25,784 research outputs found
Present Risk, Future Risk Or No Risk - Measuring and Predicting Perceptions of Health Risks of a Hazardous Waste Landfill
Given that perceived risk is multidimensional, the authors seek better understanding by focusing on health risks and, more particularly, on their temporality. In this way, they attempt to measure more meaningfully psychological influences on risk perceptions
Bubbles in Metropolitan Housing Markets
A commonsense and empirically supported approach to explaining metropolitan real house price changes is for the theory to describe an equilibrium price level to which the market is constantly adjusting. The determinants of real house price appreciation, then, can be divided into two groups, one that explains changes in the equilibrium price and the other that accounts for the adjustment dynamics or changing deviations from the equilibrium price. The former group includes the growth in real income and real construction costs and changes in the real after-tax interest rate. The latter group consists of lagged real appreciation and the difference between the actual and equilibrium real house price levels. Either group of variables can explain a little over two-fifths of the variation in real house price movements in 30 cities over the 1977-92 period; together, they explain three-fifths.
A Bayesian analysis of the 27 highest energy cosmic rays detected by the Pierre Auger Observatory
It is possible that ultra-high energy cosmic rays (UHECRs) are generated by
active galactic nuclei (AGNs), but there is currently no conclusive evidence
for this hypothesis. Several reports of correlations between the arrival
directions of UHECRs and the positions of nearby AGNs have been made, the
strongest detection coming from a sample of 27 UHECRs detected by the Pierre
Auger Observatory (PAO). However, the PAO results were based on a statistical
methodology that not only ignored some relevant information (most obviously the
UHECR arrival energies but also some of the information in the arrival
directions) but also involved some problematic fine-tuning of the correlation
parameters. Here we present a fully Bayesian analysis of the PAO data
(collected before 2007 September), which makes use of more of the available
information, and find that a fraction F_AGN = 0.15^(+0.10)_(-0.07) of the
UHECRs originate from known AGNs in the Veron-Cetty & Veron (VCV) catalogue.
The hypothesis that all the UHECRs come from VCV AGNs is ruled out, although
there remains a small possibility that the PAO-AGN correlation is coincidental
(F_AGN = 0.15 is 200 times as probable as F_AGN = 0.00).Comment: MNRAS, accepted; 8 pages, 7 figure
Intrusion Detection Systems Using Adaptive Regression Splines
Past few years have witnessed a growing recognition of intelligent techniques
for the construction of efficient and reliable intrusion detection systems. Due
to increasing incidents of cyber attacks, building effective intrusion
detection systems (IDS) are essential for protecting information systems
security, and yet it remains an elusive goal and a great challenge. In this
paper, we report a performance analysis between Multivariate Adaptive
Regression Splines (MARS), neural networks and support vector machines. The
MARS procedure builds flexible regression models by fitting separate splines to
distinct intervals of the predictor variables. A brief comparison of different
neural network learning algorithms is also given
The Mutual Interaction Between Population III Stars and Self-Annihilating Dark Matter
We use cosmological simulations of high-redshift minihalos to investigate the
effect of dark matter annihilation (DMA) on the collapse of primordial gas. We
numerically investigate the evolution of the gas as it assembles in a
Population III stellar disk. We find that when DMA effects are neglected, the
disk undergoes multiple fragmentation events beginning at ~ 500 yr after the
appearance of the first protostar. On the other hand, DMA heating and
ionization of the gas speeds the initial collapse of gas to protostellar
densities and also affects the stability of the developing disk against
fragmentation, depending on the DM distribution. We compare the evolution when
we model the DM density with an analytical DM profile which remains centrally
peaked, and when we simulate the DM profile using N-body particles (the 'live'
DM halo). When utilizing the analytical DM profile, DMA suppresses disk
fragmentation for ~ 3500 yr after the first protostar forms, in agreement with
earlier work. However, when using a 'live' DM halo, the central DM density peak
is gradually flattened due to the mutual interaction between the DM and the
rotating gaseous disk, reducing the effects of DMA on the gas, and enabling
secondary protostars of mass ~ 1 M_sol to be formed within ~ 900 yr. These
simulations demonstrate that DMA is ineffective in suppressing gas collapse and
subsequent fragmentation, rendering the formation of long-lived dark stars
unlikely. However, DMA effects may still be significant in the early collapse
and disk formation phase of primordial gas evolution.Comment: 17 pages, 11 figures, to appear in MNRA
Current induced light emission and light induced current in molecular tunneling junctions
The interaction of metal-molecule-metal junctions with light is considered
within a simple generic model. We show, for the first time, that light induced
current in unbiased junctions can take place when the bridging molecule is
characterized by a strong charge-transfer transition. The same model shows
current induced light emission under potential bias that exceeds the molecular
excitation energy. Results based on realistic estimates of molecular-lead
coupling and molecule-radiation field interaction suggest that both effects
should be observable.Comment: 5 pages, 3 figures, RevTeX
Tort Liability, Combatant Activities, and the Question of Over-Deterrence
Immunity from tort liability for losses that are inflicted during warfare is often justified by a supposedly intuitive concern: without immunity, states and combatants will be over-deterred from engaging in combat. In this article, I test this common perception using three frameworks. First, I theoretically analyze the impact of tort liability on relevant state actors’ incentives to engage in warfare. This analysis suggests that tort law is likely to under-deter state actors in relation to their decisions on whether and how to conduct hostilities. Second, I test this conclusion through an original mixed-methods exploratory research, using Israel as a test case. My findings reveal that while tort liability under-deters state actors from engaging in warfare, it can prompt them to implement regulatory measures to minimize the state’s liability. Third, I offer a legal history analysis, exploring why Israel established an immunity from tort liability for losses it inflicts during combat in 1951, and why and how this immunity has expanded since. I show that as the Israel-Palestine conflict prolonged and intensified, state actors began viewing Palestinians’ tort claims as a civilian means of warfare and immunity from liability as the weapon needed for defending Israel’s interests
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