311 research outputs found
Thermal Field Theory and Generalized Light Front Coordinates
The dependence of thermal field theory on the surface of quantization and on
the velocity of the heat bath is investigated by working in general coordinates
that are arbitrary linear combinations of the Minkowski coordinates. In the
general coordinates the metric tensor is non-diagonal. The
Kubo, Martin, Schwinger condition requires periodicity in thermal correlation
functions when the temporal variable changes by an amount
. Light front quantization fails since
, however various related quantizations are possible.Comment: 10 page
âTrust the experts!â Risk definitions in Dutch online forums about the âswine fluâ
Citizens are becoming increasingly likely to challenge the knowledge bases underlying policy programmes that deal with risks. This paper investigates how participants in online discussions engage in interactions between expert knowledge, âcommons knowledgeâ and policy assumptions. The concept of âboundary objectsâ, arrangements that allow different groups to work together without consensus, is used to analyse the role of online discussions in these interactions. Discussions on three Dutch online forums about the swine flu are investigated according to a framework for policy argumentation. Interaction between knowledge domains was limited, and it varied in focus and nature across the three forums. Each discussion functioned as a partial approximation of a boundary object. Government organizations should be more aware of the variety of online forums in which discussions about societal risks take place. Several practical options are presented for policy-making with regard to risks
Development and Validation of a Military Training Mental Toughness Inventory
Three studies were conducted in order to develop and validate a mental toughness instrument for use in military training environments. Study 1 (n = 435) focused on item generation and testing the structural integrity of the Military Training Mental Toughness Inventory (MTMTI). The measure assessed ability to maintain optimal performance under pressure from a range of different stressors experienced by recruits during infantry basic training. Study 2 (n = 104) examined the concurrent validity, predictive validity, and test-retest reliability of the measure. Study 3 (n = 106) confirmed the predictive validity of the measure with a sample of more specialized infantry recruits. Overall, the military training mental toughness inventory demonstrated sound psychometric properties and structural validity. Furthermore, it was found to possess good test-retest reliability, concurrent validity, and predicted performance in two different training contexts with two separate samples
Equivalence of light-front and conventional thermal field theory
ONE PHYSICS ELLIPSE, COLLEGE PK, USA, MD,
20740-384
Epidemiological Tools in Focus: A Comprehensive Assessment of Their Role in Addressing Infectious Disease Challenges in Zambia
In the relentless pursuit of mitigating infectious diseases, this investigative study critically examines the nuanced application and effectiveness of epidemiological tools within the context of Zambia. The study meticulously navigates the landscape of infectious diseases in Zambia, considering its unique ecological and socio-economic features. Employing a rigorous methodology that integrates primary data from epidemiological reports, field observations, and laboratory analyses with insights from diverse scientific literature, the study investigates the types and applications of epidemiological tools such as spatial analysis, case-control studies, molecular epidemiology, and serological assays. Unfolding the challenges posed by resource constraints, data reliability issues, and the dynamic nature of infectious diseases in Zambia, the study offers a comprehensive assessment that extends to the implications of these tools for informed public health decision-making. This scholarly inquiry concludes by affirming the significance of ongoing refinement and adaptation of epidemiological tools, emphasizing their pivotal role in addressing infectious disease challenges within Zambia and advocating for their continued enhancement on the global public health stage
Wind-Blown Bubbles around Evolved Stars
Most stars will experience episodes of substantial mass loss at some point in
their lives. For very massive stars, mass loss dominates their evolution,
although the mass loss rates are not known exactly, particularly once the star
has left the main sequence. Direct observations of the stellar winds of massive
stars can give information on the current mass-loss rates, while studies of the
ring nebulae and HI shells that surround many Wolf-Rayet (WR) and luminous blue
variable (LBV) stars provide information on the previous mass-loss history. The
evolution of the most massive stars, (M > 25 solar masses), essentially follows
the sequence O star to LBV or red supergiant (RSG) to WR star to supernova. For
stars of mass less than 25 solar masses there is no final WR stage. During the
main sequence and WR stages, the mass loss takes the form of highly supersonic
stellar winds, which blow bubbles in the interstellar and circumstellar medium.
In this way, the mechanical luminosity of the stellar wind is converted into
kinetic energy of the swept-up ambient material, which is important for the
dynamics of the interstellar medium. In this review article, analytic and
numerical models are used to describe the hydrodynamics and energetics of
wind-blown bubbles. A brief review of observations of bubbles is given, and the
degree to which theory is supported by observations is discussed.Comment: To be published as a chapter in 'Diffuse Matter from Star Forming
Regions to Active Galaxies' - A volume Honouring John Dyson. Eds. T. W.
Harquist, J. M. Pittard and S. A. E. G. Falle. 22 pages, 12 figure
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