How soccer players head the ball: a test of optic acceleration cancellation theory with virtual reality

We measured the movements of soccer players heading a football in a fully immersive virtual reality environment. In mid-flight the ball’s trajectory was altered from its normal quasi-parabolic path to a linear one, producing a jump in the rate of change of the angle of elevation of gaze (α) from player to ball. One reaction time later the players adjusted their speed so that the rate of change of α increased when it had been reduced and reduced it when it had been increased. Since the result of the player’s movement was to regain a value of the rate of change close to that before the disturbance, the data suggest that the players have an expectation of, and memory for, the pattern that the rate of change of α will follow during the flight. The results support the general claim that players intercepting balls use servo control strategies and are consistent with the particular claim of Optic Acceleration Cancellation theory that the servo strategy is to allow α to increase at a steadily decreasing rate.

Comparative micromorphology of nectariferous and nectarless labellar spurs in selected clades of subtribe Orchidinae (Orchidaceae)

Floral nectar spurs are widely considered to influence pollinator behaviour in orchids. Spurs of 21 orchid species selected from within four molecularly circumscribed clades of subtribe Orchidinae (based on Platanthera s.l., Gymnadenia-Dactylorhiza s.l., Anacamptis s.l., Orchis s.s.) were examined under light and scanning electron microscopes in order to estimate correlations between nectar production (categorized as absent, trace, reservoir), interior epidermal papillae (categorized as absent, short, medium, long) and epidermal cell striations (categorized as apparently absent, weak, moderate, strong). Closely related congeneric species scored similarly, but more divergent species showed less evidence of phylogenetic constraints. Nectar secretion was negatively correlated with striations and positively correlated with papillae, which were especially frequent and large in species producing substantial reservoirs of nectar. We speculate that the primary function of the papillae is conserving energy through nectar resorption and explain the presence of large papillae in a minority of deceit-pollinated species by arguing that the papillae improve pollination because they are a tactile expectation of pollinating insects. In contrast, the prominence of striations may be a 'spandrel', simply reflecting the thickness of the overlying cuticle. Developmentally, the spur is an invagination of the labellum; it is primarily vascularized by a single 'U'-shaped primary strand, with smaller strands present in some species. Several suggestions are made for developing further, more targeted research programmes. (C) 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160, 369-387.

Tropospheric temperature trends: history of an ongoing controversy

Changes in atmospheric temperature have a particular importance in climate research because climate models consistently predict a distinctive vertical profile of trends. With increasing greenhouse gas concentrations, the surface and troposphere are consistently projected to warm, with an enhancement of that warming in the tropical upper troposphere. Hence, attempts to detect this distinct ‘fingerprint’ have been a focus for observational studies. The topic acquired heightened importance following the 1990 publication of an analysis of satellite data which challenged the reality of the projected tropospheric warming. This review documents the evolution over the last four decades of understanding of tropospheric temperature trends and their likely causes. Particular focus is given to the difficulty of producing homogenized datasets, with which to derive trends, from both radiosonde and satellite observing systems, because of the many systematic changes over time. The value of multiple independent analyses is demonstrated. Paralleling developments in observational datasets, increased computer power and improved understanding of climate forcing mechanisms have led to refined estimates of temperature trends from a wide range of climate models and a better understanding of internal variability. It is concluded that there is no reasonable evidence of a fundamental disagreement between tropospheric temperature trends from models and observations when uncertainties in both are treated comprehensively

Interpretation of ambiguity in children: a prospective study of associations with anxiety and parental interpretations

Interpretation of ambiguity is consistently associated with anxiety in children, however, the temporal relationship between interpretation and anxiety remains unclear as do the developmental origins of interpretative biases. This study set out to test a model of the development of interpretative biases in a prospective study of 110 children aged 5–9 years of age. Children and their parents were assessed three times, annually, on measures of anxiety and interpretation of ambiguous scenarios (including, for parents, both their own interpretations and their expectations regarding their child). Three models were constructed to assess associations between parent and child anxiety and threat and distress cognitions and expectancies. The three models were all a reasonable fit of the data, and supported conclusions that: (i) children’s threat and distress cognitions were stable over time and were significantly associated with anxiety, (ii) parents’ threat and distress cognitions and expectancies significantly predicted child threat cognitions at some time points, and (iii) parental anxiety significantly predicted parents cognitions, which predicted parental expectancies at some time points. Parental expectancies were also significantly predicted by child cognitions. The findings varied depending on assessment time point and whether threat or distress cognitions were being considered. The findings support the notion that child and parent cognitive processes, in particular parental expectations, may be a useful target in the treatment or prevention of anxiety disorders in children.

Timing and the holding periods of institutional real estate

The literature on investors’ holding periods for equities and bonds suggest that high transaction costs are associated with longer holding periods. Return volatility, by contrast, is associated with short-term trading and hence shorter holding periods. High transaction costs and the perceived illiquidity of the real estate market leads to an expectation of longer holding periods. Further, work on depreciation and obsolescence might suggest that there is an optimal holding period. However, there is little empirical work in the area. In this paper, data from the Investment Property Databank are used to investigate sales rate and holding period for UK institutional real estate between 1981 and 1994. Sales rates are investigated using the Cox proportional hazards framework. The results show longer holding periods than those claimed by investors. There are marked differences by type of property and sales rates vary over time. Contemporaneous returns are positively associated with an increase in the rate of sale. The results shed light on investor behaviour.

Likelihood-free estimation of model evidence

Statistical methods of inference typically require the likelihood function to be computable in a reasonable amount of time. The class of “likelihood-free” methods termed Approximate Bayesian Computation (ABC) is able to eliminate this requirement, replacing the evaluation of the likelihood with simulation from it. Likelihood-free methods have gained in efficiency and popularity in the past few years, following their integration with Markov Chain Monte Carlo (MCMC) and Sequential Monte Carlo (SMC) in order to better explore the parameter space. They have been applied primarily to estimating the parameters of a given model, but can also be used to compare models. Here we present novel likelihood-free approaches to model comparison, based upon the independent estimation of the evidence of each model under study. Key advantages of these approaches over previous techniques are that they allow the exploitation of MCMC or SMC algorithms for exploring the parameter space, and that they do not require a sampler able to mix between models. We validate the proposed methods using a simple exponential family problem before providing a realistic problem from human population genetics: the comparison of different demographic models based upon genetic data from the Y chromosome.

The information content of REIT credit rating actions and transparency

We examine the short-run and long-run price reaction of equity REIT shares following credit rating actions, testing the transparency of the REIT structure. Generally, the economic effect on the stock price is subdued for both upgrades and downgrades compared to prior literature examining the broader U.S. equity market. An examination of trading volume revealed a significant increase in trading in reaction to downgrade credit rating changes, with a more subdued response to upgrades. The findings support the notion that REITs are more publicly forthcoming about the expectation of positive news in comparison to negative news.

Available potential energy density for a multicomponent Boussinesq fluid with arbitrary nonlinear equation of state

In this paper, the concept of available potential energy (APE) density is extended to a multicomponent Boussinesq fluid with a nonlinear equation of state. As shown by previous studies, the APE density is naturally interpreted as the work against buoyancy forces that a parcel needs to perform to move from a notional reference position at which its buoyancy vanishes to its actual position; because buoyancy can be defined relative to an arbitrary reference state, so can APE density. The concept of APE density is therefore best viewed as defining a class of locally defined energy quantities, each tied to a different reference state, rather than as a single energy variable. An important result, for which a new proof is given, is that the volume integrated APE density always exceeds Lorenz’s globally defined APE, except when the reference state coincides with Lorenz’s adiabatically re-arranged reference state of minimum potential energy. A parcel reference position is systematically defined as a level of neutral buoyancy (LNB): depending on the nature of the fluid and on how the reference state is defined, a parcel may have one, none, or multiple LNB within the fluid. Multiple LNB are only possible for a multicomponent fluid whose density depends on pressure. When no LNB exists within the fluid, a parcel reference position is assigned at the minimum or maximum geopotential height. The class of APE densities thus defined admits local and global balance equations, which all exhibit a conversion with kinetic energy, a production term by boundary buoyancy fluxes, and a dissipation term by internal diffusive effects. Different reference states alter the partition between APE production and dissipation, but neither affect the net conversion between kinetic energy and APE, nor the difference between APE production and dissipation. We argue that the possibility of constructing APE-like budgets based on reference states other than Lorenz’s reference state is more important than has been previously assumed, and we illustrate the feasibility of doing so in the context of an idealised and realistic oceanic example, using as reference states one with constant density and another one defined as the horizontal mean density field; in the latter case, the resulting APE density is found to be a reasonable approximation of the APE density constructed from Lorenz’s reference state, while being computationally cheaper.

In situ and remote-sensing measurements of the mean microphysical and optical properties of industrial pollution aerosol during ADRIEX

We present a summary of the principal physical and optical properties of aerosol particles using the FAAM BAE-146 instrumented aircraft during ADRIEX between 27 August and 6 September 2004, augmented by sunphotometer, lidar and satellite retrievals. Observations of anthropogenic aerosol, principally from industrial sources, were concentrated over the northern Adriatic Sea and over the Po Valley close to the aerosol sources. An additional flight was also carried out over the Black Sea to compare east and west European pollution. Measurements show the single-scattering albedo of dry aerosol particles to vary considerably between 0.89 and 0.97 at a wavelength of 0.55 μm, with a campaign mean within the polluted lower free troposphere of 0.92. Although aerosol concentrations varied significantly from day to day and during individual days, the shape of the aerosol size distribution was relatively consistent through the experiment, with no detectable change observed over land and over sea. There is evidence to suggest that the pollution aerosol within the marine boundary layer was younger than that in the elevated layer. Trends in the aerosol volume distribution show consistency with multiple-site AERONET radiometric observations. The aerosol optical depths derived from aircraft measurements show a consistent bias to lower values than both the AERONET and lidar ground-based radiometric observations, differences which can be explained by local variations in the aerosol column loading and by some aircraft instrumental artefacts. Retrievals of the aerosol optical depth and fine-mode (<0.5 μm radius) fraction contribution to the optical depth using MODIS data from the Terra and Aqua satellites show a reasonable level of agreement with the AERONET and aircraft measurements.

An examination of climate sensitivity for idealised climate change experiments in an intermediate general circulation model

Radiative forcing and climate sensitivity have been widely used as concepts to understand climate change. This work performs climate change experiments with an intermediate general circulation model (IGCM) to examine the robustness of the radiative forcing concept for carbon dioxide and solar constant changes. This IGCM has been specifically developed as a computationally fast model, but one that allows an interaction between physical processes and large-scale dynamics; the model allows many long integrations to be performed relatively quickly. It employs a fast and accurate radiative transfer scheme, as well as simple convection and surface schemes, and a slab ocean, to model the effects of climate change mechanisms on the atmospheric temperatures and dynamics with a reasonable degree of complexity. The climatology of the IGCM run at T-21 resolution with 22 levels is compared to European Centre for Medium Range Weather Forecasting Reanalysis data. The response of the model to changes in carbon dioxide and solar output are examined when these changes are applied globally and when constrained geographically (e.g. over land only). The CO2 experiments have a roughly 17% higher climate sensitivity than the solar experiments. It is also found that a forcing at high latitudes causes a 40% higher climate sensitivity than a forcing only applied at low latitudes. It is found that, despite differences in the model feedbacks, climate sensitivity is roughly constant over a range of distributions of CO2 and solar forcings. Hence, in the IGCM at least, the radiative forcing concept is capable of predicting global surface temperature changes to within 30%, for the perturbations described here. It is concluded that radiative forcing remains a useful tool for assessing the natural and anthropogenic impact of climate change mechanisms on surface temperature.

A longitudinal study of carbon disclosure strategy: evidence from utility, energy and mining industries in the UK

The paper investigates how energy-intensive industries respond to the recent government-led carbon emission schemes through the content analysis of 306 annual and standalone reports of 25 UK listed companies from 2004 to 2012. This period of reporting captures the trend and development of corporate disclosures on carbon emissions after the launch of EU Emissions Trading Schemes (ETS) and Climate Change Act (CCA) 2008. It is found that in corresponding to strategic legitimacy theory, there is an increase in both the quality and quantity of carbon disclosures as a response to these initiatives. However, the change is gradual, which reflects in the achievement of peak disclosure period two years after the launch. It indicates that the new legislations have a lasting impact on the discourses rather than an immediate legitimacy threat from the perspective of institutional legitimacy theory. The results also show that carbon disclosures are an institutionalised practice as companies in the same industries and/or with same carbon trading account status appear to imitate and adopt the industry’s ‘best practice’ disclosure strategy to maintain legitimacy. The trend analysis suggests that the overall disclosure practice is still in its infant stage, especially in the reporting of quantitative and monetary items. The paper contributes to the social and environmental accounting literature by adopting both strategic and institutional view of legitimacy, which explains why carbon disclosures evolve in a specific way to meet the expectation of various stakeholders.

A battle of elephants: (I)legitimate ethical voices?

In this paper, we aim to distil myriad stakeholder voices through a Foucaudian theoretical apparatus in the establishment of ethical stakeholder voices amidst a takeover of a Ghanaian National Bank with ownership control by the state National Pension Fund and Insurance Company. Resonating with Foucault’s position that, the prove and an actual practice of ethical principles despite risk is non-existent within a democracy, this paper reveals how stakeholders in a takeover further their own interest to the neglect of the very germane societal expectation of a salient stakeholder role. We further fill an existing gap within the stakeholder literature that posit of stakeholders as always possessing the right and ethical voices. We conclude that, despite Foucault’s last lecture of The Courage of Truth: The Government of the Self and others having proven of a robust apparatus in distilling ethical voices from non-ethical within the realm of a democratic field, its idealist nature demands a counterfactual position.

An AeroCom assessment of black carbon in Arctic snow and sea ice

Though many global aerosols models prognose surface deposition, only a few models have been used to directly simulate the radiative effect from black carbon (BC) deposition to snow and sea ice. Here, we apply aerosol deposition fields from 25 models contributing to two phases of the Aerosol Comparisons between Observations and Models (AeroCom) project to simulate and evaluate within-snow BC concentrations and radiative effect in the Arctic. We accomplish this by driving the offline land and sea ice components of the Community Earth System Model with different deposition fields and meteorological conditions from 2004 to 2009, during which an extensive field campaign of BC measurements in Arctic snow occurred. We find that models generally underestimate BC concentrations in snow in northern Russia and Norway, while overestimating BC amounts elsewhere in the Arctic. Although simulated BC distributions in snow are poorly correlated with measurements, mean values are reasonable. The multi-model mean (range) bias in BC concentrations, sampled over the same grid cells, snow depths, and months of measurements, are −4.4 (−13.2 to +10.7) ng g−1 for an earlier phase of AeroCom models (phase I), and +4.1 (−13.0 to +21.4) ng g−1 for a more recent phase of AeroCom models (phase II), compared to the observational mean of 19.2 ng g−1. Factors determining model BC concentrations in Arctic snow include Arctic BC emissions, transport of extra-Arctic aerosols, precipitation, deposition efficiency of aerosols within the Arctic, and meltwater removal of particles in snow. Sensitivity studies show that the model–measurement evaluation is only weakly affected by meltwater scavenging efficiency because most measurements were conducted in non-melting snow. The Arctic (60–90° N) atmospheric residence time for BC in phase II models ranges from 3.7 to 23.2 days, implying large inter-model variation in local BC deposition efficiency. Combined with the fact that most Arctic BC deposition originates from extra-Arctic emissions, these results suggest that aerosol removal processes are a leading source of variation in model performance. The multi-model mean (full range) of Arctic radiative effect from BC in snow is 0.15 (0.07–0.25) W m−2 and 0.18 (0.06–0.28) W m−2 in phase I and phase II models, respectively. After correcting for model biases relative to observed BC concentrations in different regions of the Arctic, we obtain a multi-model mean Arctic radiative effect of 0.17 W m−2 for the combined AeroCom ensembles. Finally, there is a high correlation between modeled BC concentrations sampled over the observational sites and the Arctic as a whole, indicating that the field campaign provided a reasonable sample of the Arctic.

Social citizenship, housing wealth and the cost of social care: is the Care Act 2014 'Fair'?

This article assesses the extent to which it is ‘fair’ for the government to require owner-occupiers to draw on the equity accumulated in their home to fund their social care costs. The question is stimulated by the report of the Commission on Funding of Care and Support, Fairer Care Funding (the Dilnot Commission) and the subsequent Care Act 2014. The enquiry is located within the framework of social citizenship and the new social contract. It argues that the individualistic, contractarian approach, exemplified by the Dilnot Commission and reflected in the Act, raises questions when considered from the perspective of intergenerational fairness. We argue that our concerns with the Act could be addressed by inculcating an expectation of drawing on housing wealth to fund older age: a policy of asset-based welfare.

Public versus private provision of infrastructure in a neoclassical growth model

This article studies the welfare and long run allocation impacts of privatization. There are two types of capital in this model economy, one private and the other initially public (“infrastructure”). A positive externality due to infrastructure capital is assumed, so that the government could improve upon decentralized allocations internalizing the externality, but public investmentis …nanced through distortionary taxation. It is shown that privatization is welfare-improving for a large set of economies and that after privatization under-investment is optimal. When operation inefficiency in the public sectoror subsidy to infrastructure accumulation are introduced, gains from privatization are higherand positive for most reasonable combinations of parameters.