Rock avalanche dating in the Valais, Switzerland

The Saaser Vispa valley in the Valais, Switzerland, is a deglaciated valley in the Alps that has been affected by ancient rock avalanche (Bergsturz) events. These rock avalanches have mainly occurred on west facing valley sides, due to rockslides along discontinuities within mica schists dipping at around 40º into the valley. The avalanches have modified the steep glaciated ‘U shape’ valley side into less steep slopes that have enabled forestry and pastures for cattle. The avalanche deposits have been colonised by vegetation including larch trees Larix decidua. The avalanches are probably due to paraglacial adjustment following deglaciation of the valley. The removal of glacial ice buttressing and resulting stress relief cause discontinuities to open, into which snowmelt and rainwater initiate weakening of the steep rock slopes until catastrophic failure occurs, resulting in rockslides and avalanches. It is probable that the rockslides have occurred within the last several thousand years. Lichenometry and dendrochronology are being used to estimate the age of the rock avalanche deposits.Peer reviewe

Autonomous Underwater Vehicle Guidance, Navigation, and Control

A considerable volume of research has recently blossomed in the literature on autonomous underwater vehicles accepting recent developments in mathematical modeling and system identification; pitch control; information filtering and active sensing, including inductive sensors of ELF emissions and also optical sensor arrays for position, velocity, and orientation detection; grid navigation algorithms; and dynamic obstacle avoidance among others. In light of these modern developments, this article develops and compares integrative guidance, navigation, and control methodologies for the Naval Postgraduate School’s Phoenix, a submerged autonomous vehicle. The measure of merit reveals how well each of several methodologies cope with known and unknown disturbance currents that can be constant or harmonic while maintaining safe passage distance from underwater obstacles, in this case submerged mines

Lasers for Satellite Uplinks and Downlinks

The article of record as published may be found at http://dx.doi.org/10.3390/sci2030071The use of Light Amplification by Stimulated Emission of Radiation (i.e., LASERs or lasers) by the U.S. Department of Defense is not new and includes laser weapons guidance, laser-aided measurements, even lasers as weapons (e.g., Airborne Laser). Lasers in support of telecommunications is also not new. The use of laser light in fiber optics shattered thoughts on communications bandwidth and throughput. Even the use of lasers in space is no longer new. Lasers are being used for satellite-to-satellite crosslinking. Laser communication can transmit orders-of-magnitude more data using orders-of-magnitude less power and can do so with minimal risk of exposure to the sending and receiving terminals. What is new is using lasers as the uplink and downlink between the terrestrial segment and the space segment of satellite systems. More so, the use of lasers to transmit and receive data between moving terrestrial segments (e.g., ships at sea, airplanes in flight) and geosynchronous satellites is burgeoning. This manuscript examines the technological maturation of employing lasers as the signal carrier for satellite communications linking terrestrial and space systems. The purpose of the manuscript is to develop key performance parameters (KPPs) to inform U.S. Department of Defense initial capabilities documents (ICDs) for near-future satellite acquisition and development. By appreciating the history and technological challenges of employing lasers rather than traditional radio frequency sources for satellite uplink and downlink signal carrier, this manuscript recommends ways for the U.S. Department of Defense to employ lasers to transmit and receive high bandwidth, large-throughput data from moving platforms that need to retain low probabilities of detection, intercept, and exploitation (e.g., carrier battle group transiting to a hostile area of operations, unmanned aerial vehicle collecting over adversary areas). The manuscript also intends to identify commercial sector early-adopter fields and those fields likely to adapt to laser employment for transmission and receipt.U.S. Air Forc

Development of Deterministic Artificial Intelligence for Unmanned Underwater Vehicles (UUV)

The article of record as published may be found at�https://doi.org/10.3390/jmse8080578The major premise of deterministic artificial intelligence (D.A.I.) is to assert deterministic self-awareness statements based in either the physics of the underlying problem or system identification to establish governing differential equations. The key distinction between D.A.I. and ubiquitous stochastic methods for artificial intelligence is the adoption of first principles whenever able (in every instance available). One benefit of applying artificial intelligence principles over ubiquitous methods is the ease of the approach once the re-parameterization is derived, as done here. While the method is deterministic, researchers need only understand linear regression to understand the optimality of both self-awareness and learning. The approach necessitates full (autonomous) expression of a desired trajectory. Inspired by the exponential solution of ordinary differential equations and Euler�s expression of exponential solutions in terms of sinusoidal functions, desired trajectories will be formulated using such functions. Deterministic self-awareness statements, using the autonomous expression of desired trajectories with buoyancy control neglected, are asserted to control underwater vehicles in ideal cases only, while application to real-world deleterious effects is reserved for future study due to the length of this manuscript. In totality, the proposed methodology automates control and learning merely necessitating very simple user inputs, namely desired initial and final states and desired initial and final time, while tuning is eliminated completely

Vertical Carbon Nanotube Device in Nanoporous Templates

A modified porous anodic alumina template (PAA) containing a thin CNT catalyst layer directly embedded into the pore walls. CNT synthesis using the template selectively catalyzes SWNTs and DWNTs from the embedded catalyst layer to the top PAA surface, creating a vertical CNT channel within the pores. Subsequent processing allows for easy contact metallization and adaptable functionalization of the CNTs and template for a myriad of applications

Tax base erosion and inequity from Michigan's assessment growth limit: The case of Detroit

In this paper we examine the degree to which Michigan's property value assessment growth cap has eroded the tax base and created substantial differences in effective tax rates among residential properties within the City of Detroit. While the analysis focuses on a specific city with significant tax base erosion challenges, it is relevant to other cities in Michigan and across the nation, particularly in states that impose assessment growth limits. Using quantile regression techniques, we examine how an assessment growth cap alters effective tax rate distributions within and across property value groups. Results show that the cap creates a wide range of effective tax rates across properties of similar value (horizontal inequity), and similar tax payments for properties of differing values (vertical inequity)

Property Tax Delinquency - Social Contract in Crisis: The Case of Detroit

In this paper we develop a theoretical model of the individual decision to become delinquent on one’s property tax payments. We then apply the model to the City of Detroit, Michigan, USA, where the city is in the midst of bankruptcy proceedings, and a rate of property tax delinquency of 48 percent, resulting in uncollected tax revenues of about 20 percent. We use detailed parcellevel data for Detroit to evaluate the factors that affect both the probability that a property owner is tax delinquent and, conditional upon delinquency, the magnitude of the delinquency. Our estimates show that properties that have lower value, longer police response times, are nonhomestead (non-owner occupied residential properties), have a higher statutory tax rate, have a higher assessed value relative to sales price, are owned by a financial institution or by a Detroit resident, are delinquent on water bills, and for which the probability of enforcement is low are more likely to be tax delinquent These findings can be used to inform policies targeted at improving tax compliance within the City

Vertical Carbon Nanotube Devices With Nanoscale Lengths Controlled Without Lithography

Vertical single-walled carbon nanotubes (vSWCNTs) are synthesized within highly ordered porous anodic alumina (PAA) templates supported on Si substrates. A process for obtaining thin-film PAA with long-range ordered nanopores is presented in this paper. Each nanopore contains at most one v-SWCNT that is supported by a dielectric and addressed by electrochemically formed Pd nanowire source contacts and evaporated Pd drain contacts. Characteristics of these completely vertical, two-terminal nanotube devices are presented. Control of the v-SWCNT length is demonstrated using a straightforward etching process with lengths of less than 100 nm achieved without the need for complex/expensive lithography. This effective nanoscale length control of highly ordered v-SWCNTs provides a practical basis for the realization of CNT-based nanoelectronics

Against the flow: evidence of multiple recent invasions of warmer continental shelf waters by a Southern Ocean brittle star

The Southern Ocean is anomalously rich in benthos. This biodiversity is native, mostly endemic and perceived to be uniquely threatened from climate- and anthropogenically- mediated invasions. Major international scientific effort throughout the last decade has revealed more connectivity than expected between fauna north and south of the worlds strongest marine barrier – the Polar Front (the strongest jet of the Antarctic Circumpolar Current). To date though, no research has demonstrated any radiations of marine taxa out from the Southern Ocean, except at abyssal depths (where conditions differ much less). Our phylogeographic investigation of one of the most ubiquitous and abundant clades at high southern latitudes, the ophiuroids (brittlestars), shows that one of them, Ophiura lymani, has gone against the flow. Remarkably our genetic data suggest that O. lymani has successfully invaded the South American shelf from Antarctica at least three times, in recent (Pleistocene) radiation. Many previous studies have demonstrated links within clades across the PF this is the first in which northwards directional movement of a shelf-restricted species is the only convincing explanation. Rapid, recent, regional warming is likely to facilitate multiple range shift invasions into the Southern Ocean, whereas movement of cold adapted fauna (considered highly stenothermal) out of the Antarctic to warmer shelves has, until now, seemed highly unlikely