Significant elastic anisotropy in Ti1−x_{1-x}Alx_xN alloys

Strong compositional-dependent elastic properties have been observed theoretically and experimentally in Ti$_{1-x}$Al$_x$ N alloys. The elastic constant, C$_{11}$, changes by more than 50% depending on the Al-content. Increasing the Al-content weakens the average bond strength in the local octahedral arrangements resulting in a more compliant material. On the other hand, it enhances the directional (covalent) nature of the nearest neighbor bonds that results in greater elastic anisotropy and higher sound velocities. The strong dependence of the elastic properties on the Al-content offers new insight into the detailed understanding of the spinodal decomposition and age hardening in Ti$_{1-x}$Al$_x$N alloys.Comment: 3 figures, 3 page

Multiagent Negotiation for Fair and Unbiased Resource Allocation

This paper proposes a novel solution for the n agent cake cutting (resource allocation) problem. We propose a negotiation protocol for dividing a resource among n agents and then provide an algorithm for allotting portions of the resource. We prove that this protocol can enable distribution of the resource among n agents in a fair manner. The protocol enables agents to choose portions based on their internal utility function, which they do not have to reveal. In addition to being fair, the protocol has desirable features such as being unbiased and verifiable while allocating resources. In the case where the resource is two-dimensional (a circular cake) and uniform, it is shown that each agent can get close to l/n of the whole resource

3D-Cell-Annotator : an open-source active surface tool for single-cell segmentation in 3D microscopy images

aSummary: Segmentation of single cells in microscopy images is one of the major challenges in computational biology. It is the first step of most bioimage analysis tasks, and essential to create training sets for more advanced deep learning approaches. Here, we propose 3D-Cell-Annotator to solve this task using 3D active surfaces together with shape descriptors as prior information in a semi-automated fashion. The software uses the convenient 3D interface of the widely used Medical Imaging Interaction Toolkit (MITK). Results on 3D biological structures (e.g. spheroids, organoids and embryos) show that the precision of the segmentation reaches the level of a human expert.Peer reviewe

Testing hypotheses for the function of the carnivoran baculum using finite-element analysis

The baculum (os penis) is a mineralized bone within the glans of the mammalian penis and is one of the most morphologically diverse structures in the mammal skeleton. Recent experimental work provides compelling evidence for sexual selection shaping the baculum, yet the functional mechanism by which this occurs remains unknown. Previous studies have tested biomechanical hypotheses for the role of the baculum based on simple metrics such as length and diameter, ignoring the wealth of additional shape complexity present. For the first time, to our knowledge, we apply a computational simulation approach (finite-element analysis; FEA) to quantify the three-dimensional biomechanical performance of carnivoran bacula (n = 74) based upon high-resolution micro-computed tomography scans. We find a marginally significant positive correlation between sexual size dimorphism and baculum stress under compressive loading, counter to the ‘vaginal friction’ hypothesis of bacula becoming more robust to overcome resistance during initial intromission. However, a highly significant negative relationship exists between intromission duration and baculum stress under dorsoventral bending. Furthermore, additional FEA simulations confirm that the presence of a ventral groove would reduce deformation of the urethra. We take this as evidence in support of the ‘prolonged intromission’ hypothesis, suggesting the carnivoran baculum has evolved in response to pressures on the duration of copulation and protection of the urethra

Data for: Dictatorship versus manipulability

Computer program calculating our non-dictatorship index for the respective voting rules

Data for: Dictatorship versus manipulability

Computer program calculating our non-dictatorship index for the respective voting rules.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Descriptors for mechanical strength and slip-induced crack-blunting in refractory ceramics

Understanding the competition between brittleness and plasticity in refractory ceramics is of importance for aiding design of hard materials with enhanced fracture resistance. We carry out ab initio and classical molecular dynamics (AIMD and CMD) investigations at temperatures between 300 and 1200 K to identify atomic-scale mechanisms responsible for brittle fracture vs slip-induced crack-blunting in Ti-N ceramics. AIMD simulations of single-crystal and notched TiN lattices (1100 atoms) subject to tensile and shear deformation serve to verify predictions of mechanical properties separately obtained by CMD. Benchmarked by AIMD results, CMD is thus confidently used to probe the mechanical response of large (40000 atoms) notched TiN and TiNx models under mode-I tension. Although crack growth occurs in most cases, CMD simulations reveal that typically-brittle TiN and TiNx ceramics can - for comparable rates of accumulation of tensile and shear stress around a flaw - prevent fracture via nucleation and emission of dislocations from the notch tip. Furthermore, we identify descriptors based on properties calculated for ideal single-crystals which reproduce trends in mechanical behavior of flawed lattices. Specifically: (i) the probability of notched ceramics to resist fracture via slip-induced plasticity exhibits linear relationship with ideal tensile-to-shear strength ratios (Iplasticity), (ii) at parity of Iplasticity values, the effective strength (fracture stress) of defective systems ranks according to the tensile strength of corresponding single-crystal phases. The descriptors proposed in this work pave the way for high-throughput screening of ceramics that may combine high strength to superior fracture resistance at room and elevated temperature

3D-Cell-Annotator: an open-source active surface tool for single-cell segmentation in 3D microscopy images

Segmentation of single cells in microscopy images is one of the major challenges in computational biology. It is the first step of most bioimage analysis tasks, and essential to create training sets for more advanced deep learning approaches. Here, we propose 3D-Cell-Annotator to solve this task using 3D active surfaces together with shape descriptors as prior information in a semi-automated fashion. The software uses the convenient 3D interface of the widely used Medical Imaging Interaction Toolkit (MITK). Results on 3D biological structures (e.g. spheroids, organoids, embryos) show that the precision of the segmentation reaches the level of a human expert