Dichromatic polynomials and Potts models summed over rooted maps

We consider the sum of dichromatic polynomials over non-separable rooted planar maps, an interesting special case of which is the enumeration of such maps. We present some known results and derive new ones. The general problem is equivalent to the $q$-state Potts model randomized over such maps. Like the regular ferromagnetic lattice models, it has a first-order transition when $q$ is greater than a critical value $q_c$, but $q_c$ is much larger - about 72 instead of 4.Comment: 29 pages, three figures changes in App D, introduction and acknowledgement

Origins of the Ambient Solar Wind: Implications for Space Weather

The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress -- in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue connected with a 2016 ISSI workshop on "The Scientific Foundations of Space Weather." 44 pages, 9 figure

Collisional and Radiative Processes in Optically Thin Plasmas

Most of our knowledge of the physical processes in distant plasmas is obtained through measurement of the radiation they produce. Here we provide an overview of the main collisional and radiative processes and examples of diagnostics relevant to the microphysical processes in the plasma. Many analyses assume a time-steady plasma with ion populations in equilibrium with the local temperature and Maxwellian distributions of particle velocities, but these assumptions are easily violated in many cases. We consider these departures from equilibrium and possible diagnostics in detail

periscope: sub-genomic RNA identification in SARS-CoV-2 genomic sequencing data

We have developed periscope, a tool for the detection and quantification of sub-genomic RNA (sgRNA) in SARS-CoV-2 genomic sequence data. The translation of the SARS-CoV-2 RNA genome for most open reading frames (ORFs) occurs via RNA intermediates termed “sub-genomic RNAs”. sgRNAs are produced through discontinuous transcription which relies on homology between transcription regulatory sequences (TRS-B) upstream of the ORF start codons and that of the TRS-L which is located in the 5’ UTR. TRS-L is immediately preceded by a leader sequence. This leader sequence is therefore found at the 5’ end of all sgRNA. We applied periscope to 1,155 SARS-CoV-2 genomes from Sheffield, UK and validated our findings using orthogonal datasets and in vitro cell systems. Using a simple local alignment to detect reads which contain the leader sequence we were able to identify and quantify reads arising from canonical and non-canonical sgRNA. We were able to detect all canonical sgRNAs at expected abundances, with the exception of ORF10. A number of recurrent non-canonical sgRNAs are detected. We show that the results are reproducible using technical replicates and determine the optimum number of reads for sgRNA analysis. In VeroE6 ACE2+/− cell lines, periscope can detect the changes in the kinetics of sgRNA in orthogonal sequencing datasets. Finally, variants found in genomic RNA are transmitted to sgRNAs with high fidelity in most cases. This tool can be applied to all sequenced COVID-19 samples worldwide to provide comprehensive analysis of SARS-CoV-2 sgRNA

The present and future of QCD

This White Paper presents an overview of the current status and future perspective of QCD research, based on the community inputs and scientific conclusions from the 2022 Hot and Cold QCD Town Meeting. We present the progress made in the last decade toward a deep understanding of both the fundamental structure of the sub-atomic matter of nucleon and nucleus in cold QCD, and the hot QCD matter in heavy ion collisions. We identify key questions of QCD research and plausible paths to obtaining answers to those questions in the near future, hence defining priorities of our research over the coming decades

Oekologischer Zustand und Stabilitaet von Flussseen von Spree und Dahme und ihre Reaktionen auf Belastungsaenderungen Abschlussbericht

A comparative investigation of the polymictic lakes in the area of the rivers Spree and Dahme, ''Grosser Mueggelsee'', ''Seddinsee'' and ''Langer See'', and of the ''Flakensee'', situated in a secondary catchment area, with hydrochemical regards (main nutrients P, N, Si), hydrophysical regards (O2, pH, radiation, temperature), and hydrobiological regards (phytoplankton, zooplankton, macrophytobenthos, macrozoobenthos, fish spawn) was carried out during the period from March to December in both 1992 and 1993. The phytoplankton, zooplankton, makrozoobenthos and fish spawn were characterized as to their structure and performance parameters. A single mapping of the macrophytobenthos in a total of 12 river bank transects was carried out. The most important results are presented in the form of annual curves of the main parameters describing the condition of the lakes, and analysed as to their importance for the condition of the lakes and their functional connection with the catchment area (external and internal budgets of P and N). Methodologically new approaches for the characterization of important indicators of ecosystemal functions were developed and tested as to their biological indicating valency (pigments specific to groups of algae, zytophotometric determination of pigment contents in blue algae and diatoms, heterocyst frequency, amino acid contents in Phragmites australis as an indicator of N supply and rhizome aeration, algae-specific grazing rates). The validity of known models for describing the condition of rivers and lakes was verified regarding these lakes. Important ecological steering quantities for the water condition of lakes with different flow rates were worked out. (orig.)Es wurden die im Spree-Dahme-Flussgebiet liegenden polymiktischen Seen Grosser Mueggelsee, Seddinsee und Langer See sowie der in einem Nebeneinzugsgebiet gelegene Flakensee nach hydrochemischen (Hauptnaehrstoffe P, N, Si) und hydrophysikalischen (O2, pH, Strahlung, Temperatur) und hydrobiologischen Kriterien (Phytoplankton, Zooplankton, Makrophytobenthos, Makrozoobenthos, Gelegeguerte) im Jahresgang 1992 und 1993 von Maerz bis Dezember vergleichend untersucht. Phytoplankton, Zooplankton, Makrozoobenthos sowie der Gelegeguerte wurden nach Struktur und Leistungsparametern charakterisiert. Das Makrophytobenthos wurde einmalig an insgesamt 12 Uferquertrassekten kartiert. Die wesentlichen Ergebnisse werden in Form von Jahresgaengen der wichtigsten Beschaffenheitsparameter dargestellt und hinsichtlich ihrer Bedeutung fuer den Zustand der Seen sowie ihre funktionelle Verknuepfung mit dem Einzugsgebiet (Externe und interne Bilanzen fuer P und N) analysiert. Dabei wurden auch neue methodische Ansaetze zur Charakterisierung wichtiger oekosystemarer Funktionstraeger entwickelt und hinsichtlich ihrer bioindikatorischen Valenz ueberprueft (algengruppenspezifische Pigmente, zytophotometrische Bestimmung der Pigmentgehalte bei Blaualgen und Kieselalgen, Heterocystenfrequenz, Aminosaeuregehalte bei Phragmites australis zur Indikation der N-Versorgung und der Belueftung des Rhizomes, algenspezifische Grazingraten). Die Gueltigkeit bekannter Modelle zur Beschreibung des Gewaesserzustandes hinsichtlich dieser Seen wurde ueberprueft. Es konnten wichtige oekologische Steuergroessen fuer die Wasserbeschaffenheit unterschiedlich stark durchflossener Seen herausgearbeitet werden. (orig.)SIGLEAvailable from TIB Hannover: F95B2129 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman