Impact of a Lock Failure on Commodity Transportation on the Mississippi or Illinois Waterway

This in-depth study for the Illinois Chamber of Commerce determines the economic impact of lock failures on the Illinois and Upper Mississippi Rivers.Agricultural and Food Policy, Crop Production/Industries, Livestock Production/Industries,

Choice of antenna geometry for microwave power transmission from solar power satellites

A comparison is made between square and circular transmitting antennas for solar power satellite microwave power transmission. It is seen that the exclusion zone around the rectenna needed to protect populations from microwaves is smaller for a circular antenna operating at 2.45 GHz than it is for a square antenna at that frequency. If the frequency is increased, the exclusion zone size remains the same for a square antenna, but becomes even smaller for a circular antenna. Peak beam intensity is the same for both antennas if the frequency and antenna area are equal. The circular antenna puts a somewhat greater amount of power in the main lobe and somewhat less in the side lobes. Since rain attenuation and atmospheric heating remain problems above 10 GHz, it is recommended that future solar power satellite work concentrate on circular transmitting antennas at frequencies of roughly 10 GHz

A case study investigation of academic library support for open educational resources in Scottish universities

The aim of the research was to investigate why and how Scottish university libraries support open educational resources and to assess their ability to provide support services for their development and use within higher education institutions. There has been little research on the role of academic libraries in supporting open educational resources in Scotland and previous research found that there is a lack of awareness of them in Scottish higher education institutions and few have open educational resources policies. The case study methodology therefore involved two Scottish academic libraries providing open educational resources services. The libraries’ motivation includes supporting teaching and learning and the development of educator digital skills and copyright knowledge. However, there are a number of barriers limiting the services the libraries are able to provide, particularly lack of human resources. The research confirmed the findings of previous research on the importance of institutional commitment, incentives for educator engagement, and understanding of copyright and licensing issues by educators and library staff

The lightness of water vapor helps to stabilize tropical climate.

Moist air is lighter than dry air at the same temperature, pressure, and volume because the molecular weight of water is less than that of dry air. We call this the vapor buoyancy effect. Although this effect is well documented, its impact on Earth's climate has been overlooked. Here, we show that the lightness of water vapor helps to stabilize tropical climate by increasing the outgoing longwave radiation (OLR). In the tropical atmosphere, buoyancy is horizontally uniform. Then, the vapor buoyancy in the moist regions must be balanced by warmer temperatures in the dry regions of the tropical atmosphere. These higher temperatures increase tropical OLR. This radiative effect increases with warming, leading to a negative climate feedback. At a near present-day surface temperature, vapor buoyancy is responsible for a radiative effect of 1 W/m2 and a negative climate feedback of about 0.15 W/m2 per kelvin

An interoceptive predictive coding model of conscious presence

We describe a theoretical model of the neurocognitive mechanisms underlying conscious presence and its disturbances. The model is based on interoceptive prediction error and is informed by predictive models of agency, general models of hierarchical predictive coding and dopaminergic signaling in cortex, the role of the anterior insular cortex (AIC) in interoception and emotion, and cognitive neuroscience evidence from studies of virtual reality and of psychiatric disorders of presence, specifically depersonalization/derealization disorder. The model associates presence with successful suppression by top-down predictions of informative interoceptive signals evoked by autonomic control signals and, indirectly, by visceral responses to afferent sensory signals. The model connects presence to agency by allowing that predicted interoceptive signals will depend on whether afferent sensory signals are determined, by a parallel predictive-coding mechanism, to be self-generated or externally caused. Anatomically, we identify the AIC as the likely locus of key neural comparator mechanisms. Our model integrates a broad range of previously disparate evidence, makes predictions for conjoint manipulations of agency and presence, offers a new view of emotion as interoceptive inference, and represents a step toward a mechanistic account of a fundamental phenomenological property of consciousness

Construction of weakly CUD sequences for MCMC sampling

In Markov chain Monte Carlo (MCMC) sampling considerable thought goes into constructing random transitions. But those transitions are almost always driven by a simulated IID sequence. Recently it has been shown that replacing an IID sequence by a weakly completely uniformly distributed (WCUD) sequence leads to consistent estimation in finite state spaces. Unfortunately, few WCUD sequences are known. This paper gives general methods for proving that a sequence is WCUD, shows that some specific sequences are WCUD, and shows that certain operations on WCUD sequences yield new WCUD sequences. A numerical example on a 42 dimensional continuous Gibbs sampler found that some WCUD inputs sequences produced variance reductions ranging from tens to hundreds for posterior means of the parameters, compared to IID inputs.Comment: Published in at http://dx.doi.org/10.1214/07-EJS162 the Electronic Journal of Statistics (http://www.i-journals.org/ejs/) by the Institute of Mathematical Statistics (http://www.imstat.org

A pseudo-matched filter for chaos

A matched filter maximizes the signal-to-noise ratio of a signal. In the recent work of Corron et al. [Chaos 20, 023123 (2010)], a matched filter is derived for the chaotic waveforms produced by a piecewise-linear system. Motivated by these results, we describe a pseudo-matched filter, which removes noise from the same chaotic signal. It consists of a notch filter followed by a first-order, low-pass filter. We compare quantitatively the matched filter's performance to that of our pseudo-matched filter using correlation functions in a simulated radar application. On average, the pseudo-matched filter performs with a correlation signal-to-noise ratio that is 2.0 dB below that of the matched filter. Our pseudo-matched filter, though somewhat inferior in comparison to the matched filter, is easily realizable at high speed (> 1 GHz) for potential radar applications

Impacts of Water Supply Changes on the Rice Market of Lao PDR: Stochastic Analysis of Supply and Demand Model

Laotian rice producers in upland areas experience highly fluctuating yields and production and producers in wet season rice areas in the southern region face high price risk. This paper examines the exposure to risk of producers in both regions facing changes in water supplies. A supply and demand model of rice in Laos, considering water supply changes, is developed and stochastic elements are added to the model to represent uncertainty in climatic variables. Furthermore, the risks associated with price and production fluctuation are evaluated by using the differences between market and certainty equivalent prices. The results show that the coefficient of variation of production is higher in upland rice than wet and dry season rice, i.e., 0.3226, and if the fluctuation of water supply increases 20%, the coefficient of variation of production will increase about 20% for all type of rice cultivation. In the case of expanding water supply fluctuations, potentially due to climatic change, the price risk of wet season rice will increase from 48.5 kip to 150.8 kip while that of upland and dry season rice will increase from 66.4 kip to 94.9 kip and 14.3 kip to 20.5 kip respectively. Examining provincial price risk of wet season rice, the differences between market and certainty equivalent prices are 56.3 kip and 33.9 kip in Champasack and Attapeu provinces. The regions or provinces which suffer highly fluctuating production and price risk may need to consider alternative water management and harvesting methods.water supply change, rice supply and demand model, stochastic model, Lao PDR, Q11, Q25, Crop Production/Industries, Resource /Energy Economics and Policy,