Two new, remarkably colored species of the Neotropical catfish genus Cetopsorhamdia Eigenmann & Fisher, 1916 (Siluriformes, Heptapteridae) from Chapada dos Parecis, western Brazil, with an assessment of the morphological characters bearing on their phylogenetic relationships

Two new species of heptapterid catfish genus Cetopsorhamdia are described from close localities in western Brazil, at Chapada dos Parecis, an area with extremely high level of endemism. One species is from the upper Rio Madeira system, Rondônia State, and the other from the upper Rio Tapajós system, Mato Grosso State. The two species are diagnosed, among several other features, by their markedly distinctive color patterns, with the former having well-defined quadrangular marks in trunk flanks while the latter bearing irregular, vertical bars along the trunk. The monophyly of Cetopsorhamdia is discussed, with two putative synapomorphies being proposed to support the genus. Potentially informative morphological characters to resolve the internal relationships of the genus are presented and discussed. Despite the striking external differences between the two species herein described, they are found to likely form a clade

A new species of Rhamdella Eigenmann & Eigenmann, 1888 (Siluriformes: Heptapteridae) from the coastal basins of southern Brazil

Rhamdella zelimai, new species, is described from the coastal river drainages in northeastern Rio Grande do Sul and southern Santa Catarina States, Brazil. The new species is readily distinguished from its congeners by the hypertrophy of the rictal fold, mainly its lower portion, consisting of a large and fleshy lobe that bends ventrally on itself. The phylogenetic relationships of the new species are assessed and it was recovered as belonging to the clade composed of R. eriarcha (from the laguna dos Patos basin), R. longiuscula (from the rio Uruguai), and R. cainguae (from the lower rio Paraná)

Adição de Zn e absorção, translocação e utilização de Zn e P por cultivares de cafeeiro

A crescente exigência de nutrientes, especialmente micronutrientes, pelos cultivares de café vem exigindo uma melhor compreensão da dinâmica desses nutrientes no sistema solo-planta. Com o objetivo de avaliar o efeito de concentrações de Zn (0,4 ; 1,3 e 2,3 mimol Zn L-1) na solução nutritiva sobre o crescimento, produção de matéria seca, eficiência de absorção, translocação e utilização de Zn e P em dois cultivares de café (Coffea arabica cv. Catuaí e Coffea canephora cv. Conilon), foi realizado um experimento sob delineamento inteiramente casualizado com esquema fatorial 3 × 2 (três doses de Zn e dois cultivares) com três repetições. Plantas de café dos dois cultivares estudados foram cultivadas em casa de vegetação, com solução nutritiva completa por 50 dias, após os quais receberam solução nutritiva modificada com três doses de Zn. Aos 114 dias após a transferência para a solução nutritiva modificada, as plantas foram coletadas e separadas em folhas superiores, inferiores, caule e raízes. Foram avaliadas altura do caule, número de ramificações laterais, área foliar, produção de matéria seca e conteúdos de P e Zn nas diversas partes da planta, além das eficiências de absorção, translocação e utilização de P e Zn. A dose 2,3 mimol Zn L-1 proporcionou os maiores valores para as características de crescimento avaliadas, tanto para o cultivar Catuaí, quanto para Conilon. Os maiores conteúdos de Zn observados no Catuaí indicam que este é mais exigente em Zn que o Conilon na fase de mudas. O Conilon apresentou menores eficiências de absorção e translocação e maior eficiência de utilização de Zn, refletindo sua menor demanda por este nutriente. As concentrações de Zn empregadas neste experimento não promoveram interação Zn-P.The increasing nutrient requirement of coffee varieties, specially of micronutrients, is claiming for a better understanding of the dynamics of these nutrients in the soil-plant system. Having this in mind a greenhouse experiment in a completely randomized design, 3 × 2 factorial scheme and three replications was conducted to evaluate the effect of three Zn levels (0.4 , 1.3 and 2.3 mumol L-1) and two coffee species (Coffea arabica cv. Catuaí and Coffea canephora cv. Conilon) on: (i) growth characteristics; (ii) Zn and P contents; and (iii) Zn and P uptake, translocation and utilization efficiencies. Plants were grown in complete nutrient solution along 50 days, when they were transferred to three Zn levels. Plants were harvested and separated in leaves, stem and roots 114 days after the transference. Stem height, leaf area, dry matter yield, Zn and P contents, and Zn and P uptake, translocation and utilization efficiencies were evaluated. The largest growth characteristics were observed with 2.3 mumol L-1. The highest Coffea arabica cv Catuaí Zn contents suggest that this species has higher Zn demand than Coffea canephora cv. Conilon. Conilon cultivar showed the lowest Zn uptake and translocation efficiencies and the highest Zn utilization efficiency; what reflects its lower Zn demand. The Zn-P interaction was not observed with the Zn levels employed in this experiment

Zn addition and Zn and P uptake, translocation and utilization by coffee cultivars

A crescente exigência de nutrientes, especialmente micronutrientes, pelos cultivares de café vem exigindo uma melhor compreensão da dinâmica desses nutrientes no sistema solo-planta. Com o objetivo de avaliar o efeito de concentrações de Zn (0,4 ; 1,3 e 2,3 mimol Zn L-1) na solução nutritiva sobre o crescimento, produção de matéria seca, eficiência de absorção, translocação e utilização de Zn e P em dois cultivares de café (Coffea arabica cv. Catuaí e Coffea canephora cv. Conilon), foi realizado um experimento sob delineamento inteiramente casualizado com esquema fatorial 3 × 2 (três doses de Zn e dois cultivares) com três repetições. Plantas de café dos dois cultivares estudados foram cultivadas em casa de vegetação, com solução nutritiva completa por 50 dias, após os quais receberam solução nutritiva modificada com três doses de Zn. Aos 114 dias após a transferência para a solução nutritiva modificada, as plantas foram coletadas e separadas em folhas superiores, inferiores, caule e raízes. Foram avaliadas altura do caule, número de ramificações laterais, área foliar, produção de matéria seca e conteúdos de P e Zn nas diversas partes da planta, além das eficiências de absorção, translocação e utilização de P e Zn. A dose 2,3 mimol Zn L-1 proporcionou os maiores valores para as características de crescimento avaliadas, tanto para o cultivar Catuaí, quanto para Conilon. Os maiores conteúdos de Zn observados no Catuaí indicam que este é mais exigente em Zn que o Conilon na fase de mudas. O Conilon apresentou menores eficiências de absorção e translocação e maior eficiência de utilização de Zn, refletindo sua menor demanda por este nutriente. As concentrações de Zn empregadas neste experimento não promoveram interação Zn-P.The increasing nutrient requirement of coffee varieties, specially of micronutrients, is claiming for a better understanding of the dynamics of these nutrients in the soil-plant system. Having this in mind a greenhouse experiment in a completely randomized design, 3 × 2 factorial scheme and three replications was conducted to evaluate the effect of three Zn levels (0.4 , 1.3 and 2.3 mumol L-1) and two coffee species (Coffea arabica cv. Catuaí and Coffea canephora cv. Conilon) on: (i) growth characteristics; (ii) Zn and P contents; and (iii) Zn and P uptake, translocation and utilization efficiencies. Plants were grown in complete nutrient solution along 50 days, when they were transferred to three Zn levels. Plants were harvested and separated in leaves, stem and roots 114 days after the transference. Stem height, leaf area, dry matter yield, Zn and P contents, and Zn and P uptake, translocation and utilization efficiencies were evaluated. The largest growth characteristics were observed with 2.3 mumol L-1. The highest Coffea arabica cv Catuaí Zn contents suggest that this species has higher Zn demand than Coffea canephora cv. Conilon. Conilon cultivar showed the lowest Zn uptake and translocation efficiencies and the highest Zn utilization efficiency; what reflects its lower Zn demand. The Zn-P interaction was not observed with the Zn levels employed in this experiment

Scientists’ warning to humanity on the freshwater biodiversity crisis

Funding was funded by National Science Foundation (US) (Grant Nos. 0614334, 0741450, 1354511), Svenska Forskningsrådet Formas (Grant No. 2016-02045), H2020 European Research Council (Grant No. AdG 250189) and Instituto Nacional de Ciência e Tecnologia de Ciência Animal (Grant No. 306455/2014-5).Freshwater ecosystems provide irreplaceable services for both nature and society. The quality and quantity of freshwater affect biogeochemical processes and ecological dynamics that determine biodiversity, ecosystem productivity, and human health and welfare at local, regional and global scales. Freshwater ecosystems and their associated riparian habitats are amongst the most biologically diverse on Earth, and have inestimable economic, health, cultural, scientific and educational values. Yet human impacts to lakes, rivers, streams, wetlands and groundwater are dramatically reducing biodiversity and robbing critical natural resources and services from current and future generations. Freshwater biodiversity is declining rapidly on every continent and in every major river basin on Earth, and this degradation is occurring more rapidly than in terrestrial ecosystems. Currently, about one third of all global freshwater discharges pass through human agricultural, industrial or urban infrastructure. About one fifth of the Earth’s arable land is now already equipped for irrigation, including all the most productive lands, and this proportion is projected to surpass one third by midcentury to feed the rapidly expanding populations of humans and commensal species, especially poultry and ruminant livestock. Less than one fifth of the world’s preindustrial freshwater wetlands remain, and this proportion is projected to decline to under one tenth by midcentury, with imminent threats from water transfer megaprojects in Brazil and India, and coastal wetland drainage megaprojects in China. The Living Planet Index for freshwater vertebrate populations has declined to just one third that of 1970, and is projected to sink below one fifth by midcentury. A linear model of global economic expansion yields the chilling prediction that human utilization of critical freshwater resources will approach one half of the Earth’s total capacity by midcentury. Although the magnitude and growth of the human freshwater footprint are greater than is generally understood by policy makers, the news media, or the general public, slowing and reversing dramatic losses of freshwater species and ecosystems is still possible. We recommend a set of urgent policy actions that promote clean water, conserve watershed services, and restore freshwater ecosystems and their vital services. Effective management of freshwater resources and ecosystems must be ranked amongst humanity’s highest priorities.PostprintPeer reviewe

Quantum simulation of battery materials using ionic pseudopotentials

Ionic pseudopotentials are widely used in classical simulations of materials to model the effective potential due to the nucleus and the core electrons. Modeling fewer electrons explicitly results in a reduction in the number of plane waves needed to accurately represent the states of a system. In this work, we introduce a quantum algorithm that uses pseudopotentials to reduce the cost of simulating periodic materials on a quantum computer. We use a qubitization-based quantum phase estimation algorithm that employs a first-quantization representation of the Hamiltonian in a plane-wave basis. We address the challenge of incorporating the complexity of pseudopotentials into quantum simulations by developing highly-optimized compilation strategies for the qubitization of the Hamiltonian. This includes a linear combination of unitaries decomposition that leverages the form of separable pseudopotentials. Our strategies make use of quantum read-only memory subroutines as a more efficient alternative to quantum arithmetic. We estimate the computational cost of applying our algorithm to simulating lithium-excess cathode materials for batteries, where more accurate simulations are needed to inform strategies for gaining reversible access to the excess capacity they offer. We estimate the number of qubits and Toffoli gates required to perform sufficiently accurate simulations with our algorithm for three materials: lithium manganese oxide, lithium nickel-manganese oxide, and lithium manganese oxyfluoride. Our optimized compilation strategies result in a pseudopotential-based quantum algorithm with a total runtime four orders of magnitude lower than the previous state of the art for a fixed target accuracy

A Radical Mechanism for the Vanadium-Catalyzed Deoxydehydration of Glycols

We propose a novel mechanism for the deoxydehydration (DODH) reaction of glycols catalyzed by a [Bu4N][VO2(dipic)] complex (dipic = pyridine-2,6-dicarboxylate) using triphenylphosphine as a reducing agent. Using density functional theory, we have confirmed that the preferred sequence of reaction steps involves reduction of the V(V) complex by phosphine, followed by condensation of the glycol into a [VO(dipic)(-O-CH2CH2-O-)] V(III) complex (6), which then evolves to the alkene product, with recovery of the catalyst. In contrast to the usually invoked closed-shell mechanism for the latter steps, where 6 suffers a [3+2] retrocycloaddition, we have found that the homolytic cleavage of one of the C–O bonds in 6 is preferred by 12 kcal/mol. The resulting diradical intermediate then collapses to a metallacycle that evolves to the product through an aromatic [2+2] retrocycloaddition. We use this key change in the mechanism to propose ways to design better catalysts for this transformation. The analysis of the mechanisms in both singlet and triplet potential energy surfaces, together with the location of the MECPs between them, showcases this reaction as an interesting example of two-state reactivity.Xunta de Galicia and Ministerio de Economiá y Competitividad for funding through Projects EM2014/040 and CTQ2013-48937-C2-1-P and CTQ2013-48937-C2-2-P, respectively. R.S. thanks the Junta de Castilla y León for funding through projects BU237U13 and BU076U16

Using community phylogenetics to assess phylogenetic structure in the fitzcarrald region of Western Amazonia

© 2020 The Authors. Di versity and Distributions Published by SBI. Here we explore the use of community phylogenetics as a tool to document patterns of biodiversity in the Fitzcarrald region, a remote area in Southwestern Amazonia. For these analyses, we subdivide the region into basin-wide assemblages encompassing the headwaters of four Amazonian tributaries (Urubamba, Yuruá, Purús and Las Piedras basins), and habitat types: river channels, terra firme (non-floodplain) streams, and floodplain lakes. We present a robust, well-documented collection of fishes from the region including 272 species collected from 132 field sites over 63 field days and four years, comprising the most extensive collection of fishes from this region to date. We conduct a preliminary community phylogenetic analysis based on this collection and recover results largely statistically indistinguishable from the random expectation, with only a few instances of phylogenetic structure. Based on these results, and of those published in other recent biogeographic studies, we conclude that the Fitzcarrald fish species pool accumulated over a period of several million years, plausibly as a result of dispersal from the larger species pool of Greater Amazonia

Design of Electrostatic Aberration Correctors for Scanning Transmission Electron Microscopy

In a scanning transmission electron microscope (STEM), producing a high-resolution image generally requires an electron beam focused to the smallest point possible. However, the magnetic lenses used to focus the beam are unavoidably imperfect, introducing aberrations that limit resolution. Modern STEMs overcome this by using hardware aberration correctors comprised of many multipole elements, but these devices are complex, expensive, and can be difficult to tune. We demonstrate a design for an electrostatic phase plate that can act as an aberration corrector. The corrector is comprised of annular segments, each of which is an independent two-terminal device that can apply a constant or ramped phase shift to a portion of the electron beam. We show the improvement in image resolution using an electrostatic corrector. Engineering criteria impose that much of the beam within the probe-forming aperture be blocked by support bars, leading to large probe tails for the corrected probe that sample the specimen beyond the central lobe. We also show how this device can be used to create other STEM beam profiles such as vortex beams and probes with a high degree of phase diversity, which improve information transfer in ptychographic reconstructions