Orbital Fluctuation-Induced Triplet Superconductivity : Mechanism of Superconductivity in Sr2RuO4{\rm Sr}_{2}{\rm RuO}_{4}

The mechanism of superconductivity in ${\rm Sr}_{2}{\rm RuO}_{4}$ is studied using a degenerate Hubbard model within the weak coupling theory. When the system approaches the orbital instability which is realized due to increasing the on-site Coulomb interaction between the electrons in the different orbitals, it is shown that the triplet superconductivity appears. This superconducting mechanism is only available in orbitally degenerate systems with multiple Fermi surfaces.Comment: 5 pages, 4 figure

The Magnitude And Persistence Of Soil No, N2O, Ch4, And Co, Fluxes From Burned Tropical Savanna In Brazil

Among all global ecosystems, tropical savannas are the most severely and extensively affected by anthropogenic burning. Frequency of fire in cerrado,a type of tropical savanna covering 25% of Brazil, is 2 to 4 years. In 1992 we measured soil fluxes of NO, N2O, CH4, and CO2 from cerrado sites that had been burned within the previous 2 days, 30 days, 1 year, and from a control site last burned in 1976. NO and N2O fluxes responded dramatically to fire with the highest fluxes observed from newly burned soils after addition of water. Emissions of N-trace gases after burning were of similar magnitude to estimated emissions during combustion. NO fluxes immediately after burning are among the highest observed for any ecosystem studied to date. These rates declined with time after burning and had returned to control levels 1 year after the burn. An assessment of our data suggested that tropical savanna, burned or unburned, is a major source of NO to the troposphere. Cerrado appeared to be a minor source of N2O and a sink for atmospheric CH4. Burning also elevated CO2 fluxes, which remained detectably elevated 1 year later

Distribution Of Demersal Fishes Of The Caribbean Sea Found Below 2,000 Meters

Abyssal fishes of the Caribbean Sea are known from the work of six research vessels, yet only one ofthese collections has been reported. The most recent collection, that of the USNS BARTLETTin 1981, contains 13 new records of rare fish to the Caribbean, including two undescribed species. Twelve species accounts are given, documenting the new finds, along with some taxonomic changes from previous reports. Zoogeographical analysis revealed that the abyssal fish fauna of the Caribbean basins reflects a depauperate, tropical, western Atlantic subunit of a broader, circumglobal pattern of the world\u27s abyssal fish fauna

The application of metacommunity theory to the management of riverine ecosystems

River managers strive to use the best available science to sustain biodi versity and ecosystem function. T o achieve this goal requires consideration of processes at different scales. Metacommunity theory describes how multiple species from differ- ent communities potentially interact with local-scale environmental drivers to influ- ence population dynamics and community structure. However, this body of knowledge has only rarely been used to inform management practices for river ecosystems. In this article, we present a conceptual model outlining how the metacommunity processes of local niche sorting and dispersal can influence the outcomes of management interventions and provide a series of specific recommen- dations for applying these ideas as well as research needs. In all cases, we identify situations where traditional approaches to riverine management could be enhanced by incorporating an understanding of metacommunity dynamics. A common theme is developing guidelines for assessing the metacommunity context of a site or region, evaluating how that context may affect the desired outcome, and incorporat- ing that understanding into the planning process and methods used. To maximize the effectiveness of management activities, scientists, and resource managers should update the toolbox of approaches to riverine management to reflect theoretical advances in metacommunity ecology

Global patterns of the double mutualism phenomenon

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordData deposition: Data available from the Dryad Digital Repository: (Fuster et al. 2018).A double mutualism (DM) occurs when two interacting species benefit each other in two different functions, e.g. when an animal species acts both as pollinator and seed disperser of the same plant. Besides the double benefit, a DM also imposes a larger risk to both functions if the performance of one partner declines. We conducted the first global review of DMs involving pollinators and seed dispersers, aiming to: 1) assess their prevalence across ecosystems and biogeographical regions; 2) identify the main plant and animal taxa, and their traits, implicated in DMs; and 3) evaluate the conservation status of double mutualist species. We compiled published and unpublished DM records using specific search terms, noting the species involved, their conservation status and geographic location, as well as the type of study (species vs community‐level) in which the DM was detected. We identified 302 DM cases involving 207 plant and 92 animal species from 16 mainland and 17 island areas. Most records come from tropical regions and islands. Animals included birds (62%), mammals (22%), and reptiles (16%), mostly opportunist species; only 18% were nectarivores. Plants were mainly fleshy‐fruited shrub or tree species (59%) with actinomorphic flowers that were visited by several or many pollinator species (87%). Most (56%) DMs were detected in community‐level studies. DMs are mostly prevalent in ecosystems with limited food resources and mutualist partners, and with high generalization levels. Nearly 30% of the species involved in DMs are threatened according to IUCN criteria, 68% of which are found on islands. The high prevalence of DM on islands paired with the threat status of island species suggest that the loss of a double mutualists and its cascading consequences may have a severe impact on community composition and functioning of fragile island ecosystems.Spanish Governmen

Mapeamento e comparação de acordos de proteção de investimentos internacionais na América latina e central 1990 a 2018

MAPEAMENTO E COMPARAÇÃO DE ACORDOS DE PROTEÇÃO DE INVESTIMENTOS INTERNACIONAIS NA AMÉRICA LATINA E CENTRAL 1990 A 201