113 research outputs found
Ultra-low Q values for neutrino mass measurements
We investigate weak nuclear decays with extremely small kinetic energy
release (Q value) and thus extremely good sensitivity to the absolute neutrino
mass scale. In particular, we consider decays into excited daughter states, and
we show that partial ionization of the parent atom can help to tune Q values to
<< 1 keV. We discuss several candidate isotopes undergoing beta+, beta-, bound
state beta, or electron capture decay, and come to the conclusion that a
neutrino mass measurement using low-Q decays might only be feasible if no
ionization is required, and if future improvements in isotope production
technology, nuclear mass spectroscopy, and atomic structure calculations are
possible. Experiments using ions, however, are extremely challenging due to the
large number of ions that must be stored. New precision data on nuclear
excitation levels could help to identify further isotopes with low-Q decay
modes and possibly less challenging requirements.Comment: 7 pages, 2 figures; v2: Typos corrected, references adde
Is a stock overfished if it is depleted by overfishing? A response to the rebuttal of Agnew et al. to Froese and Proelss âEvaluation and legal assessment of certified seafoodâ
This contribution is a response to the rebuttal of Agnew et al. (2012) to Froese and Proelss (2012) âEvaluation and legal assessment of certified seafoodâ. It corrects some factually wrong statements in the rebuttal, revisits the definitions of âdepletedâ and âoverfishedâ, and notes that the rebuttal agrees with the international definition of âoverfishingâ (F>FMSY) that was used by Froese and Proelss (2012). The rebuttal presents an analysis of 45 MSC-certified stocks. Of these, 27% are âdepletedâ (according to the definition used by MSC) or âoverfishedâ (according to the definition used by Froese and Proelss 2012) and 16% are subject to âoverfishingâ, basically confirming the critique of Froese and Proelss (2012). This response concludes that MSC has to change its rules for certification such that (1) overfishing is not allowed and (2) âdepletedâ stocks are marked as such. ĂąÂș This paper confirms previous definitions of âoverfishingâ and âoverfishedâ. ĂąÂș It notes that MSC-certified fisheries may engage in overfishing. ĂąÂș It notes that MSC acknowledges ongoing overfishing in 16% of certified stocks. ĂąÂș It notes that MSC acknowledges that 27% of certified stocks are depleted
Evaluation and Legal Assessment of Certified Seafood
This study presents a legal review of international treaties to derive sound definitions of overfishing. It examines seafood stocks that were certified by the Marine Stewardship Council (MSC) or Friend of the Sea (FOS). Stock size and fishing pressure were compared with the internationally agreed reference points which both organizations have accepted. No suitable status information was found for 11% (MSC) to 53% (FOS) of the certified stocks. For the stocks with available status information, 19% (FOS) to 31% (MSC) had overfished stock sizes and were subject to ongoing overfishing. An analysis of legal implications of certification of overfished stocks suggests that a certifying body cannot be held liable for a violation of internationally agreed standards unless the domestic law of its home country so regulates. States may ban the import of fish products from overfished stocks, but only in very specific cases. Possible causes for the certification of overfished stocks are discussed and recommendations are given on how the certifiers could improve their performance. The study concludes that it is still reasonable to buy certified seafood, because the percentage of moderately exploited, healthy stocks is 3-4 times higher in certified than in non-certified seafood
Persistence of Anderson localization in Schr\"odinger operators with decaying random potentials
We show persistence of both Anderson and dynamical localization in
Schr\"odinger operators with non-positive (attractive) random decaying
potential. We consider an Anderson-type Schr\"odinger operator with a
non-positive ergodic random potential, and multiply the random potential by a
decaying envelope function. If the envelope function decays slower than
at infinity, we prove that the operator has infinitely many
eigenvalues below zero. For envelopes decaying as at infinity,
we determine the number of bound states below a given energy ,
asymptotically as . To show that bound states located at
the bottom of the spectrum are related to the phenomenon of Anderson
localization in the corresponding ergodic model, we prove: (a) these states are
exponentially localized with a localization length that is uniform in the decay
exponent ; (b)~ dynamical localization holds uniformly in
A critical appraisal of appendage disparity and homology in fishes
Fishes are both extremely diverse and morphologically disparate. Part of this disparity can be observed in the numerous possible fin configurations that may differ in terms of the number of fins as well as fin shapes, sizes and relative positions on the body. Here, we thoroughly review the major patterns of disparity in fin configurations for each major group of fishes and discuss how median and paired fin homologies have been interpreted over time. When taking into account the entire span of fish diversity, including both extant and fossil taxa, the disparity in fin morphologies greatly complicates inferring homologies for individual fins. Given the phylogenetic scope of this review, structural and topological criteria appear to be the most useful indicators of fin identity. We further suggest that it may be advantageous to consider some of these fin homologies as nested within the larger framework of homologous finâforming morphogenetic fields. We also discuss scenarios of appendage evolution and suggest that modularity may have played a key role in appendage disparification. Fin modules reâexpressed within the boundaries of finâforming fields could explain how some fins may have evolved numerous times independently in separate lineages (e.g., adipose fin), or how new fins may have evolved over time (e.g., anterior and posterior dorsal fins, pectoral and pelvic fins). We favour an evolutionary scenario whereby median appendages appeared from a unique field of competence first positioned throughout the dorsal and ventral midlines, which was then redeployed laterally leading to paired appendages.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151971/1/faf12402_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151971/2/faf12402.pd
Abstracts from the 8th International Conference on cGMP Generators, Effectors and Therapeutic Implications
This work was supported by a restricted research grant of Bayer AG
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