Cohomological finiteness conditions for a class of metabelian groups

We consider a class of metabelian groups first studied by Baumslag and Stammbach and we show that these groups are consistent with the Bieri-Groves conjecture which relates cohomological finiteness conditions to the Bieri-Neumann-Strebel sigma invariant.Comment: 10 pages Accepted for publication in the Bulletin of the London Mathematical Societ

Hermetically-sealing seawater sampler

This paper describes a device that seals samples of seawater in situ in an aluminum or copper tube in millimeter quantities such that the dissolved gases are retained and can be transferred to vacuum systems without either the loss of the contained gases or the introduction of air. The instrument has been tested to depths of 4000 m in the open ocean under modestly harsh conditions

Hydrocarbons identified in extracts from estuarine water accommodated no. 2 fuel oil by gas chromatography-mass spectrometry

Results are presented on a computerized gas chromatograph-mass spectrometer analysis of methylene chloride and n-heptane extracts of a No. 2 fuel oil accommodated estuarine water sample. The analytical method is briefly described, and the limitations on the identifications are categorized. Some attempt was made to determine major and trace constituents in the water accommodate. Altogether 66 hydrocarbon compounds were identified specifically, and 75 compounds were partially identified. Seven compounds could be recognized as major constituents of the water accommodated oil and ten were present only as traces. The aromatic compounds found were alkyl benzenes, naphthalene, tetralin, indane, biphenyl, fluorene, anthracene, and some of their alkyl substituted isomers in the range of carbon numbers C7 to C15. Four n-alkanes, C10 to C13, were found along with four other assorted hydrocarbons

Trace elements in the pelagic coelenterate, Velella lata

Twelve elements (Cu, Ni, Mn, Ti, Si, Cr, Sr, V, Ba, Ag, Pb, and Mo), not previously reported from the genus Velella, were found in the ash of V. lata; zirconium was also searched for but was not found. Cu, Ni, Mn, Ti, Mg, Ca, and Al were determined quantitatively. The concentration of trace elements in the whole animal and in five different tissues of V. lata was determined in specimens ranging from 14.4 to 84.6 mm in length. The Mg:Ca ratio in Velella is lower than that in sea water but. higher than that in Scyphozoa. Presumably this is due to concentration of magnesium in the chlorophyll of commensal zooxanthellae

Amidoschwarz10B in der forensischen Spurenuntersuchung: Vergleichende Untersuchungen an forensischem Spurenmaterial

Zusammenfassung: Blutspuren gehören zu den aussagekräftigsten Spuren in der forensischen Fallanalyse. Einerseits kann die Beurteilung von Aussehen, Menge, Form und Verteilung an Tatorten Hinweise auf den Tathergang geben. Andererseits lassen sich heute auch aus kleinsten Blutmengen zumeist vollständige DNA-Profile erstellen, die dann ebenfalls eine Rekonstruktion des Tatablaufs und über die molekulargenetische DNA-Analyse Aussagen zur Tatbeteiligung von Personen ermöglichen. In der vorgestellten Studie wurden Vollblutproben auf unterschiedliche Spurenträger aufgebracht und mithilfe des Hexagon OBTI® auf das Vorhandensein von Blut hin untersucht. Nach Inkubation mit 2 verschiedenen Zubereitungen von Amidoschwarz10B konnte gezeigt werden, dass dessen Einsatz zu starken Beeinträchtigungen bzw. falsch-negativen Ergebnissen des OBTI führen kann. Ein negativer Einfluss von Amidoschwarz10B auf das Probenmaterial war hingegen bei den nachfolgend durchgeführten DNA-Analysen nicht festzustelle

Finding largest small polygons with GloptiPoly

A small polygon is a convex polygon of unit diameter. We are interested in small polygons which have the largest area for a given number of vertices $n$. Many instances are already solved in the literature, namely for all odd $n$, and for $n=4, 6$ and 8. Thus, for even $n\geq 10$, instances of this problem remain open. Finding those largest small polygons can be formulated as nonconvex quadratic programming problems which can challenge state-of-the-art global optimization algorithms. We show that a recently developed technique for global polynomial optimization, based on a semidefinite programming approach to the generalized problem of moments and implemented in the public-domain Matlab package GloptiPoly, can successfully find largest small polygons for $n=10$ and $n=12$. Therefore this significantly improves existing results in the domain. When coupled with accurate convex conic solvers, GloptiPoly can provide numerical guarantees of global optimality, as well as rigorous guarantees relying on interval arithmetic

The chameleon groups of Richard J. Thompson: automorphisms and dynamics

The automorphism groups of several of Thompson's countable groups of piecewise linear homeomorphisms of the line and circle are computed and it is shown that the outer automorphism groups of these groups are relatively small. These results can be interpreted as stability results for certain structures of PL functions on the circle. Machinery is developed to relate the structures on the circle to corresponding structures on the line

Organic compounds in surface sediments and oyster tissues from the Chesapeake Bay

This report contains three parts. In Part I, the methodology to extract and analyze sediment and oyster tissue samples from the Chesapeake Bay is described in detail. Remaining problems are clearly identified. Part II contains the results and their discussion. Part III contains a number of appendices with detailed data. For those readers interested in still more detail, the complete bank of processed data is on computer tapes at this institute and at the Environmental Protection Agency-Chesapeake Bay Program office at Annapolis, Maryland. Also included in Part III we give the results of volatile halogenated organic compounds determined in water collected near the outfalls of several chlorine using facilities as well as from river mouths. The distribution of the total and a few specific organic compounds within the Bay is presented by histograms. Mass spectrometric analyses clearly reveal the fact that one specific class of organic compounds, hydrocarbons, are the most prominent pollutants in the Bay. The application of two different search routines, one concentrating on compounds at levels \u3e50 ppb and the other on temporal changes, allows a quick determination of areas where problems may exist and where additional research may be indicated. Two unusual sediment samples collected during the fall 1979 cruise are discussed separately: Sample 2-19-S which clearly indicates a recent dumping of DDT and polychlorinated biphenyls, and Sample 2-27-S which contained very high concentrations of unsubstituted polynuclear aromatics