Shape in an Atom of Space: Exploring quantum geometry phenomenology

A phenomenology for the deep spatial geometry of loop quantum gravity is introduced. In the context of a simple model, an atom of space, it is shown how purely combinatorial structures can affect observations. The angle operator is used to develop a model of angular corrections to local, continuum flat-space 3-geometries. The physical effects involve neither breaking of local Lorentz invariance nor Planck scale suppression, but rather reply on only the combinatorics of SU(2) recoupling. Bhabha scattering is discussed as an example of how the effects might be observationally accessible.Comment: 14 pages, 7 figures; v2 references adde

Triply Special Relativity

We describe an extension of special relativity characterized by {\it three} invariant scales, the speed of light, $c$, a mass, $\kappa$ and a length $R$. This is defined by a non-linear extension of the Poincare algerbra, $\cal A$, which we describe here. For $R\to \infty$, $\cal A$ becomes the Snyder presentation of the $\kappa$-Poincare algebra, while for $\kappa \to \infty$ it becomes the phase space algebra of a particle in deSitter spacetime. We conjecture that the algebra is relevant for the low energy behavior of quantum gravity, with $\kappa$ taken to be the Planck mass, for the case of a nonzero cosmological constant $\Lambda = R^{-2}$. We study the modifications of particle motion which follow if the algebra is taken to define the Poisson structure of the phase space of a relativistic particle.Comment: 13 page

Towards Loop Quantization of Plane Gravitational Waves

The polarized Gowdy model in terms of Ashtekar-Barbero variables is further reduced by including the Killing equations for plane-fronted parallel gravitational waves with parallel rays. The resulting constraint algebra, including one constraint derived from the Killing equations in addition to the standard ones of General Relativity, are shown to form a set of first-class constraints. Using earlier work by Banerjee and Date the constraints are expressed in terms of classical quantities that have an operator equivalent in Loop Quantum Gravity, making space-times with pp-waves accessible to loop quantization techniques.Comment: 14 page

Accounting as practice

In this paper we seek to debate some of the problems affecting positivist accounting research, and how the adoption of organizational theory grounded on qualitative methods can fruitfully contribute to advance research in the area. To this end we draw on research we have previously conducted in Portuguese public hospitals to discuss how the incorporation of power issues, institutional entrepreneurship, hybridization, institutional logics and institutional work in accounting studies fosters in-depth explanations of accounting practice.info:eu-repo/semantics/publishedVersio

Neutralizing antibody response during acute and chronic hepatitis C virus infection

Little is known about the role of Abs in determining the outcome of hepatitis C virus (HCV) infection. By using infectious retroviral pseudotypes bearing HCV glycoproteins, we measured neutralizing Ab (nAb) responses during acute and chronic HCV infection. In seven acutely infected health care workers, only two developed a nAb response that failed to associate with viral clearance. In contrast, the majority of chronically infected patients had nAbs. To determine the kinetics of strain-specific and crossreactive nAb emergence, we studied patient H, the source of the prototype genotype 1a H77 HCV strain. An early weak nAb response, specific for the autologous virus, was detected at seroconversion. However, neutralization of heterologous viruses was detected only between 33 and 111 weeks of infection. We also examined the development of nAbs in 10 chimpanzees infected with H77 clonal virus. No nAb responses were detected in three animals that cleared virus, whereas strain-specific nAbs were detected in six of the seven chronically infected animals after approximately 50 weeks of infection. The delayed appearance of high titer crossreactive nAbs in chronically infected patients suggests that selective mechanism(s) may operate to prevent the appearance of these Abs during acute infection. The long-term persistence of these nAbs in chronically infected patients may regulate viral replication

Creating an Effective Regional Alignment Strategy for the U.S. Army

View the Executive SummaryAs the war in Afghanistan draws to a close, the Army increasingly is focused upon “regionally aligning” its forces. To do so effectively, however, it must undertake several initiatives. First, the Army must acknowledge and liberate the unique productive capabilities (talents) of each individual. Second, it must shift from process-oriented, industrial age personnel management to productivity-focused, information age talent management. Third, the Army must foster enduring human relationships between its organizations and the governments, militaries, and populations to which they are regionally aligned. Hand in hand with this, it must redesign its Force Generation Model to create regional expertise at both individual and organizational levels. Finally, the Army must ensure that regional alignment does not degrade the worldwide “flex” capabilities of its forces.https://press.armywarcollege.edu/monographs/1474/thumbnail.jp

Quantum Dynamics without the Wave Function

When suitably generalized and interpreted, the path-integral offers an alternative to the more familiar quantal formalism based on state-vectors, selfadjoint operators, and external observers. Mathematically one generalizes the path-integral-as-propagator to a {\it quantal measure} $\mu$ on the space $\Omega$ of all ``conceivable worlds'', and this generalized measure expresses the dynamics or law of motion of the theory, much as Wiener measure expresses the dynamics of Brownian motion. Within such ``histories-based'' schemes new, and more ``realistic'' possibilities open up for resolving the philosophical problems of the state-vector formalism. In particular, one can dispense with the need for external agents by locating the predictive content of $\mu$ in its sets of measure zero: such sets are to be ``precluded''. But unrestricted application of this rule engenders contradictions. One possible response would remove the contradictions by circumscribing the application of the preclusion concept. Another response, more in the tradition of ``quantum logic'', would accommodate the contradictions by dualizing $\Omega$ to a space of ``co-events'' and effectively identifying reality with an element of this dual space.Comment: plainTeX, 24 pages, no figures. To appear in a special volume of {\it Journal of Physics A: Mathematical and General} entitled ``The Quantum Universe'' and dedicated to Giancarlo Ghirardi on the occasion of his 70th birthday. Most current version is available at http://www.physics.syr.edu/~sorkin/some.papers/ (or wherever my home-page may be

In situ studies of algal biomass in relation to physicochemical characteristics of the Salt Plains National Wildlife Refuge, Oklahoma, USA

This is the first in a series of experiments designed to characterize the Salt Plains National Wildlife Refuge (SPNWR) ecosystem in northwestern Oklahoma and to catalogue its microbial inhabitants. The SPNWR is the remnant of an ancient ocean, encompassing ~65 km(2 )of variably hypersaline flat land, fed by tributaries of the Arkansas River. Relative algal biomass (i.e., chlorophyll concentrations attributed to Chlorophyll-a-containing oxygenic phototrophs) and physical and chemical parameters were monitored at three permanent stations for a one-year period (July 2000 to July 2001) using a nested block design. Salient features of the flats include annual air temperatures that ranged from -10 to 40°C, and similar to other arid/semi-arid environments, 15–20-degree daily swings were common. Shade is absent from the flats system; intense irradiance and high temperatures (air and sediment surface) resulted in low water availability across the SPNWR, with levels of only ca. 15 % at the sediment surface. Moreover, moderate daily winds were constant (ca. 8–12 km h(-1)), sometimes achieving maximum speeds of up to 137 km h(-1). Typical of freshwater systems, orthophosphate (PO(4)(3-)) concentrations were low, ranging from 0.04 to <1 μM; dissolved inorganic nitrogen levels were high, but spatially variable, ranging from ca. 250–600 μM (NO(3)(- )+ NO(2)(-)) and 4–166 μM (NH(4)(+)). Phototroph abundance was likely tied to nutrient availability, with high-nutrient sites exhibiting high Chl-a levels (ca. 1.46 mg m(-2)). Despite these harsh conditions, the phototrophic microbial community was unexpectedly diverse. Preliminary attempts to isolate and identify oxygenic phototrophs from SPNWR water and soil samples yielded 47 species from 20 taxa and 3 divisions. Our data indicate that highly variable, extreme environments might support phototrophic microbial communities characterized by higher species diversity than previously assumed