Isoperimetric inequalities vs. upper curvature bounds

The Dehn function of a metric space measures the area necessary in order to fill a closed curve of controlled length by a disc. As a main result, we prove that a length space has curvature bounded above by $\kappa$ in the sense of Alexandrov if and only if its Dehn function is bounded above by the Dehn function of the model surface of constant curvature $\kappa$. This extends work of Lytchak and the second author from locally compact spaces to the general case. A key ingredient in the proof is the construction of minimal discs with suitable properties in certain ultralimits. Our arguments also yield quantitative local and stable versions of our main result. The latter has implications on the geometry of asymptotic cones

ISSP 1999 Germany: Social Inequality III ; ZUMA report on the German study

ZUMA erstellt englischsprachige Berichte über die Implementation der ISSP-Untersuchungen in Deutschland, um Nutzer aus dem Ausland mit Basisinformationen über die einzelnen Untersuchungen zu versorgen. ISSP geht in Deutschland zusammen mit dem deutschen SSP (ALLBUS) ins Feld. Für ALLBUS/ISSP liegen detaillierte Methodenberichte in deutsch vor. Die einzelnen ISSP-Berichte schließen relevante Informationen für Vergleichsstudien ein (Details für Items im Laufe der Jahre, Details zur Feldforschung in anderen Ländern), die für die Nutzer der deutschen ALLBUS/ISSP-Daten weniger wichtig sind und daher vom deutschen Bericht nicht abgedeckt werden. Die in den ISSP-Berichten beschriebenen Details über Stichproben und Feldphase liegen zwischen dem, was in den längeren ALLBUS/ISSP-Berichten enthalten ist, und den tabellarischen Übersichten in den ISSP-Untersuchungsbeschreibungen und den ISSP-Monitoring-Berichten, die zusammen mit den ISSP-Datensätzen auf der Website des Zentralarchivs verfügbar sind. (ICEÜbers)"ZUMA produces English reports on the German implementations of ISSP studies to provide non-German users with basic information about each study. The German ISSP is now fielded together with the German GSS (ALLBUS) and detailed methods reports for the ALLBUS/ ISSP studies are available in German. The individual ISSP reports include information relevant for those conducting comparative analyses (e.g. details of items across years, details of other countries fielding) of less relevance for users of the German ALLBUS/ ISSP data set and thus not covered in the German report. The detail provided in the ISSP reports on aspects such as sampling and fielding lies between that of the longer ALLBUS/ ISSP reports and the information available in tabular form in the ISSP Study Descriptions and the ISSP Study Monitoring reports that are published with ISSP merged data sets on the Central Archive web pages." (author's abstract

ISSP 2000 Germany: Environment II ; ZUMA report on the German study

ZUMA erstellt englischsprachige Berichte über die Implementation der ISSP-Untersuchungen in Deutschland, um Nutzer aus dem Ausland mit Basisinformationen über die einzelnen Untersuchungen zu versorgen. ISSP geht in Deutschland zusammen mit dem deutschen SSP (ALLBUS) ins Feld. Für ALLBUS/ISSP liegen detaillierte Methodenberichte in deutsch vor. Die einzelnen ISSP-Berichte schließen relevante Informationen für Vergleichsstudien ein (Details für Items im Laufe der Jahre, Details zur Feldforschung in anderen Ländern), die für die Nutzer der deutschen ALLBUS/ISSP-Daten weniger wichtig sind und daher vom deutschen Bericht nicht abgedeckt werden. Die in den ISSP-Berichten beschriebenen Details über Stichproben und Feldphase liegen zwischen dem, was in den längeren ALLBUS/ISSP-Berichten enthalten ist, und den tabellarischen Übersichten in den ISSP-Untersuchungsbeschreibungen und den ISSP-Monitoring-Berichten, die zusammen mit den ISSP-Datensätzen auf der Website des Zentralarchivs verfügbar sind. (ICEÜbers)"ZUMA produces English reports on the German implementations of ISSP studies to provide non-German users with basic information about each study. The German ISSP is now fielded together with the German GSS (ALLBUS) and detailed methods reports for the ALLBUS/ ISSP studies are available in German. The individual ISSP reports include information relevant for those conducting comparative analyses (e.g. details of items across years, details of other countries fielding) of less relevance for users of the German ALLBUS/ ISSP data set and thus not covered in the German report. The detail provided in the ISSP reports on aspects such as sampling and fielding lies between that of the longer ALLBUS/ ISSP reports and the information available in tabular form in the ISSP Study Descriptions and the ISSP Study Monitoring reports that are published with ISSP merged data sets on the Central Archive web pages." (author's abstract

Every atom-atom map can be explained by electron pushing diagrams

Chemical reactions can be understood as transformations of multigraphs (molecules) that preserve vertex labels (atoms) and degrees (sums of bonding and non-bonding electrons), thereby implying the atom-atom map of a reaction. The corresponding reaction mechanism is often described by an electron pushing diagram that explains the transformation by consecutive local relocations of invidudal edges (electron pairs). Here, we show that every degree-preserving map between multigraphs, and thus every atom-atom map, can be generated by cyclic electron pushing. Moreover, it is always possible to decompose such an explanation into electron pushing diagrams involving only four electron pairs. This in turn implies that every reaction can be decomposed into a sequence of elementary reactions that involve at most two educt molecules and two product molecules. Hence, the requirement of a mechanistic explantion in terms of electron pushing and small imaginary transition states does not impose a combinatorial constraint on the feasibility of hypothetical chemical reactions

The prognostic value of DLCO and pulmonary blood flow in patients with pulmonary hypertension

Background Cardiac output is a prognostic marker in patients with pulmonary hypertension. Pulmonary blood flow as a surrogate for cardiac output can be measured non-invasively by inert gas rebreathing. We hypothesized that pulmonary blood flow can predict outcome in patients with pulmonary hypertension. Methods From January 2009 to January 2012, we measured pulmonary blood flow by inert gas rebreathing in outpatients with pulmonary hypertension. Patients with pulmonary hypertension confirmed by right heart catheterization and a valid inert gas rebreathing maneuver were followed until January 2016. The investigated outcome was all-cause mortality. Results We included 259 patients (mean age 65 +/- 13 years, 53% female) with pulmonary hypertension and classified into groups 1 (n = 103), 2 (n = 26), 3 (n = 80), and 4 (n = 50) according to the current pulmonary hypertension classification system. The median time between pulmonary hypertension diagnosis and inert gas rebreathing was 9 (IQR 0; 36) months. During a median follow-up time of 51 (IQR 20; 68) months, 109 patients (42%) died. Parameters significantly associated with survival (in order of decreasing statistical strength) were diffusion capacity of the lung for carbon monoxide (DLCO), 6-minute walk distance (6-MWD), age, NTpro-BNP, WHO functional class, group 3 pulmonary hypertension, and tricuspid annular plane systolic excursion (TAPSE), while baseline hemodynamics and pulmonary blood flow were not. In multivariable Cox regression analysis, DLCO, age, 6-MWD, and TAPSE remained significant and independent predictors of the outcome. DLCO as the strongest parameter also significantly predicted survival in aetiological subgroups except for group 4. Conclusions DLCO is a strong and independent predictor for survival in patients with pulmonary hypertension of different aetiologies, while pulmonary blood flow measured by inert gas rebreathing is not

SMB Operation for Three-Fraction Separations: Purification of Plasmid DNA

The Simulated Moving Bed technology is extended to incorporate a cleaning in place step, and it is then applied by exploiting size exclusion chromatography to purify plasmid DNA. Experimental performances are discussed in the light of our theoretical understanding of the SMB behavio

Centers of complex networks

The central vertices in complex networks are of particular interest because they might play the role of organizational hubs. Here, we consider three different geometric centrality measures, excentricity, status, and centroid value, that were originally used in the context of resource placement problems. We show that these quantities lead to useful descriptions of the centers of biological networks which often, but not always, correlate with a purely local notion of centrality such as the vertex degree. We introduce the notion of local centers as local optima of a centrality value “landscape” on a network and discuss briefly their role

Engineering of a conditional allele reveals multiple roles of XRN2 in Caenorhabditis elegans development and substrate specificity in microRNA turnover

Although XRN2 proteins are highly conserved eukaryotic 5′→3′ exonucleases, little is known about their function in animals. Here, we characterize Caenorhabditis elegans XRN2, which we find to be a broadly and constitutively expressed nuclear protein. An xrn-2 null mutation or loss of XRN2 catalytic activity causes a molting defect and early larval arrest. However, by generating a conditionally mutant xrn-2ts strain de novo through an approach that may be also applicable to other genes of interest, we reveal further functions in fertility, during embryogenesis and during additional larval stages. Consistent with the known role of XRN2 in controlling microRNA (miRNA) levels, we can demonstrate that loss of XRN2 activity stabilizes some rapidly decaying miRNAs. Surprisingly, however, other miRNAs continue to decay rapidly in xrn-2ts animals. Thus, XRN2 has unanticipated miRNA specificity in vivo, and its diverse developmental functions may relate to distinct substrates. Finally, our global analysis of miRNA stability during larval stage 1 reveals that miRNA passenger strands (miR*s) are substantially less stable than guide strands (miRs), supporting the notion that the former are mostly byproducts of biogenesis rather than a less abundant functional specie