725 research outputs found
Transforming (perceived) Rigidity in Environmental Law Through Adaptive Governance
The Endangered Species Act (ESA) is often portrayed as a major source of instability and crisis in river basins of the U. S. West, where the needs of listed fish species frequently clash with agriculture dependent on federal irrigation projects subject to ESA Section 7 prohibitions on federal agency actions likely to jeopardize listed species or adversely modify critical habitat. Scholarship on Section 7 characterizes the process as unwaveringly rigid, the legal “hammer†forcing federal agencies to consider endangered species’ needs when proposing operations and management plans for federally funded irrigation. In this paper, we identify barriers to an integrated approach to Section 7 implementation and characterize a set of strategies for overcoming its rigidity that may have broader applicability. We draw on lessons derived from the Klamath Basin along the Oregon-California border, where cross-scale processes and venues involving interagency collaboration among leaders in the U.S. Fish and Wildlife Service, the National Marine Fisheries Service, and the U.S. Bureau of Reclamation supported efforts to replace an ecologically and socially fragmented Upper Basin/Lower Basin approach to ESA implementation fraught with conflict. The result was the nation’s first joint biological opinion (BiOp), which effectively institutionalized an adaptive, flexible, integrated approach to water sharing among competing interests. Keys to success included existing collaborative capacity related to shifting stakeholder networks, trust, and relationships and a shift in local agency culture facilitated by empathic leadership leading to a greater sense of shared responsibility for Section 7 compliance. A collaborative hydrologic modeling process enhanced participatory capacity, facilitated transformative social and technical learning, and cultivated greater understanding of the social-ecological system among key stakeholders. The 2013 joint BiOp exemplifies both governmental capacity for flexibility and evolution within the constraints of formal law and the potential for greater integration among federal agencies and between federal agencies and stakeholders involved in ESA implementation
Topological Charge Correlators, Spectral Bounds, and Contact Terms
The structure of topological charge fluctuations in the QCD vacuum is
strongly restricted by the spectral negativity of the Euclidean 2-point
correlator for and the presence of a positive contact term. Some
examples are considered which illustrate the physical origin of these
properties.Comment: Lattice 2002 Conference Proceeding
Recommended from our members
CRADA final report for CRADA number Y-1293-0185: Process modelling and machining operations development
Lockheed Martin Energy Systems, Inc. and Ferro Corporation (formerly W. R. Grace, the original CRADA partner) have collaborated on an effort to develop techniques and processes for the cost-effective machining of ceramic components. The purpose of this effort was to develop a machining model, and grinding equipment machines and techniques for fabricating precision ceramic components. This project was designed to support Department of Energy (DOE) technical needs in manufacturing hard materials as well as enabling U.S. industry to maintain a position of leadership in the production of precision grinding machines and the machining of structural ceramic components
Colloquium: geometric phases of light: insights from fiber bundle theory
Geometric phases are ubiquitous in physics; they act as memories of the transformation of a physical system. In optics, the most prominent examples are the Pancharatnam-Berry phase and the spin-redirection phase. Recent technological advances in phase and polarization structuring have led to the discovery of additional geometric phases of light. The underlying mechanism for all of these is provided by fiber bundle theory. This Colloquium reviews how fiber bundle theory not only sheds light on the origin of geometric phases of light but also lays the foundations for the exploration of high-dimensional state spaces, with implications for topological photonics and quantum communications
Multiple Transitions to Chaos in a Damped Parametrically Forced Pendulum
We study bifurcations associated with stability of the lowest stationary
point (SP) of a damped parametrically forced pendulum by varying
(the natural frequency of the pendulum) and (the amplitude of the external
driving force). As is increased, the SP will restabilize after its
instability, destabilize again, and so {\it ad infinitum} for any given
. Its destabilizations (restabilizations) occur via alternating
supercritical (subcritical) period-doubling bifurcations (PDB's) and pitchfork
bifurcations, except the first destabilization at which a supercritical or
subcritical bifurcation takes place depending on the value of . For
each case of the supercritical destabilizations, an infinite sequence of PDB's
follows and leads to chaos. Consequently, an infinite series of period-doubling
transitions to chaos appears with increasing . The critical behaviors at the
transition points are also discussed.Comment: 20 pages + 7 figures (available upon request), RevTex 3.
Initial Leakage Under Pit and Fissure Sealants Assessed by Neutron Activation
An improved neutron activation method and a model system were used to study microleakage associated with three pit and fissure sealants. Both the sealant and the etching procedure were evaluated on enamel surfaces as well as in prepared model pits. Leakage was reduced to 3 to 4 μg for all three materials, and the etching process was relatively ineffective in forming an initial seal.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66699/2/10.1177_00220345740530062501.pd
Bounds and optimisation of orbital angular momentum bandwidths within parametric down-conversion systems
The measurement of high-dimensional entangled states of orbital angular
momentum prepared by spontaneous parametric down-conversion can be considered
in two separate stages: a generation stage and a detection stage. Given a
certain number of generated modes, the number of measured modes is determined
by the measurement apparatus. We derive a simple relationship between the
generation and detection parameters and the number of measured entangled modes.Comment: 6 pages, 4 figure
Dutch guidelines for physiotherapy in patients with stress urinary incontinence: An update
Introduction and hypothesis: Stress urinary incontinence (SUI) is the most common form of incontinence impacting on quality of life (QOL) and is associated with high financial, social, and emotional costs. The purpose of this study was to provide an update existing Dutch evidence-based clinical practice guidelines (CPGs) for physiotherapy management of patients with stress urinary incontinence (SUI) in order to support physiotherapists in decision making and improving efficacy and uniformity of care. Materials and methods: A computerized literature search of relevant databases was performed to search for information regarding etiology, prognosis, and physiotherapy assessment and management in patients with SUI. Where no evidence was available, recommendations were based on consensus. Clinical application of CPGs and feasibility were reviewed. The diagnostic process consists of systematic history taking and physical examination supported by reliable and valid assessment tools to determine physiological potential for recovery. Therapy is related to different problemcategories. SUI treatment is generally based on pelvic floor muscle exercises combined with patient education and counseling. An important strategy is to reduce prevalent SUI by reducing influencing risk factors. Results: Scientific evidence supporting assessment and management of SUI is strong. Conclusions: The CPGs reflect the current state of knowledge of effective and tailor-made intervention in SUI patients
Development and evaluation of a method to define a tibial coordinate system through the fitting of geometric primitives
Coordinate system definition is a critical element of biomechanical modeling of the knee, and cases of skeletal trauma present major technical challenges. This paper presents a method to define a tibial coordinate system by fitting geometric primitives to surface anatomy requiring minimal user input. The method presented here utilizes a conical fit to both the tibial shaft and femoral condyles to generate independent axes forming the basis of a tibial coordinate system. Definition of the tibial axis showed high accuracy when shape fitting to ≥50 mm of shaft with <3° of angular variation from the axis obtained using the full tibia. Repeatability and reproducibility of the axis was compared using intraclass correlation coefficients which showed excellent intra- and inter-observer agreement across cases. Additionally, shape fitting to the distal femoral condyles showed high accuracy compared to the reference axis established automatically through identifying the medial and lateral epicondyles (<4°). Utilizing geometric primitives to estimate functional axes for the tibia and femur removes reliance on anatomical landmarks that can be displaced by fracture or inaccurately identified by observers. Furthermore, fitting of such primitives provides a more complete understanding of the true bony anatomy, which cannot be done through simple landmark identification.Stuart C. Millar, John B. Arnold, Lucian B. Solomon, Dominic Thewlis and François Frayss
Molecular Dynamics Simulation of Semiflexible Polyampholyte Brushes - The Effect of Charged Monomers Sequence
Planar brushes formed by end-grafted semiflexible polyampholyte chains, each
chain containing equal number of positively and negatively charged monomers is
studied using molecular dynamics simulations. Keeping the length of the chains
fixed, dependence of the average brush thickness and equilibrium statistics of
the brush conformations on the grafting density and the salt concentration are
obtained with various sequences of charged monomers. When similarly charged
monomers of the chains are arranged in longer blocks, the average brush
thickness is smaller and dependence of brush properties on the grafting density
and the salt concentration is stronger. With such long blocks of similarly
charged monomers, the anchored chains bond to each other in the vicinity of the
grafting surface at low grafting densities and buckle toward the grafting
surface at high grafting densities.Comment: 8 pages,7 figure
- …