The initiation of subduction: criticality by addition of water?

Subduction is a major process of plate tectonics; however, its initiation is not understood. We used high-resolution (less than 1 kilometer) finite-element models based on rheological data of the lithosphere to investigate the role played by water on initiating subduction. A solid-fluid thermomechanical instability is needed to drive a cold, stiff, and negatively buoyant lithosphere into the mantle. This instability can be triggered slowly by sedimentary loading over a time span of 100 million years. Our results indicate that subduction can proceed by a double feedback mechanism (thermoelastic and thermal-rheological) promoted by lubrication due to water.     

Preface:Upgrading of the Forest Information Technology

I have been engagedinthe study,teaching,research and services of the surveyingtechnologyfor nearlythirtyyears,butit was onlytenyears agothat I beganto useitininnovativeforest studies.The lasttenyears has witnessed mysophisticationinscholarlyresearch,andtodaythe studies we areundertaking already involves the management of forest resources through information management,forest engineering,forest fire prevention,forest security,further investigation of forest knowledge,afforestation decision supp…     

Piaeodicton: the traces of infaunal xenophyophores?

A xenophyophore found just below the surface of a box core of modern deep-sea sediment from the Japan Trench has a threadlike plasma body that extends through horizontal, anastomosing networks of organically bound sediment tubes (the organism's test). The tubes resemble somne of the polygonal networks of the trace fossil Paleodictyon. Such xenophyophores may be the makers of Paleodictyon, and the complex, regular geometry of Paleodictyon may be determined by the xenophyophore's anastomosing body shape.     

Rings of uranus: invisible and impossible?

Neither the dynamical nor the optical properties of the rings of Uranus are easily understood, unless it is assumed that they are not rings in the ordinary sense but simply volatile material in the orbits of several individual small satellites. It is possible that other natural satellites may also leave such rings in their wakes.     

ASIAN-AMERICAN SCIENTISTS: New Breed of Protester Asks: Why Not Us?

For nearly a year prior to this past June, grad student Roger Hu had been following with increasing anxiety the case of Wen Ho Lee, the Los Alamos National Laboratory physicist who had been arrested and jailed in New Mexico under suspicion of mishandling classified data. Now Hu struggles to keep up with his Massachusetts Institute of Technology classes in computer science and electrical engineering in his new life as an activist.     

Connectivity of marine populations: open or closed?

Most marine populations are thought to be well connected via long-distance dispersal of larval stages. Eulerian and Lagrangian flow models, coupled with linear mortality estimates, were used to examine this assumption. The findings show that when simple advection models are used, larval exchange rates may be overestimated; such simplistic models fail to account for a decrease of up to nine orders of magnitude in larval concentrations resulting from diffusion and mortality. The alternative process of larval retention near local populations is shown to exist and may be of great importance in the maintenance of marine population structure and management of coastal marine resources.     

Farmers’ perceptions of climate change: identifying types

Ambitious targets to reduce greenhouse gas (GHG) emissions from agriculture have been set by both national governments and their respective livestock sectors. We hypothesize that farmer self-identity influences their assessment of climate change and their willingness to implement measures which address the issue. Perceptions of climate change were determined from 286 beef/sheep farmers and evaluated using principal component analysis (PCA). The analysis elicits two components which evaluate identity (productivism and environmental responsibility), and two components which evaluate behavioral capacity to adopt mitigation and adaptation measures (awareness and risk perception). Subsequent Cluster Analyses reveal four farmer types based on the PCA scores. ‘The Productivist’ and ‘The Countryside Steward’ portray low levels of awareness of climate change, but differ in their motivation to adopt pro-environmental behavior. Conversely, both ‘The Environmentalist’ and ‘The Dejected’ score higher in their awareness of the issue. In addition, ‘The Dejected’ holds a high sense of perceived risk; however, their awareness is not conflated with an explicit understanding of agricultural GHG sources. With the exception of ‘The Environmentalist’, there is an evident disconnect between perceptions of agricultural emission sources and their contribution towards GHG emissions amongst all types. If such linkages are not conceptualized, it is unlikely that behavioral capacities will be realized. Effective communication channels which encourage action should target farmers based on the groupings depicted. Therefore, understanding farmer types through the constructs used in this study can facilitate effective and tailored policy development and implementation.     

Carbyne forms of carbon: do they exist?

Almost 15 years have passed since carbynes entered the literature as new forms of elemental carbon. They recently attracted attention as possible interstellar dust constituents and as carriers of presolar noble gases in meteorites. Their existence and that of the related mineral chaoite are questioned, and a reevaluation of previous data is suggested.