Leadership, social capital and incentives promote successful fisheries

One billion people depend on seafood as their primary source of protein and 25% of the world's total animal protein comes from fisheries. Yet a third of fish stocks worldwide are overexploited or depleted. Using individual case studies, many have argued that community-based co-management should prevent the tragedy of the commons because cooperative management by fishers, managers and scientists often results in sustainable fisheries. However, general and multidisciplinary evaluations of co-management regimes and the conditions for social, economic and ecological success within such regimes are lacking. Here we examine 130 co-managed fisheries in a wide range of countries with different degrees of development, ecosystems, fishing sectors and type of resources. We identified strong leadership as the most important attribute contributing to success, followed by individual or community quotas, social cohesion and protected areas. Less important conditions included enforcement mechanisms, long-term management policies and life history of the resources. Fisheries were most successful when at least eight co-management attributes were present, showing a strong positive relationship between the number of these attributes and success, owing to redundancy in management regulations. Our results demonstrate the critical importance of prominent community leaders and robust social capital, combined with clear incentives through catch shares and conservation benefits derived from protected areas, for successfully managing aquatic resources and securing the livelihoods of communities depending on them. Our study offers hope that co-management, the only realistic solution for the majority of the world's fisheries, can solve many of the problems facing global fisheries.     

Vernier templating and synthesis of a 12-porphyrin nano-ring

Templates are widely used to arrange molecular components so they can be covalently linked into complex molecules that are not readily accessible by classical synthetic methods. Nature uses sophisticated templates such as the ribosome, whereas chemists use simple ions or small molecules. But as we tackle the synthesis of larger targets, we require larger templates-which themselves become synthetically challenging. Here we show that Vernier complexes can solve this problem: if the number of binding sites on the template, n(T), is not a multiple of the number of binding sites on the molecular building blocks, n(B), then small templates can direct the assembly of relatively large Vernier complexes where the number of binding sites in the product, n(P), is the lowest common multiple of n(B) and n(T) (refs 8, 9). We illustrate the value of this concept for the covalent synthesis of challenging targets by using a simple six-site template to direct the synthesis of a 12-porphyrin nano-ring with a diameter of 4.7?nm, thus establishing Vernier templating as a powerful new strategy for the synthesis of large monodisperse macromolecules.     

Body plan innovation in treehoppers through the evolution of an extra wing-like appendage

Body plans, which characterize the anatomical organization of animal groups of high taxonomic rank, often evolve by the reduction or loss of appendages (limbs in vertebrates and legs and wings in insects, for example). In contrast, the addition of new features is extremely rare and is thought to be heavily constrained, although the nature of the constraints remains elusive. Here we show that the treehopper (Membracidae) 'helmet' is actually an appendage, a wing serial homologue on the first thoracic segment. This innovation in the insect body plan is an unprecedented situation in 250 Myr of insect evolution. We provide evidence suggesting that the helmet arose by escaping the ancestral repression of wing formation imparted by a member of the Hox gene family, which sculpts the number and pattern of appendages along the body axis. Moreover, we propose that the exceptional morphological diversification of the helmet was possible because, in contrast to the wings, it escaped the stringent functional requirements imposed by flight. This example illustrates how complex morphological structures can arise by the expression of ancestral developmental potentials and fuel the morphological diversification of an evolutionary lineage.     

Transient ferromagnetic-like state mediating ultrafast reversal of antiferromagnetically coupled spins

Ferromagnetic or antiferromagnetic spin ordering is governed by the exchange interaction, the strongest force in magnetism. Understanding spin dynamics in magnetic materials is an issue of crucial importance for progress in information processing and recording technology. Usually the dynamics are studied by observing the collective response of exchange-coupled spins, that is, spin resonances, after an external perturbation by a pulse of magnetic field, current or light. The periods of the corresponding resonances range from one nanosecond for ferromagnets down to one picosecond for antiferromagnets. However, virtually nothing is known about the behaviour of spins in a magnetic material after being excited on a timescale faster than that corresponding to the exchange interaction (10-100?fs), that is, in a non-adiabatic way. Here we use the element-specific technique X-ray magnetic circular dichroism to study spin reversal in GdFeCo that is optically excited on a timescale pertinent to the characteristic time of the exchange interaction between Gd and Fe spins. We unexpectedly find that the ultrafast spin reversal in this material, where spins are coupled antiferromagnetically, occurs by way of a transient ferromagnetic-like state. Following the optical excitation, the net magnetizations of the Gd and Fe sublattices rapidly collapse, switch their direction and rebuild their net magnetic moments at substantially different timescales; the net magnetic moment of the Gd sublattice is found to reverse within 1.5 picoseconds, which is substantially slower than the Fe reversal time of 300 femtoseconds. Consequently, a transient state characterized by a temporary parallel alignment of the net Gd and Fe moments emerges, despite their ground-state antiferromagnetic coupling. These surprising observations, supported by atomistic simulations, provide a concept for the possibility of manipulating magnetic order on the timescale of the exchange interaction.     

Dynamics of human adipose lipid turnover in health and metabolic disease

Adipose tissue mass is determined by the storage and removal of triglycerides in adipocytes. Little is known, however, about adipose lipid turnover in humans in health and pathology. To study this in vivo, here we determined lipid age by measuring (14)C derived from above ground nuclear bomb tests in adipocyte lipids. We report that during the average ten-year lifespan of human adipocytes, triglycerides are renewed six times. Lipid age is independent of adipocyte size, is very stable across a wide range of adult ages and does not differ between genders. Adipocyte lipid turnover, however, is strongly related to conditions with disturbed lipid metabolism. In obesity, triglyceride removal rate (lipolysis followed by oxidation) is decreased and the amount of triglycerides stored each year is increased. In contrast, both lipid removal and storage rates are decreased in non-obese patients diagnosed with the most common hereditary form of dyslipidaemia, familial combined hyperlipidaemia. Lipid removal rate is positively correlated with the capacity of adipocytes to break down triglycerides, as assessed through lipolysis, and is inversely related to insulin resistance. Our data support a mechanism in which adipocyte lipid storage and removal have different roles in health and pathology. High storage but low triglyceride removal promotes fat tissue accumulation and obesity. Reduction of both triglyceride storage and removal decreases lipid shunting through adipose tissue and thus promotes dyslipidaemia. We identify adipocyte lipid turnover as a novel target for prevention and treatment of metabolic disease.     

Cell-type-specific replication initiation programs set fragility of the FRA3B fragile site

Common fragile sites have long been identified by cytogeneticists as chromosomal regions prone to breakage upon replication stress. They are increasingly recognized to be preferential targets for oncogene-induced DNA damage in pre-neoplastic lesions and hotspots for chromosomal rearrangements in various cancers. Common fragile site instability was attributed to the fact that they contain sequences prone to form secondary structures that may impair replication fork movement, possibly leading to fork collapse resulting in DNA breaks. Here we show, in contrast to this view, that the fragility of FRA3B--the most active common fragile site in human lymphocytes--does not rely on fork slowing or stalling but on a paucity of initiation events. Indeed, in lymphoblastoid cells, but not in fibroblasts, initiation events are excluded from a FRA3B core extending approximately 700 kilobases, which forces forks coming from flanking regions to cover long distances in order to complete replication. We also show that origins of the flanking regions fire in mid-S phase, leaving the site incompletely replicated upon fork slowing. Notably, FRA3B instability is specific to cells showing this particular initiation pattern. The fact that both origin setting and replication timing are highly plastic in mammalian cells explains the tissue specificity of common fragile site instability we observed. Thus, we propose that common fragile sites correspond to the latest initiation-poor regions to complete replication in a given cell type. For historical reasons, common fragile sites have been essentially mapped in lymphocytes. Therefore, common fragile site contribution to chromosomal rearrangements in tumours should be reassessed after mapping fragile sites in the cell type from which each tumour originates.