Search

Many coral reef fish species form predictable, transient spawning aggregations. Many aggregations are overfished, making them a target for spatial management. Here, we develop a per-recruit model to evaluate the performance of no-take marine reserves protecting transient spawning aggregations. The model consists of only 14 demographic and exploitation-related parameters. We applied the model to a protogynous grouper and a gonochoristic rabbitfish from Seychelles and tested six scenarios regarding the extent of protected areas, the level of fish spawning-site fidelity, and fishing effort redistribution post reserve implementation. Spawning aggregation reserves improve spawning-stock biomass-per-recruit and reduce the sex ratio bias in protogynous populations for all scenarios examined. However, these benefits are often small and vary among the different scenarios and as a function of sexual ontogeny. In all scenarios, increases in yield-per-recruit do not occur or are negligible. The long-term yield increases due to spawning aggregation reserves may still occur, but only if spawning-stock biomass recovery results in a recruitment subsidy. Given these limited benefits, the value of no-take reserves must be weighed against those of other management options, such as fishing effort reduction and seasonal fishery closures. The latter is particularly appropriate when spawning and non-spawning areas overlap in space.

We developed delta generalised additive models (GAMs) to predict the spatial distribution of different size classes of South African hakes, Merluccius capensis and M. paradoxus, using demersal trawl survey data and geographical (latitude and longitude) and environmental features (depth, temperature, bottom dissolved oxygen and sediment type). Our approach consists of fitting, for each hake size class, two independent models, a binomial GAM and a quasi-Poisson GAM, whose predictions are then combined using the delta method. Delta GAMs were validated using an iterative cross-validation procedure, and their predictions were then employed to produce distribution maps for the southern Benguela. Delta GAM predictions confirmed existing knowledge about the spatial distribution patterns of South African hakes, and brought new insights into the factors influencing the presence/absence and abundance of these species. Our GAM approach can be used to produce distribution maps for spatially explicit ecosystem models of the southern Benguela in a rigorous and objective way. Ecosystem models are critical features of the ecosystem approach to fisheries, and distribution maps constructed using our GAM approach will enable a reliable allocation of species biomasses in spatially explicit ecosystem models, which will increase trust in the spatial overlaps and, therefore, the trophic interactions predicted by these models.Keywords: distribution maps, Merluccius capensis, Merluccius paradoxus, South Africa, spatial distributions

International audience; The ecosystem model OSMOSE-WFS was employed to evaluate natural mortality rates and fishing scenarios for Gulf of Mexico (GOM) red grouper (Epinephelus mono). OSMOSE-WFS represents major high trophic level (HIT.) groups of species of the West Florida Shelf, is forced by the biomass of plankton and benthos groups, and has a monthly tin-se step. The present application of the model uses a recently developed 'stochastic mortality algorithm' to resolve the mortality processes of HTL groups. OSMOSE-WFS predictions suggest that the natural mortality rate of juveniles of GOM red grouper is high and essentially due to predation, while the bulk of the natural mortality of adult red grouper results from causes not represented in OSMOSE-WFS such as, presumably, red tides. These results were communicated to GOM red grouper stock assessments. Moreover, OSMOSE-WFS indicate that altering the fishing mortality of GOM red grouper may have no global impact on the biomass of the major prey of red grouper, due to the high complexity and high redundancy of the modeled system. By contrast altering the fishing mortality of GOM red grouper may have a large impact on the biomass of its major competitors. Increasing the fishing mortality of red grouper would increase the biomass of major competitors, due to reduced competition for food. Conversely, decreasing the fishing mortality of red grouper would diminish the biomass of major competitors, due to increased predation pressure on the juveniles of the major competitors by red grouper. The fishing scenarios that we evaluated may have slightly different impacts in the real world, due to some discrepancies between the diets of red grouper and its major competitors predicted by OSMOSE-WFS and the observed ones. Modifications in OSMOSE-WFS are suggested to reduce these discrepancies. (C) 2015 Elsevier B.V. All rights reserved.

Spatially explicit models are needed to thoroughly evaluate the potential effectiveness of marine protected areas in particular locations. These models have traditionally parameterized a spatially non-varying settler–recruit relationship (SRR), which is often the large-scale, non-spatial stock–recruitment or egg–recruit relationship used for stock assessments. A recent study demonstrated that the initial slope of local SRRs should be adjusted so as to correctly estimate population persistence, and proposed an analytical methodology to carry out the adjustment. This methodology cannot be used to evaluate small-scale SRRs for more complex spatially explicit models, in particular when adults of the study population are mobile beyond simple home range movements. Here we propose a numerical methodology for estimating the parameters of local SRRs for complex spatially and seasonally explicit population models, from parameters of a large-scale, non-spatial SRR. The consideration of spatial and seasonal patterns of fishing mortality rates, reproduction and larval dispersal results in discrepancies between spatial monthly models and equivalent non-spatial annual models in terms of global spawning stock biomass. The adjustment of the initial slope of small-scale SRRs is necessary so as not to underestimate population persistence, and also reduces discrepancies between spatially and seasonally explicit models and their non-spatial annual counterparts.

The detection and investigation of EUV heated, extended and non-hydrostatic upper atmospheres around terrestrial exoplanets would provide important insights into the interaction of the host stars plasma environment as well as the evolution of Earth-type planets their atmospheres and possible magnetic environments. We discuss different scenarios where one can expect that Earth-like planets should experience non-hydrostatic upper atmosphere conditions so that dynamically outward flowing neutral atoms can interact with the stellar plasma flow so that huge hydrogen coronae and energetic neutral atoms (ENA) can be produced via charge exchange. By observing the size of the extended upper atmospheres and related ENA-clouds and by determining the velocities of the surrounding hydrogen atoms, conclusions can be drawn in respect to the origin of these features. Due to the large number of M-type stars in our neighbourhood and their long periods of strong and moderate stellar activity in comparison to G-stars, we expect that M-type stars represent the most promising candidates for the detection of hydrogen ENA-clouds and the subsequent study of the interaction between the host star and the planets’ upper atmosphere. We show that the low mass of M-type stars also makes them preferable targets to observe extended hydrogen clouds around terrestrial exoplanets with a mass as low as one Earth mass. Transit follow-up observations in the UV-range of terrestrial exoplanets around M-type stars with space observatories such as the World Space Observatory-UV (WSO-UV) would provide a unique opportunity to shed more light on the early evolution of Earth-like planets, including those of our own Solar System.

Adult and juvenile mobility has a considerable influence on the functioning of marine protected areas. It is recognized that adult and juvenile movement reduces the core benefits of protected areas, namely protecting the full age–structure of marine populations, while at the same time perhaps improving fisheries yield over the no-reserve situation through export of individuals from protected areas. Nevertheless, the study of the consequences of movement on protected area functioning is unbalanced. Significant attention has been paid to the influence of certain movement patterns, such as diffusive movement and home ranges, while the impacts of others, such as density-dependent movements and ontogenetic migrations, have been relatively ignored. Here we review the diversity of density-independent and density-dependent movement patterns, as well as what is currently known about their consequences for the conservation and fisheries effects of marine protected areas. We highlight a number of ‘partially addressed’ issues in marine protected area research, such as the effects of reserves targeting specific life phases, and a number of essentially unstudied issues, such as density-dependent movements, nomadism, ontogenetic migrations, behavioral polymorphism and ‘dynamic’ reserves that adjust location as a realtime response to habitat changes. Assessing these issues will be essential to creating effective marine protected area networks for mobile species and accurately assessing reserve impacts on these species.

Unter Lernervorstellungen werden Konzepte verstanden, die nicht mit den wissenschaftlich akzeptierten einher gehen. Lernervorstellungen zum Loslichkeitskonzept sind international empirisch sehr gut erfasst. Dieser Beitrag stellt den Stand der Forschungsergebnisse der letzten drei Jahrzehnte zusammen. Insgesamt 41 Studien wurden dafur ausgewertet und gefundene Lernervorstellungen kategorisiert. Mit dieser Zusammenstellung liegt zum einen eine Grundlage fur weitere Forschungsarbeiten im Bereich der Schulervorstellungsforschung zum Loslichkeitskonzept vor. Zum anderen dient sie Lehrkraften der Antizipation moglicher Verstandnisschwierigkeiten und somit einer an die Bedurfnisse der Lernenden angepassten Unterrichtsvorbereitung. We understand students' conceptions as explanatory approaches that are not consistent with the scientific agreed conceptions. There already exists a large number of empirical research concerning students' conceptions about the solution concept. This paper gives a resume about the research in this area in the last three decades. In total 41 studies were analyzed and all documented students' conceptions categorized. This review on the one hand could serve further research in developing and mediating the solution concept. On the other hand it could help teachers to anticipate possible difficulties in understanding the scientific conceptions and therefore, to prepare an adequate classroom practice.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Dichte ist eine Stoffeigenschaft und wird im Chemieanfangsunterricht zur Charakterisierung der Stoffe herangezogen. Oft liegt bereits aus dem Physikunterricht ein Verstandnis uber die Dichte homogener Korper als Quotient aus Masse und Volumen vor. Mit der Einfuhrung eines Teilchenmodells besteht bei einer unreflektierten Verwendung der lebensweltlichen Vorstellung des „dicht-aneinander-gedrangt-seins“ die Gefahr alternativer Konzepte, sodass zum Beispiel die Unloslichkeit oder Nicht-Mischbarkeit uber die Dichte zu erklaren versucht wird. Dieser Beitrag zeigt konkrete Beispiele dieser Problematik auf und pladiert fur eine regelmasige Thematisierung der Problematik im Unterricht. Density is one characteristic property of a substance that is taught in the very beginning of chemistry classroom practice. Students often know this property from Physic lessons as quotient of mass and volume. When learning about the particle nature of matter there is a danger of confusing the density concept. Students explain the insolubility or the immiscibility with high density: the particles are densely packed, it is hard to break the compound. This paper is discussing this issue, using concrete examples and suggesting to be attentive to it in critical phases of classroom practice.

International audience; We applied the individual-based, multi-species OSMOSE modeling approach to the West Florida Shelf, with the intent to inform ecosystem-based management (EBM) in this region. Our model, referred to as ‘OSMOSE-WFS’, explicitly considers both pelagic-demersal and benthic high trophic level (HTL) groups of fish and invertebrate species, and is forced by the biomass of low trophic level groups of species (plankton and benthos). We present a steady-state version of the OSMOSE-WFS model describing trophic interactions in the West Florida Shelf in the 2000s. OSMOSE-WFS was calibrated using a recently developed evolutionary algorithm that allowed simulated biomasses of HTL groups to match observed biomasses over the period 2005–2009. The validity of OSMOSE-WFS was then evaluated by comparing simulated diets to observed ones, and the simulated trophic levels to those in an Ecopath model of the West Florida Shelf (WFS Reef fish Ecopath). Finally, OSMOSE-WFS was used to explore the trophic structure of the West Florida Shelf in the 2000s and estimate size-specific natural mortality rates for a socio-economically important species, gag grouper (Mycteroperca microlepis). OSMOSE-WFS outputs were in full agreement with observations as to the body size and ecological niche of prey of the different HTL groups, and to a lesser extent in agreement with the observed species composition of the diet of HTL groups. OSMOSE-WFS and WFS Reef fish Ecopath concurred on the magnitude of the instantaneous natural mortality of the different life stages of gag grouper over the period 2005–2009, but not always on the main causes of natural mortality. The model evaluations conducted here provides a strong basis for ongoing work exploring fishing and environmental scenarios so as to inform EBM. From simple size-based predation rules, we were indeed able to capture the complexity of trophic interactions in the West Florida Shelf, and to identify the predators, prey and competitors of socio-economically important species as well as pivotal prey species of the ecosystem.

The synthesis and single crystal X-ray structures of four adducts of squaric acid with cyclic nitrogen bases are reported. Extensive hydrogen bonding, ionic interactions and (in one case) π-π-interactions lead to layered, and to two- and three-dimensional assemblies. [Pyrimidinium][ hydrogenquadratate] (1) has a layer structure, consisting of head-to-tail infinite chains of pyrimidinium and [HC4O4]− ions, which are cross-linked by short N-H···O and C-H···O hydrogen bonds. [C9H11N2][HC4O4] ・0.5H2C4O4 (2), the adduct of a benzodiazepin and squaric acid, has a ladder-structure. Chains of [HC4O4]− ions and H2C4O4 molecules in alternating order form the ladder-beam. Layers of cations and anions in the ratio 2:1 build the crosspieces at an angle of 49° to the beam. The layers contain dimers of [HC4O4]− ions. [H2L2][HC4O4]2 (3) with L2 = 5,6,7,8,9,14,15,16,17,18-decahydrodibenzo[e,l]-1,4,8,11-tetraaza-cyclotetradecine shows zigzag chains made of [HC4O4]− ions. Between the [H2L2]2+ and the [HC4O4]− ions π-π interactions exist besides up to four N-H···O hydrogen bonds. The [H2L2]2+ ions possess two different conformations. [H2cyclam][C2O4] ·4H2O (4) contains strongly undulated layers of the composition [C4O4 ·4H2O]2−. The cations, which show two intramolecular N-H···N hydrogen bonds with N···N distances of 2.870 (3) Å , are interlinked at an angle of 41.5°.

A case of poisoning with a Cotoneaster sp. is described in a llama ( Lama glama). The clinical signs were dyspnea, with congested mucous membranes, chewing, recumbency, and opisthotonos. Several hours after ingestion of the plant, the llama died, despite treatment with sodium thiosulfate and nitrite. Necropsy revealed approximately 676 g of leaves and fruit of Cotoneaster in the first compartment of the stomach. The blood was light red and did not clot. Because Cotoneaster sp. contains low concentrations of cyanogenic glycosides, toxicosis occurs only following massive ingestion of plant material.

In disposed waste are quite a lot of reusable substances of high value. These residual products can be transferred into commercial products in dependency to the adequate technology either as raw material for secondary processes, as operating supplies or as ingredients of novel products. Numerous valuable substances in food production are suitable for separation and recycling at the end of their life cycle even though present separation and recycling processes are not absolutely cost saving. Based on a concept of food production in its entirety the actual state is exemplary demonstrated at the potato starch industry in its occurrence, quantity and utilisation of the residual products. The target state of a clean production process will be realised by the development of multifunctional food ingredients. The outlined concept can be naturally transferred to several areas of industrial food production. The intentions of this research area are located at the development of techniques, which fulfil the conditions of environmental protection with costs to a minimum.