452 research outputs found
Van Kampen Colimits and Path Uniqueness
Fibred semantics is the foundation of the model-instance pattern of software
engineering. Software models can often be formalized as objects of presheaf
topoi, i.e, categories of objects that can be represented as algebras as well
as coalgebras, e.g., the category of directed graphs. Multimodeling requires to
construct colimits of models, decomposition is given by pullback.
Compositionality requires an exact interplay of these operations, i.e.,
diagrams must enjoy the Van Kampen property. However, checking the validity of
the Van Kampen property algorithmically based on its definition is often
impossible.
In this paper we state a necessary and sufficient yet efficiently checkable
condition for the Van Kampen property to hold in presheaf topoi. It is based on
a uniqueness property of path-like structures within the defining congruence
classes that make up the colimiting cocone of the models. We thus add to the
statement "Being Van Kampen is a Universal Property" by Heindel and
Soboci\'{n}ski the fact that the Van Kampen property reveals a presheaf-based
structural uniqueness feature
Brave New Genomes: Report on the BMBF-funded CRISPR.kitchen - Genome Hacking Retreat, 13-17 March 2017, Munich, Germany
Artificial intelligence in human genomics: Mapping research and existing and emerging applications
Targeted ‘knockdown’ of spliceosome function in mammalian cells
The existence of two sophisticated parallel splicing machineries in multicellular organisms has raised intriguing questions—ranging from their impact on proteome expansion to the evolution of splicing and of metazoan genomes. Exploring roles for the distinct splicing systems in vivo has, however, been restricted by the lack of techniques to selectively inhibit their function in cells. In this study, we show that morpholino oligomers complementary to the branch-site recognition elements of U2 or U12 small nuclear RNA specifically suppress the function of the two splicing systems in mammalian cells. The data provide the first evidence for a role of distinct spliceosomes in pre-mRNA splicing from endogenous mammalian genes and establish a tool to define roles for the different splicing machineries in vivo
Bacteriophages in medicine, agriculture and food industry – application perspectives, innovation and regulatory issues. TAB-Fokus
In view of the major challenges to the health of humans, animals and the environment (One Health), especially due to antibiotic resistance, phages represent a relevant option – the potential of which should be investigated and exploited more intensively. Under the current framework conditions, however, it seems to be unlikely that the use of phages for therapeutic purposes in medicine or for applications in agriculture and the food industry will become established in the EU or in Germany better or on a larger scale than it has been so far. To achieve this, it would be necessary to make the legal framework conditions more suitable and flexible, to create special approval programmes and economic incentive structures (e. g. for novel antimicrobial drugs) and to promote research and development activities on phages in a more targeted way. A more intensive exchange on these issues between politics, science, industry, regulatory authorities and – in the case of phage therapy – stakeholders from the health system, such as health insurance companies and patient representatives, should be strived for. This could be the starting point both for tangible practice-oriented steps to design regulations at the national level and for initiatives to make regulation at the EU level more flexible.
TAB-Fokus no. 43 provides a compact four-page overview of the contents and results of the TAB report (in German only): "Bakteriophagen in Medizin, Land- und Lebensmittelwirtschaft – Anwendungsperspektiven, Innovations- und Regulierungsfragen. Innovationsanalyse" (for details see Relations in KITopen)
Effective Theory of 3H and 3He
We present a new perturbative expansion for pionless effective field theory
with Coulomb interactions in which at leading order the spin-singlet
nucleon-nucleon channels are taken in the unitarity limit. Presenting results
up to next-to-leading order for the Phillips line and the neutron-deuteron
doublet-channel phase shift, we find that a perturbative expansion in the
inverse 1S0 scattering lengths converges rapidly. Using a new systematic
treatment of the proton-proton sector that isolates the divergence due to
one-photon exchange, we renormalize the corresponding contribution to the
3H-3He binding energy splitting and demonstrate that the Coulomb force in
pionless EFT is a completely perturbative effect in the trinucleon bound-state
regime. In our new expansion, the leading order is exactly isospin-symmetric.
At next-to-leading order, we include isospin breaking via the Coulomb force and
two-body scattering lengths, and find for the energy splitting
(E_B(3He)-E_B(3H))^NLO = (-0.86 +/- 0.17) MeV.Comment: 37 pages, 14 figures, published versio
Nuclear Physics Around the Unitarity Limit
We argue that many features of the structure of nuclei emerge from a strictly
perturbative expansion around the unitarity limit, where the two-nucleon S
waves have bound states at zero energy. In this limit, the gross features of
states in the nuclear chart are correlated to only one dimensionful parameter,
which is related to the breaking of scale invariance to a discrete scaling
symmetry and set by the triton binding energy. Observables are moved to their
physical values by small, perturbative corrections, much like in descriptions
of the fine structure of atomic spectra. We provide evidence in favor of the
conjecture that light, and possibly heavier, nuclei are bound weakly enough to
be insensitive to the details of the interactions but strongly enough to be
insensitive to the exact size of the two-nucleon system.Comment: 6 pages, 3 figures, published version, rewritten for clarit
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