The Olrog’s Gull Larus atlanticus is an endemic and threatened species of the south-western Atlantic. Little is known about its movements during the non-breeding period. The objective of this study was to analyse the migration of the species by tracking adults from Bahía San Blas (Buenos Aires province, Argentina) with geolocators and using information of sightings of ringed gulls. Differences between males and females were evaluated using tracking data and ringed data were used to determine age differences. A single core area (kernel 50%) from 21 tracked birds was identified. This area included the study colony and also other breeding colonies located up to 300 km to the north. The range area (kernel 95%) included coastal areas up to 1,000 km from the colony. All sightings of ringed gulls (n = 41) occurred north of the breeding colony, however 12 adult individuals were sighted during the winter in its breeding grounds. Our results suggest the occurrence of partial migration behavior in Olrog’s Gull. The migration pattern reported here implies than during the non-breeding season, breeding and wintering areas away from the nesting grounds should be considered as one system in the design of conservation strategies for this regionally threatened gull.

Alien species are a driver of biodiversity loss, with impacts of different aliens on native species varying considerably. Identifying the contributions of alien species to native species declines could help target management efforts. Globally, seabirds breeding on islands have proven to be highly susceptible to alien species. The breeding colonies of the pink-footed shearwater (Ardenna creatopus) are threatened by the negative impacts of alien mammals. We combined breeding monitoring data with a hierarchical model to separate the effects of different alien mammal assemblages on the burrow occupancy and hatching success of the pink-footed shearwater in the Juan Fernández Archipelago, Chile. We show that alien mammals affected the rates of burrow occupancy, but had little effect on hatching success. Rabbits produced the highest negative impacts on burrow occupancy, whereas the effects of other alien mammals were more uncertain. In addition, we found differences in burrow occupancy between islands regardless of their alien mammal assemblages. Managing rabbits will improve the reproductive performance of this shearwater, but research is needed to clarify the mechanisms by which alien mammals affect the shearwaters and to explain why burrow occupancy varies between islands.

In the present work, the photocatalytic activity of metal Fe-Zn nanoparticles was evaluated through the degradation of the synthetic AZO colorant allura red. A Phytosynthesis method developed here takes advantage for the first time of the plant extract of Hydrocotyle ranunculoides as the reducing agent. A fitted Folin-Ciocalteu assay showed about 40% of total polyphenolic compounds used in the nanoparticles generation. UV-Vis and TEM analysis allowed identification of the nanoparticles as oxides of Fe and Zn. Finally, during measurement of the photocatalytic activity a load of 0.5 g/L was applied on a 15 μM solution of allura red as standard model pollutant, while environmental oxygen was used as the initiating agent. Tests showed a 66% degradation of the azo-type dye obeying a degradation kinetics of the first order after short times.

Although modern lines for dealing with missing data are well established from the 1970s, today there is a challenge when researchers encounter this problem in multilevel models. First, there is a variety of existing software to handle missing data based on multiple imputation (MI), currently pointed out by experts as the most promising strategy. Second, the two principal paradigms of MI are joint modelling (JM) and fully conditional specification (FCS), one more complication because they are not equally useful depending on the combination of multilevel model and the estimated parameters affected by missing data. Technical literature do not contribute to ease the number of decisions that researcher has to do. Given these inconveniences, the present paper has three objectives. (1) To present a thorough revision of the most recently developed software and functions about multiple imputation in multilevel models. (2) We derive a set of suggestions, recommendations, and guides for helping researchers to handle missing data. We list a number of key questions to consider when analyzing multilevel models. (3) Finally, based on the previous relevant questions, we present two detailed examples using the recommended R packages to be easy for the researcher applying multiple imputation in multilevel models.

Transition metal dichalcogenide materials MX2 (M = Mo;W;X = S; Se) are being thoroughly studied due to their novel two-dimensional structure, that is associated with exceptional optical and transport properties. From a computational point of view, Density Functional Theory simulations perform very well in these systems and are an indispensable tool to predict and complement experimental results. However, due to the time and length scales where even the most efficient DFT implementations can reach today, this methodology suffers of stringent limitations to deal with finite temperature simulations or electron-lattice coupling when studying excitation states: the unit cells required to study, for instance, systems with thermal fluctuations or large polarons would require a large computational power. Multi-scale techniques, like the recently proposed Second Principles Density Functional Theory, can go beyond these limitations but require the construction of tight-binding models for the systems under investigation. In this work, we compare two such methods to construct the bands of WSe2. In particular, we compare the result of (i) Wannier-based model construction with (ii) the band fitting method of Liu et al.,[1] where the top of the valence band and the bottom of the conduction band are modeled by three bands symmetrized to have mainly Tungsten dz2, dxy and dx2-y2character. Our results emphasize the differences between these two approaches and how band fitting model construction leads to an overestimation of the localization of the real-space basis in a tight-binding representation.

Six new species of Piezocerini (Coleoptera: Cerambycidae: Cerambycinae) are described: Alienosternus sanjacintero, Hemilissa bifasciata, Hemilissa erikae, Hemilissa claudiae, and Migorybia santossilvai from Colombia and Alienosternus wappesi from Bolivia. The genus Alienosternus Martins, 1976 is recorded for the first time for Colombia and Bolivia, and the genus Migorybia Martins, 1985 is recorded for the first time for Colombia. The geographical distribution of three species is expanded, and keys to species of Alienosternus and Hemilissa Pascoe, 1858 are provided.

This research presents a new theory that explains analytically the behaviour of any fully developed incompressible turbulent pipe flow, steady or unsteady. We propose the name of theory of underlying laminar flow (TULF), because its main consequence is the description of any turbulent pipe flow as the sum of two components: the underlying laminar flow (ULF) and the purely turbulent component (PTC). We use the framework of the TULF to explain analytically most of the important and interesting phenomena reported in He & Jackson (J. Fluid Mech., vol. 408, 2000, pp. 1–38). To do so, we develop a simple model for the pressure gradient and Reynolds shear stress that could be applied to the linearly accelerated pipe flow described by He & Jackson (2000). The following features of the unsteady flow are explained: the deformation undergone by the mean velocity profiles during the transient, the velocity overshoot observed in the more rapid excursions, the dual deformation of mean velocity profiles when overshoots are present, the laminarisation effects described during acceleration, the rapid decrease of the Reynolds shear stress upon approaching the wall that brings forth the laminar sublayer, and some other minor effects. A new field is defined to characterise the degree of turbulence within the flow, directly calculable from the theory itself. Arguably, this new field would describe the degree of turbulence in a pipe flow more accurately than the familiar turbulence intensity parameter. Finally, a paradox is found in the deformation of the unsteady mean velocity profiles with respect to equal-Reynolds-number steady profiles, which is duly explained. The research also predicts the occurrence of mean velocity undershoots if the flow is decreased rapidly enough.

Biodiversity conservation in forest fragments surrounded by a low-quality matrix requires an understanding of how ecological conditions prevailing in the matrix enter the fragments and interact with local habitat conditions. We assessed the regeneration of oak species along edge–interior gradients in forest fragments at the periphery of Mexico City. The abundance of oak saplings was sampled along transects to the forest, while the edge effect was analysed using segmented zero-inflated Poisson models for abundance data. Three oak species were dominant in terms of their relative abundances: Quercus laeta, Quercus castanea and Quercus obtusata. Regeneration of nine oak species responded nonlinearly to the edge distance, with greater sapling abundance from the edge up to 10 m into the fragment. Canopy cover and tree height decreased from edge to fragment interior, while saplings increased in open areas within the fragments (i.e., independent of edge distance). A posterior analysis indicated that Q. obtusata reacted positively to edges. These results indicate that oak regeneration is promoted by suitable habitat conditions near the boundaries. Therefore, we suggest that forest management should focus on promoting seed production and oak establishment in forest interior habitats.

The Bay of Málaga is located in a high biodiversity and productivity area that harbours a wide variety of commercial species exploited by different fishing fleets. Benthic and demersal fauna from circalittoral soft bottoms have been studied using a benthic dredge (BD) (8 sampling stations) and an otter trawl (OT) (8 sampling stations on a seasonal basis). Some sediment and water column variables, as well as the trawling activity, have also been studied and used for analysing their linkage with the fauna. A total of 287 species have been found in these bottoms and fish, molluscs and crustaceans represented the most diverse and abundant faunistic groups. A new record of the decapod Hippolyte leptometrae for Spanish waters is also included in this study. Some multivariate analyses using BD samples indicated the presence of three assemblages, but these seem to represent different facies of a single benthic community due to the absence of acute sediment changes and significant differences in the fauna. OT samples only displayed differences related to seasons but not to sediment types or depth. These seasonal differences seem to be linked to biological and ecological features of both dominant and/or commercial species. Mud and organic matter contents (%OM) in sediment, as well as the temperature, were the main variables linked to the spatial distribution of the benthic community identified with BD, whereas medium and coarse sand as well as gravel contents were the main variables linked to the changes of the epibenthic and demersal assemblage resulting from OT samples. The information of this study is of importance for improving the knowledge on the biodiversity of circalittoral soft bottoms of the Mediterranean and Alboran Sea as well as for the potential creation of a Marine Fisheries Reserve in the Bay of Málaga.