Unshakable loyalty in the food sector: sustainable customer retention. Empirical study of organic food consumers in Germany

Because of high competitive pressure in the food sector producers and retailers constantly increase their marketing efforts to convince consumers of their own products, services, brands or stores. One of the main goals is to generate loyal consumers because they are less likely to switch to competitors and more tolerant of price increases than non-loyal consumers. But what is true consumer loyalty? Repurchases are often used as an approximate indicator of loyalty. But the marketing literature emphasises that to identify ??true loyalty?? it is important to consider both consumers?? purchasing patterns as well as consumers?? underlying attitudes. Thus, true loyalty includes both a behavioural component, which results in repeated purchases, and an attitudinal component, which results in a dispositional commitment to a product, brand, or company and associates a unique value with it. However, regarding the food sector and the characteristics of food products, the question arises whether the above mentioned strict definition of true consumer loyalty can be applied to the food sector. Our paper aims to empirically test this question. To do so we conducted 27 semi-structured in-depth interviews with regular customers of a German organic food retailer in March/April 2009.     

Flexible Zinc–Tin Oxide Thin Film Transistors Operating at 1 kV for Integrated Switching of Dielectric Elastomer Actuators Arrays

Flexible high‐voltage thin‐film transistors (HVTFTs) operating at more than 1 kV are integrated with compliant dielectric elastomer actuators (DEA) to create a flexible array of 16 independent actuators. To allow for high‐voltage operation, the HVTFT implements a zinc–tin oxide channel, a thick dielectric stack, and an offset gate. At a source–drain bias of 1 kV, the HVTFT has a 20 µA on‐current at a gate voltage bias of 30 V. Their electrical characteristics enable the switching of DEAs which require drive voltages of over 1 kV, making control of an array simpler in comparison to the use of external high‐voltage switching. These HVTFTs are integrated in a flexible haptic display consisting of a 4 × 4 matrix of DEAs and HVTFTs. Using a single 1.4 kV supply, each DEA is independently switched by its associated HVTFT, requiring only a 30 V gate voltage for full DEA deflection. The 4 × 4 display operates well even when bent to a 5 mm radius of curvature. By enabling DEA switching at low voltages, flexible metal‐oxide HVTFTs enable complex flexible systems with dozens to hundreds of independent DEAs for applications in haptics, Braille displays, and soft robotics.     

Stand der Technik: Anschmierungen in Radial-Zylinderrollenlagern

Forschung im Ingenieurwesen - Anschmierungen innerhalb von Wälzlagern zählen zu den Verschleißarten, die bis heute nicht vollständig verstanden wurden. Bekannt ist, dass...     

Regulating self-organized collaborative learning: the importance of homogeneous problem perception,immediacy and intensity of strategy use

Very often, university students deliberately form self-organized study groups, e.g. to study collaboratively for an upcoming exam. Yet, very little is known about what regulation problems such self-organized study groups encounter during their learning process and how they try to cope with these problems. Therefore, this study investigates how completely self-organized groups (i.e., non-guided groups outside the classroom that form without external impulse) regulate their collaborative learning process when faced with different kinds of regulation problems. More specifically, we tested the hypotheses that members of self-organized study groups are more satisfied with their group learning experience (a) the more homogeneous their problem perceptions are within their group, (b) the more they apply immediate (rather than non-immediate) strategies to remedy their regulation problems, and (c) the more frequently they apply regulation strategies. In a longitudinal study, N?=?122 students, voluntarily studying for their exams in N?=?52 groups, were asked to indicate the types of problems they experienced, the types of strategies they used to tackle those problems, and their satisfaction with their group learning experience after each of their self-organized study meetings. Hierarchical linear modeling confirmed all hypotheses. Qualitative analysis of two selected groups’ self-reported situational data provided additional insights about the mechanisms that may have contributed to the results. Our study provides important directions for future research, including the recommendation to identify the processes by which groups (a) can reach homogeneity of problem perceptions and (b) coordinate the choice of appropriate strategies within the group.

     

Visualizing complexities: the human limits of air traffic control

Air traffic management is organized into filters in order to prevent tactical controllers from dealing with complex conflicting situations. In this article, we describe an experiment showing that a dynamic conflict display could improve human performance on complex conflict situations. Specifically, we designed a display tool that represents the conflicting portions of aircraft trajectories and the evolution of the conflict zone when the user adds a maneuver to an aircraft. The tool allows the user to dynamically check the potential conflicting zones with the computer mouse before making a maneuver decision. We tested its utility on a population of forty students: twenty air traffic controller (ATC) students at the end of their initial training and twenty engineering students with the same background but no ATC training. They had to solve conflicts involving 2–5 aircraft with a basic display and with the dynamic visualization tool. Results show that in easy situations (2 aircraft), performance is similar with both displays. However, as the complexity of the situations grows (from 3 to 5 aircraft), the dynamic visualization tool enables users to solve the conflicts more efficiently. Using the tool leads to fewer unsolved conflicts and shorter delays. No significant differences are found between the two test groups except for delays: ATC students give maneuvers that generate less delays than engineering students. These results suggest that humans are better able to manage complex situations with the help of our conflict visualization tool.     

Plasma lipoproteins and liver lipids in two breeds of geese with different susceptibility to hepatic steatosis: Changes induced by development and force-feeding

Susceptibility to fatty liver in the force-fed goose is partly under genetic control. However, the mechanisms leading to liver steatosis in this avian model are poorly understood, but may involve perturbation in hepatic lipoprotein synthesis. Plasma lipoproteins were fractionated by density gradient ultracentrifugation from plasma of geese differing in their susceptibility to liver steatosis (Landes breed, highly susceptible; Rhine breed, partly resistant). The concentrations and chemical compositions of the major lipoprotein classes (VLDL, IDL, LDL and HDL) were characterized at 8, 22 and 27 wk of age and compared to the lipid composition of the corresponding liver. In non-force-fed geese, the lipoprotein profile was typical of birds, with high-density lipoprotein (HDL) predominating (4–5 g/L). However, at 22 and 27 wk of age, very low-density lipoprotein (VLDL) levels were significantly lower in Landes geese suggesting that this breed may possess a lower ability to export liver lipids, which would explain its susceptibility to liver steatosis when overfed. The livers of force-fed geese were specifically enriched in triglyceride, and to a lesser extent, in cholesteryl esters and non-esterified fatty acids as compared to those of control geese of the same age (27 wk). This accumulation of lipids was more pronounced in the Landes breed and was responsible for the higher liver weight in that breed. In both breeds, liver steatosis was accompanied by an increase in plasma levels of HDL (11 g/L), whereas low-density lipoproteins were essentially absent. An increase in VLDL plasma levels occurred in the Landes breed only (2.51 g/Lvs 1.85 g/L in the Rhine breed), and was positively correlated with liver weight. However, VLDL in force-fed geese in both breeds were deficient in triglyceride (28–29% by wt) but enriched in cholesterol (41% by wt). These results indicate that a defect in the incorporation of triglyceride into nascent hepatic VLDL may result in liver steatosis in this species.     

Contact stresses in the glenoid component in total shoulder arthroplasty

Several studies of retrieved glenoid components from total shoulder arthroplasty show an erosion of the rim, surface irregularities, component fracture and wear resulting from polyethylene deformation in vivo. Particles resulting from polyethylene wear might be one of the reasons for the very high rate of glenoid component loosening found clinically. Because wear can be the result of high contact stresses, the aim of this study is to find out whether or not contact stresses are high enough to cause wear of the glenoid component and what influence the component type and geometry have on polyethylene contact stresses for different humerus abduction angles. Elasticity theory is used in a parametric study of contact stresses in several glenoid component designs. A finite element method is used to confirm the accuracy of the analytical solution. The analysis shows that the peak stress generated in glenoid components under conditions of normal living can be as high as 25 MPa; since this exceeds the polyethylene yield strength, wear and also cold flow of the components can be expected. It is predicted that more conforming components have lower contact stresses, which might result in lower wear rate and less cold flow. It is also found that a metal-backed component promotes higher contact stresses than an all-polyethylene component with the same total thickness, therefore it can be expected that metal-backed components have inferior wear properties.     

Assessment of patient organ doses and effective doses using the VIP-Man adult male phantom for selected cone-beam CT imaging procedures during image guided radiation therapy

A Monte Carlo based computational procedure for determining organ doses and effective doses has been described for two procedures used in newly developed image-guided radiation treatment: kilovoltage cone-beam computed tomography (kV CBCT) and mega-voltage computed tomography (MV CBCT). A whole-body patient computational phantom, VIP-Man phantom, is employed for Monte Carlo dose calculations. Results indicate that the thyroid dose is always the highest in head and neck (H&N) scan for both kV and MV CBCT, and the bladder dose is the highest in prostate scan for both kV and MV CBCT. For the VIP-Man phantom, it has been found that the effective dose for kV CBCT (assuming a total exposure of 1350 mAs) is approximately 9.5 mSv for the two anatomical sites, whereas the effective dose for MV CBCT (assuming a total of 6 monitor unit) ranges from 5.10 mSv for the H&N case to 8.39 mSv for the prostate scan. The estimated whole-body effective doses allow different imaging procedures to be compared and evaluated.     

Are conductance plateaus independent events in atomic point contact measurements? A statistical approach

Conductance-elongation curves of gold atomic wires are measured using a scanning tunneling microscope break junction technique at room temperature. Landauer's conductance plateaus are individually identified and statistically analyzed. Both the probabilities to observe and the lengths of the two last plateaus (at conductance values close to 2e(2)/h and 4e(2)/h) are studied. All results converge to show that the occurrences of these two conductance plateaus on a conductance-elongation curve are statistically independent events.