Reproductive sharing in animal societies: reproductive incentives or incomplete control by dominant breeders?

Optimal skew models explain reproductive sharing within social groups as resulting from reproductive incentives given by controlling dominants to subordinates in return for peaceful cooperation. We explore two versions of an alternative, the incomplete control model, for the evolution of reproductive sharing within groups. In this model, dominants have only limited control over the allocation of reproduction and must expend effort to increase their share of the total group output We show that, when the relatedness between dominant and subordinate is symmetrical, (1) the subordinate's fraction of reproduction either increases with, or is insensitive to, the subordinate's genetic relatedness, r, to the dominant in both versions of the incomplete control model, whereas the subordinate's fraction of reproduction decreases with increasing r in the optimal skew model, (2) the subordinate's share of reproduction in the incomplete control model must exceed that in the optimal skew model, and (3) ecological factors affecting solitary breeding success do not directly affect the subordinate's share of reproduction in incomplete control model but do in the optimal skew model. When dominant-subordinate relatedness is asymmetrical (as is often the case in parent-offspring associations), the incomplete control model predicts no reproduction by the subordinate offspring regardless of group size for groups containing any mixture of unrelated and full-sibling subordinates, whereas the optimal skew models predict that such reproduction is possible when the group size is three or more. The available evidence indicates a negative relationship between relatedness and a subordinate's reproductive share in both vertebrate and hymenopteran societies, apparently supporting the predictions of the optimal skew, not incomplete control, class of models. However, such a negative relationship is not necessarily inconsistent with the incomplete control model when, as is true for some vertebrate studies, it results from a comparison of skews in genetically monogamous, nonincestuous groups of parents and their offspring (asymmetric relatednesses) with skews in groups of nonkin (symmetric relatednesses). Both models predict higher skews in parent-offspring associations. Occasional reproduction by subordinate offspring in groups of asymmetrical relatedness when such groups are larger than dyads is more consistent with the optimal skew model, however. Overall, current data on reproductive skew and its relationships to intragroup aggression and ecological constraints support the optimal skew model, but more data are needed to rule out the incomplete control model. These models are examples of two different general views of intrasocietal evolution: the tug-of-war view, in which group members engage in a struggle over resources, and the transactional view, in which group members exchange parcels of reproduction to induce beneficial behavior from each othe

Assessment of the performance of a turbulence closure model: along the tidally-influenced Kaipara River to the estuary, NZ

The success of many coastal management projects hinges on the ability to predict the dispersal and settling of sediment particles. Hydrodynamic models have enabled the efficient simulation of sediment transport scenarios at large spatial scales and long time scales. However, these models have limited predictive capacity owing to an incomplete understanding of the processes involved. Turbulence has been shown to have a substantial influence on sediment transport by influencing flocculation (i.e. aggregation of particles), hence driving the behaviour of particles (e.g. deposition, erosion, mixing). Turbulence tends to promote aggregation at low shear stresses and cause floc breakups at high shear stresses. However, despite the key role of turbulence in coastal modelling, there is not a unique approach but several methods to describe turbulence, each based on a different combination of assumptions. We present modelling results exploring the performance of one closure scheme implemented in a hydrodynamic and sediment transport model, Delft3D. The assessment of the performance of the model is based on comparisons with measured data collected in the heavily sediment-laden Kaipara river, New Zealand. Data was collected in October 2013 using Lagrangian “flocdrifter” platforms released at multiple locations to capture both hydrodynamic and sediment data. In general the model was found to be able to reproduce the right order of magnitude of dissipation rates. However, turbulence characteristics in some sections of the river, usually in the vicinity of abrupt bends, are relatively poorly reproduced. Future work will aim to use the present model to improve the conceptual understanding of fundamental physical processes, in particular the effect of turbulence on flocculation, and floc formation and breakup in estuarine and riverine systems

Do hydrotherapy exercise programmes improve exercise tolerance and quality of life in patients with chronic heart failure? A systematic review

The purpose of this study was to evaluate whether hydrotherapy programmes improve exercise tolerance and quality of life in patients with chronic heart failure. Data sources utilised were EBSCO, Scopus, Medline, PubMed, OVID, Proquest, PEDro and Cochrane Systematic Reviews databases. A systematic review of randomised controlled trials or quasi randomised controlled trials investigated hydrotherapy compared with a suitable control. Methodological quality was assessed using a modified version of the Downs and Black critical appraisal tool. Findings demonstrated that hydrotherapy was well tolerated with few adverse events reported. Two studies demonstrated hydrotherapy intervention groups significantly improved 6MWT from baseline (p≤0.05), while two studies found significantly greater improvements when compared to non-exercising (p=0.01) and land based exercising (p=0.001) controls. Four studies found significant gains (p≤0.05) in VO2 peak from baseline following hydrotherapy interventions. Two studies reported significant (p=0.01) intragroup improvements in total score of the Minnesota Living with Heart Failure Questionnaire in hydrotherapy intervention groups when compared with baseline and a non-exercising control respectively. In conclusion, hydrotherapy exercise programmes were well tolerated and appear to improve exercise capacity and quality of life in people with chronic heart failure but firm conclusions could not be drawn due to the poor to moderate quality of the evidence

Genome sequence and plasmid transformation of the model high-yield bacterial cellulose producer Gluconacetobacter hansenii ATCC 53582.

Bacterial cellulose is a strong, highly pure form of cellulose that is used in a range of applications in industry, consumer goods and medicine. Gluconacetobacter hansenii ATCC 53582 is one of the highest reported bacterial cellulose producing strains and has been used as a model organism in numerous studies of bacterial cellulose production and studies aiming to increased cellulose productivity. Here we present a high-quality draft genome sequence for G. hansenii ATCC 53582 and find that in addition to the previously described cellulose synthase operon, ATCC 53582 contains two additional cellulose synthase operons and several previously undescribed genes associated with cellulose production. In parallel, we also develop optimized protocols and identify plasmid backbones suitable for transformation of ATCC 53582, albeit with low efficiencies. Together, these results provide important information for further studies into cellulose synthesis and for future studies aiming to genetically engineer G. hansenii ATCC 53582 for increased cellulose productivity

Processed foods available in the Pacific Islands

BACKGROUND: There is an increasing reliance on processed foods globally, yet food composition tables include minimal information on their nutrient content. The Pacific Islands share common trade links and are heavily reliant on imported foods. The objective was to develop a dataset for the Pacific Islands on nutrient composition of processed foods sold and their sources. METHODS: Information on the food labels, including country of origin, nutrient content and promotional claims were recorded into a standardised dataset. Data were cleaned, converted to per 100 g data as needed and then checked for anomalies and recording errors. Setting: Five representative countries were selected for data collection, based on their trading patterns: Fiji, Guam, Nauru, New Caledonia, and Samoa. Data were collected in the capitals, in larger stores which import their own foods. Subjects: Processed foods in stores. RESULTS: The data from 6041 foods and drinks were recorded. Fifty four countries of origin were identified, with the main provider of food for each Pacific Island country being that with which it was most strongly linked politically. Nutrient data were not provided for 6% of the foods, imported from various countries. Inaccurate labels were found on 132 products. Over one-quarter of the foods included some nutrient or health-related claims. CONCLUSIONS: The globalisation of the food supply is having considerable impacts on diets in the Pacific Islands. While nutrient labels can be informative for consumers looking for healthier options, difficulties still exist with poor labelling and interpretation can be challenging

An argument for the use of Aristotelian method in bioethics

The main claim of this paper is that the method outlined and used in Aristotle's Ethics is an appropriate and credible one to use in bioethics. Here “appropriate” means that the method is capable of establishing claims and developing concepts in bioethics and “credible” that the method has some plausibility, it is not open to obvious and immediate objection. It begins by suggesting why this claim matters and then gives a brief outline of Aristotle's method. The main argument is made in three stages. First, it is argued that Aristotelian method is credible because it compares favourably with alternatives. In this section it is shown that Aristotelian method is not vulnerable to criticisms that are made both of methods that give a primary place to moral theory (such as utilitarianism) and those that eschew moral theory (such as casuistry and social science approaches). As such, it compares favourably with these other approaches that are vulnerable to at least some of these criticisms. Second, the appropriateness of Aristotelian method is indicated through outlining how it would deal with a particular case. Finally, it is argued that the success of Aristotle's philosophy is suggestive of both the credibility and appropriateness of his method.</p