321 research outputs found
Gesundheit für alle?! Zur psychischen Belastung von inter- und transgeschlechtlichen Menschen
Synaptic Cleft Segmentation in Non-Isotropic Volume Electron Microscopy of the Complete Drosophila Brain
Neural circuit reconstruction at single synapse resolution is increasingly
recognized as crucially important to decipher the function of biological
nervous systems. Volume electron microscopy in serial transmission or scanning
mode has been demonstrated to provide the necessary resolution to segment or
trace all neurites and to annotate all synaptic connections.
Automatic annotation of synaptic connections has been done successfully in
near isotropic electron microscopy of vertebrate model organisms. Results on
non-isotropic data in insect models, however, are not yet on par with human
annotation.
We designed a new 3D-U-Net architecture to optimally represent isotropic
fields of view in non-isotropic data. We used regression on a signed distance
transform of manually annotated synaptic clefts of the CREMI challenge dataset
to train this model and observed significant improvement over the state of the
art.
We developed open source software for optimized parallel prediction on very
large volumetric datasets and applied our model to predict synaptic clefts in a
50 tera-voxels dataset of the complete Drosophila brain. Our model generalizes
well to areas far away from where training data was available
Polarized light-flavor antiquarks from Drell-Yan processes of h+\vec{N}\to\vec{l^{+-}} + l^{-+} + X
We propose a formula to determine the first moment of difference between the
polarized - and -quarks in the nucleon, {\it i.e.} from the Drell-Yan processes in collisions of unpolarized
hadrons with longitudinally polarized nucleons by measuring outgoing lepton
helicities. As coefficients in the differential cross section depend on the
- and -quark numbers in the unpolarized hadron beam, the difference
can be independently tested by changing the hadron
beam. Moreover, a formula for estimating the -factor in Drell-Yan processes
is also suggested.Comment: 10 pages, 1 figur
TrakEM2 Software for Neural Circuit Reconstruction
A key challenge in neuroscience is the expeditious reconstruction of neuronal circuits. For model systems such as Drosophila and C. elegans, the limiting step is no longer the acquisition of imagery but the extraction of the circuit from images. For this purpose, we designed a software application, TrakEM2, that addresses the systematic reconstruction of neuronal circuits from large electron microscopical and optical image volumes. We address the challenges of image volume composition from individual, deformed images; of the reconstruction of neuronal arbors and annotation of synapses with fast manual and semi-automatic methods; and the management of large collections of both images and annotations. The output is a neural circuit of 3d arbors and synapses, encoded in NeuroML and other formats, ready for analysis
Drell-Yan forward-backward and spin asymmetries for arbitrary vector boson production at next-to-leading order
Longitudinally polarized, unpolarized and forward-backward mass differential
cross sections for Drell-Yan lepton-pair production by arbitrary vector bosons
are calculated in next-to-leading order (NLO) QCD. Analytical results are
presented in a form valid for all consistent -dimensional regularization
schemes, with the mass factorization scheme kept general. NLO predictions for
all Drell-Yan type processes (, and ) at BNL's
relativistic heavy ion collider (RHIC) are made using polarized parton
distributions which fit the recent deep-inelastic scattering data. These are
examined as tools in the determination of the polarized parton distributions
and the unpolarized ratio. NLO predictions for the
forward-backward lepton asymmetry at Fermilab are made and the precision
determination of from future runs is studied. In all the
above, the QCD corrections are found to be significant. An introductory
discussion is given of various theoretical issues, such as allowable
factorization and regularization schemes, and scale dependences.Comment: 34 pages, figures included, revtex. Some discussions and references
added/modified. In more compact form. To appear in Phys. Rev.
Election proximity and representation focus in party-constrained environments
Do elected representatives have a time-constant representation focus or do they adapt their focus depending on election proximity? In this article, we examine these overlooked theoretical and empirical puzzles by looking at how reelection-seeking actors adapt their legislative behavior according to the electoral cycle. In parliamentary democracies, representatives need to serve two competing principals: their party and their district. Our analysis hinges on how representatives make a strategic use of parliamentary written questions in a highly party-constrained institutional context to heighten their reselection and reelection prospects. Using an original data set of over 32,000 parliamentary questions tabled by Portuguese representatives from 2005 to 2015, we examine how time interacts with two key explanatory elements: electoral vulnerability and party size. Results show that representation focus is not static over time and, in addition, that electoral vulnerability and party size shape strategic use of parliamentary questions
On the reliability of a simple method for scoring phenotypes to estimate heritability: A case study with pupal color in Heliconius erato phyllis, Fabricius 1775 (Lepidoptera, Nymphalidae)
In this paper, two methods for assessing the degree of melanization of pupal exuviae from the butterfly Heliconius erato phyllis, Fabricius 1775 (Lepidoptera, Nymphalidae, Heliconiini) are compared. In the first method, which was qualitative, the exuviae were classified by scoring the degree of melanization, whereas in the second method, which was quantitative, the exuviae were classified by optical density followed by analysis with appropriate software. The heritability (h2) of the degree of melanization was estimated by regression and analysis of variance. The estimates of h 2 were similar with both methods, indicating that the qualitative method could be particularly suitable for field work. The low estimates obtained for heritability may have resulted from the small sample size (n = 7-18 broods, including the parents) or from the allocation-priority hypothesis in which pupal color would be a lower priority trait compared to morphological traits and adequate larval development
An Integrated Micro- and Macroarchitectural Analysis of the Drosophila Brain by Computer-Assisted Serial Section Electron Microscopy
A new software package allows for dense electron microscopy reconstructions of neuronal networks in the fruit fly brain, and reveals specific differences in microcircuits between insects and vertebrates
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