The abolition of the earnings rule for UK pensioners

The US has legislated to abolish its social security earnings test. A priori it is not possible to predict the effect this will have on work incentives. Using data from the Family Expenditure Survey we show that the abolition of the earnings rule in the UK increased the number of hours worked by men. The lack of any evidence of a reduction in hours may be a consequence of those who previously earned more than the earnings threshold deferring pension receipt at an actuarially favourable rate. This is consistent with there being little evidence of a significant change in the number of deferrals after the earnings rule was abolished

Household portfolios in the UK

This paper presents a detailed analysis of the composition of household portfolios, using both aggregate and micro-data. Among the key findings are that: Most household wealth is held in the form of housing and pensions. Over time, there has been a shift away from housing towards financial assets, driven largely by the growth in life and pension funds. Liquid financial wealth (excluding life and pension funds) is not predominantly held in risky form. By far the most commonly held asset is an interest-bearing account at a bank or building society account. Of people with positive (liquid) financial wealth, more than half is held in savings accounts. The importance of risky assets in an individual's portfolio varies according to their characteristics. The unconditional portfolio share held in risky assets (i.e. averaged across those with and without any risky assets) rises with both age and total financial wealth. However, most of the variation in unconditional portfolio shares is due to differences in ownership rates as opposed to the proportion of the portfolio held in risky assets. Looking only at the people within each wealth decile who have risky assets, the conditional portfolio share is relatively constant across wealth, suggesting a possible role for entry costs or other fixed costs in explaining portfolio holdings. Multivariate analysis shows that the conditional portfolio share in risky assets actually falls with age as classical portfolio theory would predict. Finally, the tax treatment of savings products has an effect on portfolio choice. Separate probit regressions for the ownership of tax-favoured assets and similar assets without the tax exemption, show that, controlling for other factors, marginal tax rates are important in determining asset ownership. These results are in accordance with those found by Poterba in the US.

Review of antiskid and brake dynamics research

The behavior of various antiskid systems was investigated under controlled conditions. Results from utilizing a single main wheel of a DC-9 aircraft suggest that the systems investigated perform well under most circumstances but there may be room for improvement. For example, it was demonstrated that pressure bias modulation can adversely affect the response of antiskid systems to rapid changes in the runway friction level. Results also indicate that antiskid systems designed to operate at a slip ratio of approximately 0.1 can provide a maximum braking effort without undue loss in the cornering capability of the tire. Time histories of braking friction coefficient were shown to provide a means of determining antiskid system performance and for systems that employed pressure bias modulation it was shown that performance could also be estimated from time histories of brake pressure and torque

Regular quantum graphs

We introduce the concept of regular quantum graphs and construct connected quantum graphs with discrete symmetries. The method is based on a decomposition of the quantum propagator in terms of permutation matrices which control the way incoming and outgoing channels at vertex scattering processes are connected. Symmetry properties of the quantum graph as well as its spectral statistics depend on the particular choice of permutation matrices, also called connectivity matrices, and can now be easily controlled. The method may find applications in the study of quantum random walks networks and may also prove to be useful in analysing universality in spectral statistics.Comment: 12 pages, 3 figure

Noise measurements at Stockton Airport obtained during engineering evaluation of two-segment approaches in a 727-222 aircraft

The results of acoustic measurements made on a 727-222 aircraft during standard ILS and two-segment approaches are presented. The aircraft was equipped with a special purpose glide slope computer to provide the capability of making two-segment noise abatement approaches. For upper segment computations, the computer used barometric-corrected pressure altitude and the slant range to a DME transmitter which was colocated with the glide slope transmitter. The computer used the ILS glide slope deviation for lower segment computations. Additional measurements were made on 737 revenue aircraft using the Stockton Airport. The purpose of the acoustical portion of the test was to measure and identify the noise levels during the various approaches

Status of recent aircraft braking and cornering research

The sources of degraded performance which sometimes occurs under adverse runway conditions, are investigated to obtain data necessary to the development of more advanced systems, in an effort to insure safe ground handling operations under all-weather conditions. Tire-to-ground friction characteristics are determined under braking conditions which closely resemble those of airplanes under heavy braking. Braking data from single-wheel landing loads track tests are related with those available from full-scale flight tests

Behavior of aircraft antiskid breaking systems on dry and wet runway surfaces: A slip-ratio-controlled system with ground speed reference from unbraked nose wheel

An experimental investigation was conducted at the Langley aircraft landing loads and traction facility to study the braking and cornering response of a slip ratio controlled aircraft antiskid braking system with ground speed reference derived from an unbraked nose wheel. The investigation, conducted on dry and wet runway surfaces, utilized one main gear wheel, brake, and tire assembly of a DC-9 series 10 airplane. During maximum braking, the average ratio of the drag force friction coefficient developed by the antiskid system to the maximum drag force friction coefficient available was higher on the dry surface than on damp and flooded surfaces, and was reduced with lighter vertical loads, higher yaw angles, and when new tire treads were replaced by worn treads. Similarly, the average ratio of side force friction coefficient developed by the tire under antiskid control to the maximum side force friction coefficient available to a freely rolling yawed tire decreased with increasing yaw angle, generally increased with ground speed, and decreased when tires with new treads were replaced by those with worn treads

Noise measurements taken at LAX during operational evaluation of two-segment approaches in a 727-200 aircraft

A series of seven noise measurements were made each day over a period of fifteen days. The first and last flights each day were made by a specially instrumented 727-200 aircraft being used to evaluate the operational effectiveness of two-segment noise abatement approaches in scheduled service. Noise measurements were made to determine the noise reduction benefits of the two-segment approaches