7,028 research outputs found
Why special relativity should not be a template for a fundamental reformulation of quantum mechanics
In a comparison of the principles of special relativity and of quantum mechanics, the former theory is marked by its relative economy and apparent explanatory simplicity. A number of theorists have thus been led to search for a small number of postulates - essentially information theoretic in nature - that would play the role in quantum mechanics that the relativity principle and the light postulate jointly play in Einstein's 1905 special relativity theory. The purpose of the present paper is to resist this idea, at least in so far as it is supposed to reveal the fundamental form of the theory. It is argued that the methodology of Einstein's 1905 theory represents a victory of pragmatism over explanatory depth; and that its adoption only made sense in the context of the chaotic state state of physics at the start of the 20th century - as Einstein well knew
Mad about the boy? Hollywood stardom and masculinity subverted in 'The Swimmer'
As Burt Lancaster dives into one luxurious pool after another in 'The Swimmer' (1968), he is increasingly implicated as a casualty of a compromised and hypocritical generation. The product of a confused, transitional moment in Hollywood cinema, the film appears to exploit the starâs subversion of his 1950s muscle-man persona. Yet it is questionable whether Lancaster had ever embodied this without ambiguity or parody to begin with. Moreover, the film emphasizes not the nuances of East Coast pool culture which preoccupied John Cheever (who wrote the story upon which the film is based), but the swimming pool as an arena for the display of the Hollywood star body. As such, it is difficult to judge whether or not the film is supposed to be a parody of older forms, and whether or not it should be viewed as camp, difficulties which are compounded when one investigates the considerable creative role of Lancaster in the filmâs troubled production history. At a moment when the âbutch shiftâ in late sixtiesâ gay culture revealed a preoccupation with reconfiguring men as objects of desire in a manner which transcended traditional associations with sexual abnormality, a process reflected in Cheeverâs writings, The Swimmer at times embodies an outdated Narcissism. Yet although inconsistent, the film nonetheless displays an impulse to enacting forms of Naturalism â drained swimming pools, bodies shivering from overexposure â which would become dominant in seventiesâ representations of masculinity
Using Unmanned Aerial Vehicles to Quantify Erosion Control Measures on a Reclaimed Central Utah Coal Mine
For certain landscape reclamation efforts surrounding, the Utah Division of Oil Gas and Mining (UDOGM) utilizes a surface roughing technique called âpockingâ. The process of pocking establishes closely spaced gouges approximately 1.2 meters in diameter and 0.5 meters deep across a reclaimed landscape in order to reduce surface erosion and promote plant growth on steep terrain in arid regions. Pocks are designed as a series of micro watersheds that trap water to aid in plant establishment and reduces overland flow of water. Over time vegetation grows within the pocks as they infill with sediment. While this method is considered an effective reclamation technique, its effectiveness has, to date, relied on observation only. This research will utilize consumer grade unmanned aerial systems (UASs) commonly known as âdronesâ, to develop a technique by which pocks can be monitored and the effectiveness of pocking can be quantified. To this end, UAS overflights spanning two years (2019-2020) resulted in high-resolution (2.5cm) ortho imagery as well as digital terrain data at the same resolution. A comparison of the data collected across these two years identified erosion and deposition within and between pocks as well as the establishment and spread of seeded vegetation. The results also identified a spatial pattern of landscape subsidence as the reclaimed landscape settled. We found that, with effective geographic control, low-cost, off-the-shelf, consumer grade drones are an effective tool to monitor and quantify changes in reclaimed landscapes
Dairy Discharges: How National Pork Producers Council Misconstrues the Clean Water Act and Diminishes Protection for New Mexico\u27s Polluted Tributary Groundwater
A new map-making algorithm for CMB polarisation experiments
With the temperature power spectrum of the cosmic microwave background (CMB)
at least four orders of magnitude larger than the B-mode polarisation power
spectrum, any instrumental imperfections that couple temperature to
polarisation must be carefully controlled and/or removed. Here we present two
new map-making algorithms that can create polarisation maps that are clean of
temperature-to-polarisation leakage systematics due to differential gain and
pointing between a detector pair. Where a half wave plate is used, we show that
the spin-2 systematic due to differential ellipticity can also by removed using
our algorithms. The algorithms require no prior knowledge of the imperfections
or temperature sky to remove the temperature leakage. Instead, they calculate
the systematic and polarisation maps in one step directly from the time ordered
data (TOD). The first algorithm is designed to work with scan strategies that
have a good range of crossing angles for each map pixel and the second for scan
strategies that have a limited range of crossing angles. The first algorithm
can also be used to identify if systematic errors that have a particular spin
are present in a TOD. We demonstrate the use of both algorithms and the ability
to identify systematics with simulations of TOD with realistic scan strategies
and instrumental noise.Comment: 11 pages, 6 figure
Optimal scan strategies for future CMB satellite experiments
The B-mode polarisation power spectrum in the Cosmic Microwave Background
(CMB) is about four orders of magnitude fainter than the CMB temperature power
spectrum. Any instrumental imperfections that couple temperature fluctuations
to B-mode polarisation must therefore be carefully controlled and/or removed.
We investigate the role that a scan strategy can have in mitigating certain
common systematics by averaging systematic errors down with many crossing
angles. We present approximate analytic forms for the error on the recovered
B-mode power spectrum that would result from differential gain, differential
pointing and differential ellipticity for the case where two detector pairs are
used in a polarisation experiment. We use these analytic predictions to search
the parameter space of common satellite scan strategies in order to identify
those features of a scan strategy that have most impact in mitigating
systematic effects. As an example we go on to identify a scan strategy suitable
for the CMB satellite proposed for the ESA M5 call. considering the practical
considerations of fuel requirement, data rate and the relative orientation of
the telescope to the earth. Having chosen a scan strategy we then go on to
investigate the suitability of the scan strategy.Comment: 21 pages, 11 figures, Comments welcom
High-Performance Architecture for Color Error Diffusion
Error diffusion is one of the most widely used algorithms for halftoning gray scale and color images. It works by distributing the thresholding error of each pixel to unprocessed neighboring pixels, while maintaining the average value of the image. Error diffusion results in inter-pixel data dependencies that prohibit a simplistic data pipelining processing approach and increase the memory requirements of the system. In this paper, we present a multiprocessing approach to overcome these difficulties, which results in a novel architecture for high performance hardware implementation of error diffusion algorithms. The proposed architecture is scalable, flexible, cost effective, and may be adopted for processing gray scale or color images. The key idea in this approach is to simultaneously process pixels in separate rows and columns in a diagonal arrangement, so that data dependencies across processing elements are avoided. The processor was realized using an FPGA implementation and may be used for real-time image rendering in high-speed scanning or printing. The entire system runs at the input clock rate, allowing the performance to scale linearly with the clock rate. Higher data rate applications required by future applications will automatically be supported using more advanced high-speed FPGA technologies
Removing beam asymmetry bias in precision CMB temperature and polarisation experiments
Asymmetric beams can create significant bias in estimates of the power
spectra from CMB experiments. With the temperature power spectrum many orders
of magnitude stronger than the B-mode power spectrum any systematic error that
couples the two must be carefully controlled and/or removed. Here, we derive
unbiased estimators for the CMB temperature and polarisation power spectra
taking into account general beams and general scan strategies. A simple
consequence of asymmetric beams is that, even with an ideal scan strategy where
every sky pixel is seen at every orientation, there will be residual coupling
from temperature power to B-mode power if the orientation of the beam asymmetry
is not aligned with the orientation of the co-polarisation. We test our
correction algorithm on simulations of two temperature-only experiments and
demonstrate that it is unbiased. The simulated experiments use realistic scan
strategies, noise levels and highly asymmetric beams. We also develop a
map-making algorithm that is capable of removing beam asymmetry bias at the map
level. We demonstrate its implementation using simulations and show that it is
capable of accurately correcting both temperature and polarisation maps for all
of the effects of beam asymmetry including the effects of temperature to
polarisation leakage.Comment: 18 pages, 9 figure
An Empirical Analysis of the Economic Impact of Federal Terrorism Reinsurance
This paper examines the role of the federal government in the market for terrorism reinsurance. We investigate the stock price response of affected industries to a sequence of thirteen events culminating in the enactment of the Terrorism Risk Insurance Act (TRIA) of 2002. In the industries most likely to be affected by TRIA banking, construction, insurance, real estate investment trusts, transportation, and public utilities the stock price effect was primarily negative. The Act was at best value-neutral for property-casualty insurers because it eliminated the option not to offer terrorism insurance. The negative response of the other industries may be attributable to the Act's impeding more efficient private market solutions, failing to address nuclear, chemical, and biological hazards, and reducing market expectations of federal assistance following future terrorist attacks.
- âŚ