Optimal Economic Landscapes with Habitat Fragmentation Effects

Habitat fragmentation is widely considered a primary threat to biodiversity. This paper develops a theoretical model of land use to analyze the optimal conservation of landscapes when land quality is spatially heterogeneous and wildlife habitat is fragmented and socially valuable. When agriculture is the primary cause of fragmentation, we show that reforestation efforts should be targeted to the most fragmented landscapes with an aggregate share of forest equal to a threshold, defined by the ratio of the opportunity cost of conversion to the social value of core forest. When urban development is the primary cause of fragmentation, we show how spatial heterogeneity in amenities and household neighbor preferences affect the optimal landscape and the design of land-use policies.Land Economics/Use,

Targeting Incentives to Reduce Habitat Fragmentation

This paper develops a theoretical model to analyze the spatial targeting of incentives for the restoration of forested landscapes when wildlife habitat can be enhanced by reducing fragmentation. The key theoretical result is that the marginal net benefits of increasing forest are convex, indicating that corner solutions--converting either none or all of the agricultural land in a section to forest--may be optimal. Corner solutions are directly linked to the spatial process determining habitat benefits and the regulator's incomplete information regarding landowner opportunity costs. We present findings from a large-scale empirical landscape simulation that supports our key theoretical results.

Privacy-Preserving Shortest Path Computation

Navigation is one of the most popular cloud computing services. But in virtually all cloud-based navigation systems, the client must reveal her location and destination to the cloud service provider in order to learn the fastest route. In this work, we present a cryptographic protocol for navigation on city streets that provides privacy for both the client's location and the service provider's routing data. Our key ingredient is a novel method for compressing the next-hop routing matrices in networks such as city street maps. Applying our compression method to the map of Los Angeles, for example, we achieve over tenfold reduction in the representation size. In conjunction with other cryptographic techniques, this compressed representation results in an efficient protocol suitable for fully-private real-time navigation on city streets. We demonstrate the practicality of our protocol by benchmarking it on real street map data for major cities such as San Francisco and Washington, D.C.Comment: Extended version of NDSS 2016 pape

SPX-101 is stable in and retains function after exposure to cystic fibrosis sputum

Background: In healthy lungs, epithelial sodium channel (ENaC) is regulated by short, palate, lung, and nasal clone 1 (SPLUNC1). In cystic fibrosis (CF), ENaC is hyperactivated in part due to a loss of SPLUNC1 function. We have developed SPX-101 to replace the lost function of SPLUNC1 in the CF lung. Methods: Expression of SPLUNC1 was determined in sputum from healthy and CF donors. Stability of SPLUNC1, S18 (the ENaC regulatory domain of SPLUNC1), and SPX-101 was determined in sputum from CF donors and towards neutrophil elastase. Activity of SPX-101 after exposure to CF sputum was determined in airway epithelial cells from CF donors and in the βENaC transgenic mouse model. Results: SPLUNC1 protein expression is significantly reduced in CF as compared to healthy sputum. SPLUNC1 is rapidly degraded in CF sputum as well as by a number of individual proteases known to be found in the sputum. SPX-101, but not S18, is stable in CF sputum. Finally, SPX-101 retains its ability to internalize ENaC, regulate airway surface liquid height, and increase survival of βENaC mice after exposure to CF sputum. Conclusions: Our results demonstrate that SPX-101, but not SPLUNC1 or S18, is stable in CF sputum. These results support the therapeutic development of SPX-101 for the treatment of cystic fibrosis.Fil: Sesma, Juliana. Spyryx Biosciences; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Wu, Bryant. Spyryx Biosciences; Estados UnidosFil: Stuhlmiller, Timothy J.. Spyryx Biosciences; Estados UnidosFil: Scott, David W.. Spyryx Biosciences; Estados Unido

An Evaluation of the Mechanical Behavior of Bronze-NI Composites Produced by Selective Laser Sintering

Mechanical properties of Bronze-Nickel composites produced by Selective Laser Sintering (SLS) were evaluated by constant displacement tension tests. These were studied as a function of SLS process parameters - laser power density, scan speed, scan spacing, scan direction and layer thickness. The strength data was then correlated to the microstructure and the part bulk density. To further enhance the part densities and the mechanical properties, post-SLS sintering was studied. The relationships between SLS process parameters, post-SLS sintering parameters and the resulting microstructures, part bulk density and the mechanical properties will be described.Mechanical Engineerin

SPMHD simulations of Structure Formation

The intracluster medium of galaxy clusters is permeated by {\mu}G magnetic fields. Observations with current and future facilities have the potential to illuminate the role of these magnetic fields play in the astrophysical processes of galaxy clusters. To obtain a greater understanding of how the initial seed fields evolve to the magnetic fields in the intracluster medium requires magnetohydrodynamic simulations. We critically assess the current Smoothed Particle Magneto-Hydrodynamics (SPMHD) schemes, especially highlighting the impact of a hyperbolic divergence cleaning scheme and artificial resistivity switch on the magnetic field evolution in cosmological simulations of the formation of a galaxy cluster using the N-body/SPMHD code gcmhd++. The impact and performance of the cleaning scheme and two different schemes for the artificial resistivity switch is demonstrated via idealized test cases and cosmological simulations. We demonstrate that the hyperbolic divergence cleaning scheme is effective at suppressing the growth of the numerical divergence error of the magnetic field and should be applied to any SPMHD simulation. Although the artificial resistivity is important in the strong field regime, it can suppress the growth of the magnetic field in the weak field regime, such as galaxy clusters. With sufficient resolution, simulations with divergence cleaning can reproduce observed magnetic fields. We conclude that the cleaning scheme alone is sufficient for galaxy cluster simulations, but our results indicate that the SPMHD scheme must be carefully chosen depending on the regime of the magnetic field.Comment: 15 pages, 11 figures, published (MNRAS 476 2890