Reconciliation of a Quantum-Distributed Gaussian Key

Two parties, Alice and Bob, wish to distill a binary secret key out of a list of correlated variables that they share after running a quantum key distribution protocol based on continuous-spectrum quantum carriers. We present a novel construction that allows the legitimate parties to get equal bit strings out of correlated variables by using a classical channel, with as few leaked information as possible. This opens the way to securely correcting non-binary key elements. In particular, the construction is refined to the case of Gaussian variables as it applies directly to recent continuous-variable protocols for quantum key distribution.Comment: 8 pages, 4 figures. Submitted to the IEEE for possible publication. Revised version to improve its clarit

Moving Walkways, Escalators, and Elevators

We study a simple geometric model of transportation facility that consists of two points between which the travel speed is high. This elementary definition can model shuttle services, tunnels, bridges, teleportation devices, escalators or moving walkways. The travel time between a pair of points is defined as a time distance, in such a way that a customer uses the transportation facility only if it is helpful. We give algorithms for finding the optimal location of such a transportation facility, where optimality is defined with respect to the maximum travel time between two points in a given set.Comment: 16 pages. Presented at XII Encuentros de Geometria Computacional, Valladolid, Spai

Finding Multiple New Optimal Locations in a Road Network

We study the problem of optimal location querying for location based services in road networks, which aims to find locations for new servers or facilities. The existing optimal solutions on this problem consider only the cases with one new server. When two or more new servers are to be set up, the problem with minmax cost criteria, MinMax, becomes NP-hard. In this work we identify some useful properties about the potential locations for the new servers, from which we derive a novel algorithm for MinMax, and show that it is efficient when the number of new servers is small. When the number of new servers is large, we propose an efficient 3-approximate algorithm. We verify with experiments on real road networks that our solutions are effective and attains significantly better result quality compared to the existing greedy algorithms

Changes at treeline within the San Juan Mountains of Colorado

Repeat photography is a field method to study landscape change over time, yet most studies use a single pair of photographs spanning upwards of a century or more to ascertain change. In this study, I used repeat photography to study vegetation change across high-elevation environments within the San Juan Mountains of southwestern Colorado on decadal time scales. At five photo sites, I compared present conditions to both a historical photograph (ca. 1875-1910) and one from 2002 to determine if climate-induced thresholds have impacted high-elevation forests. Results from this research suggest that (1) tree establishment is increasing at 80% of photo sites and (2) spruce beetle-induced mortality is evident at 60% of sites. To increase the temporal resolution of when the spruce beetle outbreak occurred, I used remote sensing change detection analysis for the periods 2003-2011 and 2011-2019., Given the level of change detected between 2011-2019, spruce beetle-induced mortality along upper treeline likely originated within the past eight years. Overall, results from repeat photography used in conjunction with remote sensing provide multiple lines of evidence that ecological change had a resulted from the crossing of a climate threshold over the past decade. Findings from this research suggest that hotter drought is already impacting high-elevation treeline environments in parts of the San Juan Mountains.Includes bibliographical reference

Large Coercivity in Nanostructured Rare-earth-free MnxGa Films

The magnetic hysteresis of MnxGa films exhibit remarkably large coercive fields as high as 2.5 T when fabricated with nanoscale particles of a suitable size and orientation. This coercivity is an order of magnitude larger than in well-ordered epitaxial film counterparts and bulk materials. The enhanced coercivity is attributed to the combination of large magnetocrystalline anisotropy and ~ 50 nm size nanoparticles. The large coercivity is also replicated in the electrical properties through the anomalous Hall effect. The magnitude of the coercivity approaches that found in rare-earth magnets, making them attractive for rare-earth-free magnet applications

Effects of lesions of the nucleus accumbens core on choice between small certain rewards and large uncertain rewards in rats

BACKGROUND: Animals must frequently make choices between alternative courses of action, seeking to maximize the benefit obtained. They must therefore evaluate the magnitude and the likelihood of the available outcomes. Little is known of the neural basis of this process, or what might predispose individuals to be overly conservative or to take risks excessively (avoiding or preferring uncertainty, respectively). The nucleus accumbens core (AcbC) is known to contribute to rats' ability to choose large, delayed rewards over small, immediate rewards; AcbC lesions cause impulsive choice and an impairment in learning with delayed reinforcement. However, it is not known how the AcbC contributes to choice involving probabilistic reinforcement, such as between a large, uncertain reward and a small, certain reward. We examined the effects of excitotoxic lesions of the AcbC on probabilistic choice in rats. RESULTS: Rats chose between a single food pellet delivered with certainty (p = 1) and four food pellets delivered with varying degrees of uncertainty (p = 1, 0.5, 0.25, 0.125, and 0.0625) in a discrete-trial task, with the large-reinforcer probability decreasing or increasing across the session. Subjects were trained on this task and then received excitotoxic or sham lesions of the AcbC before being retested. After a transient period during which AcbC-lesioned rats exhibited relative indifference between the two alternatives compared to controls, AcbC-lesioned rats came to exhibit risk-averse choice, choosing the large reinforcer less often than controls when it was uncertain, to the extent that they obtained less food as a result. Rats behaved as if indifferent between a single certain pellet and four pellets at p = 0.32 (sham-operated) or at p = 0.70 (AcbC-lesioned) by the end of testing. When the probabilities did not vary across the session, AcbC-lesioned rats and controls strongly preferred the large reinforcer when it was certain, and strongly preferred the small reinforcer when the large reinforcer was very unlikely (p = 0.0625), with no differences between AcbC-lesioned and sham-operated groups. CONCLUSION: These results support the view that the AcbC contributes to action selection by promoting the choice of uncertain, as well as delayed, reinforcement

Psychosocial Correlates of Korean Adolescents' Physical Activity Behavior

The purpose of this study was to test the association of psychological and social variables in explaining the physical activity behavior of a random sample of secondary school students in Korea. Participants included 1,347 students enrolled in the 7th to 12th grades (males, 943; females, 404). Four Korean-version questionnaires were used to explore possible associations between psychosocial variables and physical activity among adolescents. Data were analyzed using correlation analysis and structural equation modeling. Results indicated that all of the psychosocial variables showed statistically significant intercorrelations, and were clearly correlated with physical activity behavior. The psychosocial variables accounted for 40.6% of the variance in the adolescents' physical activity behavior, and the proposed model had an excellent fit for exploring relationships among psychological variables, social support, and physical activity behavior. This study offers the first evidence of psychosocial constructs as predictors of Korean adolescents' physical activity behavior

Ecology of greater sage-grouse populations inhabiting the northwestern Wyoming Basin

Range-wide population declines of greater sage-grouse (Centrocercus urophasianus; sage-grouse) have been largely attributed to habitat loss and fragmentation. However, the specific conservation threats affecting the ecology of sage-grouse populations may diff er by region. Although the status of the Bear Lake Plateau and Valley (BLPV) sagegrouse populations in the Wyoming Basin has been monitored using male lek counts since the 1960s, little was known about their ecology, seasonal movements, and habitat use patterns. From 2010–2012, we radio-marked 153 sage-grouse (59 females and 94 males) with very high frequency necklace-style radio-collars throughout the BLPV study area, which encompassed parts of Bear Lake County, Idaho, and Rich County, Utah. We subsequently monitored the radio-marked sage-grouse to estimate the factors affecting vital rates, seasonal movements, and habitat use. Radio-marked sage-grouse primarily used seasonal habitats in Idaho and Utah, but some individuals used seasonal habitats in Wyoming. The average annual survival rate for the radio-marked sage-grouse was 53% (±3%). Average female nest success (23%; 95% CI = 18–29%) was lower than range-wide estimates. Brood success varied between 2011 and 2012, with higher brood survival observed in 2012. Twenty-four percent of radio-marked sage-grouse were migratory, engaging in seasonal movements ≥10 km. Annual home range estimates using kernel density estimator (101 km2) for radio-marked sage-grouse were within estimates previously reported. However, poor recruitment attributed to low nest and brood survival may be impacting overall population stability. Because the radio-marked sage-grouse used seasonal habitats in 3 states, we recommend that Utah, Idaho, and Wyoming coordinate in the development of a tri-state management plan to better conserve this population

The Initial Stages of Implementing the Western Quail Management Plan

The Western Association of Fish and Wildlife Agencies (WAFWA) established the Western Quail Working Group (WQWG) in July 2009. A memorandum of understanding (MOU) was signed by the western agencies responsible for quail management (Arizona, California, Colorado, Idaho, Kansas, Montana, Nevada, Oklahoma, New Mexico, Oregon, Texas, Utah, and Washington) as ‘‘a cooperative agreement to improve management and implement strategies for conservation of western quail and their habitats.’’ The primary habitat management goals identified by the group are outlined in the Western Quail Management Plan, published by the Wildlife Management Institute in January 2010. Some of the past accomplishments of the WQWG, highlighted at recent WAFWA meetings, include shrub density reductions in New Mexico, riparian habitat restoration in Texas, private landowner habitat improvement cost-share in Kansas, and mesquite removal monitoring in Arizona. Management of western quail and their habitats has traditionally been accomplished on a relatively fine, local scale, so many of the current efforts to implement management practices identified in the plan are undocumented. A need identified by the WQWG is to better engage technical staff to guide outcomes and deliverables outlined in the plan. Additionally, the group is working to update the MOU to include Federal Land Management agencies, to better facilitate land management between state and federal agencies. A technical meeting with state and federal agency staff is scheduled for May 2017 in New Mexico to discuss state progress on implementing the Western Quail Management Plan, and how to increase state interest and efforts towards quail management. The discussions of the technical meeting will be presented at Quail 8

Practical learning method for multi-scale entangled states

We describe a method for reconstructing multi-scale entangled states from a small number of efficiently-implementable measurements and fast post-processing. The method only requires single particle measurements and the total number of measurements is polynomial in the number of particles. Data post-processing for state reconstruction uses standard tools, namely matrix diagonalisation and conjugate gradient method, and scales polynomially with the number of particles. Our method prevents the build-up of errors from both numerical and experimental imperfections