Age effects on visual perceptual decisions of ambiguous stimuli

The brain is constantly making choices while interpreting the environment. To understand how age affects visual decision-making, we investigated age-related changes in spontaneous percept switches and percept choices during intermittent presentations of ambiguous stimuli. Spontaneous switches can be triggered by different visual stimuli, such as monocular ambiguous visual stimuli or binocular rivalry images. An ambiguous visual stimulus has multiple and equally plausible interpretations, such as the bi-stable rotating sphere. In such a sphere two transparently moving dots are moving in opposite directions and due to structure-from-motion the stimulus is perceived as a 3-dimensional rotating sphere moving in one or the opposite direction. During binocular rivalry experiments, the left and the right eye receive different input simultaneously. During stimulus-presentation only one of the two presented images is perceived, and the other image is suppressed. Dominance durations (the time a percept remains dominant) are typically in the order of several seconds. In this study, 52 observers ranging from 17 to 72 years old, viewed bi-stable rotating spheres and binocular rivalry stimuli and were forced to make a choice between two percepts. Stimuli were presented continuously for 2 minutes or intermittently for 1 second, with a range of inter-stimulus intervals (0.125 - 2 seconds). The results show that dominance durations during continuous viewing are longer for older subjects for the binocular rivalry stimulus but not for the bi-stable rotating spheres. For the intermittent stimulus presentation, perceptual alternations decrease at an older age in binocular rivalry, while for the bi-stable rotating sphere there are only differences in perceptual alternations among different age groups at a short off-duration. Based on these results, we conclude that the effect of age is not a general phenomenon for ambiguous stimuli. Visual decisions are more stimulus dependent, rather than experience dependent

It support for mass customization

Many authors have written about Mass Customization and its features and categories. Literature on the implementation of Mass Customization, and in particular the supporting information technology, is scant. This paper attempts to fill this gap by focusing on this subject. We determine the key functional requirements and identify possible implementations to show the existence of enabling information technologies for Mass Customization

A quantum phase transition from triangular to stripe charge order in NbSe2_{2}

The competition between proximate electronic phases produces a complex phenomenology in strongly correlated systems. In particular, fluctuations associated with periodic charge or spin modulations, known as density waves, may lead to exotic superconductivity in several correlated materials. However, density waves have been difficult to isolate in the presence of chemical disorder, and the suspected causal link between competing density wave orders and high temperature superconductivity is not understood. Here we use scanning tunneling microscopy to image a previously unknown unidirectional (stripe) charge density wave (CDW) smoothly interfacing with the familiar tri-directional (triangular) CDW on the surface of the stoichiometric superconductor NbSe$_2$. Our low temperature measurements rule out thermal fluctuations, and point to local strain as the tuning parameter for this quantum phase transition. We use this discovery to resolve two longstanding debates about the anomalous spectroscopic gap and the role of Fermi surface nesting in the CDW phase of NbSe$_2$. Our results highlight the importance of local strain in governing phase transitions and competing phenomena, and suggest a new direction of inquiry for resolving similarly longstanding debates in cuprate superconductors and other strongly correlated materials.Comment: PNAS in pres

Signatures of the charge density wave collective mode in the infrared optical response of VSe₂

We present a detailed study of the bulk electronic structure of high quality VSe$_{2}$ single crystals using optical spectroscopy. Upon entering the charge density wave phase below the critical temperature of 112 K, the optical conductivity of VSe$_2$ undergoes a significant rearrangement. A Drude response present above the critical temperature is suppressed while a new interband transition appears around 0.07\,eV. From our analysis, we estimate that part of the spectral weight of the Drude response is transferred to a collective mode of the CDW phase. The remaining normal state charge dynamics appears to become strongly damped by interactions with the lattice as evidenced by a mass enhancement factor m$^{*}$/m$\approx$3. In addition to the changes taking place in the electronic structure, we observe the emergence of infrared active phonons below the critical temperature associated with the 4a x 4a lattice reconstruction

The chiral phase transition in charge ordered 1T-TiSe2

It was recently discovered that the low temperature, charge ordered phase of 1T-TiSe2 has a chiral character. This unexpected chirality in a system described by a scalar order parameter could be explained in a model where the emergence of relative phase shifts between three charge density wave components breaks the inversion symmetry of the lattice. Here, we present experimental evidence for the sequence of phase transitions predicted by that theory, going from disorder to non-chiral and finally to chiral charge order. Employing X-ray diffraction, specific heat, and electrical transport measurements, we find that a novel phase transition occurs ~7 K below the main charge ordering transition in TiSe2, in agreement with the predicted hierarchy of charge ordered phases.Comment: 5 pages, 3 figures; includes additional experimental and theoretical results; fixed typo

Pet-related bacterial zoonotic infections:Three cases of severe infections in the immunocompromised host

Pets can have many positive effects on their owners. However, close contact with pets offers optimal conditions for transmission of micro-organisms. Especially immunocompromised patients are at risk for zoonotic infections. Here we describe the diagnosis, microbiology and treatment of three patients with severe zoonotic infections with Helicobacter canis, Pasteurella multocida and Capnocytophaga canimorsus. With this case report we would like to emphasize the importance of awareness for pet-related zoonotic infections in immunocompromised patients

Topology of chalcogen chains

We investigate the topological properties of the helical atomic chains occurring in elemental selenium and tellurium. We postulate a realistic model that includes spin-orbit interaction and show this to be topologically non-trivial, with a topological invariant protected by a crystalline symmetry. We describe the end-states, which are orbitally polarized, with an orbital density modulation strongly peaked at the edge. Furthermore, we propose a simplified model that decomposes into three orbital chains, allowing us to define a topological invariant protected by a crystalline symmetry. We contrast this result with recent observations made for the orbital Su-Schrieffer-Heeger model containing a $p$-orbital zigzag chain.Comment: 10 figure