Search results: Found 4

Listing 1 - 4 of 4
Sort by
Crystal Growth and Stoichiometry of Strongly Correlated Intermetallic Cerium Compounds (Book chapter)

Authors: ---
ISBN: 9789533076102 Year: DOI: 10.5772/29675 Language: English
Publisher: IntechOpen Grant: FP7 Ideas: European Research Council - 227378
Subject: Science (General)
Added to DOAB on : 2019-01-17 11:47:58
License:

Loading...
Export citation

Choose an application

Abstract

Strongly correlated electron systems are among the most active research topics in modern condensed matter physics. In strongly correlated materials the electron interaction energies

dominate the electron kinetic energy which leads to unconventional properties. Heavy

fermion compounds form one of the classes of such materials. In heavy fermion compounds

the interaction of itinerant electrons with local magnetic moments generates quasiparticles

with masses up to several 1000 electron masses. This may be accompanied by exciting

properties, such as unconventional superconductivity in a magnetic environment, non-Fermi

liquid behavior and quantum criticality. Strong electronic correlations are responsible for

physical phenomena on a low energy scale. Consequently, these phenomena have to be

studied at low temperatures. This, in turn, requires ultimate quality of single crystals to

avoid that the low temperature intrinsic properties are covered by extrinsic effects due to

off-stoichiometry, impurities or other crystal imperfections.

Keywords

stoichiometry --- growth --- crystal

The Microbial Regulation of Global Biogeochemical Cycles

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889192977 Year: Pages: 241 DOI: 10.3389/978-2-88919-297-7 Language: English
Publisher: Frontiers Media SA
Subject: Geography --- Microbiology --- Science (General)
Added to DOAB on : 2015-12-10 11:59:07
License:

Loading...
Export citation

Choose an application

Abstract

Global biogeochemical cycles of carbon and nutrients are increasingly affected by human activities. So far, modeling has been central for our understanding of how this will affect ecosystem functioning and the biogeochemical cycling of carbon and nutrients. These models have been forced to adopt a reductive approach built on the flow of carbon and nutrients between pools that are difficult or even impossible to verify with empirical evidence. Furthermore, while some of these models include the response in physiology, ecology and biogeography of primary producers to environmental change, the microbial part of the ecosystem is generally poorly represented or lacking altogether. The principal pool of carbon and nutrients in soil is the organic matter. The turnover of this reservoir is governed by microorganisms that act as catalytic converters of environmental conditions into biogeochemical cycling of carbon and nutrients. The dependency of this conversion activity on individual environmental conditions such as pH, moisture and temperature has been frequently studied. On the contrary, only rarely have the microorganisms involved in carrying out the processes been identified, and one of the biggest challenges for advancing our understanding of biogeochemical processes is to identify the microorganisms carrying out a specific set of metabolic processes and how they partition their carbon and nutrient use. We also need to identify the factors governing these activities and if they result in feedback mechanisms that alter the growth, activity and interaction between primary producers and microorganisms. By determining how different groups of microorganisms respond to individual environmental conditions by allocating carbon and nutrients to production of biomass, CO2 and other products, a mechanistic as well as quantitative understanding of formation and decomposition of organic matter, and the production and consumption of greenhouse gases, can be achieved. In this Research Topic, supported by the Swedish research councils' programme "Biodiversity and Ecosystem Services in a Changing Landscape" (BECC), we intend to promote this alternative framework to address how cycling of carbon and nutrients will be altered in a changing environment from the first-principle mechanisms that drive them – namely the ecology, physiology and biogeography of microorganisms – and on up to emerging global biogeochemical patterns. This novel and unconventional approach has the potential to generate fresh insights that can open up new horizons and stimulate rapid conceptual development in our basic understanding of the regulating factors for global biogeochemical cycles. The vision for the research topic is to facilitate such progress by bringing together leading scientists as proponents of several disciplines. By bridging Microbial Ecology and Biogeochemistry, connecting microbial activities at the micro-scale to carbon fluxes at the ecosystem-scale, and linking above- and belowground ecosystem functioning, we can leap forward from the current understanding of the global biogeochemical cycles.

Progress in Ecological Stoichiometry

Authors: --- --- --- --- et al.
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889456215 Year: Pages: 382 DOI: 10.3389/978-2-88945-621-5 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Microbiology
Added to DOAB on : 2019-01-23 14:53:43
License:

Loading...
Export citation

Choose an application

Abstract

Ecological stoichiometry concerns the way that the elemental composition of organisms shapes their ecology. It deals with the balance or imbalance of elemental ratios and how that affects organism growth, nutrient cycling, and the interactions with the biotic and abiotic worlds. The elemental composition of organisms is a set of constraints through which all the Earth’s biogeochemical cycles must pass. All organisms consume nutrients and acquire compounds from the environment proportional to their needs. Organismal elemental needs are determined in turn by the energy required to live and grow, the physical and chemical constraints of their environment, and their requirements for relatively large polymeric biomolecules such as RNA, DNA, lipids, and proteins, as well as for structural needs including stems, bones, shells, etc. These materials together constitute most of the biomass of living organisms. Although there may be little variability in elemental ratios of many of these biomolecules, changing the proportions of different biomolecules can have important effects on organismal elemental composition. Consequently, the variation in elemental composition both within and across organisms can be tremendous, which has important implications for Earth’s biogeochemical cycles. It has been over a decade since the publication of Sterner and Elser’s book, Ecological Stoichiometry (2002). In the intervening years, hundreds of papers on stoichiometric topics ranging from evolution and regulation of nutrient content in organisms, to the role of stoichiometry in populations, communities, ecosystems and global biogeochemical dynamics have been published. Here, we present a collection of contributions from the broad scientific community to highlight recent insights in the field of Ecological Stoichiometry.

Tropical Forest Ecology and Management for the Anthropocene

Authors: ---
ISBN: 9783039219643 / 9783039219650 Year: Pages: 242 DOI: 10.3390/books978-3-03921-965-0 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General)
Added to DOAB on : 2020-01-07 09:08:26
License:

Loading...
Export citation

Choose an application

Abstract

This Special Issue looks forward as well as backward to best analyze the forest conservation challenges of the Caribbean. This is made possible by 75 years of research and applications by the United States Department of Agriculture, International Institute of Tropical Forestry (the Institute) of Puerto Rico. It transforms Holocene-based scientific paradigms of the tropics into Anthropocene applications and outlooks of wilderness, managed forests, and urban environments. This volume showcases how the focus of the Institute’s programs is evolving to support sustainable tropical forest conservation despite uncertain conditions. The manuscripts showcased here highlight the importance of shared stewardship and a long-term, hands-on approach to conservation, research programs, and novel organizations intended to meet contemporary conservation challenges. Policies relevant to the Anthropocene, as well as the use of experiments to anticipate future responses of tropical forests to global warming, are reexamined in these pages. Urban topics include how cities can co-produce new knowledge to spark sustainable and resilient transformations. Long-term results and research applications of topics such as soil biota, migratory birds, tropical vegetation, substrate chemistry, and the tropical carbon cycle are also described in the volume. Moreover, the question of how to best use land on a tropical island is addressed. This volume is intended to be of interest to all actors involved in long-term sustainable forest management and research in light of the historical lessons and future directions that may come out of a better understanding of tropical cities and forests in the Anthropocene epoch.

Keywords

Anthropocene --- Forest Service --- vision --- contemporary conservation --- biomass --- allometry --- volume expansion factors --- soil organic carbon --- tropical forest area --- forest inventory data --- novel forests --- tree plantations --- secondary forests --- mature forests --- dry tropical forests --- humid tropical forests --- tropical deforestation --- annual cycle --- carry over effects --- climate change --- Guánica --- Nearctic-Neotropical --- novel forests --- stoichiometry of leaf litter --- nitrogen fixing trees --- naturalized species --- C/N --- C/P --- and N/P ratios --- Puerto Rico --- Caribbean --- element concentration in leaf litter --- succession --- species dominance --- tropical forests --- invertebrates --- microbiota --- soil biota --- litter --- wood --- latitude --- elevation --- disturbance --- gradients --- tropical karst --- element concentration --- N/P ratios --- Ca/Al relationship --- ?13C --- ?15N --- knowledge co-production --- idiom of co-production --- knowledge infrastructures --- knowledge systems --- knowledge systems analysis --- cities --- land use governance --- Anthropocene --- disturbance --- hurricane --- succession --- long-term --- basal area --- species composition --- trees --- tropical --- Luquillo Experimental Forest --- Caribbean --- land use planning --- tropical agriculture --- tropical forests --- geospatial analyses --- n/a --- landscape conservation --- network governance --- strategic teams --- communications --- leadership --- adaptive management --- tropical forest --- Anthropocene --- U.S. Forest Service Planning Rule --- El Yunque National Forest --- Luquillo Experimental Forest --- introduced species --- leaf C and N densities --- novel forests --- photosynthetic nitrogen use-efficiency --- leaf mass per area --- Tropical Forestry Research --- Long-Term Ecological Research --- Tropical Forest Management --- Tropical Forest Conservation --- Luquillo Experimental Forest --- tropical --- experiments --- manipulations --- large-scale --- Puerto Rico --- Caribbean --- conservation --- American tropics --- long-term ecological research --- tropical forest management --- Anthropocene --- Puerto Rico

Listing 1 - 4 of 4
Sort by
Narrow your search