of course, proportionately larger deployments of CO₂-free energy sources are needed for more energy-intensive scenarios.Nuclear power must dominate as the source of CO₂-free energy since it is proven, dependable, available on a large scale, and economic. Social objections to nuclear energy in some countries and quarters are seen as well-meaning but misguided distractions from solving the energy and environmental crises that are now facing world sustainability. The time for real technical, social and political action is now.     

Assessing Human Impact of Organizational Crises: Reliability and Validity of the Triage Assessment Scale for Organizations (TAS:O)

The present study evaluated the reliability and validity of the Triage Assessment Survey: Organizations (TAS:O), a 27-item, 5-point, Likert summated rating scale. One hundred and seventeen participants responded to the TAS:O after reading mild, moderate, marked and severe organizational crisis scenarios. The overall Cronbach's alpha and split-half reliability were both .93. Confirmatory factor analysis revealed three factors, supporting the hypothesis that the TAS:O is comprised of three distinct factors (i.e., Affect, Behavior, and Cognition). An analysis of variance provided evidence that the TAS:O has the capacity to distinguish among mild, moderate, marked, and severe crises. Because this research is the first to evaluate the TAS:O, further studies are needed to strengthen confidence in the psychometric properties of this scale.     

Professional integrity in clinical research

In response to public concern over abuses in human medical experimentation, the dominant approach to the ethics of clinical research during the past 30 years has been regulation, particularly via institutional review board review and approval of scientific protocols and written consent forms. However, the effectiveness of regulatory mechanisms in ensuring the ethical conduct of clinical research is limited. Little attention has been devoted to the nature and role of professional integrity of physician investigators, a conscientious framework for guiding investigators in the socially important but morally complex activity of clinical research. Professional integrity is vital in forging an ethically sound relationship between investigators and patient volunteers, a relationship that differs in important ways from the patient-physician relationship in standard clinical practice. We examine critically 2 models of the moral identity of physician investigators, the investigator as clinician and the investigator as scientist; in neither of these 2 models can the physician investigator eliminate completely the moral conflicts posed by clinical research. The professional integrity of physician investigators depends on a coherent moral identity that is proper to the enterprise of clinical research. The roles of clinician and scientist must be integrated to manage conscientiously the ethical complexity, ambiguity, and tensions between the potentially competing loyalties of science and care of volunteer patients.     

Temperature and modulation characteristics of resonant-cavitylight-emitting diodes

Resonant-cavity light-emitting diodes (RCLED) are novel, high-efficiency light-emitting diodes which employ optical microcavities. These diodes have higher intensities and higher spectral purity as compared to conventional LEDs. Analytical formulas are derived for the enhancement of the spontaneous emission along the optical axis of the cavity. The design rules for high-efficiency operation of RCLEDs are established. The temperature dependence of the emission intensity is analyzed in the range 20-80° and it is described by an exponential dependence with a characteristic temperature of 112 K. The modulation characteristics of RCLEDs exhibit 3 dB frequencies of 580 MHz. Eye diagrams at transmission rates of 622 Mb/s are wide open indicating the suitability of RCLEDs for high-speed data transmission     

A 16-Kbit Θ-search associative memory

The design of a high-capacity Θ-search associative memory (Θ∈{<,>,⩽,⩾,=≠}) is presented. PSPICE simulation and layouts show that the proposed Θ-search associative memory chip consisting of 256 words, each 64-b long, can fit on a 13.5-mm×9.5-mm chip. It can perform maskable Θ-search operations over its contents in 110 ns     

Psychopharmacotherapy for addictive and comorbid disorders: current studies

Proper diagnosis of comorbid disorders is crucial in treatment planning for the dually diagnosed. Since psychoactive substance use can obfuscate the diagnosis, special care must be taken to exclude organically based syndromes. Adequate periods of abstinence should first be achieved and subsequently the patient re-examined for residual symptoms compatible with a nonaddictive, nonsubstance-induced psychiatric disorder. The integration of concurrent treatment of both the mental and the addictive disorders appears to be the best approach for treatment of comorbid psychiatric and addictive disorders. An abstinence-based model that typically utilizes a 12-step group therapy is often employed for the addictive illnesses. Other forms of psychosocial therapies such as case managers are being used as well. Presently, physicians' prescribing practices for comorbid addicted patients are based on traditional approaches to use of medications in psychiatric patients, and their attitudes towards addictive disorders may play a significant role in determining the overall success of treatment.     

A Maximum Entropy Approach for Collaborative Filtering

Collaborative filtering (CF) involves predicting the preferences of a user for a set of items given partial knowledge of the user's preferences for other items, while leveraging a database of profiles for other users. CF has applications e.g. in predicting Web sites a person will visit and in recommending products. Fundamentally, CF is a pattern recognition task, but a formidable one, often involving a huge feature space, a large data set, and many missing features. Even more daunting is the fact that a CF inference engine must be capable of predicting any (user-selected) items, given any available set of partial knowledge on the user's other preferences. In other words, the model must be designed to solve any of a huge (combinatoric) set of possible inference tasks. CF techniques include memory-based, classification-based, and statistical modelling approaches. Among these, modelling approaches scale best with large data sets and are the most adept at handling missing features. The disadvantage of these methods lies in the statistical assumptions (e.g. feature independence), which may be unjustified. To address this shortcoming we propose a new model-based CF method, based on the maximum entropy principle. For the MS Web application, the new method is demonstrated to outperform a number of CF approaches, including naive Bayes and latent variable (cluster) models, support vector machines (SVMs), and the (Pearson) correlation method.