On the Origin of Risk Sensitivity: the Energy Budget Rule Revisited

The risk-sensitive foraging theory formulated in terms of the (daily) energy budget rule has been influential in behavioural ecology as well as other disciplines. Predicting risk-aversion on positive budgets and risk-proneness on negative budgets, however, the budget rule has recently been challenged both empirically and theoretically. In this paper, we critically review these challenges as well as the original derivation of the budget rule and propose a `gradual' budget rule, which is normatively derived from a gradual nature of risk sensitivity and encompasses the conventional budget rule as a special case. The gradual budget rule shows that the conventional budget rule holds when the expected reserve is close enough to a threshold for overnight survival, selection pressure being significant. The gradual view also reveals that the conventional budget rule does not need to hold when the expected reserve is not close enough to the threshold, selection pressure being insignificant. The proposed gradual budget rule better fits the empirical findings including those that used to challenge the conventional budget rule.Comment: 13 pages, 4 figure

Regional Beveridge Curves: A Latent Variable Approach

It is important to understand how labour markets in different regions are affected by ‘common’ or ‘national’ shocks including national macroeconomic, monetary and fiscal policies. This paper applies a new econometric approach - involving an unobserved components model - to identify the direction and timing of the shifts in regional Beveridge Curves. The method allows for the presence of common national factor(s) and region specific factor(s) in the determination of activity in labour markets including regional specific loadings on the common factor. The method is applied to Australian data. The results show that equilibrium unemployment rate vary by region and over time. In terms of implications for policies to reduce unemployment, these results suggest a key potential role for regional policies.

The Decision Value Computations in the vmPFC and Striatum Use a Relative Value Code That is Guided by Visual Attention

There is a growing consensus in behavioral neuroscience that the brain makes simple choices by first assigning a value to the options under consideration and then comparing them. Two important open questions are whether the brain encodes absolute or relative value signals, and what role attention might play in these computations.Weinvestigated these questions using a human fMRI experiment with a binary choice task in which the fixations to both stimuli were exogenously manipulated to control for the role of visual attention in the valuation computation. We found that the ventromedial prefrontal cortex and the ventral striatum encoded fixation-dependent relative value signals: activity in these areas correlated with the difference in value between the attended and the unattended items. These attention-modulated relative value signals might serve as the input of a comparator system that is used to make a choice

The value of statistical life and cost–benefit evaluations of landmine clearance in Cambodia

Development agencies spend approximately US$400 million per year on landmine clearance. Yet many cost–benefit evaluations suggest that landmine clearance is socially wasteful because costs appear to far outweigh social benefits. This paper presents new estimates of the benefits of clearing landmines based on a contingent valuation survey in two provinces in rural Cambodia where we asked respondents questions that elicit their trade-offs between money and the risk of death from landmine accidents. The estimated Value of a Statistical Life (VSL) is US$ 0.4 million. In contrast, most previous studies of landmine clearance use foregone income or average GDP per capita, which has a lifetime value of only US$ 2,000 in Cambodia. Humanitarian landmine clearance emerges as a more attractive rural development policy when appropriate estimates of the VSL are used

Gravitational Wave Production At The End Of Inflation

We consider gravitational wave production due to parametric resonance at the end of inflation, or ``preheating''. This leads to large inhomogeneities which source a stochastic background of gravitational waves at scales inside the comoving Hubble horizon at the end of inflation. We confirm that the present amplitude of these gravitational waves need not depend on the inflationary energy scale. We analyze an explicit model where the inflationary energy scale is ~10^9 GeV, yielding a signal close to the sensitivity of Advanced LIGO and BBO. This signal highlights the possibility of a new observational ``window'' into inflationary physics, and provides significant motivation for searches for stochastic backgrounds of gravitational waves in the Hz to GHz range, with an amplitude on the order of \Omega_{gw}(k)h^2 ~ 10^-11. Finally, the strategy used in our numerical computations is applicable to the gravitational waves generated by many inhomogeneous processes in the early universe.Comment: 4 pages, Revtex, 2 figures. v2 References added, discussion clarified and improved. v3 further clarification, typo regarding source corrected. Basic results unchange

The value of statistical life and cost-benefit evaluations of landmine clearance in Cambodia

Development agencies spend approximately US$400 million per year on landmine clearance. Yet many cost-benefit evaluations suggest that landmine clearance is socially wasteful because costs appear to far outweigh social benefits. This paper presents new estimates of the benefits of clearing landmines based on a contingent valuation survey in two provinces in rural Cambodia where we asked respondents questions that elicit their tradeoffs between money and the risk of death from landmine accidents. The estimated Value of a Statistical Life (VSL) is US$0.4 million. In contrast, most previous studies of landmine clearance use foregone income or average GDP per capita, which has a lifetime value of only US$2,000 in Cambodia. Humanitarian landmine clearance emerges as a more attractive rural development policy when appropriate estimates of the VSL are used

The behaviour of remolded Batu Pahat soft clay with different OCR values under cyclic loading

The Batu Pahat Soft Clay, (BPSC) of Universiti Tun Hussein Onn Malaysia, (UTHM) were low in shear strength, bearing capacity, and suffer large settlements when subjected to loading. They undergo varies of dynamic cyclic loadings during their design lifetime and the response was typically more complex, requiring engineers to investigate the dynamic behaviour of soils thoroughly in the laboratory. The objectives of this research were to simulate remolded Batu Pahat Soft Clay (RBPSC) samples with different σv’, to study the dynamic shear modulus, G and damping ratio, D of (RBPSC) under cyclic loading with different f, OCRs, σv’ and σc’ and to analyses the correlation between G and D of the (RBPSC) with the OCR values under cyclic loading. As result, the 100 x 50 mm of remoulded samples are succeed simulated by using large strain consolidation apparatus of 50, 80 and 100 kPa of pre consolidation stress, contain moisture ranging within 42 to 55%. The series of remolded consolidated undrained dynamic cyclic triaxial test were ran under OCR of 1, 2, 3.85 and 4. Hence, it could be concluded that the G decreased when increasing of f and OCRs subjected to increasing axial strain while the G corresponding to each σv’ increases slightly as the σv’ becomes higher. The D shows minor increased when increasing of the f, OCRs and σv’ when subjected to increasing axial strain. Thus, input of parameter G and D can be review as technical values to key design structure on top of soil layer

AN EMPLOYMENT EQUATION FOR AUSTRALIA: 1966-2001

We model the relationship between hours of work and employment and argue that unless actual hours are varying with a change in ‘standard hours’, actual hours should not appear in the long-run component of an equation for employment. If however standard hours are changing then it is desirable that this variable be incorporated into the employment equation. Our theoretical model yields an expression for the elasticity of employment with respect to standard hours which shows that the elasticity is related to the size of the premium for overtime. Using quarterly data for the period 1966:3 – 2001:3 we estimate a new employment equation for Australia incorporating standard hours of work. We find empirical support for our approach and we provide new estimates of the elasticity of employment with respect to the real wage and GDP. We also find a marked asymmetry in the response of employment to variations in real GDP and real wages in recession periods as against non-recession periods.Employment Determination, Demand for Labor, Australia

A FRAMEWORK FOR UNDERSTANDING CHANGES IN THE UNEMPLOYMENT RATE IN A FLOWS CONTEXT: AN EXAMINATION NET FLOWS IN THE AUSTRALIAN LABOUR MARKET

In this paper we develop a framework which is appropriate for the systematic investigation of the relationship between net (and gross) flows between different labour market states and movements in the unemployment rate. We use that framework to investigate the behaviour of net flows of persons between employment, unemployment and not in the labour force in Australia between 1979-2003 and the relationship of these flows to changes in the unemployment rate over that period. We find that: flows from unemployment to employment exceed flows from employment to unemployment and that this is the case even in recessions; flows from employment to not in the labour force exceed flows from not in the labour force to employment and that this is the case even in booms, and; flows from not in the labour force to unemployment exceed flows from unemployment to not in the labour force even in recessions. Another important finding is that the reason why the participation rate is negatively correlated with the unemployment rate is because net flows from employment to both unemployment and to not in the labour force are highly correlated. It cannot be explained by flows occurring between unemployment and not in the labour force.Worker Flows Business Cycle Unemployment Participation Rate