Guest Editorial on Museum Ethics

Museum ethics refer to the values on which museums found their operations. Therefore, they constitute a key issue in the museum world. In the last decade, there have been books, papers, institutions and individuals that solely discuss museum ethics. This collection of papers aims to contribute to this discussion. It is the published outcome of a session hosted at the 'Fourth International Conference on Information Law' (ICIL, 20th – 21st May 2011, Thessaloniki, Greece).1 This guest editorial explains the overall conception of this collection and provides an insider’s view of the papers

The impact of body and head dynamics on motion comfort assessment

Head motion is a key determinant of motion comfort and differs substantially from seat motion due to seat and body compliance and dynamic postural stabilization. This paper compares different human body model fidelities to transmit seat accelerations to the head for the assessment of motion comfort through simulations. Six-degree of freedom dynamics were analyzed using frequency response functions derived from an advanced human model (AHM), a computationally efficient human model (EHM) and experimental studies. Simulations of dynamic driving show that human models strongly affected the predicted ride comfort (increased up to a factor 3). Furthermore, they modestly affected sickness using the available filters from the literature and ISO-2631 (increased up to 30%), but more strongly affected sickness predicted by the subjective vertical conflict (SVC) model (increased up to 70%)

The Impact of Management Practices on Soil Fertility and Foliar Nutrient Concentrations in a Spruce (Picea abies Link) Forest Ecosystem of Rodopi Mountainous Area, in Northern Greece

After forest harvesting, organic matter accumulation and soil nutrient availability are usually negatively influenced, especially during the first years. The hypothesis that 15 years after selective harvesting (15Y) the increased forest biomass, together with the enhanced nutrient recycling rates, compared to 5-years after harvesting (5Y), could restore nutrient availability and organic C accumulation (both in forest floor and soil) to similar levels to the intact site, was tested. The aim of this study was to investigate the effect of the timing of management practices (intact forest-control, 5Y, 15Y) on organic matter content, nutrient concentrations in needles, forest floor and soil, in a forest ecosystem of Picea abies L., in Rodopi mountainous area, in northern Greece. Significant differences between the intact site and the other two treatments were found in: i) soil N, P, C/N and exchangeable Ca, ii) organic matter and nutrient accumulation (basically in the upper 30 cm), iii) foliar K, Fe and Zn concentrations. In conclusion: i) forest management practices clearly influenced soil fertility and organic matter accumulation, ii) 15 years after selective harvesting nutrient and organic C accumulation in forest floor, as well as K and Fe accumulation in soil were restored to similar levels to the intact sites; thus, our hypothesis was partially correct

Simulating vibration transmission and comfort in automated driving integrating models of seat, body, postural stabilization and motion perception

To enhance motion comfort in (automated) driving we present biomechanical models and demonstrate their ability to capture vibration transmission from seat to trunk and head. A computationally efficient full body model is presented, able to operate in real time while capturing translational and rotational motion of trunk and head with fore-aft, lateral and vertical seat motion. Sensory integration models are presented predicting motion perception and motion sickness accumulation using the head motion as predicted by biomechanical models

A numerical study of flow-structure interactions with application to flow past a pair of cylinders

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2004.Includes bibliographical references (v. 2, p. 587-601).Flow-structure interaction is a generic problem for many engineering applications, such as flow--induced oscillations of marine risers and cables. In this thesis a Direct Numerical Simulation (DNS) approach based on spectral/hp elements is employed. Structural motion implies changes on the boundaries of the flow domain. An Arbitrary Lagrangian Eulerian (ALE) scheme is incorporated to efficiently move the mesh without remeshing. Efficient three-dimensional simulations with periodicity in at least one space direction are achieved using Hybrid Fourier-Jacobi expansions. Both 2D and 3D formulations can treat an arbitrary number of oscillating bodies. Due to the large computational demands of the resulting systems parallel computing is used with MPI. Numerical experiments are run and systematic data sets are obtained for flow around two cylinders. Stationary cylinders in tandem and side-by-side arrangements are examined parametrically over spacing and Reynolds number. Parametric studies of tandem cylinders in prescribed motion and free oscillation are also conducted. For tandem cylinders, sudden changes in the forces occur at a critical spacing where a transition from reattachment to binary vortex regime occurs.(cont.) A hysteresis effect is observed for spacings near the nominal critical, where for given Reynolds number there are two possible solutions depending on the initial conditions. Discrepancies in the prediction of the critical spacing using 2D and 3D simulations are identified and explained. The three-dimensional effects are found to cause a weakening of the strength of the primary vortices and a delay in the inception to) binary vortex regime. When the cylinders oscillate in prescribed motion, the phase angle of the oscillations can alter significantly the hydrodynamic work on the downstream cylinder. For spacings smaller than the critical spacing, the lock-on range of frequencies is wider than that of a single cylinder. As the oscillations amplitude increases however, pockets of non-lock-on regions are found within the Arnold synchronization regions. A shift towards higher frequencies in the synchronization range is found for the in-phase oscillations compared to the anti-phase oscillations. A consistent change is found in the spanwise correlations. For the elastically mounted two-degree of freedom tandem cylinders it is found that the synchronization range of the upstream cylinder is wider when its latest shed pair of vortices intercepts the downstream cylinder.(cont.) A shifting of the synchronization curve on the reduced velocity axis is observed and explained in terms of the natural shedding frequency of the corresponding stationary system of cylinders.by Georgios V. Papaioannou.Ph.D

Blood Transfusion After Myocardial Infarction: Friend, Foe or Double-Edged Sword?

Combined mechanical and pharmacological interventions constitute the cornerstone of therapy for patients with ST-segment elevation acute myocardial infarction (AMI). These increasingly complex interventions offer morbidity and mortality advantage but are associated frequently with bleeding complications. Major bleeding is probably the most important non-cardiac complication in patients undergoing coronary artery intervention. Prior studies have identified anemia as a strong independent predictor of mortality and adverse cardiac events in this patient population. Limited data are available to guide transfusion decisions in patients with coronary artery disease and anemia either at baseline or after a complication of an angioplasty procedure.The CADILLAC study sought to determine the relationship between red blood cell transfusion and clinical outcomes in patients undergoing primary percutaneous coronary intervention for AMI. Out of 2,060 randomized patients, 82 (3.98%) received red blood cell transfusion during index hospitalization. Transfusion was independently associated with baseline anemia, older age, multivessel disease, and female gender. Patients transfused, versus patients not transfused, had significantly higher rates of one year mortality (23.9% vs. 3.4%), disabling stoke (2.5% vs. 0.5%), reinfarction (7.0% vs. 2.2%) and composite major adverse cardiac events (41.0% vs.16.6%). After multivariable adjustment for potential confounders, red blood cell transfusion was independently associated with mortality at 30 days and one year (hazard ratio 4.71 and 3.16 respectively, both p=0.0005). The authors concluded that red blood cell transfusion after primary angioplasty in the setting of an AMI may be harmful or alternatively transfusion could be a marker of markedly increased risk, with further randomized studies needed to determine the optimal threshold for red blood cell transfusion in this patient population setting

Kinematic body responses and perceived discomfort in a bumpy ride: Effects of sitting posture

The present study investigates perceived comfort and whole-body vibration transmissibility in intensive repetitive pitch exposure representing a bumpy ride. Three sitting strategies (preferred, erect, and slouched) were evaluated for perceived body discomfort and body kinematic responses. Nine male and twelve female participants were seated in a moving-based driving simulator. The slouched posture significantly increased lateral and yaw body motion and induced more discomfort in the seat back area. After three repetitive exposures, participants anticipated the upcoming motion using more-effective postural control strategies to stabilize pelvis, trunk, and head in space.Comment: 4 pages, 2 tables, 1 figur

Evaluation of motion comfort using advanced active human body models and efficient simplified models

Active muscles are crucial for maintaining postural stability when seated in a moving vehicle. Advanced active 3D non-linear full body models have been developed for impact and comfort simulation, including large numbers of individual muscle elements, and detailed non-linear models of the joint structures. While such models have an apparent potential to provide insight into postural stabilization, they are computationally demanding, making them less practical in particular for driving comfort where long time periods are to be studied. In vibrational comfort and in general biomechanical research, linearized models are effectively used. This paper evaluates the effectiveness of simplified 3D full-body human models to capture comfort provoked by whole-body vibrations. An efficient seated human body model is developed and validated using experimental data. We evaluate the required complexity in terms of joints and degrees of freedom for the spine, and explore how well linear spring-damper models can approximate reflexive postural stabilization. Results indicate that linear stiffness and damping models can well capture the human response. The results are improved by adding proportional integral derivative (PID) and head-in-space (HIS) controllers to maintain the defined initial body posture. The integrator is shown to be essential to prevent drift from the defined posture. The joint angular relative displacement is used as the input reference to each PID controller. With this model, a faster than real-time solution is obtained when used with a simple seat model. The paper also discusses the advantages and disadvantages of various models and provides insight into which models are more appropriate for motion comfort analysis