Noise driven unlimited population growth

Demographic noise causes unlimited population growth in a broad class of models which, without noise, would predict a stable finite population. We study this effect on the example of a stochastic birth-death model which includes immigration, binary reproduction and death. The unlimited population growth proceeds as an exponentially slow decay of a metastable probability distribution (MPD) of the population. We develop a systematic WKB theory, complemented by the van Kampen system size expansion, for the MPD and for the decay time. Important signatures of the MPD is a power-law tail (such that all the distribution moments, except the zeroth one, diverge) and the presence in the solution of two different WKB modes.Comment: 4 pages, 2 figure

The plight of the sense-making ape

This is a selective review of the published literature on object-choice tasks, where participants use directional cues to find hidden objects. This literature comprises the efforts of researchers to make sense of the sense-making capacities of our nearest living relatives. This chapter is written to highlight some nonsensical conclusions that frequently emerge from this research. The data suggest that when apes are given approximately the same sense-making opportunities as we provide our children, then they will easily make sense of our social signals. The ubiquity of nonsensical contemporary scientific claims to the effect that humans are essentially--or inherently--more capable than other great apes in the understanding of simple directional cues is, itself, a testament to the power of preconceived ideas on human perception

Occupational therapy practice education: A perspective from international students in the UK.

Background: Numbers of international students enrolling on occupational therapy (OT) courses in Western institutions have increased. Previous examination of these students' experience of practice education is limited. Objective: To explore the opportunities and challenges experienced by international students in OT practice education. Methods: This study adopted a phenomenological approach, recruiting six individuals from three UK universities. Data from semi-structured interviews was given thematic analysis for result interpretation. Results: Participants identified learning OT in the workplace, working in a multidisciplinary team and personal and professional development as practice education opportunities. Language difficulties, differences in communication styles, multiple cultural differences and unfamiliarity with the National Health Service (NHS) were the main challenges. Good practice educators and supportive team members were the main contributors to positive placement experiences. Conclusions: Participants gained knowledge and skills from practice education that existing healthcare literature suggests they are expected to attain. Several challenges were highlighted regarding participation in practice education. The findings reveal a need to enhance practice educators' skills in supervising international students. Universities are recommended to invest time and resources in supporting the learning needs of these students. Significance: The first study to present international students views on OT pre-registration practice placements in the UK

Evidence and Ideology in Macroeconomics: The Case of Investment Cycles

The paper reports the principal findings of a long term research project on the description and explanation of business cycles. The research strongly confirmed the older view that business cycles have large systematic components that take the form of investment cycles. These quasi-periodic movements can be represented as low order, stochastic, dynamic processes with complex eigenvalues. Specifically, there is a fixed investment cycle of about 8 years and an inventory cycle of about 4 years. Maximum entropy spectral analysis was employed for the description of the cycles and continuous time econometrics for the explanatory models. The central explanatory mechanism is the second order accelerator, which incorporates adjustment costs both in relation to the capital stock and the rate of investment. By means of parametric resonance it was possible to show, both theoretically and empirically how cycles aggregate from the micro to the macro level. The same mathematical tool was also used to explain the international convergence of cycles. I argue that the theory of investment cycles was abandoned for ideological, not for evidential reasons. Methodological issues are also discussed

Landowning, Status and Population Growth

This paper considers the effects of the landowning and land reforms on economic and demographic growth by a family-optimization model with endogenous fertility and status-seeking. A land reform provides the peasant with strong incentives to limit their family size and to improve the productivity of the land. Even though the income effect due to the land reform tends to raise fertility, a strong enough status-effect outweighs it, thus generating a decrease in population growth. The European demographic history provides supporting anecdotal evidence for this theoretical result

Population policies and education: exploring the contradictions of neo-liberal globalisation

The world is increasingly characterised by profound income, health and social inequalities (Appadurai, 2000). In recent decades development initiatives aimed at reducing these inequalities have been situated in a context of increasing globalisation with a dominant neo-liberal economic orthodoxy. This paper argues that neo-liberal globalisation contains inherent contradictions regarding choice and uniformity. This is illustrated in this paper through an exploration of the impact of neo-liberal globalisation on population policies and programmes. The dominant neo-liberal economic ideology that has influenced development over the last few decades has often led to alternative global visions being overlooked. Many current population and development debates are characterised by polarised arguments with strongly opposing aims and views. This raises the challenge of finding alternatives situated in more middle ground that both identify and promote the socially positive elements of neo-liberalism and state intervention, but also to limit their worst excesses within the population field and more broadly. This paper concludes with a discussion outling the positive nature of middle ground and other possible alternatives

Managing uncertainty: a review of food system scenario analysis and modelling

Complex socio-ecological systems like the food system are unpredictable, especially to long-term horizons such as 2050. In order to manage this uncertainty, scenario analysis has been used in conjunction with food system models to explore plausible future outcomes. Food system scenarios use a diversity of scenario types and modelling approaches determined by the purpose of the exercise and by technical, methodological and epistemological constraints. Our case studies do not suggest Malthusian futures for a projected global population of 9 billion in 2050; but international trade will be a crucial determinant of outcomes; and the concept of sustainability across the dimensions of the food system has been inadequately explored so far. The impact of scenario analysis at a global scale could be strengthened with participatory processes involving key actors at other geographical scales. Food system models are valuable in managing existing knowledge on system behaviour and ensuring the credibility of qualitative stories but they are limited by current datasets for global crop production and trade, land use and hydrology. Climate change is likely to challenge the adaptive capacity of agricultural production and there are important knowledge gaps for modelling research to address

Back to the future: environmental security in nineteenth century global politics

Environmental security is generally held to be a contemporary or even futuristic concern. However, as with many facets of security thought, this overlooks how the unparalleled technological, economic and social changes of the 19th Century forged much of the international political landscape we now inhabit. The tendency for ecological political enquiry to focus on the rise of ecocentric policy serves to obscure how many aspects of national and human security relating to environmental change were apparent in the 19th century. Human insecurity in the face of pollution and resource depletion was a part of the emergence of ecological science in response to the industrialization of Europe and North America. In addition, this was the era when European imperialism reached its apex and European nationalisms fully emerged; both of which contributed to the national securitization of the environment around much of the world in contrasting ways as the desire to both conquer and preserve nature became more evident. Environmental questions of national, human and ecological security are not peculiar to the present age and were very much apparent in 19th Century global politics