On Neural Networks as Infinite Tree-Structured Probabilistic Graphical Models

Deep neural networks (DNNs) lack the precise semantics and definitive probabilistic interpretation of probabilistic graphical models (PGMs). In this paper, we propose an innovative solution by constructing infinite tree-structured PGMs that correspond exactly to neural networks. Our research reveals that DNNs, during forward propagation, indeed perform approximations of PGM inference that are precise in this alternative PGM structure. Not only does our research complement existing studies that describe neural networks as kernel machines or infinite-sized Gaussian processes, it also elucidates a more direct approximation that DNNs make to exact inference in PGMs. Potential benefits include improved pedagogy and interpretation of DNNs, and algorithms that can merge the strengths of PGMs and DNNs

Ein Beitrag zur Erkundung der Struktur des Nördlinger Rieses auf Grund geoelektrischer Schlumberger-Sondierungen

Insgesamt stehen rund 200 Schlumberger-Sondierungen, bevorzugt angeordnet auf das Ries diagonal durchquerenden Profilen, mit Auslagen von L/2 bis zu 900m zur Verfügung. Im zentralen Krater läßt sich die Basis der pelitischen Sedimente markant erkennen, so daß ein Tiefenlinienplan derselben erstellt werden konnte. Die Meßergebnisse in der Nähe der Forschungsbohrung Nördlingen 1973 zeigen außerordentlich gute Übereinstimung mit den im Bohrloch gemessenen Verhältnissen. Der innere Wall des zentralen Kraters zeigt eine sehr inhomogene Struktur; es wird angenommen, daß er von größeren und kleineren Trümmerschollen gebildet wird. Im östlichen Bereich des Vorrieses wurden geoelektrische Sondierungen durchgeführt, um der Frage nach weiteren, außerhalb des Rieses gelegenen Ringwallstrukturen nachzugehen. Eine eindeutige Aussage konnte hier nicht aus den Messungen abgeleitet werden.There are about 200 geoelectric Schlumberger soundings, most of them arranged on profiles, which cross the Ries crater diagonally and having halfelectrode spacings up to L/2 = 900m. Within the central crater the basement of the pelitic sediments was recognized very distinct. Therefore it was possible to draw the lines of depth of this interface for the whole central crater. The soundings near to the research boring Nördlingen 1973 show excellent agreement with the borehole measurements. The inner rim of the central crater was found to be very inhomogeneous and is thought to consist of fragments of different origin. In the eastern region, outside of the Ries crater, geoelectric soundings were performed to look for possibly additional rims, but we could not find a doubtless evidence for them

Transcriptome Analysis of Targeted Mouse Mutations Reveals the Topography of Local Changes in Gene Expression.

The unintended consequences of gene targeting in mouse models have not been thoroughly studied and a more systematic analysis is needed to understand the frequency and characteristics of off-target effects. Using RNA-seq, we evaluated targeted and neighboring gene expression in tissues from 44 homozygous mutants compared with C57BL/6N control mice. Two allele types were evaluated: 15 targeted trap mutations (TRAP); and 29 deletion alleles (DEL), usually a deletion between the translational start and the 3' UTR. Both targeting strategies insert a bacterial beta-galactosidase reporter (LacZ) and a neomycin resistance selection cassette. Evaluating transcription of genes in +/- 500 kb of flanking DNA around the targeted gene, we found up-regulated genes more frequently around DEL compared with TRAP alleles, however the frequency of alleles with local down-regulated genes flanking DEL and TRAP targets was similar. Down-regulated genes around both DEL and TRAP targets were found at a higher frequency than expected from a genome-wide survey. However, only around DEL targets were up-regulated genes found with a significantly higher frequency compared with genome-wide sampling. Transcriptome analysis confirms targeting in 97% of DEL alleles, but in only 47% of TRAP alleles probably due to non-functional splice variants, and some splicing around the gene trap. Local effects on gene expression are likely due to a number of factors including compensatory regulation, loss or disruption of intragenic regulatory elements, the exogenous promoter in the neo selection cassette, removal of insulating DNA in the DEL mutants, and local silencing due to disruption of normal chromatin organization or presence of exogenous DNA. An understanding of local position effects is important for understanding and interpreting any phenotype attributed to targeted gene mutations, or to spontaneous indels

Structural and magnetic properties of an InGaAs/Fe3_3Si superlattice in cylindrical geometry

The structure and the magnetic properties of an InGaAs/Fe3Si superlattice in a cylindrical geometry are investigated by electron microscopy techniques, x-ray diffraction and magnetometry. To form a radial superlattice, a pseudomorphic InGaAs/Fe3As bilayer has been released from its substrate self-forming into a rolled-up microtube. Oxide-free interfaces as well as areas of crystalline bonding are observed and an overall lattice mismatch between succeeding layers is determined. The cylindrical symmetry of the final radial superlattice shows a significant effect on the magnetization behavior of the rolled-up layers

Fisheries

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Excited-state reaction dynamics of bacteriorhodopsin studied by femtosecond spectroscopy

The photodynamics of bacteriorhodopsin were studied by transient absorption and gain measurements after excitation with femtosecond pulses at 620 nm. With probing pulses at longer wavelengths (λ > 770 nm) the previously reported formation of the J intermediate (with a time constant of 500±100 fs) was confirmed. With probing pulses around 700 nm, a faster process with a relaxation time of 200±70 fs was observed. The data analysis strongly suggests that this kinetic constant describes the reactive motion of the polyatomic molecule on its excited-state potential energy surface, i.e. one observes directly the incipient isomerization of the retinal molecule. The minimum of the S1 potential energy surface reached in 200 fs lies approximately 13300 cm−1 above the ground state of bacteriorhodopsin and from this minimum the intermediate J is formed with a time constant of 500 fs