Towards an Unbiased Comparison of CC,BCC, and FCC Lattices in Terms of Prealiasing

In the literature on optimal regular volume sampling, the Body‐Centered Cubic (BCC) lattice has been proven to be optimal for sampling spherically band‐limited signals above the Nyquist limit. On the other hand, if the sampling frequency is below the Nyquist limit, the Face‐Centered Cubic (FCC) lattice was demonstrated to be optimal in reducing the prealiasing effect. In this paper, we confirm that the FCC lattice is indeed optimal in this sense in a certain interval of the sampling frequency. By theoretically estimating the prealiasing error in a realistic range of the sampling frequency, we show that in other frequency intervals, the BCC lattice and even the traditional Cartesian Cubic (CC) lattice are expected to minimize the prealiasing. The BCC lattice is superior over the FCC lattice if the sampling frequency is not significantly below the Nyquist limit. Interestingly, if the original signal is drastically undersampled, the CC lattice is expected to provide the lowest prealiasing error. Additionally, we give a comprehensible clarification that the sampling efficiency of the FCC lattice is lower than that of the BCC lattice. Although this is a well‐known fact, the exact percentage has been erroneously reported in the literature. Furthermore, for the sake of an unbiased comparison, we propose to rotate the Marschner‐Lobb test signal such that an undue advantage is not given to either lattice.     

HDL3-mediated cholesterol efflux from cultured enterocytes: The role of apoproteins A-I and A-II

High density lipoproteins (HDL) were recently demonstrated in an enterocyte model (CaCo-2 cells) to mediate reverse cholesterol transport by retroendocytosis. The present study was carried out to define the role of the major HDL apoproteins (apo) A-I and apo A-II in this pathway. HDL₃ was fractionated by heparin affinity chromatography into the two main fractions containing either apo A-I only (fraction A) or both apo A-I and apo A-II (fraction B). In addition, liposomes were reconstituted from purified apo A-I or apo A-II and dimyristoyl phosphatidylcholine. The cell binding properties and cholesterol efflux potential were studied in the lipoprotein fractions and the liposomes. Both fractions exhibited similar maximal binding capacities of 4427 (A) and 5041 (B) ng/mg cell protein, but their dissociation constants differed (40.5 and 167.7 μg/mL, respectively). Fraction A induced cholesterol efflux and stimulated cholesterol synthesis more than did fraction B. Fraction A mobilized both cellular free and esterified cholesterol, whereas fraction B preferentially mobilized cholesteryl esters. Liposomes, containing either apo A-I or apo A-II, showed specific binding, endocytosis and endosomal transport, and were released as intact particles. Apo A-I liposomes also mediated cholesterol efflux. In conclusion, there is evidence that the HDL₃ subfractions A and B, as well as reconstituted liposomes containing either apo A-I or apo A-II, were specifically bound and entered a retroendocytosis pathway which was directly linked to cholesterol efflux. Quantitatively, the apo A-I subfraction appeared to play the dominant role in normal enterocytes. The apo A-II content of fraction B was related to the mobilization of cholesteryl esters.     

Subsoil <Superscript>15</Superscript>N-N<Subscript>2</Subscript>O Concentrations in a Sandy Soil Profile After Application of <Superscript>15</Superscript>N-fertilizer

Studies on emissions of nitrous oxide (N₂O) from agricultural soils mostly focus on fluxes between the soil and the atmosphere or are limited to the atmosphere in the topsoil. However, in soils with shallow water tables, significant N₂O formation may occur closer to the groundwater. The aims of this study were (i) to determine the importance of subsoil N₂O formation in a sandy soil; and (ii) to obtain a quantitative insight in the contribution of subsoil N₂O to the overall losses of N₂O to the environment. We applied ¹⁵N labeled fertilizer at a rate of 5.22 kg ¹⁵N ha⁻¹; 50% as Ca(NO₃)₂ and 50% as NH₄Cl, on a mesic typic Haplaquod seeded with potatoes (Solanum tuberosum L.), and traced soil N₂O concentrations and fluxes over a one-year period. Throughout the year, total N₂O and the amount of ¹⁵N recovered in soil N₂O were highest in the subsoil, with a maximum concentration at 48 cm depth in mid-February of 19900 μl m⁻³ and 24 μg ¹⁵N m⁻³, respectively. The maximum concentration coincided with the highest water-filled pore space of 71%. The cumulative flux of N₂O was 446 g N₂O-N ha⁻¹, the recovery of ¹⁵N in this flux was 0.06%. During the summer, maximum fluxes followed high soil N₂O concentrations. During winter, no such relation was found. We concluded that the formation of N₂O was the highest in the subsoil, largely controlled by water-filled pore space rather than NO₃⁻ concentration or temperature. Although high subsoil N₂O concentrations did not lead to high surface fluxes of N₂O in the winter, artificial draining may lead to high indirect N₂O emissions through supersaturated drainage water.     

A High-Precision Time Handling Library

An appropriate assessment of end-to-end network performance presumes highly efficient time tracking and measurement with precise time control of the stopping and resuming of program operation. In this paper, a novel approach to solving the problems of highly efficient and precise time measurements on PC-platforms and on ARM-architectures is proposed. A new unified High Performance Timer and a corresponding software library offer a unified interface to the known time counters and automatically identify the fastest and most reliable time source, available in the user space of a computing system. The research is focused on developing an approach of unified time acquisition from the PC hardware and accordingly substituting the common way of getting the time value through Linux system calls. The presented approach provides a much faster means of obtaining the time values with a nanosecond precision than by using conventional means. Moreover, it is capable of handling the sequential time value, precise sleep functions and process resuming. This ability means the reduction of wasting computer resources during the execution of a sleeping process from 100% （busy-wait） to 1-1.5%, whereas the benefits of very accurate process resuming times on long waits are maintained.     

Exploring multi-user interactions with dynamic NFC-displays

Near Field Communication (NFC) is an emerging technology for touch-based mobile interactions with single- and multi-tagged objects. Although the latter may allow for simultaneous and collaborative interactions, most prototypes were not designed for multiple users and were only evaluated with single-user interactions. In this paper, we investigate the design, usability and user experience of multi-user interactions on dynamic NFC-displays. These interactive surfaces use a grid of NFC-tags for the direct manipulation of projected application user interfaces. In two user studies with three prototypes for multi-user interaction, we evaluated the performance of dynamic NFC-displays, interactions among users and the interplay between mobile devices and large displays.     

Proteomics identification of differentially expressed proteins in the muscle of dysferlin myopathy patients

The muscular dystrophies are a large and heterogeneous group of neuromuscular disorders that can be classified according to the mode of inheritance, the clinical phenotype and the molecular defect. To better understand the pathological mechanisms of dysferlin myopathy we compared the protein-expression pattern in the muscle biopsies of six patients with this disease with six patients with limb girdle muscular dystrophy 2A, five with facioscapulohumeral dystrophy and six normal control subjects. To investigate differences in the expression levels of skeletal muscle proteins we used 2-DE and MS. Western blot or immunohistochemistry confirmed relevant results. The study showed specific increase expression of proteins involved in fast-to-slow fiber type conversion (ankyrin repeat protein 2), type I predominance (phosphorylated forms of slow troponin T), sarcomere stabilization (actinin-associated LIM protein), protein ubiquitination (TRIM 72) and skeletal muscle differentiation (Rho-GDP-dissociation inhibitor ly-GDI) in dysferlin myopathy. As anticipated, we also found differential expression of proteins common to all the muscular dystrophies studied. This comparative proteomic analysis suggests that in dysferlin myopathy (i) the type I fiber predominance is an active process of fiber type conversion rather than a selective loss of type II fibers and (ii) the dysregulation of proteins involved in muscle differentiation further confirms the role of dysferlin in this process.     

How can I help you? Design principles for task-oriented speech dialog systems in customer service

Organizations are increasingly delegating customer inquiries to speech dialog systems (SDSs) to save personnel resources. However, customers often report frustration when interacting with SDSs due to poorly designed solutions. Despite these issues, design knowledge for SDSs in customer service remains elusive. To address this research gap, we employ the design science approach and devise a design theory for SDSs in customer service. The design theory, including 14 requirements and five design principles, draws on the principles of dialog theory and undergoes validation in three iterations using five hypotheses. A summative evaluation comprising a two-phase experiment with 205 participants yields positive results regarding the user experience of the artifact. This study contributes to design knowledge for SDSs in customer service and supports practitioners striving to implement similar systems in their organizations.

     

Nodes on ropes: a comprehensive data and control flow for steering ensemble simulations

Flood disasters are the most common natural risk and tremendous efforts are spent to improve their simulation and management. However, simulation-based investigation of actions that can be taken in case of flood emergencies is rarely done. This is in part due to the lack of a comprehensive framework which integrates and facilitates these efforts. In this paper, we tackle several problems which are related to steering a flood simulation. One issue is related to uncertainty. We need to account for uncertain knowledge about the environment, such as levee-breach locations. Furthermore, the steering process has to reveal how these uncertainties in the boundary conditions affect the confidence in the simulation outcome. Another important problem is that the simulation setup is often hidden in a black-box. We expose system internals and show that simulation steering can be comprehensible at the same time. This is important because the domain expert needs to be able to modify the simulation setup in order to include local knowledge and experience. In the proposed solution, users steer parameter studies through the World Lines interface to account for input uncertainties. The transport of steering information to the underlying data-flow components is handled by a novel meta-flow. The meta-flow is an extension to a standard data-flow network, comprising additional nodes and ropes to abstract parameter control. The meta-flow has a visual representation to inform the user about which control operations happen. Finally, we present the idea to use the data-flow diagram itself for visualizing steering information and simulation results. We discuss a case-study in collaboration with a domain expert who proposes different actions to protect a virtual city from imminent flooding. The key to choosing the best response strategy is the ability to compare different regions of the parameter space while retaining an understanding of what is happening inside the data-flow system.     

World lines

In this paper we present World Lines as a novel interactive visualization that provides complete control over multiple heterogeneous simulation runs. In many application areas, decisions can only be made by exploring alternative scenarios. The goal of the suggested approach is to support users in this decision making process. In this setting, the data domain is extended to a set of alternative worlds where only one outcome will actually happen. World Lines integrate simulation, visualization and computational steering into a single unified system that is capable of dealing with the extended solution space. World Lines represent simulation runs as causally connected tracks that share a common time axis. This setup enables users to interfere and add new information quickly. A World Line is introduced as a visual combination of user events and their effects in order to present a possible future. To quickly find the most attractive outcome, we suggest World Lines as the governing component in a system of multiple linked views and a simulation component. World Lines employ linking and brushing to enable comparative visual analysis of multiple simulations in linked views. Analysis results can be mapped to various visual variables that World Lines provide in order to highlight the most compelling solutions. To demonstrate this technique we present a flooding scenario and show the usefulness of the integrated approach to support informed decision making.     

Optimal search path for service in the presence of disruptions

We consider the following basic search path problem: a customer residing at a node of a network needs to obtain service from one of the facilities; facility locations are known and fixed. Facilities may become inoperational with certain probability; the state of the facility only becomes known when the facility is visited. Customer travel stops when the first operational facility is found. The objective is to minimize the expected total travel distance.