Round-trip Distance Research Articles

Logistics cost analysis of rice residues for second generation bioenergy production in Ghana

This study explores the techno-economic potential of rice residues as a bioenergy resource to meet Ghana’s energy demands. Major rice growing regions of Ghana have 70–90% of residues available for bioenergy production. To ensure cost-effective biomass logistics, a thorough cost analysis was made for two bioenergy routes. Logistics costs for a 5MWe straw combustion plant were 39.01, 47.52 and 47.89USD/t for Northern, Ashanti and Volta regions respectively. Logistics cost for a 0.25MWe husk gasification plant (with roundtrip distance 10km) was 2.64USD/t in all regions. Capital cost (66–72%) contributes significantly to total logistics costs of straw, however for husk logistics, staff (40%) and operation and maintenance costs (46%) dominate. Baling is the major processing logistic cost for straw, contributing to 46–48% of total costs. Scale of straw unit does not have a large impact on logistic costs. Transport distance of husks has considerable impact on logistic costs.

Outpatient treatment costs and their potential impact on cancer care.

Cancer creates a tremendous financial burden. Cancer-related costs are categorized into direct, indirect, and psychosocial costs. Although there have been many reports on medical care costs, which are direct, those on other costs are extremely scarce. We estimated travel time and costs required for cancer patients to receive outpatient treatment. We studied 521 cancer patients receiving anti-cancer treatment between February 2009 and December 2012 at the Outpatient Chemotherapy Center of Teikyo University Chiba Medical Center. Address data were extracted from Data Warehouse electronic medical records, and travel distance and time required for outpatient treatment were calculated via MapInfo and ACT Distance Calculator Package. Transportation costs were estimated on the basis of ¥274 (=$3.00) per kilometer. The study design was approved by an ethics review board of Teikyo University (12–851). Average round-trip travel distance, time, and cost for all patients were 26.7 km, 72.5 min, and ¥7,303 ($79.99), respectively. Cancer patients incurred a travel cost of ¥4000–¥9000 ($40.00 to $100.00) for each outpatient treatment. With population aging, seniors living alone and senior households are increasing, and outpatient visits are becoming a common burden.

Estimation of travel time and costs required for patients with cancer to receive outpatient treatment using electronic medical record data.

270 Background: Cancer creates a tremendous financial burden. Cancer-related costs are categorized into direct, indirect and psychosocial costs. Although there have been many reports on medical care costs, which are direct, those on other costs are extremely scarce. We estimated travel time and costs required for cancer patients to receive outpatient treatment. Methods: We studied 524 cancer patients given anti-cancer treatment between February 2009 and December 2012 at the Outpatient Chemotherapy Center of Teikyo University Chiba Medical Center. Address data were extracted from Data Warehouse electronic medical records, and travel distance and time required for outpatient treatment were calculated via MapInfo and ACT Distance Calculator Package. Transportation costs were estimated on the basis of ¥274 (= $3.00) per kilometer. Results: Average round-trip travel distances, times, and costs by cancer type are shown below. Average round-trip travel distance, time, and cost for all patients were 26.7 km, 72.5 minutes, and ¥7,303 ($79.99), respectively. Conclusions: Cancer patients incurred a travel cost of approximately ¥4,000 to ¥9,000 ($40.00 to $100.00) for each outpatient treatment. With population aging, seniors living alone and senior households are increasing, and outpatient visits are becoming a common burden. [Table: see text]

Elliptic curve-based RFID/NFC authentication with temperature sensor input for relay attacks

Unless specifically designed for its prevention, none of the existing RFID authentication protocols are immune to relay attacks. Relay attacks generally involve the presence of one or more adversaries who transfer unmodified messages between a prover and a verifier. Given that the message content is not modified, it is rather difficult to address relay attacks through cryptographic means. Extant attempts to prevent relay attacks involve measuring signal strength, round-trip distance, and ambient conditions in the vicinity of prover and verifier. While a majority of related authentication protocols are based on measuring the round-trip distance between prover and verifier using several single-bit challenge–response pairs, recent discussions include physical proximity verification using ambient conditions to address relay attacks. We provide an overview of existing literature on addressing relay attacks through ambient condition measurements. We then propose an elliptic curve-based mutual authentication protocol that addresses relay attacks based on (a) the surface temperature of the prover as measured by prover and verifier and (b) measured single-bit round-trip times between prover and verifier. We also evaluate the security properties of the proposed authentication protocol.

Self-Mixing Interferometry With Terahertz Quantum Cascade Lasers

Terahertz frequency quantum cascade lasers (THz QCLs) are compact sources of coherent THz radiation with potential applications that include astronomy, trace-gas sensing, and security imaging. However, the reliance on slow and incoherent thermal detectors has limited their practical use in THz systems. We demonstrate THz sensing using self-mixing (SM) interferometry, in which radiation is reflected from an object back into the QCL cavity, causing changes in the laser properties; the THz QCL thus acts simultaneously as both a source and detector. Well-established SM theory predicts a much weaker coupling in THz QCLs than in diode lasers, yielding a near-linear relationship between the phase of SM signals and the external cavity length. We demonstrate velocimetry of an oscillating reflector by monitoring SM-induced changes in the QCL drive voltage. We show that this yields data equivalent to that obtained by sensing the emitted THz power, thus allowing phase-sensitive THz-SM sensing without any external detector. We also demonstrate high-resolution SM-imaging at a round-trip distance of 21 m in air—the longest-range interferometric sensing with a THz QCL to date.

Tailpipe greenhouse gas emissions from tank trucks transporting raw milk from farms to processing plants

An analysis of greenhouse gas emissions (carbon dioxide equivalents, CO2e) was conducted from 2007 databases for 211,216 round trips of tank trucks that delivered raw milk from farms to processing plants in the United States of America. The total amount of milk was 4.81 × 109 kg, or about 17.4% of the 2007 total USA production for use as fluid milk products. Average round trip distance was 850 km resulting in tailpipe emissions of 0.050 kg CO2e kg−1 milk delivered or 0.071 kg CO2e kg−1 milk consumed representing 3.5% of the total greenhouse gas emissions for fluid milk consumed. Based on this we estimate the total emissions for fluid milk delivery from farm to processor in the US at 1.3 × 109 kg CO2e y−1. Some overall reduction in total delivery distance could be realized by realigning farm-to-processor relationships, especially in regions where farms are equally distant from multiple processors.

Dispersion-compensated wavelength beam combining of quantum-cascade-laser arrays

A multiwavelength array of distributed feedback (DFB) quantum cascade lasers (QCLs) that spans λ = 8.28 to 9.62 μm is wavelength beam combined (WBC) using both single-grating and dual-grating designs. WBC with a single grating results in a pointing error of 3-times the beam divergence for a single laser and arises from the nonlinear dispersion of the grating. By adding a second grating to compensate for the nonlinear dispersion, the pointing error is reduced to only 13% of the beam divergence for a single laser. A transceiver based on the dual-grating-WBC QCL was used to measure the transmittance of a polymer sheet placed between itself and a retroreflector over a round-trip distance of 70 meters.

Identification of Biochemical Network Modules Based on Shortest Retroactive Distances

Modularity analysis offers a route to better understand the organization of cellular biochemical networks as well as to derive practically useful, simplified models of these complex systems. While there is general agreement regarding the qualitative properties of a biochemical module, there is no clear consensus on the quantitative criteria that may be used to systematically derive these modules. In this work, we investigate cyclical interactions as the defining characteristic of a biochemical module. We utilize a round trip distance metric, termed Shortest Retroactive Distance (ShReD), to characterize the retroactive connectivity between any two reactions in a biochemical network and to group together network components that mutually influence each other. We evaluate the metric on two types of networks that feature feedback interactions: (i) epidermal growth factor receptor (EGFR) signaling and (ii) liver metabolism supporting drug transformation. For both networks, the ShReD partitions found hierarchically arranged modules that confirm biological intuition. In addition, the partitions also revealed modules that are less intuitive. In particular, ShReD-based partition of the metabolic network identified a ‘redox’ module that couples reactions of glucose, pyruvate, lipid and drug metabolism through shared production and consumption of NADPH. Our results suggest that retroactive interactions arising from feedback loops and metabolic cycles significantly contribute to the modularity of biochemical networks. For metabolic networks, cofactors play an important role as allosteric effectors that mediate the retroactive interactions.

Solar System constraints on scalar tensor theories with nonstandard action

We compute the parametrized post-Newtonian (PPN), $\ensuremath{\gamma}$, for scalar tensor gravity theory when the action functional for the scalar field is a nonstandard one, namely, the Dirac-Born-Infeld type action, used in the literature for a tachyon field. We investigate two different cases (linear and conformal couplings) when the scalar field is nonminimally coupled to gravity via the scalar curvature. We find that the PPN parameter $\ensuremath{\gamma}$, which measures the amount of space curvature per unit rest mass, becomes a function of the effective mass of the scalar field. Using this PPN parameter, we calculate the time delay $\ensuremath{\Delta}\ensuremath{\tau}$ for the signal to travel the round-trip distance between a ground-based antenna and a reflector placed in a spacecraft which is produced due to the gravitational field of the Sun. We use this $\ensuremath{\Delta}\ensuremath{\tau}$ to compare our result with that obtained by the Cassini mission and derive the constraints on the model parameters.

Will reconnecting ecosystems allow long-distance mammal migrations to resume? A case study of a zebraEquus burchellimigration in Botswana

AbstractTerrestrial wildlife migrations, once common, are now rare because of ecosystem fragmentation and uncontrolled hunting. Botswana historically contained migratory populations of many species but habitat fragmentation, especially by fences, has decreased the number and size of many of these populations. During a study investigating herbivore movement patterns in north-west Botswana we recorded a long-distance zebraEquus burchelli antiquorummigration between the Okavango Delta and Makgadikgadi grasslands, a round-trip distance of 588 km; 55% of 11 animals collared in the south-eastern peripheral delta made this journey. This was unexpected as, between 1968 and 2004, the migration could not have followed its present course because of the bisection of the route by a veterinary cordon fence. As little evidence exists to suggest that large-scale movements by medium-sized herbivores can be restored, it is of significant interest that this migration was established to the present highly directed route within 4 years of the fence being removed. The success of wildlife corridors, currently being advocated as the best way to re-establish ecosystem connectivity, relies on animals utilizing novel areas by moving between the connected areas. Our findings suggest that medium-sized herbivores may be able to re-establish migrations relatively quickly once physical barriers have been removed and that the success of future system linkages could be increased by utilizing past migratory routes.

Ross Ice Shelf (Antarctica) in situ radio-frequency attenuation

AbstractWe have measured the in situ average electric field attenuation length, 〈Lα〉, for radio-frequency signals broadcast vertically through the Ross Ice Shelf, Antarctica. We chose a location, Moore Embayment, south of Minna Bluff, known for its high reflectivity at the ice–sea interface. We confirmed specular reflection and used the return pulses to measure the average attenuation length from 75–1250 MHz over the round-trip distance of 1155 m. We find 〈Lα〉 to vary from ∼500 m at 75 MHz to ∼300 m at 1250 MHz, with an experimental uncertainty of 55–15 m.

A modern Fizeau experiment for education and outreach purposes

On the occasion of the laser's 50th anniversary, we performed a modern Fizeau experiment, measuring the speed of light with a laser beam passing over the city centre of Marseille. For a round trip distance of almost 5 km, the measurement has reached an uncertainty of about 10−4, mainly due to atmospheric fluctuations. We present the experimental and pedagogical challenges of this brilliant outreach experiment.

낙엽송 인공림 목재 생산임업 전과정평가

Energy use and greenhouse gas emissions of Larch roundwood production forestry were analysed using life cycle assessment (LCA). Application of LCA for forestry operations and forest products is a developing field of study in Korea. Larch roundwood production system comprises seedling production, silvicultural operations, felling and logging (log extraction). From the results of life cycle inventory analysis, among various forestry operations, roundwood extraction (hauling and loading of felled roundwood) had about three quarters of the total energy use and GHG emissions. The life-cycle energy use and GHG emissions of roundwood production at forest were 6.921kgCO2e/m3 and 94.02MJ/m3, respectively. The total life-cycle energy use and GHG emissions including roundwood transportation from the forest to the sawmill(roundtrip distance of 150km) were 12.232kgCO2e/m3 and 168.76MJ/m3, respectively. To reduce energy use and GHG emissions in forestry, optimization of wood production and transportation system decreasing fossil fuel use is required.

Post-Newtonian Reference Frames for Advanced Theory of the Lunar Motion and for a New Generation of Lunar Laser Ranging

Post-Newtonian Reference Frames for Advanced Theory of the Lunar Motion and for a New Generation of Lunar Laser RangingWe overview a set of post-Newtonian reference frames for a comprehensive study of the orbital dynamics and rotational motion of Moon and Earth by means of lunar laser ranging (LLR). We employ a scalar-tensor theory of gravity depending on two post-Newtonian parameters, β and γ, and utilize the relativistic resolutions on reference frames adopted by the International Astronomical Union (IAU) in 2000. We assume that the solar system is isolated and space-time is asymptotically flat at infinity. The primary reference frame covers the entire space-time, has its origin at the solar-system barycenter (SSB) and spatial axes stretching up to infinity. The SSB frame is not rotating with respect to a set of distant quasars that are forming the International Celestial Reference Frame (ICRF). The secondary reference frame has its origin at the Earth-Moon barycenter (EMB). The EMB frame is locally-inertial and is not rotating dynamically in the sense that equation of motion of a test particle moving with respect to the EMB frame, does not contain the Coriolis and centripetal forces. Two other local frames - geocentric (GRF) and selenocentric (SRF) - have their origins at the center of mass of Earth and Moon respectively and do not rotate dynamically. Each local frame is subject to the geodetic precession both with respect to other local frames and with respect to the ICRF because of their relative motion with respect to each other. Theoretical advantage of the dynamically non-rotating local frames is in a more simple mathematical description. Each local frame can be aligned with the axes of ICRF after applying the matrix of the relativistic precession. The set of one global and three local frames is introduced in order to fully decouple the relative motion of Moon with respect to Earth from the orbital motion of the Earth-Moon barycenter as well as to connect the coordinate description of the lunar motion, an observer on Earth, and a retro-reflector on Moon to directly measurable quantities such as the proper time and the round-trip laser-light distance. We solve the gravity field equations and find out the metric tensor and the scalar field in all frames which description includes the post-Newtonian multipole moments of the gravitational field of Earth and Moon. We also derive the post-Newtonian coordinate transformations between the frames and analyze the residual gauge freedom.

The quiver of projectives in hereditary categories with Serre duality

Let k be an algebraically closed field and A a k -linear hereditary category satisfying Serre duality with no infinite radicals between the preprojective objects. If A is generated by the preprojective objects, then we show that A is derived equivalent to rep k Q for a so-called strongly locally finite quiver Q . To this end, we introduce light cone distances and round trip distances on quivers which will be used to investigate sections in stable translation quivers of the form Z Q .

Telemedicine in the management of chronic pain: a cost analysis study

Telemedicine provides patients with easy and remote access to consultant expertise irrespective of geographic location. In a randomized controlled trial, this study has applied a rigorous costing methodology to the use of telemedicine in chronic pain management. We performed a randomized two-period crossover trial comparing in-person (IP) consultation with telemedicine (TM) consultation in the management of chronic pain. Over an 18-month period, 26 patients each completed two diaries capturing their direct and indirect travel costs, daily pain scores, and satisfaction with physician consultation. Costing models were developed to account for direct, indirect, fixed, and variable costs in order to perform break-even analyses. Sensitivity analysis was performed over a broad range of assumptions. Direct patient costs were significantly lower in the TM group than in the IP group, with median cost and interquartile range 133 dollars (28-377) vs 443 dollars (292-1075), respectively (P = 0.001). More patients were highly satisfied with the TM consultation than with the IP consultation (56 and 24%, respectively; P < 0.05). Break-even annual patient volume was estimated at 57 patients. A two-way sensitivity analysis controlling for annual patient volume and round-trip distance indicated that TM remains cost-effective at volumes >50 patients/year or at round-trip distances >200 km. Telemedicine is cost-effective over a broad range of assumptions, including annual patient volumes, travel distance, fuel costs, amortization, and discount rates. This study provides data from a real-world setting to determine relevant thresholds and targets for establishing a TM program for patients who are undergoing chronic pain therapy.

Long Daily Movements of Wolves, &lt;em&gt;Canis lupus&lt;/em&gt;, During Pup Rearing

Wolves, Canis lupus, on Ellesmere Island traveled a daily round-trip distance of 40.2 km from their den to a landfill during July 2008, plus an undetermined distance hunting after leaving the landfill. Although long travels by Wolves are well known, this appears to be the first documentation of long daily movements by Wolves rearing pups.

Local food, food miles and carbon emissions: A comparison of farm shop and mass distribution approaches

This paper provides a critical commentary on the conception of food miles followed by an empirical application of food miles to two contrasting food distribution systems based on carbon emissions accounting within these systems. The comparison is between the carbon emissions resultant from operating a large-scale vegetable box system and those from a supply system where the customer travels to a local farm shop. The study is based on fuel and energy use data collected from one of the UK’s largest suppliers of organic produce. The findings suggest that if a customer drives a round-trip distance of more than 6.7 km in order to purchase their organic vegetables, their carbon emissions are likely to be greater than the emissions from the system of cold storage, packing, transport to a regional hub and final transport to customer’s doorstep used by large-scale vegetable box suppliers. Consequently some of the ideas behind localism in the food sector may need to be revisited.

Pre‐clinical remote telesurgery trial of a da Vinci telesurgery prototype

The objective of this study was to perform a pre-clinical remote telesurgery trial of a da Vinci telesurgery prototype on a surgical-grade virtual private network. A da Vinci telesurgery-enabled prototype was used to conduct surgical trials across a 17 MB/s bandwidth VPNe network spanning 2848 km round-trip landline distance from London, Ontario, to Halifax, Nova Scotia, Canada. The outcomes measured during the trial were surgical times and quality of anastomoses. Network configuration resulted in observed latencies of 370 ms with 140 ms due to transport delay. The da Vinci telesurgery prototype performed well subjectively and average porcine pyeloplasty anastomotic times were 20.7 +/- 4.7 min. This work constitutes an early evaluation of the da Vinci telesurgery prototype for conceptually remote telesurgical operations. This study clearly demonstrated the feasibility of remote telesurgery using the da Vinci platform to perform a complex surgical task.

Mate inspection patterns in the female beaugregory damselfish (Stegastes leucostictus)

We observed female beaugregory damselfish (Stegastes leucostictus) as they interacted with males to see whether their movements fit the predictions of different mate-search models. We established high-quality and low-quality groups with low variance in breeding site quality and a medium-quality, high-variance breeding site group and compared focal observations of female nonforaging forays in each group. Only 8% of 137 forays monitored resulted in spawning events. Eighty-nine percent of the forays were less than 240 s and were within 7 m of the focal female’s territory. Average foray times and straight-line foray distances did not differ for females traveling between males in each group. Females entered high-quality breeding sites at a higher rate than low-quality sites and round-trip distances were also greatest in high-quality groups, indicating that females were following a more convoluted path. We interpret these results to mean that (a) female beaugregories separate the tasks of mate assessment and mate choice by conducting information-gathering forays between mating events, (b) forays are energetically costly and therefore usually short in duration and overall distance traveled, (c) information collection takes approximately the same time for high-quality and low-quality mates, but (d) females will alter their foray patterns in high-quality areas to collect additional information. These data are also consistent with the hypothesis that females optimize their search by employing a tiered process of assessment during information-gathering forays, first using an adjustable threshold to accept or reject each male based on his courtship and subsequently a fixed threshold to assess the quality of each breeding site.