Showing papers by "Russian Academy of Sciences published in 2012"
Daniel J. Klionsky1, Fábio Camargo Abdalla2, Hagai Abeliovich3, Robert T. Abraham4 +1284 more•Institutions (463)
TL;DR: These guidelines are presented for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes.
Abstract: In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
4,316 citations
TL;DR: Two types of nonlinear control algorithms are presented for uncertain linear plants, stabilizing polynomial feedbacks that allow to adjust a guaranteed convergence time of system trajectories into a prespecified neighborhood of the origin independently on initial conditions.
Abstract: Two types of nonlinear control algorithms are presented for uncertain linear plants. Controllers of the first type are stabilizing polynomial feedbacks that allow to adjust a guaranteed convergence time of system trajectories into a prespecified neighborhood of the origin independently on initial conditions. The control design procedure uses block control principles and finite-time attractivity properties of polynomial feedbacks. Controllers of the second type are modifications of the second order sliding mode control algorithms. They provide global finite-time stability of the closed-loop system and allow to adjust a guaranteed settling time independently on initial conditions. Control algorithms are presented for both single-input and multi-input systems. Theoretical results are supported by numerical simulations.
2,380 citations
Max Planck Society1, Massachusetts Institute of Technology2, Harvard University3, University of California, Berkeley4, University of Washington5, Bilkent University6, Chinese Academy of Sciences7, University of California, Santa Cruz8, University of Arizona9, Russian Academy of Sciences10, Howard Hughes Medical Institute11
TL;DR: The genomic sequence provides evidence for very low rates of heterozygosity in the Denisova, probably not because of recent inbreeding, but instead because of a small population size, and illuminates the relationships between humans and archaics, including Neandertals, and establishes a catalog of genetic changes within the human lineage.
Abstract: We present a DNA library preparation method that has allowed us to reconstruct a high-coverage (30×) genome sequence of a Denisovan, an extinct relative of Neandertals. The quality of this genome allows a direct estimation of Denisovan heterozygosity indicating that genetic diversity in these archaic hominins was extremely low. It also allows tentative dating of the specimen on the basis of “missing evolution” in its genome, detailed measurements of Denisovan and Neandertal admixture into present-day human populations, and the generation of a near-complete catalog of genetic changes that swept to high frequency in modern humans since their divergence from Denisovans.
1,690 citations
TL;DR: An overview of the recent surgical intraoperational applications of indocyanine green fluorescence imaging methods, the basics of the technology, and instrumentation used is given.
Abstract: The purpose of this paper is to give an overview of the recent surgical intraoperational applications of indocyanine green fluorescence imaging methods, the basics of the technology, and instrumentation used. Well over 200 papers describing this technique in clinical setting are reviewed. In addition to the surgical applications, other recent medical applications of ICG are briefly examined.
1,000 citations
University of Vienna1, Austrian Academy of Sciences2, Ilia State University3, Slovak Academy of Sciences4, University of Innsbruck5, University of Granada6, Mediterranean Agronomic Institute of Chania7, Norwegian University of Science and Technology8, Russian Academy of Sciences9, University of Molise10, Babeș-Bolyai University11, University of Pavia12, University of Geneva13, University of Parma14, University of Lausanne15, Open University of Cyprus16
TL;DR: In this article, the authors used 867 vegetation samples above the treeline from 60 summit sites in all major European mountain systems to show that ongoing climate change gradually transforms mountain plant communities.
Abstract: Climate impact studies have indicated ecological fingerprints of recent global warming across a wide range of habitats1, 2. Although these studies have shown responses from various local case studies, a coherent large-scale account on temperature-driven changes of biotic communities has been lacking3, 4. Here we use 867 vegetation samples above the treeline from 60 summit sites in all major European mountain systems to show that ongoing climate change gradually transforms mountain plant communities. We provide evidence that the more cold-adapted species decline and the more warm-adapted species increase, a process described here as thermophilization. At the scale of individual mountains this general trend may not be apparent, but at the larger, continental scale we observed a significantly higher abundance of thermophilic species in 2008, compared with 2001. Thermophilization of mountain plant communities mirrors the degree of recent warming and is more pronounced in areas where the temperature increase has been higher. In view of the projected climate change5, 6 the observed transformation suggests a progressive decline of cold mountain habitats and their biota.
943 citations
TL;DR: It is proposed that energy-related biomarkers can be used to determine the conditions when these metabolic transitions occur and thus predict ecological consequences of stress exposures, and assist in explaining and predicting the species' distribution limits in the face of the environmental change and informing the conservation efforts and resource management practices.
940 citations
TL;DR: Measurements of full quantum mechanical probability distributions of matter-wave interference are used to study the relaxation dynamics of a coherently split one-dimensional Bose gas and obtained comprehensive information about the dynamical states of the system.
Abstract: Understanding relaxation processes is an important unsolved problem in many areas of physics. A key challenge is the scarcity of experimental tools for the characterization of complex transient states. We used measurements of full quantum mechanical probability distributions of matter-wave interference to study the relaxation dynamics of a coherently split one-dimensional Bose gas and obtained comprehensive information about the dynamical states of the system. After an initial rapid evolution, the full distributions reveal the approach toward a thermal-like steady state characterized by an effective temperature that is independent from the initial equilibrium temperature of the system before the splitting process. We conjecture that this state can be described through a generalized Gibbs ensemble and associate it with prethermalization.
934 citations
TL;DR: Biological systems are considered that are capable of dynamic self-organization, i.e., spontaneous emergence of spatio-temporal order with the formation of various spatio -temporal patterns.
Abstract: Biological systems are considered that are capable of dynamic self-organization, i.e., spontaneous emergence of spatio-temporal order with the formation of various spatio-temporal patterns. A cell is involved in the organization of ontogenesis of all stages. Embryonic cells exhibit coordinated social behavior and generate ordered morphological patterns displaying variability and equifinality of development. Physical and topological patterns are essential for biological systems as an imperative that restricts and directs biological morphogenesis. Biological self-organization is directed and fixed by natural selection during which selection of the most sustainable, flexible, modular systems capable of adaptive self-organization occurs.
850 citations
TL;DR: The background values of trace elements were dominated by sediment source regions in coal-bearing strata in China as mentioned in this paper, and the genetic types for trace-element enrichment of Chinese coals include source-rock- controlled, marine-environment-controlled, hydrothermal-fluid-controlled (including magmatic-, low-temperature-hydrothermalfluid-, and submarine-exhalation-controlled subtypes), groundwater-controlled and volcanic-ash-controlled.
837 citations
TL;DR: This article showed that glacier shrinkage is most pronounced in peripheral, lower-elevation ranges near the densely populated forelands, where snow and glacial meltwater is essential for water availability.
Abstract: Climate-driven changes in glacier-fed streamflow regimes have direct implications on freshwater supply, irrigation and hydropower potential. Reliable information about current and future glaciation and runoff is crucial for water allocation, a complex task in Central Asia, where the collapse of the Soviet Union has transformed previously interdependent republics into autonomous upstream and downstream countries. Although the impacts of climate change on glaciation and runoff have been addressed in previous work undertaken in the Tien Shan (known as the ‘water tower of Central Asia’), a coherent, regional perspective of these findings has not been presented until now. Here we show that glacier shrinkage is most pronounced in peripheral, lower-elevation ranges near the densely populated forelands, where summers are dry and where snow and glacial meltwater is essential for water availability. Shifts of seasonal runoff maxima have already been observed in some rivers, and it is suggested that summer runoff will further decrease in these rivers if precipitation and discharge from thawing permafrost bodies do not compensate sufficiently for water shortfalls.
723 citations
TL;DR: The results suggest that the crown group dates back to the Carboniferous, ∼309 Ma (95% interval: 291--347 Ma), and diversified into major extant lineages much earlier than previously thought, well before the Triassic.
Abstract: Phylogenies are usually dated by calibrating interior nodes against the fossil record. This relies on indirect methods that, in the worst case, misrepresent the fossil information. Here, we contrast such node dating with an approach that includes fossils along with the extant taxa in a Bayesian total-evidence analysis. As a test case, we focus on the early radiation of the Hymenoptera, mostly documented by poorly preserved impression fossils that are difficult to place phylogenetically. Specifically, we compare node dating using nine calibration points derived from the fossil record with total-evidence dating based on 343 morphological characters scored for 45 fossil (4-20% complete) and 68 extant taxa. In both cases we use molecular data from seven markers (∼5 kb) for the extant taxa. Because it is difficult to model speciation, extinction, sampling, and fossil preservation realistically, we develop a simple uniform prior for clock trees with fossils, and we use relaxed clock models to accommodate rate variation across the tree. Despite considerable uncertainty in the placement of most fossils, we find that they contribute significantly to the estimation of divergence times in the total-evidence analysis. In particular, the posterior distributions on divergence times are less sensitive to prior assumptions and tend to be more precise than in node dating. The total-evidence analysis also shows that four of the seven Hymenoptera calibration points used in node dating are likely to be based on erroneous or doubtful assumptions about the fossil placement. With respect to the early radiation of Hymenoptera, our results suggest that the crown group dates back to the Carboniferous, ∼309 Ma (95% interval: 291-347 Ma), and diversified into major extant lineages much earlier than previously thought, well before the Triassic. (Bayesian inference; fossil dating; morphological evolution; relaxed clock; statistical phylogenetics.)
Harvard University1, Massachusetts Institute of Technology2, University College London3, University of Hong Kong4, Aix-Marseille University5, University of Geneva6, University of Antioquia7, National Scientific and Technical Research Council8, University of Buenos Aires9, Universidade Federal do Rio Grande do Sul10, Federal University of Paraná11, National Autonomous University of Mexico12, Mexican Social Security Institute13, Instituto Politécnico Nacional14, Nestlé15, Universidad Autónoma de Nuevo León16, University of Santiago de Compostela17, Cayetano Heredia University18, University of Chicago19, Russian Academy of Sciences20, Université de Montréal21, University of Costa Rica22, University of Bern23, Swiss Institute of Bioinformatics24, University of Tarapacá25, Paul Sabatier University26, University of California, Berkeley27, Yale University28, Semel Institute for Neuroscience and Human Behavior29
TL;DR: It is shown that the initial peopling followed a southward expansion facilitated by the coast, with sequential population splits and little gene flow after divergence, especially in South America.
Abstract: The peopling of the Americas has been the subject of extensive genetic, archaeological and linguistic research; however, central questions remain unresolved. One contentious issue is whether the settlement occurred by means of a single migration or multiple streams of migration from Siberia. The pattern of dispersals within the Americas is also poorly understood. To address these questions at a higher resolution than was previously possible, we assembled data from 52 Native American and 17 Siberian groups genotyped at 364,470 single nucleotide polymorphisms. Here we show that Native Americans descend from at least three streams of Asian gene flow. Most descend entirely from a single ancestral population that we call 'First American'. However, speakers of Eskimo-Aleut languages from the Arctic inherit almost half their ancestry from a second stream of Asian gene flow, and the Na-Dene-speaking Chipewyan from Canada inherit roughly one-tenth of their ancestry from a third stream. We show that the initial peopling followed a southward expansion facilitated by the coast, with sequential population splits and little gene flow after divergence, especially in South America. A major exception is in Chibchan speakers on both sides of the Panama isthmus, who have ancestry from both North and South America.
Austrian Academy of Sciences1, University of Vienna2, Ilia State University3, Spanish National Research Council4, University of Innsbruck5, University of Granada6, Mediterranean Agronomic Institute of Chania7, Norwegian University of Science and Technology8, Slovak Academy of Sciences9, Russian Academy of Sciences10, University of Molise11, Babeș-Bolyai University12, University of Pavia13, University of Geneva14, University of Parma15, University of Lausanne16
TL;DR: Recent changes in vascular plant species richness observed in a standardized monitoring network across Europe’s major mountain ranges are presented and indicate that high-altitude species, and in particular the rich endemic alpine flora of many Mediterranean mountain ranges, will come under increasing pressure in the predicted warmer and drier climates in this region.
Abstract: In mountainous regions, climate warming is expected to shift species' ranges to higher altitudes. Evidence for such shifts is still mostly from revisitations of historical sites. We present recent (2001 to 2008) changes in vascular plant species richness observed in a standardized monitoring network across Europe's major mountain ranges. Species have moved upslope on average. However, these shifts had opposite effects on the summit floras' species richness in boreal-temperate mountain regions (+3.9 species on average) and Mediterranean mountain regions (-1.4 species), probably because recent climatic trends have decreased the availability of water in the European south. Because Mediterranean mountains are particularly rich in endemic species, a continuation of these trends might shrink the European mountain flora, despite an average increase in summit species richness across the region.
TL;DR: In this article, the authors present data on widespread abnormal accumulations of lanthanides and yttrium (REY) in many coal deposits worldwide, including coal seams and coal ashes, as well as in the host and basement rocks of some coal basins.
TL;DR: Numerically and experimentally a novel mechanism of deterministic magnetization reversal in a ferrimagnet driven by an ultrafast heating of the medium resulting from the absorption of a sub-picosecond laser pulse without the presence of a magnetic field is shown.
Abstract: The question of how, and how fast, magnetization can be reversed is a topic of great practical interest for the manipulation and storage of magnetic information. It is generally accepted that magnetization reversal should be driven by a stimulus represented by time-non-invariant vectors such as a magnetic field, spin-polarized electric current, or cross-product of two oscillating electric fields. However, until now it has been generally assumed that heating alone, not represented as a vector at all, cannot result in a deterministic reversal of magnetization, although it may assist this process. Here we show numerically and demonstrate experimentally a novel mechanism of deterministic magnetization reversal in a ferrimagnet driven by an ultrafast heating of the medium resulting from the absorption of a sub-picosecond laser pulse without the presence of a magnetic field.
TL;DR: The molecular basis of PD appears to be tightly coupled to the aggregation of α-synuclein and the factors that affect its conformation, and the influence of environmental and genetic factors on this process is examined.
TL;DR: It is shown that matching sequences that are no longer able to elicit defense, still guide the CRISPR/Cas acquisition machinery to foreign DNA, thus making the spacer acquisition process adaptive and leading to restoration of CRISpr/Cas-mediated protection.
Abstract: The clustered regularly interspaced short palindromic repeats (CRISPR) system protects prokaryotes from foreign DNA. Here, bacteriophage DNA containing mutations that can circumvent this response are shown to be incorporated into the CRISPR locus, allowing bacteria to remember previous infections in an adaptive manner.
TL;DR: This work demonstrates control over the hierarchical step-growth polymerization of multicompartment micelles into micron-scale segmented supracolloidal polymers as an example of programmable mesoscale colloidal hierarchies via well-defined patchy nanoobjects.
Abstract: Hierarchical self-assembly offers elegant and energy-efficient bottom-up strategies for the structuring of complex materials. For block copolymers, the last decade witnessed great progress in diversifying the structural complexity of solution-based assemblies into multicompartment micelles. However, a general understanding of what governs multicompartment micelle morphologies and polydispersity, and how to manipulate their hierarchical superstructures using straightforward concepts and readily accessible polymers remains unreached. Here we demonstrate how to create homogeneous multicompartment micelles with unprecedented structural control via the intermediate pre-assembly of subunits. This directed self-assembly leads to a step-wise reduction of the degree of conformational freedom and dynamics and avoids undesirable kinetic obstacles during the structure build-up. It yields a general concept for homogeneous populations of well-defined multicompartment micelles with precisely tunable patchiness, while using simple linear ABC triblock terpolymers. We further demonstrate control over the hierarchical step-growth polymerization of multicompartment micelles into micron-scale segmented supracolloidal polymers as an example of programmable mesoscale colloidal hierarchies via well-defined patchy nanoobjects.
TL;DR: It is shown that Cascade efficiently locates target sequences in negatively supercoiled DNA, but only if these are flanked by a protospacer-adjacent motif (PAM), which exclusively involves the crRNA-complementary DNA strand.
TL;DR: In this article, the main types and mechanisms of magnetoelectric interactions and conditions of their origin are discussed, as well as potentially practical materials that display magneto-lectric properties at room temperature.
Abstract: The last decade has witnessed a significant growth of research into materials with coupled magnetic and electric properties. Reviewed here are the main types and mechanisms of magnetoelectric interactions and conditions of their origin. Special attention is given to potentially practical materials that display magnetoelectric properties at room temperature. Example applications of magnetoelectric materials and multiferroics in information and energy saving technologies are discussed.
TL;DR: Four topics are focused on: the current controversy surrounding propagating intensity perturbations along coronal loops, the interpretation of propagating transverse loop oscillations, the ongoing search for coronal (torsional) Alfvén waves, and the rapidly developing topic of quasi-periodic pulsations in solar flares.
Abstract: Recent observations have revealed that magnetohydrodynamic (MHD) waves and oscillations are ubiquitous in the solar atmosphere, with a wide range of periods. We give a brief review of some aspects of MHD waves and coronal seismology that have recently been the focus of intense debate or are newly emerging. In particular, we focus on four topics: (i) the current controversy surrounding propagating intensity perturbations along coronal loops, (ii) the interpretation of propagating transverse loop oscillations, (iii) the ongoing search for coronal (torsional) Alfven waves, and (iv) the rapidly developing topic of quasi-periodic pulsations in solar flares.
TL;DR: The impregnation of the mesoporous metal-organic framework (MOF) MIL-101 by nonvolatile acids H(2)SO(4) and H(3)PO(4), which affords solid materials with potent proton-conducting properties at moderate temperatures, which is critically important for the proper function of on-board automobile fuel cells.
Abstract: The extensive implementation of hydrogen-powered technology today is limited by a number of fundamental problems related to materials research. Fuel-cell hydrogen conversion technology requires proton-conducting materials with high conductivity at intermediate temperatures up to 120 °C. The development of such materials remains challenging because the proton transport of many promising candidates is based on extended microstructures of water molecules, which deteriorate at temperatures above the boiling point. Here we show the impregnation of the mesoporous metal–organic framework (MOF) MIL-101 by nonvolatile acids H2SO4 and H3PO4. Such a simple approach affords solid materials with potent proton-conducting properties at moderate temperatures, which is critically important for the proper function of on-board automobile fuel cells. The proton conductivities of the H2SO4@MIL-101 and H3PO4@MIL-101 at T = 150 °C and low humidity outperform those of any other MOF-based materials and could be compared with the ...
TL;DR: A 2.8-million-year record of Arctic climate is developed using a sediment core from a lake in northeastern Russia that was formed more than 3.5 million years ago by a meteorite impact, suggesting strong interhemispheric climate connectivity.
Abstract: The reliability of Arctic climate predictions is currently hampered by insufficient knowledge of natural climate variability in the past. A sediment core from Lake El'gygytgyn in northeastern (NE) ...
TL;DR: This review summarizes the data on microbial steroid conversion obtained since 2003 and describes methods for enhancement of bioprocess productivity, selectivity of target reactions, and application of microbial transformations for production of valuable pharmaceutical ingredients and precursors.
Abstract: Studies of steroid modifications catalyzed by microbial whole cells represent a well-established research area in white biotechnology. Still, advances over the last decade in genetic and metabolic engineering, whole-cell biocatalysis in non-conventional media, and process monitoring raised research in this field to a new level. This review summarizes the data on microbial steroid conversion obtained since 2003. The key reactions of structural steroid functionalization by microorganisms are highlighted including sterol side-chain degradation, hydroxylation at various positions of the steroid core, and redox reactions. We also describe methods for enhancement of bioprocess productivity, selectivity of target reactions, and application of microbial transformations for production of valuable pharmaceutical ingredients and precursors. Challenges and prospects of whole-cell biocatalysis applications in steroid industry are discussed.
TL;DR: The OFETs and complementary-like inverters are among the best reported organic devices to date, in terms of mobility, voltage gain, symmetry, p-and n-type channel balance, low operating voltage window and high ON/OFF ratio as discussed by the authors.
Abstract: strong intermolecular interactions and with reversible reduction and oxidation reactions characterized by means of optical, electrical, and morphological investigations on thin indigo fi lms. The OFETs and complementary-like inverters are among the best reported organic devices to date, in terms of mobility, voltage gain, symmetry, p- and n-type channel balance, low operating voltage window and high ON/OFF ratio. Moreover, these devices show that high performance electronics can be fabricated entirely from non-toxic, biodegradable, and extremely cheap materials.
TL;DR: The obtained results indicate that the low-frequency noise in combination with other sensing parameters can allow one to achieve the selective gas sensing with a single pristine graphene transistor.
Abstract: We show that vapors of different chemicals produce distinguishably different effects on the low-frequency noise spectra of graphene. It was found in a systematic study that some gases change the electrical resistance of graphene devices without changing their low-frequency noise spectra while other gases modify the noise spectra by inducing Lorentzian components with distinctive features. The characteristic frequency fc of the Lorentzian noise bulges in graphene devices is different for different chemicals and varies from fc = 10–20 Hz to fc = 1300–1600 Hz for tetrahydrofuran and chloroform vapors, respectively. The obtained results indicate that the low-frequency noise in combination with other sensing parameters can allow one to achieve the selective gas sensing with a single pristine graphene transistor. Our method of gas sensing with graphene does not require graphene surface functionalization or fabrication of an array of the devices with each tuned to a certain chemical.
TL;DR: The Double Chooz experiment has observed 8,249 candidate electron antineutrino events in 227.93 live days with 33.71 GW-ton-years (reactor power x detector mass x livetime) exposure using a 10.3 cubic meter fiducial volume detector located at 1050 m from the reactor cores of the Choock nuclear power plant in France as discussed by the authors.
Abstract: The Double Chooz experiment has observed 8,249 candidate electron antineutrino events in 227.93 live days with 33.71 GW-ton-years (reactor power x detector mass x livetime) exposure using a 10.3 cubic meter fiducial volume detector located at 1050 m from the reactor cores of the Chooz nuclear power plant in France. The expectation in case of theta13 = 0 is 8,937 events. The deficit is interpreted as evidence of electron antineutrino disappearance. From a rate plus spectral shape analysis we find sin^2 2{\theta}13 = 0.109 \pm 0.030(stat) \pm 0.025(syst). The data exclude the no-oscillation hypothesis at 99.9% CL (3.1{\sigma}).
TL;DR: In this article, the shape of the spectral distortions caused by energy release due to annihilating dark matter, decaying relict particles, dissipation of acoustic waves, and quasi-instantaneous heating was explicitly computed.
Abstract: The energy spectrum of the cosmic microwave background (CMB) allows us to constrain episodes of energy release in the early Universe. In this paper, we revisit and refine computations of the cosmological thermalization problem. For this purpose a new code, called CosmoTherm, was developed that allows us to solve the coupled photon–electron Boltzmann equation in the expanding, isotropic Universe for a small spectral distortion in the CMB. We explicitly compute the shape of the spectral distortions caused by energy release due to (i) annihilating dark matter; (ii) decaying relict particles; (iii) dissipation of acoustic waves; and (iv) quasi-instantaneous heating. We also demonstrate that (v) the continuous interaction of CMB photons with adiabatically cooling non-relativistic electrons and baryons causes a negativeμ-type CMB spectral distortion of ΔIν/Iν∼ 10−8 in the GHz spectral band. We solve the thermalization problem including improved approximations for the double Compton and Bremsstrahlung emissivities, as well as the latest treatment of the cosmological recombination process. At redshifts z≲ 103, the matter starts to cool significantly below the temperature of the CMB so that at very low frequencies, free–free absorption alters the shape of primordial distortions significantly. In addition, the cooling electrons down-scatter CMB photons, introducing a small late negative y-type distortion at high frequencies. We also discuss our results in the light of the recently proposed CMB experiment PIXIE, for which CosmoTherm should allow detailed forecasting. Our current computations show that for energy injection because of points (ii) and (iv), PIXIE should allow us to improve existing limits, while the CMB distortions caused by the other processes seem to remain unobservable with the currently proposed sensitivities and spectral bands of PIXIE.
University of Bristol1, University of Oregon2, Macquarie University3, Imperial College London4, University of Wyoming5, University of Exeter6, Centre national de la recherche scientifique7, Osaka City University8, University of Wisconsin-Madison9, University of New South Wales10, American Museum of Natural History11, Australian National University12, University of Bern13, Slovenian Academy of Sciences and Arts14, Sofia University15, University of Göttingen16, University of Montpellier17, Canadian Forest Service18, Geological Survey of Denmark and Greenland19, University of Newcastle20, École Polytechnique Fédérale de Lausanne21, Monash University22, Australian Nuclear Science and Technology Organisation23, University of Bremen24, UPRRP College of Natural Sciences25, University of Calgary26, University of Tennessee27, University of Cologne28, Virginia Tech29, Russian Academy of Sciences30, University of Wisconsin–Oshkosh31, Sapienza University of Rome32, Katholieke Universiteit Leuven33, University of Chile34, University of Queensland35, University of Münster36, University of the Witwatersrand37, Stockholm University38, Laval University39, University of Franche-Comté40, Geode41, University of Plymouth42, Fordham University43, University of the Free State44, Kyoto Prefectural University45, University of Orléans46, University of Kansas47, University of Geneva48, Central Washington University49, Chinese Academy of Sciences50
TL;DR: This article analyzed sedimentary charcoal records to show that the changes in fire regime over the past 21,000 yrs are predictable from changes in regional climates and showed that fire increases monotonically with changes in temperature and peaks at intermediate moisture levels.
Abstract: Climate is an important control on biomass burning, but the sensitivity of fire to changes in temperature and moisture balance has not been quantified. We analyze sedimentary charcoal records to show that the changes in fire regime over the past 21,000 yrs are predictable from changes in regional climates. Analyses of paleo- fire data show that fire increases monotonically with changes in temperature and peaks at intermediate moisture levels, and that temperature is quantitatively the most important driver of changes in biomass burning over the past 21,000 yrs. Given that a similar relationship between climate drivers and fire emerges from analyses of the interannual variability in biomass burning shown by remote-sensing observations of month-by-month burnt area between 1996 and 2008, our results signal a serious cause for concern in the face of continuing global warming.