We introduce a type of isomorphism among strategic games that we call localisomorphism. Local isomorphisms is a weaker version of the notions of strongand weak game isomorphism introduced in [J. Gabarro, A. Garcia and M. Serna,Theor. Comput. Sci. 412 (2011) 6675–6695]. In a localisomorphism it is required to preserve, for any player, the player’s preferences on thesets of strategy profiles that differ only in the action selected by this player. We showthat the game isomorphism problem for local isomorphism is equivalent to the same problemfor strong or weak isomorphism for strategic games given in: general, extensive andformula general form. As a consequence of the results in [J. Gabarro, A. Garcia and M.Serna, Theor. Comput. Sci. 412 (2011) 6675–6695] thisimplies that local isomorphism problem for strategic games is equivalent to (a) thecircuit isomorphism problem for games given in general form, (b) the boolean formulaisomorphism problem for formula games in general form, and (c) the graph isomorphismproblem for games given in explicit form.

The western Mediterranean is an important fishing area in which the Spanish longline fleet operates. Longline fisheries affect several species of marine mammals, sea turtles, sharks and seabirds, all of which are especially sensitive to fishing mortality. Given international efforts to identify and reduce the bycatch of sensitive species, an onboard observer program was implemented by the Spanish Oceanographic Institute (IEO, Instituto Español de Oceanografía). The aim of the present study was to report data on marine mammal bycatch in the western Mediterranean. The additional aim was to improve knowledge about the possible effects of the Spanish longline fisheries on cetacean populations, particularly Risso’s dolphin, and to suggest improvements to fisheries management. Data on marine mammal bycatch were collected during the period 2000–2009. Differences are reported for catch per unit effort (CPUE, defined as marine mammals per 1000 hooks) for each type of gear (n = 7), as well as their effect on specific marine mammal species. A total of 5 398 297 hooks were monitored, which yielded 56 marine mammals belonging to 4 different species. Our results indicate that Risso’s dolphin is the species most affected by the longline fishery in the western Mediterranean (n = 33). We built a predictive model for Risso’s dolphin bycatch using variables associated with the technical characteristics of the fishery, geographic location and seasonality. We performed a binary logistic regression of the presence/absence of Risso’s dolphin bycatch to test whether the probability of incidentally catching one or more dolphins may be predicted by some of the explanatory variables selected. Our results indicate that Risso’s dolphin was mainly caught using Japanese longline (LLJAP) or an experimental home-based longline (LLHBexp) over the continental shelf. Because LLHBexp is an experimental type of gear that was only used occasionally by the fleet, controlling the use of LLJAP over the continental shelf could strongly reduce the impact of these fisheries on populations of Risso’s dolphin in the western Mediterranean.

Shredders play a major ecological role in temperate streams, but their numerical importance is highly variable within the tropics. Detailed studies on the diets of tropical stream invertebrates are advisable to be able to better describe and understand this variation. Here, we examined the diets of invertebrates collected from the leaf litter of three tropical streams in Colombia, using gut content analysis. Fine and coarse particulate organic matter were the main food resources for invertebrates, which could be divided into four main dietary groups: predators, shredders, specialist collectors and generalist collectors. While the specialist collectors were the most numerically abundant group (54%), shredder biomass accounted for 63% of total invertebrate biomass, suggesting that shredders play a significant ecological role in the study streams. We describe the diets of 12 out of 47 taxa that were previously unknown, which indicates that knowledge about the feeding ecology of tropical stream invertebrates is still incipient.

Simple games cover voting systems in which a single alternative, such as a bill or anamendment, is pitted against the status quo. A simple game or a yes-no voting system is aset of rules that specifies exactly which collections of “yea” votes yield passage of theissue at hand. Each of these collections of “yea” voters forms a winning coalition. We areinterested in performing a complexity analysis on problems defined on such families ofgames. This analysis as usual depends on the game representation used as input. Weconsider four natural explicit representations: winning, losing, minimal winning, andmaximal losing. We first analyze the complexity of testing whether a game is simple andtesting whether a game is weighted. We show that, for the four types of representations,both problems can be solved in polynomial time. Finally, we provide results on thecomplexity of testing whether a simple game or a weighted game is of a special type. Weanalyze strongness, properness, weightedness, homogeneousness, decisiveness andmajorityness, which are desirable properties to be fulfilled for a simple game. Finally,we consider the possibility of representing a game in a more succinct and natural way andshow that the corresponding recognition problem is hard.

This paper studies the computational complexity of the properinterval colored graph problem (PICG), when the input graphis a colored caterpillar, parameterized by hair length. In order prove ourresult we establish a close relationship between the PICG anda graph layout problem the proper colored layout problem(PCLP). We show a dichotomy: the PICG and thePCLP are NP-complete for colored caterpillars of hair length ≥2, while both problems are in P for colored caterpillarsof hair length <2.For the hardness results we provide a reduction from the multiprocessor scheduling problem, while the polynomial time resultsfollow from a characterization in terms of forbidden subgraphs.

We consider the parallel approximability of two problems arising from high multiplicity scheduling, namely the unweighted model with variable processing requirements and the weighted model with identical processing requirements. These two problems are known to be modelled by a class of quadratic programs that are efficiently solvable in polynomial time. On the parallel setting, both problems are P-complete and hence cannot be efficiently solved in parallel unless P = NC. To deal with the parallel approximablity of these problems, we show first a parallel additive approximation procedure to a subclass of multi-valued quadratic programming, called smooth multi-valued QP, which is defined by imposing certain restrictions on the coefficients of the instance. We use this procedure to obtain parallel approximation to dense instances of the two problems by observing that dense instances of these problems are instances of smooth multi-valued QP. The dense instances of the problems considered here are defined similarly as for other combinatorial problems in the literature. For such instances we can find in parallel a near optimal schedule. The definition of smooth multi-valued QP as well as the procedure for approximating it in parallel are of interest independently of the application to the scheduling problems considered in this paper.

The brain development and performance of rats fed throughout two generations with an indigenous maize tortilla-based diet was studied. The experiment compared casein control with five different diets produced from: regular fresh masa; regular, enriched dry masa flour containing thiamin, riboflavin, niacin, folic acid, Fe and Zn (REDMF); dry masa flour fortified with 60g/kg defatted soyabean meal and enriched (FEDMF); enriched quality protein maize (QPM) flour (EQPM); QPM flour fortified with 30g/kg defatted soyabean meal and enriched (FEQPM). In both generations, brain and cerebellum weights and myelin concentration were significantly higher (p<0·05) in rats fed the FEDMF and FEQPM diets. There was no significant difference (p>0·05) in brain DNA in first-generation rats; however, second-generation rats fed FEDMF, EQPM and FEQPM tortillas had higher cerebral DNA, neuron size and brain activity as estimated by the RNA:DNA ratio. Short-term and long-term memory performance in the Morris maze improved (p<0·05) among rats fed the FEDMF, FEQPM and EQPM diets. Second-generation rats fed the FEDMF and FEQPM diets had a superior (p<0·05) working memory and learning performance. The utilisation of regular or QPM tortillas enriched with selected micronutrients and fortified with soyabean is highly recommended to assure adequate brain development. The high lysine–tryptophan QPM made it possible to save half of the soyabean flour without sacrificing the nutritional value of soyabean-fortified tortillas.

This work deals with convergence theorems and bounds on the cost of several layout measures for lattice graphs, random lattice graphs and sparse random geometric graphs. Specifically, we consider the following problems: Minimum Linear Arrangement, Cutwidth, Sum Cut, Vertex Separation, Edge Bisection and Vertex Bisection. For full square lattices, we give optimal layouts for the problems still open. For arbitrary lattice graphs, we present best possible bounds disregarding a constant factor. We apply percolation theory to the study of lattice graphs in a probabilistic setting. In particular, we deal with the subcritical regime that this class of graphs exhibits and characterize the behaviour of several layout measures in this space of probability. We extend the results on random lattice graphs to random geometric graphs, which are graphs whose nodes are spread at random in the unit square and whose edges connect pairs of points which are within a given distance. We also characterize the behaviour of several layout measures on random geometric graphs in their subcritical regime. Our main results are convergence theorems that can be viewed as an analogue of the Beardwood, Halton and Hammersley theorem for the Euclidean TSP on random points in the unit square.

We show that some classical P-complete problems can be solved efficiently in average NC. The probabilistic model we consider is the sample space of input descriptions of the problem with the underlying distribution being the uniform one. We present parallel algorithms that use a polynomial number of processors and have expected time upper bounded by (e ln 4 + o(1))log n, asymptotically with high probability, where n is the instance size.