Information loss from dimensionality reduction in 5D-Gaussian spectral data

Understanding the loss of information in spectral analytics is a crucial first step towards finding root causes for failures and uncertainties using spectral data in artificial intelligence models built from modern complex data science applications. Here, we show from a very simple entropy model analysis with quantum statistics of spectral data, that the relative loss of information from dimensionality reduction due to projection of an initial five-dimensional state onto two-dimensional diagrams is less than one percent in the parameter range of small data sets with sample sizes on the order of few hundreds data samples. From our analysis, we also conclude that the density and expectation value of the entropy probability distribution increases with the sample number and sample size using artificial data models derived from random sampling Monte-Carlo simulation methods.Comment: 4 pages, 3 figure

Architecture Fully Fashioned - Exploration of foamed spacer fabrics for textile based building skins

“Architecture Fully Fashioned” is about lightweight design and new textile based building skins. Fully fashioned refers to a textile production technology wherein all parts of a piece of cloth are produced in one integrated production process, ready to wear the moment they leave the machine. Fully fashioned powerskin in an architectural sense implies a light, highly prefabricated textile envelope with minimum needs of installation work on the building site.To develop these new textile powerskins, experimental student works and applied research projects at Frankfurt University of Applied Science investigate the potential of the combination of textile technologies with foaming technologies. This paper focuses on so called spacer fabrics and a research project called 3dTEX and founded by Zukunf Bau, where wall elements from foamed spacer fabrics presently are under development. The aim of the paper is to present 3dTEX within the context of the accompanying experimental student design works and to show the so far achieved results for a prefabricated, lightweight, self supporting and highly insulated foamed textile skin, with reduced needs of installation work on the building site. This has been achieved by using the spacer fabric as lost formwork and using 3d-textile technologies, so as woven or warp-knitted spacer fabrics, in order to receive complex geometrical sandwich-like textiles. Together with the foam they become FabricFoam©. The new selfsupporting building elements not only offer possibilities for complex architectonical geometries including loadbearing structures, but also a wide range of surface designs in terms of structures, colours and additional functionalities. The focus of 3dTEX is on the development of appropriate textile geometries for one- ore two-layer textile elements, depending on the choosen textile technologies. Foamed, they become lightweight, insulated elements, where the two layer textile can even be transformed into a ready-made, rear-ventilated, insulated wall element made from gradient fibre and foam material, able to absorb tensile and compressive forces at the same time.The challenge for 3dTEX is to close the knowledge gap about what kind of textile technology can produce the envisioned textile geometry with which kind of fibre material. Further, 3dTEX research is about the appropriate, possibly in-situ, foaming technology and foam material, so that fibre and foam materials match as an aesthetic architectural element and in terms of mechanical and building physics as well as in terms of grey energy and recycling aspects.

Alkylation of rabbit muscle creatine kinase surface methionine residues inhibits enzyme activity in vitro

Creatine kinase (CK) catalyzes the formation of phosphocreatine from adenosine triphosphate (ATP) and creatine. The highly reactive free cysteine residue in the active site of the enzyme (Cys283) is considered essential for the enzymatic activity. In previous studies we demonstrated that Cys283 is targeted by the alkylating chemical warfare agent sulfur mustard (SM) yielding a thioether with a hydroxyethylthioethyl (HETE)-moiety. In the present study, the effect of SM on rabbit muscle CK (rmCK) activity was investigated with special focus on the alkylation of Cys283 and of reactive methionine (Met) residues. For investigation of SM-alkylated amino acids in rmCK, micro liquid chromatography-electrospray ionization high-resolution tandem-mass spectrometry measurements were performed using the Orbitrap technology. The treatment of rmCK with SM resulted in a decrease of enzyme activity. However, this decrease did only weakly correlate to the modification of Cys283 but was conclusive for the formation of Met70-HETE and Met179-HETE. In contrast, the activity of mutants of rmCK produced by side-directed mutagenesis that contained substitutions of the respective Met residues (Met70Ala, Met179Leu, and Met70Ala/Met179Leu) was highly resistant against SM. Our results point to a critical role of the surface exposed Met70 and Met179 residues for CK activity

Decoding neural responses to temporal cues for sound localization

The activity of sensory neural populations carries information about the environment. This may be extracted from neural activity using different strategies. In the auditory brainstem, a recent theory proposes that sound location in the horizontal plane is decoded from the relative summed activity of two populations in each hemisphere, whereas earlier theories hypothesized that the location was decoded from the identity of the most active cells. We tested the performance of various decoders of neural responses in increasingly complex acoustical situations, including spectrum variations, noise, and sound diffraction. We demonstrate that there is insufficient information in the pooled activity of each hemisphere to estimate sound direction in a reliable way consistent with behavior, whereas robust estimates can be obtained from neural activity by taking into account the heterogeneous tuning of cells. These estimates can still be obtained when only contralateral neural responses are used, consistently with unilateral lesion studies. DOI: http://dx.doi.org/10.7554/eLife.01312.001

Minimal vertex covers on finite-connectivity random graphs - a hard-sphere lattice-gas picture

The minimal vertex-cover (or maximal independent-set) problem is studied on random graphs of finite connectivity. Analytical results are obtained by a mapping to a lattice gas of hard spheres of (chemical) radius one, and they are found to be in excellent agreement with numerical simulations. We give a detailed description of the replica-symmetric phase, including the size and the entropy of the minimal vertex covers, and the structure of the unfrozen component which is found to percolate at connectivity $c\simeq 1.43$. The replica-symmetric solution breaks down at $c=e\simeq 2.72$. We give a simple one-step replica symmetry broken solution, and discuss the problems in interpretation and generalization of this solution.Comment: 32 pages, 9 eps figures, to app. in PRE (01 May 2001

Statistical mechanics of the vertex-cover problem

We review recent progress in the study of the vertex-cover problem (VC). VC belongs to the class of NP-complete graph theoretical problems, which plays a central role in theoretical computer science. On ensembles of random graphs, VC exhibits an coverable-uncoverable phase transition. Very close to this transition, depending on the solution algorithm, easy-hard transitions in the typical running time of the algorithms occur. We explain a statistical mechanics approach, which works by mapping VC to a hard-core lattice gas, and then applying techniques like the replica trick or the cavity approach. Using these methods, the phase diagram of VC could be obtained exactly for connectivities $c<e$, where VC is replica symmetric. Recently, this result could be confirmed using traditional mathematical techniques. For $c>e$, the solution of VC exhibits full replica symmetry breaking. The statistical mechanics approach can also be used to study analytically the typical running time of simple complete and incomplete algorithms for VC. Finally, we describe recent results for VC when studied on other ensembles of finite- and infinite-dimensional graphs.Comment: review article, 26 pages, 9 figures, to appear in J. Phys. A: Math. Ge

Comparing the Performances of Apes (Gorilla gorilla, Pan troglodytes, Pongo pygmaeus) and Human Children (Homo sapiens) in the Floating Peanut Task

Recently, Mendes et al. [1] described the use of a liquid tool (water) in captive orangutans. Here, we tested chimpanzees and gorillas for the first time with the same “floating peanut task.” None of the subjects solved the task. In order to better understand the cognitive demands of the task, we further tested other populations of chimpanzees and orangutans with the variation of the peanut initially floating or not. Twenty percent of the chimpanzees but none of the orangutans were successful. Additional controls revealed that successful subjects added water only if it was necessary to obtain the nut. Another experiment was conducted to investigate the reason for the differences in performance between the unsuccessful (Experiment 1) and the successful (Experiment 2) chimpanzee populations. We found suggestive evidence for the view that functional fixedness might have impaired the chimpanzees' strategies in the first experiment. Finally, we tested how human children of different age classes perform in an analogous experimental setting. Within the oldest group (8 years), 58 percent of the children solved the problem, whereas in the youngest group (4 years), only 8 percent were able to find the solution

Frequency-Invariant Representation of Interaural Time Differences in Mammals

Interaural time differences (ITDs) are the major cue for localizing low-frequency sounds. The activity of neuronal populations in the brainstem encodes ITDs with an exquisite temporal acuity of about . The response of single neurons, however, also changes with other stimulus properties like the spectral composition of sound. The influence of stimulus frequency is very different across neurons and thus it is unclear how ITDs are encoded independently of stimulus frequency by populations of neurons. Here we fitted a statistical model to single-cell rate responses of the dorsal nucleus of the lateral lemniscus. The model was used to evaluate the impact of single-cell response characteristics on the frequency-invariant mutual information between rate response and ITD. We found a rough correspondence between the measured cell characteristics and those predicted by computing mutual information. Furthermore, we studied two readout mechanisms, a linear classifier and a two-channel rate difference decoder. The latter turned out to be better suited to decode the population patterns obtained from the fitted model