Causal explanations for the evolution of ‘low gear’ locomotion in insular ruminants

Aim: Mammals on islands often undergo remarkable evolutionary changes. The acquisition of ‘low gear’ locomotion, namely short and robust limb elements, has been typically associated with the island syndrome in large mammals and, especially, ruminants. Here we provide an investigative framework to examine biotic and abiotic selective factors hypothesized to influence evolution of this peculiar type of gait. Location: Islands worldwide. Taxon: Bovidae. Methods: We calculated response variables associated with ‘low gear’ locomotion in 21 extinct and extant insular bovids. We assembled data on the physiography of 11 islands and on life history and ecological traits of the focal taxa. We estimated 10 predictors (island area and four topographic indices, body mass, body size divergence, number of predators and competitors, large mammal richness) and used multiple regressions, regression trees, and random forests to assess their contextual importance. Results: The acquisition of ‘low gear’ locomotion generally happens on islands with a small number of competitors. However, the roughness of the island terrain appears to be also important, without being a main driver. Finally, although the most extreme cases of ‘low gear’ locomotion occurred on islands with no mammalian predators, our models show a non-significant relationship with this factor. Main conclusions: The evolution of ‘low gear’ locomotion in insular ruminants does not simply result from phyletic dwarfing and predatory release. Variation in morphological responses within Bovidae to ecological and topographic traits suggests, instead, a complex interplay of biotic and abiotic factors. Current understanding on the main drivers of species evolutionary pathways and biogeographic patterns are disproportionally based on few taxa, mainly vertebrates, and in some extreme cases (like this one) even on few species. Here we show how adding more data, even within the same taxonomic group, can challenge historically accepted macroevolutionary and macroecological concepts

Review of the flower-inhabiting water scavenger beetle genus Cycreon (Coleoptera, Hydrophilidae), with descriptions of new species and comments on its biology

The hydrophilid genus Cycreon Orchymont, 1919, previously known from two historical specimens only, is reviewed based on the numerous material collected recently from the inflorescences of various Araceae species in the Malay Peninsula and Borneo. Four species are recognized in the genus: C. sculpturatus Orchymont, 1919 from Sumatra, C. armandi Shatrovskiy, 2017 from Singapore, C. adolescens sp. n. from peninsular Malaysia, and C. floricola sp. n. with two subspecies, the nominotypical one from Peninsular Malaysia, and C. floricola borneanus subsp. n. from Borneo. All species are very similar, differing only by the pronotal punctation, shape of the clypeus and the mentum, and the form of the median lobe of the aedeagus. Specimens of C. floricola sp. n. and C. adolescens sp. n. were collected from inflorescences of various genera of the family Araceae. The field observations and analysis of mid gut contents indicates that they feed on organic material on internal organs of the inflorescences, including the pollen of the host plant. They were also observed to carry a large amount of pollen and are likely pollinators of their host species of Araceae

A Finite-Volume-Based Module for Unsaturated Poroelasticity

In this chapter, we present fv-unsat, a multipoint finite-volume–based solver for unsaturated flow in deformable and nondeformable porous media. The latter is described using the mixed form of Richards’ equation, whereas the former by the equations of unsaturated poroelasticity. The module aims at flexibility, relying heavily on discrete operators and equations, exploiting the automatic differentiation framework provided by the MATLAB Reservoir Simulation Toolbox (MRST). Our examples cover two numerical convergence tests and two three-dimensional practical applications, including the water infiltration process in a nondeformable soil column and a realistic desiccation process of a deformable clay sample using atmospheric boundary conditions. The resulting convergence rates are in agreement with previously reported rates for single-phase models, and the practical applications capture the physical processes accurately.publishedVersio

Thin static charged dust Majumdar-Papapetrou shells with high symmetry in D >= 4

We present a systematical study of static D >= 4 space-times of high symmetry with the matter source being a thin charged dust hypersurface shell. The shell manifold is assumed to have the following structure S_(beta) X R^(D-2-beta), beta (in the interval ) is dimension of a sphere S_(beta). In case of (beta) = 0, we assume that there are two parallel hyper-plane shells instead of only one. The space-time has Majumdar-Papapetrou form and it inherits the symmetries of the shell manifold - it is invariant under both rotations of the S_(beta) and translations along R^(D-2-beta). We find a general solution to the Einstein-Maxwell equations with a given shell. Then, we examine some flat interior solutions with special attention paid to D = 4. A connection to D = 4 non-relativistic theory is pointed out. We also comment on a straightforward generalisation to the case of Kastor-Traschen space-time, i.e. adding a non-negative cosmological constant to the charged dust matter source.Comment: Accepted in Int. J. Theor. Phy

FORTALECIMIENTO DE LOS ASPECTOS ENDEBLES DE LAS MIPYMES PARA INCREMENTAR LA PRODUCTIVIDAD EN LA GENERACIÓN DE EMPLEOS

Las MIPYME tienen un papel importante en la economía de todos los países, en algunos debido a sus políticas regulatorias, apoyos u otro tipo de incentivos, estas empresas son más productivas. Esto se refiere a que tienen la posibilidad de alentar al comercio interno y ser un pilar Importante para la creación de empleos. Existe variedad de literatura relacionada con el tema de MIPYMES, algunos de los estudios que se encontraron se centraron básicamente en tres cosas: Innovación tecnológica, incentivo y financiamiento y generador de empleos, estos tres aspectos son medulares para analizar y dictar información precisa referente a la competitividad de las MIPYME en México, dado que a partir de estos pilares las empresas se concentran en desarrollar sus competencias y fortalecer sus debilidades ante los cambios globales y económicos que existen alrededor de las empresas y aún más del nacimiento de empresas que por un apoyo deficiente o mala organización desaparecen los primeros años

From QoS Distributions to QoE Distributions: a System's Perspective

In the context of QoE management, network and service providers commonly rely on models that map system QoS conditions (e.g., system response time, paket loss, etc.) to estimated end user QoE values. Observable QoS conditions in the system may be assumed to follow a certain distribution, meaning that different end users will experience different conditions. On the other hand, drawing from the results of subjective user studies, we know that user diversity leads to distributions of user scores for any given test conditions (in this case referring to the QoS parameters of interest). Our previous studies have shown that to correctly derive various QoE metrics (e.g., Mean Opinion Score (MOS), quantiles, probability of users rating "good or better", etc.) in a system under given conditions, there is a need to consider rating distributions obtained from user studies, which are often times not available. In this paper we extend these findings to show how to approximate user rating distributions given a QoS-to-MOS mapping function and second order statistics. Such a user rating distribution may then be combined with a QoS distribution observed in a system to finally derive corresponding distributions of QoE scores. We provide two examples to illustrate this process: 1) analytical results using a Web QoE model relating waiting times to QoE, and 2) numerical results using measurements relating packet losses to video stall pattern, which are in turn mapped to QoE estimates. The results in this paper provide a solution to the problem of understanding the QoE distribution in a system, in cases where the necessary data is not directly available in the form of models going beyond the MOS, or where the full details of subjective experiments are not available.Comment: 4th International Workshop on Quality of Experience Management (QoE Management 2020), featured by IEEE Conference on Network Softwarization (IEEE NetSoft 2020), Ghent, Belgiu

Towards the understanding of the graphene oxide structure: How to control the formation of humic- and fulvic-like oxidized debris

Former structural models of graphene oxide (GO) indicated that it consists of graphene-like sheets with oxygen groups, and no attention was paid to the resulting sheet size. We now provide evidence of the complex GO structure consisting of large and small GO sheets (or oxidized debris). Different oxidation reactions were studied. KMnO4 derived GO consists of large sheets (20–30 wt.%), and oxidized debris deposits, which are formed by humic- and fulvic-like fragments. Large GO sheets contain oxygen groups, especially at the edges, such as carbonyl, lactone and carboxylic groups. Humic-like debris consists of an amorphous gel containing more oxygenated groups and trapped water molecules. The main desorbable fraction upon heating is the fulvic-like material, which contains oxygen groups and fragments with high edge/surface ratio. KClO3 in HNO3 or the Brodie method produces a highly oxidized material but at the flake level surface only; little oxidized debris and water contents are found. It is noteworthy that an efficient basal cutting of the graphitic planes in addition to an effective intercalation is caused by KMnO4, and the aid of NaNO3 makes this process even more effective, thus yielding large monolayers of GO and a large amount of humic- and fulvic-like substances.The authors thank the Government of Spain, Ministry for Economy and Competiveness, for financial support of project CTQ2013-44213-R, and Generalitat Valenciana for projects PROMETEOII/2014/007 and ISIC/2012/008. IRP thanks the Government of Spain, Ministry of Science and Education, for PhD Scholarship in the FPU program