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Darwin's frogs Rhinoderma darwinii and Rhinoderma rufum are the only known species of amphibians in which males brood their offspring in their vocal sacs. We propose these frogs as flagship species for the conservation of the Austral temperate forests of Chile and Argentina. This recommendation forms part of the vision of the Binational Conservation Strategy for Darwin's Frogs, which was launched in 2018. The strategy is a conservation initiative led by the IUCN SSC Amphibian Specialist Group, which in 2017 convened 30 governmental, non-profit and private organizations from Chile, Argentina and elsewhere. Darwin's frogs are iconic examples of the global amphibian conservation crisis: R. rufum is categorized as Critically Endangered (Possibly Extinct) on the IUCN Red List, and R. darwinii as Endangered. Here we articulate the conservation planning process that led to the development of the conservation strategy for these species and present its main findings and recommendations. Using an evidence-based approach, the Binational Conservation Strategy for Darwin's Frogs contains a comprehensive status review of Rhinoderma spp., including critical threat analyses, and proposes 39 prioritized conservation actions. Its goal is that by 2028, key information gaps on Rhinoderma spp. will be filled, the main threats to these species will be reduced, and financial, legal and societal support will have been achieved. The strategy is a multi-disciplinary, transnational endeavour aimed at ensuring the long-term viability of these unique frogs and their particular habitat.
Insects in the subfamily Ischnorhininae (Hemiptera: Auchenorrhyncha: Cercopidae), known as spittlebugs or froghoppers, are mainly distributed in the Neotropical region. A few genera include pest species of economic relevance, including Prosapia Fennah, 1949. Two new species from Mexico and Costa Rica are now described for this genus, and a key to species is proposed for the P. inferens (Walker, 1858) species group.
There is no agreement regarding which solvent is more suitable to obtain sol–gel–derived titania (TiO2) samples with an enhanced photocatalytic behavior. Furthermore, the solvent effect on the preparation of TiO2-RGO (reduced graphene oxide) nanocomposites has not been published yet and could be an attractive experimental strategy to modulate structure and properties. On the basis of these observations, TiO2-RGO nanocomposites were fabricated in this study. It was evaluated for the influence of using either isopropyl (IsoprOH) or ethyl (EtOH) alcohol on the textural and photocatalytic properties of the prepared materials. The use of IsoprOH led to samples with smaller crystallite size, narrower apparent band gap, smaller isoelectric point, larger adsorption capacity, and higher photocatalytic activity. In addition, the incorporation of RGO into TiO2 greatly improved the adsorption capacity and photocatalytic activity of the latter. However, the optimal loading of RGO to prepare composites with enhanced photocatalytic activities was 1 wt%. This finding can be related to the stacking of RGO sheets when concentrations above 1 wt% are used, which could prevent UV light to reach the TiO2 particles and also decrease the photocatalytic capacity of the composites. Moreover, materials with RGO concentration above 1 wt% could exhibit a highly negatively charged surface, which may decrease the separation of the generated electron–hole pairs and lead to faster recombination rates of charge carriers.
To determine the association between the use of opioids and benzodiazepines and the risk of falls with hip fracture in populations older than 65 years in Colombia.
A case-control study with patients older than 65 years with diagnosis of hip fracture. Two controls were obtained per case. The drugs dispensed in the previous 30 days were identified. Sociodemographic, diagnostic, pharmacological (opioids and benzodiazepines), and polypharmacy variables were analyzed. A logistic regression model was used to analyze the risk of fall with hip fracture while using these drugs.
We included 287 patients with hip fractures and 574 controls. There was a female predominance (72.1%) and a mean age of 82.4 ± 8.0 years. Of the patients, 12.7% had been prescribed with opioids and 4.2% with benzodiazepines in the previous month. The adjusted multivariate analysis found that using opioids (OR:4.49; 95%CI:2.72–7.42) and benzodiazepines (OR:3.73; 95%CI:1.60–8.70) in the month prior to the event was significantly associated with a greater probability of suffering a fall with hip fracture.
People who are taking opioids and benzodiazepines have increased risk for hip fracture in Colombia. Strategies to educate physicians regarding the pharmacology of older adults should be strengthened.
Based on Pettigrew and Meertens’ Blatant and Subtle Prejudice Scale (1995), a new scale for assessing the expression of prejudice is proposed in this article. The original scale has been changed in three ways: (a) items were rewritten to avoid double assertions, (b) three new items were considered to adequately measure the ‘denial of positive emotions’ component, and (c) biased wording of the ‘cultural differences’ domain items measuring perceived cultural differences rather than prejudices was removed. We used a representative sample of 500 participants living in Antofagasta, in Chile. Confirmatory factor and a hierarchical regression analyses support the proposed new scale. This instrument provides two measures: one general measure related to the intensity of prejudice expression and a second measure indicating the presence or absence of prejudice for each component type (Rejection, Intimacy, Values, Emotions, and Culture). The scale was confirmed for both genders; 45.2% of the participants scored a medium-high to extremely high expression of prejudice towards Bolivians immigrants.
The surrounding area of the St. Peter and St. Paul Archipelago (SPSPA) (0°55′10″N 29°20′33″W) was investigated in order to verify the physical and chemical influences in species composition and abundance, and the patterns of distribution of phytoplankton in the water column, especially in the thermocline depths. The expedition was held on board the Cruzeiro do Sul Hydro-oceanographic ship, from 21 to 23 July 2010 in two perpendicular and opposite transects. A cylinder-conical net and Niskin bottles were used. Two water masses were identified (Tropical Water and South Atlantic Central Water), and the thermocline depths varied from 40 to 110 m. A total of 128 species of phytoplanktonic organisms were identified, belonging to four phyla. The most conspicuous species was the cyanobacteria Trichodesmium thiebautii; nevertheless, 22 species were considered new registers for the region. The total phytoplanktonic density (1 × 103 to 183 × 103 cells l−1) was low and typical of oligotrophic regions, decreasing slightly with depth. Among the 35 species identified in the vertical distribution, 22 were present in the thermocline depth. The total density of Trichodesmium thiebautii, Oxytoxum longiceps and Protoperidinium minimum had significant correlations with the physical and chemical parameters. These data indicate that SPSPA can be associated to an island mass effect in the local oceanic circulation that mainly affects the physical and chemical characteristics of the surrounding waters. Consequently, these interactions influence the phytoplanktonic community, mainly those located at the end of the photic zone and those that are under the influence of thermocline oscillation.
In this paper, we develop and study numerical methods for the two-mode shallow water equations recently proposed in [S. STECHMANN, A. MAJDA, and B. KHOUIDER, Theor. Comput. Fluid Dynamics, 22 (2008), pp. 407-432]. Designing a reliable numerical method for this system is a challenging task due to its conditional hyperbolicity and the presence of nonconservative terms. We present several numerical approaches—two operator splitting methods (based on either Roe-type upwind or central-upwind scheme), a central-upwind scheme and a path-conservative central-upwind scheme—and test their performance in a number of numerical experiments. The obtained results demonstrate that a careful numerical treatment of nonconservative terms is crucial for designing a robust and highly accurate numerical method.
The main purpose of our study is to compare the beliefs of Spanish and Chilean university students about the effects that same-sex parents might have on their children. A total of 491 participants completed the study (208 Spaniards and 283 Chileans). The results indicate a kind of modern and subtle rejection based on hetero-normativity. Furthermore, the results indicated the effects of sex (men have a greater degree of rejection), traditional and sexist opinions linked to a greater rejection of same-sex parents, and the contact variable which inversely correlates with this rejection. The results show that the etiology of homosexual orientation also correlates with rejection of same-sex parents when it is believed that homosexuality is learned or can be changed.
The Flemish painter Simón Pereyns travelled to New Spain in 1566 as a member of the viceroyal court. In two important paintings La Virgen del Perdón (1568) and San Cristóbal (1588) we identified wide use of blue smalt pigment, a potassium glass with cobalt oxide. The color of this material depends on its manufacture process, from pale greyish blue to violet or dark blue. The more blue color the more expensive the pigment. On the 16th century market the commerce of smalt was divided into many categories based on the material quality. Historical archive documents testify smalt imports from Seville to New Spain in two different qualities: fine and smalt woody ashes. In Pereyns` paintings the smalt was used in specific parts of the composition as the dark sky in landscapes, shadows of draperies and under layers in order to create a color background for the figures. Nowadays, in these areas, the alteration of the paint layer is evident. The blue has been changed into brown color. Optical microscopy (MO), scanning and transmission electron microscopies were performed in order to characterize the particles of smalt. The degradation of potassium glass was verified, as a consequence of aging and degradation process due to environmental conditions. These phenomena are well known and study on European paintings. In this research our aim is to explore the intentional use of smalt on Pereyns’ compositions and how color change as a consequence of microscopic materials instability can influence the contemporary reception of the paintings. Many paintings from New Spain have a dull, dark and limited palette but the original was very different. The remarks about the color of New Spain's paintings should considered the normal aging of the paint components, studied by materials science and art history.
The diets and trophic ecology of the dominant fish species from the marine coastal region of Aveiro (north-western Portugal) caught during a summer survey were studied. Mysids were the most important prey group for the fish assemblage analysed. As a consequence, there was a high dietary overlap between species and a low incidence of piscivory. Nevertheless, a clear segregation of trophic niches was observed, with one group (comprising the species Chelidonichthys cuculus, Callionymus lyra, Dicologlossa cuneata and Pomatoschistus lozanoi) showing a stronger preference for infaunal epibenthic prey, such as polychaetes and amphipods, another group (including Arnoglossus imperialis, Arnoglossus laterna, Chelidonichthys obscurus, Chelidonichthys lucernus, Echiichthys vipera, Pagellus acarne and Trisopterus luscus) preying mostly upon suprabenthic prey, mainly mysids, and a third group (Engraulis encrasicolus and Trachurus trachurus) feeding largely on planktonic prey like copepods. Some species, including A. imperialis, C. lyra, E. vipera, T. trachurus and T. luscus, showed ontogenic diet shifts that may be related to the habitat occupied by different size-classes and/or to their ability to capture prey of different size.
The goal of this paper is to obtain a well-balanced, stable, fast, and robust HLLC-type
approximate Riemann solver for a hyperbolic nonconservative PDE system arising in a
turbidity current model. The main difficulties come from the nonconservative nature of the
system. A general strategy to derive simple approximate Riemann solvers for
nonconservative systems is introduced, which is applied to the turbidity current model to
obtain two different HLLC solvers. Some results concerning the non-negativity preserving
property of the corresponding numerical methods are presented. The numerical results
provided by the two HLLC solvers are compared between them and also with those obtained
with a Roe-type method in a number of 1d and 2d test problems. This comparison shows that,
while the quality of the numerical solutions is comparable, the computational cost of the
HLLC solvers is lower, as only some partial information of the eigenstructure of the
matrix system is needed.
We report experiments in which a flow rate of a fluid with a viscosity discharges into an immiscible liquid of viscosity that flows in parallel with the axis of the injector. When the outer capillary number verifies the condition , where and indicate, respectively, the outer velocity and the interfacial tension coefficient, and if the inner-to-outer velocity ratio is such that , with the inner radius of the injector, a jet is formed with the same type of cone–jet geometry as predicted by the numerical results of Suryo & Basaran (Phys. Fluids, vol. 18, 2006, p. 082102). For extremely low values of the velocity ratio , we find that the diameter of the jet emanating from the tip of the cone is so small that drops with sizes below can be formed. We also show that, through this simple method, concentrated emulsions composed of micrometre-sized drops with a narrow size distribution can be generated. Moreover, thanks to the information extracted from numerical simulations of boundary-integral type and using the slender-body approximation due to Taylor (Proceedings of the 11th International Congress of Applied Mechanics, Munich, 1964, pp. 790–796), we deduce a third-order, ordinary differential equation that predicts, for arbitrary values of the three dimensionless numbers that control this physical situation, namely, , and , the shape of the jet and the sizes of the drops generated. Most interestingly, the influence of the geometry of the injector system on the jet shape and drop size enters explicitly into the third-order differential equation through two functions that can be easily calculated numerically. Therefore, our theory can be used as an efficient tool for the design of new emulsification devices.
Xavier Guerrero (1896-1974) had an important role in the so-called Mexican Mural Renaissance, as a technical leader in the murals painted by Roberto Montenegro and Diego Rivera in the early 1920’s. Jean Charlot, Diego Rivera and David Alfaro Siqueiros considered him as a sophisticated fresco craftsman, whose knowledge came from a popular mural painters guild.
In 1941 the Mexican Government donated a School to Chillan, a Chilean town almost destroyed by a strong earthquake. David Alfaro Siqueiros and Xavier Guerrero were commissioned to paint murals on the Mexico School. Between 1941-1942 Guerrero decorated several walls and the staircase ceiling, the mural program is called De México a Chile (From Mexico to Chile). In 2010 another earthquake destroyed part of the ceiling. This study is part of the diagnosis project of De México a Chile, and consists in the characterization of the mortar and painting layers with optical microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermal analysis (TGA), while textural properties of the mortars were studied with nitrogen adsorption-desorption techniques.
Analytical results show a stratigraphic sequence composed of several layers of Portland and lime combinations, and also an interesting painting technique that possibly involves the Portland cement setting process, with the development of specular gypsum.
This paper discuss the presence of powdered glass and quartz integrated in the red lake layers of two paintings attributed to the Sevillian painter Bartolome Esteban Murillo that belongs to the Guadalajara’s Regional Museum’s art collection. A laboratory experimental reproduction of the Sevillian painting technique was made using three different lakes (cochineal, madder lake and brazilwood) mixed with four varieties of glass to explore the optical properties and the influence of the transparent and translucent aggregates into the oil paint layers. The experimental reproductions were analyzed using ultraviolet-visible spectroscopy, optical and fluorescence microscopy and scanning electron microscopy (SEM-EDX). A comparison between the originals and the reproduced red lakes layers was carried out to understand the artistic process of Murillo’s color application. Preliminary results suggest that glass was not used as a siccative agent as the historical treatises mentioned but mainly as an additive to increase brightness, thickness and color saturation of the red lake layers related to the artist’s intention.
In this paper, a novel hyperspectral image acquisition system able to obtain a set of narrowband images (~2,25 nm of bandwidth) and the related composition of monochrome images in the near-infrared is described. The aim of this system is to discriminate the materials by their optical spectral response in the range of 900-1700 nm. This system has been developed in the framework of a collaborative project that includes the improvement of the automatic composition of reflectographic mosaics in order to study the underdrawing of large formats big artworks in real-time. The main features of this project are detailed in this paper. Furthermore, a few enlightening results of the hyperspectral system and new lines of research are shown.
This work shows current research on lithic raw material used by the ancient Maya of Toniná. The core of the city of Toniná lies on a steep-sided hill of calcareous sandstones from the shallow marine deposits dated as Oligocene, in the Chiapas Highlands of Southern Mexico. Results of paleontological fieldwork in Toniná show several biostrome sediments mound-like with tabular bafflestones and large coquina flagstones, which are sheet-like rocks enriched with fossil mollusk shells, corals, encrusted organisms, and calcareous debris. The people of Toniná intentionally selected and carved these rocks for use as building blocks and bricks on floors, walls, and stairways. At least two coquina flagstones measuring about 1.90 m long were identified in an archeological context most likely associated with carved stelae. Also non-marine carbonate rocks such as a crudely banded travertine and spongy calcareous tufa from recent sediments of freshwater environments surrounding Toniná were used by the Maya as a raw material on walls, columns, reliefs and murals base.
Results of the chemical, mineralogical and micromorphological analysis on plaster and bedding mortars from the walls of Toniná display a slightly interbedded lime of sparry calcite cemented in a highly porous groundmass with silt-to pebble-size of calcareous and siliciclastic rock-crushed aggregates, sand, and soil remains. Lime fabric reveals enclosing quartz grains, granular calcite crystals, and carbonaceous inclusions which may suggest that the lime has been made from a burnt grain-rich limestone with fibrous cement and porous microfabric. WDX analysis in lime lumps of plaster reveal an average amount of 1.37 wt% MgO associated with a limestone source ranging from regular to a magnesium-enriched limestone (1 to 2 wt %). XRF detect a strontium-rich level in the calcite matrix of plaster which is as high as that of fossil shells, tufa, and coquina. Finally, XRD shows that the mean amount of calcite in plaster is 95 wt% and lower amount (2-2.5w%) of siliciclastic minerals: quartz and albite. In contrast, calcite in mortar ranges less than 90.1 wt%. The concentrations of non-carbonate minerals, such as quartz and albite, are higher than those in plaster because mortar incorporates more siliciclastic rock remains, sand and clay.
The taxonomy of pedunculate cirripedes belonging to the genus Pollicipes has essentially remained unchanged since Charles Darwin described them in his exhaustive work on the Cirripedia. This genus includes three species of stalked barnacles: Pollicipes pollicipes in the north-eastern Atlantic, P. polymerus in the north-eastern Pacific and P. elegans in the central-eastern Pacific. However, a population genetics analysis of P. pollicipes suggested the presence of a putative cryptic species collected from the Cape Verde Islands in the central-eastern Atlantic. This study examines the morphology of these genetically divergent specimens and compares them with that of representative Atlantic samples of the biogeographically closely related P. pollicipes and with the poorly described P. elegans. Molecular data, including mitochondrial COX1 and nuclear ribosomal interspaces sequences, were obtained for all species of the genus Pollicipes. Morphological distinctiveness, diagnostic characters, congruent divergence level and monophyletic clustering, at both nuclear and mitochondrial loci support the taxonomic status of this new species, Pollicipes darwini.
The Small Pelagic Fish and Climate Change (SPACC) program was created to facilitate research on the dynamics of populations of small pelagic fish, including anchovy and sardine. These populations exhibit large variations in size, extent, and production on the scale of decades. At times, anchovy and sardine alternate in abundance. Collectively, small pelagic fish often occupy a central role in the food web they occur in, often described as a wasp-waist ecosystem. Humans are an integral part of those ecosystems. Variability of populations of small pelagic fish is believed to be due primarily to variations in climate and fishing, but the mechanisms of these relations remain unknown in most cases. It is also uncertain whether these ecosystems alternate between states, e.g. regimes, and whether inherent variability may limit our ability to predict their future states. The fisheries for populations of small pelagic fish are increasingly global in nature. While the global catch of small pelagic fish constitutes approximately one quarter of the world fish catch and has been relatively constant during the past several decades, the catch of individual taxa and stocks varies much more. The management of these fisheries will be challenged by increasing demand for human consumption and mariculture in light of their finite and variable production, importance within the ecosystem, and unprecedented climate change, and will depend on both science and governance. We recommend continued, global research on climate change effects on small pelagic fish, and its periodic assessment for use by decision makers.