DNA Rereplication Is Susceptible to Nucleotide-Level Mutagenesis.

The sources of genome instability, a hallmark of cancer, remain incompletely understood. One potential source is DNA rereplication, which arises when the mechanisms that prevent the reinitiation of replication origins within a single cell cycle are compromised. Using the budding yeast Saccharomyces cerevisiae, we previously showed that DNA rereplication is extremely potent at inducing gross chromosomal alterations and that this arises in part because of the susceptibility of rereplication forks to break. Here, we examine the ability of DNA rereplication to induce nucleotide-level mutations. During normal replication these mutations are restricted by three overlapping error-avoidance mechanisms: the nucleotide selectivity of replicative polymerases, their proofreading activity, and mismatch repair. Using lys2InsEA14 , a frameshift reporter that is poorly proofread, we show that rereplication induces up to a 30× higher rate of frameshift mutations and that this mutagenesis is due to passage of the rereplication fork, not secondary to rereplication fork breakage. Rereplication can also induce comparable rates of frameshift and base-substitution mutations in a more general mutagenesis reporter CAN1, when the proofreading activity of DNA polymerase ε is inactivated. Finally, we show that the rereplication-induced mutagenesis of both lys2InsEA14 and CAN1 disappears in the absence of mismatch repair. These results suggest that mismatch repair is attenuated during rereplication, although at most sequences DNA polymerase proofreading provides enough error correction to mitigate the mutagenic consequences. Thus, rereplication can facilitate nucleotide-level mutagenesis in addition to inducing gross chromosomal alterations, broadening its potential role in genome instability

Approximate expression for the dynamic structure factor in the Lieb-Liniger model

Recently, Imambekov and Glazman [Phys. Rev. Lett. 100, 206805 (2008)] showed that the dynamic structure factor (DSF) of the 1D Bose gas demonstrates power-law behaviour along the limiting dispersion curve of the collective modes and calculated the corresponding exponents exactly. Combining these recent results with a previously obtained strong-coupling expansion we present an interpolation formula for the DSF of the 1D Bose gas. The obtained expression is further consistent with exact low energy exponents from Luttinger liquid theory and shows nice agreement with recent numerical results.Comment: 4 pages, 3 figure

From gamma ray line signals of dark matter to the LHC

We explore the relationship between astrophysical gamma-ray signals and LHC signatures for a class of phenomenologically successful secluded dark matter models, motivated by recent evidence for a ~130 GeV gamma-ray line. We consider in detail scenarios in which interactions between the dark sector and the standard model are mediated by a vev-less scalar field \phi, transforming as an N-plet (N > 3) under SU(2)_L. Since some of the component fields of \phi carry large electric charges, loop induced dark matter annihilation to \gamma \gamma and \gamma Z can be enhanced without the need for non-perturbatively large couplings, and without overproduction of continuum gamma-rays from other final states. We discuss prospects for other experimental tests, including dark matter-nucleon scattering and production of \phi at the LHC, where future searches for anomalous charged tracks may be sensitive. The first LHC hints could come from the Higgs sector, where loop corrections involving \phi lead to significantly modified h to \gamma \gamma and h to \gamma Z branching ratios.Comment: 27 pages, 10 figures. v2: added references, fixed import-order issue with cleveref and hyperref. v3: updated to journal version. v4: erratum correction to figs. 7-8 for monojet/monophoton cross-section

The course of research into the economic consequences of German works councils

In a recent survey, Frege (2002) concludes that economic analysis of the works council has reached a `dead end´. The present treatment offers a different conclusion based on a more encompassing review of the evidence. It will identify three distinct phases in the economic analysis of codetermination at the workplace. While Frege just considered studies from the first two phases, it is the third phase of research that contains some of the most positive evaluations to date of works council impact. Even if such estimates appear much exaggerated and the effect of works councils is likely to be small on average, the new literature redirects our research effort towards the factors that produce swings around this average, including differences in works council types and their workplace environments. -- In einem jüngst veröffentlichten Überblicksartikel kommt Frege (2002) zu dem Schluss, die ökonomische Analyse des Betriebsrats sei in eine Sackgasse geraten. Die vorliegende Arbeit zieht ein anderes Fazit, das auf einer umfassenderen Betrachtung der empirischen Evidenz beruht. Dabei werden drei Phasen der ökonomischen Analyse der betrieblichen Mitbestimmung unterschieden. Während Frege nur Studien aus den ersten beiden Phasen berücksichtigte, ist es gerade die dritte Forschungsphase, die einige der positivsten Bewertungen von Betriebsräten enthält. Selbst wenn derartige Einschätzungen stark übertrieben erscheinen und der Betriebsratseffekt im Durchschnitt relativ gering sein dürfte, weist die neuere Literatur darauf hin, dass unsere Forschungsbemühungen sich stärker auf Faktoren konzentrieren sollten, die Schwankungen um diesen Durchschnitt hervorrufen (wie z.B. unterschiedliche Typen von Betriebsräten und deren Arbeitsplatzumgebung).Works council,codetermination,Germany

Extreme morphologies of mantis shrimp larvae

Larvae of stomatopods (mantis shrimps) are generally categorized into four larval types: antizoea, pseudozoea (both representing early larval stages), alima and erichthus (the latter two representing later larval stages). These categories, however, do not reflect the existing morphological diversity of stomatopod larvae, which is largely unstudied. We describe here four previously unknown larval types with extreme morphologies. All specimens were found in the collections of the Zoological Museum, University of Copenhagen and were collected during the Danish Dana Expedition round the world 1928-30. These new larval types all represent erichthus-type larvae, especially differing in their shield morphologies. The shield morphology ranges from almost spherical to rather disc-like, with sometimes extremely elongated spines, but only a general systematic assignment of the larvae was possible. Further investigations of these larvae are crucial to understand their life habits and ecological impact, especially as stomatopod and other crustacean larvae might have a much more important position in the marine ecosystems than their corresponding adults

The (Parlous) State of German Unions

This paper traces the profound decline in German unionism over the course of the last three decades. Today just one in five workers is a union member, and it is now moot whether this degree of penetration is consistent with a corporatist model built on encompassing unions. The decline in union membership and density is attributable to external forces that have confronted unions in many countries (such as globalization and compositional changes in the workforce) and to some specifically German considerations (such as the transition process in postcommunist Eastern Germany) and sustained intervals of classic insider behavior on the part of German unions. The ‘correctives’ have included mergers between unions, decentralization, and wages that are more responsive to unemployment. At issue is the success of these innovations. For instance, the trend toward decentralization in collective bargaining hinges in part on the health of that other pillar of the dual system of industrial relations, the works council. But works council coverage has also declined, leading some observers to equate decentralization with deregulation. While this conclusion is likely too radical, German unions are at the cross roads. It is argued here that if they fail to define what they stand for, are unable to increase their presence at the workplace, and continue to lack convincing strategies to deal with contemporary economic and political trends working against them, then their decline may become a rout.

Excitable human dynamics driven by extrinsic events in massive communities

Using empirical data from a social media site (Twitter) and on trading volumes of financial securities, we analyze the correlated human activity in massive social organizations. The activity, typically excited by real-world events and measured by the occurrence rate of international brand names and trading volumes, is characterized by intermittent fluctuations with bursts of high activity separated by quiescent periods. These fluctuations are broadly distributed with an inverse cubic tail and have long-range temporal correlations with a $1/f$ power spectrum. We describe the activity by a stochastic point process and derive the distribution of activity levels from the corresponding stochastic differential equation. The distribution and the corresponding power spectrum are fully consistent with the empirical observations.Comment: 9 pages, 3 figure