A Monthly Cycle in Food Expenditure and Intake by Participants in the U.S. Food Stamp Program

This paper uses nationally representative data to describe monthly cycles in food expenditure and food intake by food stamp recipients. Food expenditure peaks sharply in the first 3 days after food stamps are received. The corresponding cycle in food intake differs for various categories of food stamp recipients. Food stamp recipients who also receive AFDC appear to maintain steady food intake across the whole month, while AFDC nonrecipients experience a significant drop in intake at the end of the month. Children appear to maintain steady food intake, while adults appear to experience a significant drop. Households that conduct major grocery shopping trips more frequently than once per month maintain steady food intake, while households that shop less frequently experience a significant drop. The food stamp cycle has implications for two areas of research: the measurement of hunger and food insecurity in the United States and the measurement of the impact of the U.S. Food Stamp Program. Intramonthly patterns in food expenditure and food intake have potential implications for policy decisions about the frequency of food stamp benefit delivery, the evaluation of new electronic benefit transfer systems that are replacing traditional food stamp coupons, and nutrition education efforts.

An assessment of the potential returns of energy certificates for the UK household sector

Purpose – This article seeks to investigate the interconnections between the expectations of the impact of energy certificates issued within the UK domestic building sector through the Energy Performance of Buildings Directive (EPBD) and the actual number and financial implications of the energy saving measures (ESMs) achieved. Design/methodology/approach – The methodology uses two previously published surveys and compares these with a third independent survey by the authors focusing upon the discrepancies between planned action and implemented action, introducing the term human factor element (hfe). Findings – The article concludes that annual carbon savings arising from implementation of the Energy Performance Certificate (EPC) may be as low as 73.4?ktC over the five year term of the Kyoto Protocol even though 44 per cent of energy saving measure costs of £200 million are recouped within the same time period and savings will continue for up to 40 years. Achieving annual savings of only 14.7?ktC by 2010, such a figure represents a mere 0.3 per cent of the annual domestic 4.8?MtC savings announced by the government in its 2006 Climate Change Programme. Practical implications – Since the principal determinant in the uptake of ESMs is initial cost, it is considered that the EPBD is likely to remain an under-performing instrument in the promotion of energy sufficiency until such time as other complementary provisions are introduced. Originality/value – Sheds light upon the likely financial impact upon energy efficiency in domestic buildings by energy certificates

Joint source-channel coding for a quantum multiple access channel

Suppose that two senders each obtain one share of the output of a classical, bivariate, correlated information source. They would like to transmit the correlated source to a receiver using a quantum multiple access channel. In prior work, Cover, El Gamal, and Salehi provided a combined source-channel coding strategy for a classical multiple access channel which outperforms the simpler "separation" strategy where separate codebooks are used for the source coding and the channel coding tasks. In the present paper, we prove that a coding strategy similar to the Cover-El Gamal-Salehi strategy and a corresponding quantum simultaneous decoder allow for the reliable transmission of a source over a quantum multiple access channel, as long as a set of information inequalities involving the Holevo quantity hold.Comment: 21 pages, v2: minor changes, accepted into Journal of Physics

Time dependent transformations in deformation quantization

We study the action of time dependent canonical and coordinate transformations in phase space quantum mechanics. We extend the covariant formulation of the theory by providing a formalism that is fully invariant under both standard and time dependent coordinate transformations. This result considerably enlarges the set of possible phase space representations of quantum mechanics and makes it possible to construct a causal representation for the distributional sector of Wigner quantum mechanics.Comment: 16 pages, to appear in the J. Math. Phy

A portable explosive detector based on fluorescence quenching of pyrene deposited on coloured wax-printed μpADs

A new technique for the detection of explosives has been developed based on fluorescence quenching of pyrene on paper-based analytical devices (μPADs). Wax barriers were generated (150 °C, 5 min) using ten different colours. Magenta was found as the most suitable wax colour for the generation of the hydrophobic barriers with a nominal width of 120 μm resulting in fully functioning hydrophobic barriers. One microliter of 0.5 mg mL-1 pyrene dissolved in an 80 : 20 methanol-water solution was deposited on the hydrophobic circle (5 mm diameter) to produce the active microchip device. Under ultra-violet (UV) illumination, ten different organic explosives were detected using the μPAD, with limits of detection ranging from 100-600 ppm. A prototype of a portable battery operated instrument using a 3 W power UV light-emitting-diode (LED) (365 nm) and a photodiode sensor was also built and evaluated for the successful automatic detection of explosives and potential application for field-based screening. © 2013 The Royal Society of Chemistry

Information trade-offs for optical quantum communication

Recent work has precisely characterized the achievable trade-offs between three key information processing tasks---classical communication (generation or consumption), quantum communication (generation or consumption), and shared entanglement (distribution or consumption), measured in bits, qubits, and ebits per channel use, respectively. Slices and corner points of this three-dimensional region reduce to well-known protocols for quantum channels. A trade-off coding technique can attain any point in the region and can outperform time-sharing between the best-known protocols for accomplishing each information processing task by itself. Previously, the benefits of trade-off coding that had been found were too small to be of practical value (viz., for the dephasing and the universal cloning machine channels). In this letter, we demonstrate that the associated performance gains are in fact remarkably high for several physically relevant bosonic channels that model free-space / fiber-optic links, thermal-noise channels, and amplifiers. We show that significant performance gains from trade-off coding also apply when trading photon-number resources between transmitting public and private classical information simultaneously over secret-key-assisted bosonic channels.Comment: 6 pages, 2 figures, see related, longer article at arXiv:1105.011

Deficits in Analogical Reasoning in Adolescents with Traumatic Brain Injury

Individuals with traumatic brain injury (TBI) exhibit deficits in executive control, which may impact their reasoning abilities. Analogical reasoning requires working memory and inhibitory abilities. In this study, we tested adolescents with moderate to severe TBI and typically developing (TD) controls on a set of picture analogy problems. Three factors were varied: complexity (number of relations in the problems), distraction (distractor item present or absent), and animacy (living or non-living items in the problems). We found that TD adolescents performed significantly better overall than TBI adolescents. There was also an age effect present in the TBI group where older participants performed better than younger ones. This age effect was not observed in the TD group. Performance was affected by complexity and distraction. Further, TBI participants exhibited lower performance with distractors present than TD participants. The reasoning deficits exhibited by the TBI participants were correlated with measures of executive function that required working memory updating, attention, and attentional screening. Using MRI-derived measures of cortical thickness, correlations were carried out between task accuracy and cortical thickness. The TD adolescents showed negative correlations between thickness and task accuracy in frontal and temporal regions consistent with cortical maturation in these regions. This study demonstrates that adolescent TBI results in impairments in analogical reasoning ability. Further, TBI youth have difficulty effectively screening out distraction, which may lead to failures in comprehension of the relations among items in visual scenes. Lastly, TBI youth fail to show robust cortical–behavior correlations as observed in TD individuals