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Search Results: 1 - 10 of 326891 matches for " Jay S. Noller "
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Application of Remote-sensing Data and Decision-Tree Analysis to Mapping Salt-Affected Soils over Large Areas
Abdelhamid A. Elnaggar,Jay S. Noller
Remote Sensing , 2010, DOI: 10.3390/rs2010151
Abstract: Expert assessments for crop and range productivity of very-large arid and semiarid areas worldwide are ever more in demand and these studies require greater sensitivity in delineating the different grades or levels of soil salinity. In conjunction with field study in arid southeastern Oregon, we assess the merit of adding decision-tree analysis (DTA) to a commonly used remote-sensing method. Randomly sampled surface soil horizons were analyzed for saturation percentage, field capacity, pH and electrical conductivity (EC). IFSAR data were acquired for terrain analysis and surficial geological mapping, followed by derivation of layers for analysis. Significant correlation was found between EC values and surface elevation, bands 1, 2, 3 and 4 of the Landsat TM image, and brightness and wetness indices. Maximum-likelihood supervised classification of the Landsat images yields two salinity classes: non-saline soils (EC < 4 dSm–1), prediction accuracy of 97%, and saline soils (EC < 4 dSm–1), prediction accuracy 60%. Addition of DTA results in successful prediction of five classes of soil salinity and an overall accuracy of about 99%. Moreover, the calculated area of salt-affected soil was overestimated when mapped using remote sensing data only compared to that predicted by additionally using DTA. DTA is a promising approach for mapping soil salinity in more productive and accurate ways compared to only using remote-sensing analysis.
Focusing Anti-Corruption Efforts More Effectively: An Empirical Look at Offender Motivation—Positive, Classical, Structural and Ethical Approaches  [PDF]
Jay S. Albanese, Kristine Artello
Advances in Applied Sociology (AASoci) , 2018, DOI: 10.4236/aasoci.2018.86028
Abstract: The level of public corruption cases remains high. Interviews with 72 former investigators, prosecutors, community stakeholders and individuals with first-hand experience in corrupt activities, together with analysis of court documents, offer insight into the motivations behind the corrupt conduct in hundreds of known corruption cases. Corrupt motivations are classified into four categories: positive, classical, structural, and ethical. Empirical examples from interviews and court cases are used to show how the identified causes and correlates of corruption can be grouped and use to develop more effective anti-corruption prevention strategies. Recommendations are offered to reduce the extent of corruption by applying the principles of positive, classical, structural, and ethical explanations of corruption to reduce opportunities for corruption and improve the integrity levels of those in public service.
Constraining fast-roll inflation
Johannes Noller
Physics , 2012,
Abstract: We present constraints on how far single field inflation may depart from the familiar slow-roll paradigm. Considering a fast-roll regime while requiring a (near)-scale-invariant power spectrum introduces large self-interactions for the field and consequently large and scale-dependent non-Gaussianities. Employing this signal, we use the requirement of weak-coupling together with WMAP constraints to derive bounds on generic $P(X,\phi)$ theories of single field inflation.
Derivative Chameleons
Johannes Noller
Physics , 2012, DOI: 10.1088/1475-7516/2012/07/013
Abstract: We consider generalized chameleon models where the conformal coupling between matter and gravitational geometries is not only a function of the chameleon field \phi, but also of its derivatives via higher order co-ordinate invariants. Specifically we consider the first such non-trivial conformal factor A(\phi,X), where X is the canonical kinetic term for \phi. The associated phenomenology is investigated and we show that such theories have a new generic mass-altering mechanism, potentially assisting the generation of a sufficiently large chameleon mass in dense environments. The most general effective potential is derived for such derivative chameleon setups and explicit examples are given. Interestingly this points us to the existence of a purely derivative chameleon protected by a shift symmetry for \phi. We also discuss potential ghost-like instabilities associated with mass-lifting mechanisms and find another, mass-lowering and instability-free, branch of solutions. This suggests that, barring fine-tuning, stable derivative models are in fact typically anti-chameleons that suppress the field's mass in dense environments. Furthermore we investigate modifications to the thin-shell regime and prove a no-go theorem for chameleon effects in non-conformal geometries of the disformal type.
Non-adiabatic primordial fluctuations
J. Noller,J. Magueijo
Physics , 2009, DOI: 10.1088/0264-9381/28/10/105008
Abstract: We consider general mixtures of isocurvature and adiabatic cosmological perturbations. With a minimal assumption set consisting of the linearized Einstein equations and a primordial perfect fluid we derive the second-order action and its curvature variables. We also allow for varying equation of state and speed of sound profiles. The derivation is therefore carried out at the same level of generality that has been achieved for adiabatic modes before. As a result we find a new conserved super-horizon quantity and relate it to the adiabatically conserved curvature perturbation. Finally we demonstrate how the formalism can be applied by considering a Chaplygin gas-like primordial matter model, finding two scale-invariant solutions for structure formation.
Primordial fluctuations without scalar fields
J. Magueijo,J. Noller
Physics , 2009, DOI: 10.1103/PhysRevD.81.043509
Abstract: We revisit the question of whether fluctuations in hydrodynamical, adiabatical matter could explain the observed structures in our Universe. We consider matter with variable equation of state $w=p_0/\ep_0$ and a concomitant (under the adiabatic assumption) density dependent speed of sound, $c_s$. We find a limited range of possibilities for a set up when modes start inside the Hubble radius, then leaving it and freezing out. For expanding Universes, power-law $w(\ep_0)$ models are ruled out (except when $c_s^2\propto w \ll 1$, requiring post-stretching the seeded fluctuations); but sharper profiles in $c_s$ do solve the horizon problem. Among these, a phase transition in $c_s$ is notable for leading to scale-invariant fluctuations if the initial conditions are thermal. For contracting Universes all power-law $w(\ep_0)$ solve the horizon problem, but only one leads to scale-invariance: $w\propto \ep_0^2$ and $c_s\propto \ep_0$. This model bypasses a number of problems with single scalar field cyclic models (for which $w$ is large but constant).
Non-Gaussianity in single field models without slow-roll
Johannes Noller,Joao Magueijo
Physics , 2011, DOI: 10.1103/PhysRevD.83.103511
Abstract: We investigate non-Gaussianity in general single field models without assuming slow-roll conditions or the exact scale-invariance of the scalar power spectrum. The models considered include general single field inflation (e.g. DBI and canonical inflation) as well as bimetric models. We compute the full non-Gaussian amplitude, its size fnl, its shape, and the running with scale n_{NG}. In doing so we show that observational constraints allow significant violations of slow roll conditions and we derive explicit bounds on slow-roll parameters for fast-roll single field scenarios. A variety of new observational signatures is found for models respecting these bounds. We also explicitly construct concrete model implementations giving rise to this new phenomenology.
The coupling to matter in Massive, Bi- and Multi-Gravity
Johannes Noller,Scott Melville
Physics , 2014, DOI: 10.1088/1475-7516/2015/01/003
Abstract: In this paper we construct a family of ways in which matter can couple to one or more `metrics'/spin-2 fields in the vielbein formulation. We do so subject to requiring the weak equivalence principle and the absence of ghosts from pure spin-2 interactions generated by the matter action. Results are presented for Massive, Bi- and Multi-Gravity theories and we give explicit expressions for the effective matter metric in all of these cases.
A Software Architecture for Control of Value Production in Federated Systems
Jay S. Bayne
Journal of Systemics, Cybernetics and Informatics , 2003,
Abstract: Federated enterprises are defined as interactive commercial entities that produce products and consume resources through a network of open, free-market transactions. Value production in such entities is defined as the real-time computation of enterprise value propositions. These computations are increasingly taking place in a grid-connected space – a space that must provide for secure, real-time, reliable end-to-end transactions governed by formal trading protocols. We present the concept of a value production unit (VPU) as a key element of federated trading systems, and a software architecture for automation and control of federations of such VPUs.
Estimates for the number of visible galaxy-spanning civilizations and the cosmological expansion of life
S. Jay Olson
Physics , 2015,
Abstract: If advanced civilizations appear in the universe with a desire to expand, the entire universe can become saturated with life on a short timescale, even if such expanders appear but rarely. Our presence in an untouched Milky Way thus constrains the appearance rate of galaxy-spanning Kardashev type III (K3) civilizations, if it is assumed that some fraction of K3 civilizations will continue their expansion at intergalactic distances. We use this constraint to estimate the appearance rate of K3 civilizations for 81 cosmological scenarios by specifying the extent to which humanity could be a statistical outlier. We find that in nearly all plausible scenarios, the distance to the nearest visible K3 is cosmological. In searches where the observable range is limited, we also find that the most likely detections tend to be expanding civilizations who have entered the observable range from farther away. An observation of K3 clusters is thus more likely than isolated K3 galaxies.
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