The status of the critically endangered freshwater crayfi sh Engaewa pseudoreducta (Crustacea: Parastacidae) in south-western Australia

An update of taxonomic, distribution and conservation information for the freshwater crayfish Engaewa pseudoreducta Horwitz and Adams is presented. Engaewa pseudoreducta is formally listed as Critically Endangered by the state of Western Australia and under Australian national legislature, and informally in a recently completed international (IUCN Red List) global assessment of freshwater crayfi sh. Engaewa pseudoreducta was fi rst described on the basis of morphological characters of a small number of individuals from a single site, however the type locality was known to no longer support a population at the time of description and only one other nearby population was known prior to this study. This paper records two further populations and presents the fi rst genetic analysis of the species. DNA sequence data support the recognition of E. pseudoreducta as a species and despite the discovery of additional populations there appears no reason to lessen the conservation concern surrounding the species, particularly in light of continuing development in the area

A Novel Centralized Strategy for Coded Caching with Non-uniform Demands

Despite significant progress in the caching literature concerning the worst case and uniform average case regimes, the algorithms for caching with nonuniform demands are still at a basic stage and mostly rely on simple grouping and memory-sharing techniques. In this work we introduce a novel centralized caching strategy for caching with nonuniform file popularities. Our scheme allows for assigning more cache to the files which are more likely to be requested, while maintaining the same sub-packetization for all the files. As a result, in the delivery phase it is possible to perform linear codes across files with different popularities without resorting to zero-padding or concatenation techniques. We will describe our placement strategy for arbitrary range of parameters. The delivery phase will be outlined for a small example for which we are able to show a noticeable improvement over the state of the art.Comment: 4 pages, 3 figures, submitted to the 2018 International Zurich Seminar on Information and Communicatio

The Optimal Memory-Rate Trade-off for the Non-uniform Centralized Caching Problem with Two Files under Uncoded Placement

A new scheme for the problem of centralized coded caching with non-uniform demands is proposed. The distinguishing feature of the proposed placement strategy is that it admits equal sub-packetization for all files while allowing the users to allocate more cache to the files which are more popular. This creates natural broadcasting opportunities in the delivery phase which are simultaneously helpful for the users who have requested files of different popularities. For the case of two files, we propose a new delivery strategy based on interference alignment which enables each user to decode his desired file following a two-layer peeling decoder. Furthermore, we extend the existing converse bounds for uniform demands under uncoded placement to the nonuniform case. To accomplish this, we construct $N!$ auxiliary users, corresponding to all permutations of the $N$ files, each caching carefully selected sub-packets of the files. Each auxiliary user provides a different converse bound. The overall converse bound is the maximum of all these $N!$ bounds. We prove that our achievable delivery rate for the case of two files meets this converse, thereby establishing the optimal expected memory-rate trade-off for the case of $K$ users and two files with arbitrary popularities under uncoded placement

Reasoning on Feature Models: Compilation-Based vs. Direct Approaches

Analyzing a Feature Model (FM) and reasoning on the corresponding configuration space is a central task in Software Product Line (SPL) engineering. Problems such as deciding the satisfiability of the FM and eliminating inconsistent parts of the FM have been well resolved by translating the FM into a conjunctive normal form (CNF) formula, and then feeding the CNF to a SAT solver. However, this approach has some limits for other important reasoning issues about the FM, such as counting or enumerating configurations. Two mainstream approaches have been investigated in this direction: (i) direct approaches, using tools based on the CNF representation of the FM at hand, or (ii) compilation-based approaches, where the CNF representation of the FM has first been translated into another representation for which the reasoning queries are easier to address. Our contribution is twofold. First, we evaluate how both approaches compare when dealing with common reasoning operations on FM, namely counting configurations, pointing out one or several configurations, sampling configurations, and finding optimal configurations regarding a utility function. Our experimental results show that the compilation-based is efficient enough to possibly compete with the direct approaches and that the cost of translation (i.e., the compilation time) can be balanced when addressing sufficiently many complex reasoning operations on large configuration spaces. Second, we provide a Java-based automated reasoner that supports these operations for both approaches, thus eliminating the burden of selecting the appropriate tool and approach depending on the operation one wants to perform

A Novel Centralized Strategy for Coded Caching with Non-uniform Demands

Despite significant progress in the caching literature concerning the worst case and uniform average case regimes, the algorithms for caching with nonuniform demands are still at a basic stage and mostly rely on simple grouping and memory-sharing techniques. In this work we introduce a novel centralized caching strategy for caching with nonuniform file popularities. Our scheme allows for assigning more cache to the files which are more likely to be requested, while maintaining the same sub-packetization for all the files. As a result, in the delivery phase it is possible to perform linear codes across files with different popularities without resorting to zero-padding or concatenation techniques. We will describe our placement strategy for arbitrary range of parameters. The delivery phase will be outlined for a small example for which we are able to show a noticeable improvement over the state of the art

Visual saliency on the road: model and database dependent detection

National audienceIn the road context, objects of interest (salient or not) must be efficiently detected under any condition to ensure safety, for both driver assistance systems and autonomous vehicles. Nine representative state-of-the-art saliency models are evaluated on driving databases (human perception vs. robotics). Although not sufficient for robust detection, bottom-up saliency provides important information, especially when controlling for the classical biases.Dans le contexte routier, les objets d'intérêt (saillants ou non) doivent être efficacement détectés quelles que soient les conditions afin d'assurer la sécurité, que ce soit pour des systèmes d'assistance à la conduite ou des véhicules autonomes. Neufs modèles de saillance représentatifs de l'état de l'art sont évalués sur deux bases de données issues du contexte routier (perception humaine et robotique). Bien qu'elle ne soit pas suffisante pour la détection, la saillance visuelle bottom-up fournit des informations pertinentes, d'autant plus en la contrôlant pour ses biais classiques

Detecting sex-related changes to the metabolome of a critically endangered freshwater crayfish during the mating season

Captive breeding is a vital tool in the conservation of highly endangered species, as it is for the Margaret River hairy marron, Cherax tenuimanus, from the south west of Australia. A close relative, Cherax cainii, has almost completely displaced C. tenuimanus in the wild and is a successful aquaculture species, whereas C. tenuimanus has performed poorly in captivity. We used untargeted liquid chromatography-mass spectrometry to obtain metabolomic profiles of female and male C. tenuimanus held in controlled aquarium conditions during their reproductive period. Using repeated haemolymph sampling we tracked the metabolomic profiles of animals just prior to and for a period of up to 34 days after pairing with a similar sized potential mate. We identified 54 reproducible annotated metabolites including amino acids, fatty acids, biogenic amines, purine and pyrimidine metabolites and excretion metabolites. Hierarchical clustering analysis distinguished five metabolite clusters. Principal component-canonical variate analysis clearly distinguished females from males, both unpaired and paired; similar trends in profile changes in both sexes after pairing; and a striking shift in males upon pairing. We discuss three main patterns of metabolomic responses: differentiation between sexes; reactive responses to the disturbance of pairing; and convergent response to the disturbance of pairing for males. Females generally had higher concentrations of metabolites involved in metabolic rate, mobilisation of energy stores and stress. Responses to the disturbance of pairing were also related to elevated stress. Females were mobilising lipid stores to deposit yolk, whereas males had a rapid and strong response to pairing, with shifts in metabolites associated with gonad development and communication, indicating males could complete reproductive readiness only once paired with a female. The metabolomic profiles support a previously proposed potential mechanism for displacement of C. tenuimanus by C. cainii in the wild and identify several biomarkers for testing hypotheses regarding reproductive success using targeted metabolomics