Deaf identity among alumni of Option schools in the U.S.

This descriptive study surveys deaf identity of alumni of Option schools in the United States. The issue of deaf identity is addressed and the importance of deaf role models in Option schools is presented.

Non-normal real estate return distributions by property type in the U.K.

Investment risk models with infinite variance provide a better description of distributions of individual property returns in the IPD database over the period 1981 to 2003 than Normally distributed risk models, which mirrors results in the U.S. and Australia using identical methodology. Real estate investment risk is heteroscedastic, but the Characteristic Exponent of the investment risk function is constant across time yet may vary by property type. Asset diversification is far less effective at reducing the impact of non-systematic investment risk on real estate portfolios than in the case of assets with Normally distributed investment risk. Multi-risk factor portfolio allocation models based on measures of investment codependence from finite-variance statistics are ineffectual in the real estate context.

The statistical properties of tropical ice clouds generated by the West-African and Australian monsoons from ground-based radar-lidar observations

In the present paper we characterize the statistical properties of non-precipitating tropical ice clouds (deep ice anvils resulting from deep convection and cirrus clouds) over Niamey, Niger, West Africa, and Darwin, northern Australia, using ground-based radar–lidar observations from the Atmospheric Radiation Measurement (ARM) programme. The ice cloud properties analysed in this paper are the frequency of ice cloud occurrence, cloud fraction, the morphological properties (cloud-top height, base height, and thickness), the microphysical and radiative properties (ice water content, visible extinction, effective radius, terminal fall speed, and concentration), and the internal cloud dynamics (in-cloud vertical air velocity). The main highlight of the paper is that it characterizes for the first time the probability density functions of the tropical ice cloud properties, their vertical variability and their diurnal variability at the same time. This is particularly important over West Africa, since the ARM deployment in Niamey provides the first vertically resolved observations of non-precipitating ice clouds in this crucial area in terms of redistribution of water and energy in the troposphere. The comparison between the two sites also provides an additional observational basis for the evaluation of the parametrization of clouds in large-scale models, which should be able to reproduce both the statistical properties at each site and the differences between the two sites. The frequency of ice cloud occurrence is found to be much larger over Darwin when compared to Niamey, and with a much larger diurnal variability, which is well correlated with the diurnal cycle of deep convective activity. The diurnal cycle of the ice cloud occurrence over Niamey is also much less correlated with that of deep convective activity than over Darwin, probably owing to the fact that Niamey is further away from the deep convective sources of the region. The frequency distributions of cloud fraction are strongly bimodal and broadly similar over the two sites, with a predominance of clouds characterized either by a very small cloud fraction (less than 0.3) or a very large cloud fraction (larger than 0.9). The ice clouds over Darwin are also much thicker (by 1 km or more statistically) and are characterized by a much larger diurnal variability than ice clouds over Niamey. Ice clouds over Niamey are also characterized by smaller particle sizes and fall speeds but in much larger concentrations, thereby carrying more ice water and producing more visible extinction than the ice clouds over Darwin. It is also found that there is a much larger occurrence of downward in-cloud air motions less than 1 m s−1 over Darwin, which together with the larger fall speeds retrieved over Darwin indicates that the life cycle of ice clouds is probably shorter over Darwin than over Niamey.

Intrinsic and rational speculative bubbles in the U.S. housing market 1960-2011

This paper examines the dynamics of the residential property market in the United States between 1960 and 2011. Given the cyclically and apparent overvaluation of the market over this period, we determine whether deviations of real estate prices from their fundamentals were caused by the existence of two genres of bubbles: intrinsic bubbles and rational speculative bubbles. We find evidence of an intrinsic bubble in the market pre-2000, implying that overreaction to changes in rents contributed to the overvaluation of real estate prices. However, using a regime-switching model, we find evidence of periodically collapsing rational bubbles in the post-2000 market

Does political proximity to the U.S. cause terror?

We analyze the impact of political proximity to the United States on the occurrence and severity of terror. Employing panel data for 116 countries over the period 1975–2001 we find that countries voting in line with the U.S. are victims of more and deadlier attacks.

Hurricanes and climate: the U.S. CLIVAR working group on hurricanes

While a quantitative climate theory of tropical cyclone formation remains elusive, considerable progress has been made recently in our ability to simulate tropical cyclone climatologies and understand the relationship between climate and tropical cyclone formation. Climate models are now able to simulate a realistic rate of global tropical cyclone formation, although simulation of the Atlantic tropical cyclone climatology remains challenging unless horizontal resolutions finer than 50 km are employed. This article summarizes published research from the idealized experiments of the Hurricane Working Group of U.S. CLIVAR (CLImate VARiability and predictability of the ocean-atmosphere system). This work, combined with results from other model simulations, has strengthened relationships between tropical cyclone formation rates and climate variables such as mid-tropospheric vertical velocity, with decreased climatological vertical velocities leading to decreased tropical cyclone formation. Systematic differences are shown between experiments in which only sea surface temperature is increased versus experiments where only atmospheric carbon dioxide is increased, with the carbon dioxide experiments more likely to demonstrate the decrease in tropical cyclone numbers previously shown to be a common response of climate models in a warmer climate. Experiments where the two effects are combined also show decreases in numbers, but these tend to be less for models that demonstrate a strong tropical cyclone response to increased sea surface temperatures. Further experiments are proposed that may improve our understanding of the relationship between climate and tropical cyclone formation, including experiments with two-way interaction between the ocean and the atmosphere and variations in atmospheric aerosols.

Re-examining the U.K.'s greatest tornado outbreak: forecasting the limited extent of tornadoes along a cold front

On 23 November 1981, a strong cold front swept across the U.K., producing tornadoes from the west to the east coasts. An extensive campaign to collect tornado reports by the Tornado and Storm Research Organisation (TORRO) resulted in 104 reports, the largest U.K. outbreak. The front was simulated with a convection-permitting numerical model down to 200-m horizontal grid spacing to better understand its evolution and meteorological environment. The event was typical of tornadoes in the U.K., with convective available potential energy (CAPE) less than 150 J kg-1, 0-1-km wind shear of 10-20 m s-1, and a narrow cold-frontal rainband forming precipitation cores and gaps. A line of cyclonic absolute vorticity existed along the front, with maxima as large as 0.04 s-1. Some hook-shaped misovortices bore kinematic similarity to supercells. The narrow swath along which the line was tornadic was bounded on the equatorward side by weak vorticity along the line and on the poleward side by zero CAPE, enclosing a region where the environment was otherwise favorable for tornadogenesis. To determine if the 104 tornado reports were plausible, first possible duplicate reports were eliminated, resulting in as few as 58 tornadoes to as many as 90. Second, the number of possible parent misovortices that may have spawned tornadoes is estimated from model output. The number of plausible tornado reports in the 200-m grid-spacing domain was 22 and as many as 44, whereas the model simulation was used to estimate 30 possible parent misovortices within this domain. These results suggest that 90 reports was plausible.

Civilian casualties – do we really care? The failure of the revolution in military affairs of non-lethal weapons in the U.S., Russia and Israel

Causing civilian casualties during military operations has become a much politicised topic in international relations since the Second World War. Since the last decade of the 20th century, different scholars and political analysts have claimed that human life is valued more and more among the general international community. This argument has led many researchers to assume that democratic culture and traditions, modern ethical and moral issues have created a desire for a world without war or, at least, a demand that contemporary armed conflicts, if unavoidable, at least have to be far less lethal forcing the military to seek new technologies that can minimise civilian casualties and collateral damage. Non-Lethal Weapons (NLW) – weapons that are intended to minimise civilian casualties and collateral damage – are based on the technology that, during the 1990s, was expected to revolutionise the conduct of warfare making it significantly less deadly. The rapid rise of interest in NLW, ignited by the American military twenty five years ago, sparked off an entirely new military, as well as an academic, discourse concerning their potential contribution to military success on the 21st century battlefields. It seems, however, that except for this debate, very little has been done within the military forces themselves. This research suggests that the roots of this situation are much deeper than the simple professional misconduct of the military establishment, or the poor political behaviour of political leaders, who had sent them to fight. Following the story of NLW in the U.S., Russia and Israel this research focuses on the political and cultural aspects that have been supposed to force the military organisations of these countries to adopt new technologies and operational and organisational concepts regarding NLW in an attempt to minimise enemy civilian casualties during their military operations. This research finds that while American, Russian and Israeli national characters are, undoubtedly, products of the unique historical experience of each one of these nations, all of three pay very little regard to foreigners’ lives. Moreover, while it is generally argued that the international political pressure is a crucial factor that leads to the significant reduction of harmed civilians and destroyed civilian infrastructure, the findings of this research suggest that the American, Russian and Israeli governments are well prepared and politically equipped to fend off international criticism. As the analyses of the American, Russian and Israeli cases reveal, the political-military leaderships of these countries have very little external or domestic reasons to minimise enemy civilian casualties through fundamental-revolutionary change in their conduct of war. In other words, this research finds that employment of NLW have failed because the political leadership asks the militaries to reduce the enemy civilian casualties to a politically acceptable level, rather than to the technologically possible minimum; as in the socio-cultural-political context of each country, support for the former appears to be significantly higher than for the latter.

The spectrum of an open vertex model based on the U(q)[SU(2)] algebra at roots of unity

We study the exact solution of an N-state vertex model based on the representation of the U(q)[SU(2)] algebra at roots of unity with diagonal open boundaries. We find that the respective reflection equation provides us one general class of diagonal K-matrices having one free-parameter. We determine the eigenvalues of the double-row transfer matrix and the respective Bethe ansatz equation within the algebraic Bethe ansatz framework. The structure of the Bethe ansatz equation combine a pseudomomenta function depending on a free-parameter with scattering phase-shifts that are fixed by the roots of unity and boundary variables. (C) 2010 Elsevier B.V. All rights reserved.