Insights into torpor and behavioural thermoregulation of the endangered Juliana's golden mole

The cryptic, subterranean ways of golden moles (Chrysochloridae) hamper studies of their biology in the field. Ten species appear on the IUCN red list, but the dearth of information available for most inhibits effective conservation planning. New techniques are consequently required to further our understanding and facilitate informed conservation management decisions. We studied the endangered Juliana's golden mole Neamblysomus julianae and aimed to evaluate the feasibility of using implantable temperature sensing transmitters to remotely acquire physiological and behavioural data. We also aimed to assess potential body temperature (T-b) fluctuations in relation to ambient soil temperature (T-a) in order to assess the potential use of torpor. Hourly observations revealed that T-b was remarkably changeable, ranging from 27 to 33 degrees C. In several instances T-b declined during periods of low T-a. Such 'shallow torpor' may result in a daily energy saving of c. 20%. Behavioural thermoregulation was used during periods of high T-a by selecting cooler microclimates, while passive heating was used to raise T-b early morning when T-a was increasing. In contrast to anecdotal reports of nocturnal patterns of activity, our results suggest that activity is flexible, being primarily dependent on T-a. These results exemplify how behavioural patterns and microclimatic conditions can be examined in this and other subterranean mammal species, the results of which can be used in the urgently required conservation planning of endangered Chrysochlorid species.

Hibernation and non-shivering thermogenesis in the Hottentot golden mole (Amblysomus hottentottus longiceps)

Although heterothermy (hibernation and torpor) is a common feature among mammals, there is debate over whether it is a derived or ancestral trait relative to endothermic homeothermy. Determination of the physiological characteristics of primitive mammals is central to understanding the evolution of endothermy. Moreover, evaluation of physiological mechanisms responsible for endothermic heat production [e.g. non-shivering thermogenesis (NST)] is key to understanding how early mammals responded to historical climate changes and colonised different geographical regions. Here we investigated the capacity for NST and heterothermy in the Hottentot golden mole, a basal eutherian mammal. NST was measured as the metabolic response to injections of noradrenalin and heterothermy by recording body temperature in free-ranging animals. We found that hibernation and torpor occurred and that the seasonal phenotypic adjustment of NST capacity was similar to that found in other placental mammals. Using phylogenetically independent contrasts, we compared measured values of NST with those obtained from the literature. This showed that all variation in NST was accounted for by differences in phylogeny and not zoogeography. These findings lend support to the observation that NST and heterothermy occur in the Afrotheria, the basal placental mammalian clade. Furthermore, this work suggests that heterothermy, rather than homeothermy is a plesiomorphic trait in mammals and supports the notion that NST mechanisms are phylogenetically ancient.

Rule Britannia!: British Stock Market Returns, 1825-1870

This article presents a new series of monthly equity returns for the British stock market for the period 1825-1870. In addition to calculating capital appreciation and dividend yields, the article also estimates the effect of survivorship bias on returns. Three notable findings emerge from this study. First, stock market returns in the 1825-1870 period are broadly similar for Britain and the United States, although the British market is less risky. Second, real returns in the 1825-1870 period are higher than in subsequent epochs of British history. Third, unlike the modern era, dividends are the most important component of returns.

'Rule of Law and Politics of Anti-Corruption Campaigns in a Post-Authoritarian State- The Nigerian Case'

This article evaluates the anti-corruption campaign instituted in Nigeria following on the post-authoritarian transition in the country, with specific focus on political corruption. The anti-corruption campaign is being prosecuted within a context where law is as critical a factor as politics. This article examines whether the judiciary, in view of its accountability deficit, can offer legitimacy to the campaign. How has its questionable credentials impacted on its involvement in the campaign to sanitise public life? What has been the impact of the judicial role on the rule of law? These are some of the important questions this article seeks to answer. The inquiry in this article demonstrates how the guardian institution of the rule of law faces an uphill task in the performance of that role in a post-authoritarian context.

A heterosynaptic learning rule for neural networks

In this article we intoduce a novel stochastic Hebb-like learning rule for neural networks that is neurobiologically motivated. This learning rule combines features of unsupervised (Hebbian) and supervised (reinforcement) learning and is stochastic with respect to the selection of the time points when a synapse is modified. Moreover, the learning rule does not only affect the synapse between pre- and postsynaptic neuron, which is called homosynaptic plasticity, but effects also further remote synapses of the pre-and postsynaptic neuron. This more complex form of synaptic plasticity has recently come under investigations in neurobiology and is called heterosynaptic plasticity. We demonstrate that this learning rule is useful in training neural networks by learning parity functions including the exclusive-or (XOR) mapping in a multilayer feed-forward network. We find, that our stochastic learning rule works well, even in the presence of noise. Importantly, the mean leaxning time increases with the number of patterns to be learned polynomially, indicating efficient learning.