On the coarse-grained density and compressibility of non-ideal crystals: general theory and an application to cluster crystals

The isothermal compressibility of a general crystal is analyzed within classical density functional theory. Our approach can be used for homogeneous and unstrained crystals containing an arbitrarily high density of local defects. We start by coarse-graining the microscopic particle density and then obtain the long wavelength limits of the correlation functions of elasticity theory and the thermodynamic derivatives. We explicitly show that the long wavelength limit of the microscopic density correlation function differs from the isothermal compressibility. It also cannot be obtained from the static structure factor measured in a scattering experiment. We apply our theory to crystals consisting of soft particles which can multiply occupy lattice sites ('cluster crystals'). The multiple occupancy results in a strong local disorder over an extended range of temperatures. We determine the cluster crystals' isothermal compressibility, the fluctuations of the lattice occupation numbers and their correlation functions, and the dispersion relations. We also discuss their low-temperature phase diagram.Comment: 20 pages, 6 figures. arXiv admin note: substantial text overlap with arXiv:1206.618

Identification of proteins binding specifically to the 3′-untranslated region of granulocyte/macrophagecolony stimulating factor mRNA

The 3′-untranslated region of granulocyte/macrophage colony-stimulating factor (GM-CSF) mRNA contributes to the post-transcriptional regulation of gene expression. Degradation is partly mediated by adenosine-uridine-rich sequence elements (ARE), which serve as binding sites for specific proteins. Stabilization of RNA by phytohemagglutinin and concanavalin A treatment is dependent on regulatory sequence elements upstream of ARE. We have performed northwestern blot and filter binding assays using cell extracts and RNA sequences containing or lacking ARE. Murine and human T cell extracts (EL-4 and Jurkat) yielded two specific proteins of 93 and 94 kDa, respectively, that were binding to sequences upstream of ARE. Within this region, the human and murine RNA do not share any obvious sequence identity, yet both are target sites for the binding proteins. The smallest RNA fragments protected by the proteins from RNase A digestion, were 44 in the murine, and 38 ribonucleotides long in the human sequence. The binding activity of the 94 kDa protein derived from human Jurkat cells could be enhanced by phytohemagglutinin. The interaction with regulatory mRNA sequences and the responsiveness to phytohemagglutinin suggests that the proteins are involved in controlling GM-CSF mRNA turnove

Gamifying Navigation in Location-Based Applications

Location-based games entertain players usually by interactions at points of interest (POIs). Navigation between POIs often involve the use of either a physical or digital map, not taking advantage of the opportunity available to engage users in activities between POIs. The paper presents riddle solving as a navigational method for a location-based game. 10 families with 2-6 persons and at least one child in the age range 9- 11 years old participated in the evaluation. Results show that riddle solving as a navigational method is more enjoyable than a 2D digital map. Additional findings from video recordings, field notes, questionnaires, logging and semi-structured interviews revealed that riddle solving has potential for engaging users in learning activities

Comparison of Interstitial Fluid pH, PCO2, PO2 with Venous Blood Values During Repetitive Handgrip Exercise

We evaluated the use of a small, fiber optic sensor to measure pH, PCO2 and PO2 from forearm muscle interstitial fluid (IF) during handgrip dynamometry. PURPOSE: Compare pH, PCO2 and PO2 values obtained from venous blood with those from the IF of the flexor digitorum superficialis (FDS) during three levels of exercise intensity. METHODS: Six subjects (5M/1F), average age 29+/-5 yrs, participated in the study. A venous catheter was placed in the retrograde direction in the antecubital space and a fiber optic sensor (Paratrend, Diametrics Medical, Inc.) was placed through a 22 G catheter into the FDS muscle under ultrasound guidance. After a 45 min rest period, subjects performed three 5-min bouts of repetitive handgrip exercise (2s contraction/1 s relaxation) at attempted levels of 15%, 30% and 45% of maximal voluntary contraction. The order of the exercise bouts was random with the second and third bouts started after blood lactate had returned to baseline. Venous blood was sampled every minute during exercise and analyzed with an I-Stat CG-4+ cartridge, while IF fiber optic sensor measurements were obtained every 2 s. Change from pre-exercise baseline to end of exercise was computed for pH, PCO2 and PO2. Blood and IF values were compared with a paired t-test. RESULTS: Baseline values for pH, PCO2 and PO2 were 7.37+/-0.02, 46+/-4 mm Hg, and 36+/-6 mm Hg respectively in blood and 7.39+/-0.02, 44+/-6 mm Hg, and 35+/-14 mm Hg in IF. Average changes over all exercise levels are noted in the Table below. For each parameter the exercise-induced change was at least twice as great in IF as in blood. In blood and IF, pH and PCO2 increases were directly related to exercise intensity. Change in venous PO2 was unrelated to exercise intensity, while IF PO2 decreased with increases in exercise intensity. CONCLUSIONS: Measurement of IF pH, PCO2 and PO2 is more sensitive to exercise intensity than measurement of the same parameters in venous blood and provides continuous assessment during and after exercise

Sächsische Landschaften im Wandel: Auswertung historischer Kartenwerke für umweltwissenschaftliche Fragestellungen

Die Kenntnis des Landschaftswandels ist eine unverzichtbare Grundlage für die Bearbeitung umweltwissenschaftlicher Fragestellungen in der Raumplanung. Im Mittelpunkt des Beitrages stehen vor diesem Hintergrund die Ziele und Methoden historischer Landschaftsanalysen und die Untersuchung der Einflussfaktoren der Landschaftsentwicklung. Anhand von vier Fallstudien werden unterschiedliche Anwendungsgebiete derartiger Untersuchungen vorgestellt. Der Schwerpunkt liegt dabei einerseits auf der aus historischen Karten extrahierbaren Informationsfülle sowie andererseits auf methodischen Aspekten einer GIS- und modellbasierten Analyse des Landschaftswandels. Exemplarisch werden geeignete Kartengrundlagen für Sachsen dargestellt, die bis ins Jahr 1780 zurückgehen. Diese enthalten nicht nur Informationen über die historische Nutzung und deren Verlauf, aus ihnen lassen sich darüber hinaus wertvolle Zusatzinformationen zu früheren Landschaftszuständen gewinnen, z.B. zu historischen Landschaftsfunktionen und -potenzialen. Mit Hilfe dieser Kenntnisse lassen sich Prognosen der zukünftigen Landschaftsentwicklung ableiten und auf negative Entwicklungen kann so hingewiesen werden. In diesem Sinne verbindet der den vier Fallstudien gemeine Ansatz die klassische Landschaftsanalyse mit modernen Methoden, indem er die Untersuchungsgegenstände in ein geographisches Informationssystem (GIS) einbindet und damit ein weites Spektrum an Analysewerkzeugen eröffnet. Dazu gehört beispielsweise die statistische Analyse der räumlichen Anordnung von Landschaftselementen mit geeigneten Landschaftsstrukturmaßen.The issues of historical landscape analyses and the influencing factors of landscape development is an essential basis for environmental questions and especially for spatial planning. This paper focuses on objectives and methods of historical landscape analysis. Four case studies showing results of different projects and therewith various applications of such investigations. The main interest is to discuss methodical aspects of a GIS-based landscape analysis as well as extraction possibilities of the comprehensive historical map content. Exemplary convenient map sources of the German Free State of Saxony will be shown, which are going back to the year 1780. Former states of landscape situations contain not only historical land use information. Moreover, it is possible to achieve valuable additional information from such data, e.g. about historical pattern of landscape functions, potentials or structures. With the help of these cognitions prognoses of future landscape development are derivable and negative developments could be prevented. The here presented approach combines approaches of classical landscape analysis with modern methods such as Geographical Information Systems (GIS), their functionality for spatial analysis as well as landscape structure analysis tools

Testing a Novel Manual Communication System for Mechanically Ventilated ICU Patients

Introduction: Available communication methods for intubated patients in the ICU are insufficient to meet patient needs. Both ICU patients and their care providers report broadly unsuccessful communication attempts, resulting in less effective medical care and undue stress1,2. Use of existing methods - including letter boards, writing, and mouthing words - for mechanically ventilated (MV) patients has led to a consensus that new methods are required3. We report on the testing of a new system designed to address the communication needs of MV patients that is currently being tested in a low- to medium- acuity surgical ICU4. Methods: We have developed several generations of prototypes designed to address patient communication needs. Design of this device has focused on ICU-specific communication needs, including ICU-specific content, infection control, simple design, and capitalizing on motor movements that can be easily performed by most ICU patients. Initial testing, starting with non-MV patients able to give more detailed feedback, has begun in a low- to medium- acuity surgical ICU. Recently developed prototypes combine custom-built tablet software, focusing on the needs that nurses believe patients wish to express in the ICU setting, with a newly designed manually operated access device. The system produces visual and auditory output to allow patients to answer basic questions and effectively convey information. Results: Initial patient impressions are encouraging, particularly among patients who have recently experienced mechanical ventilation. Many patients are unfamiliar with tablet software or struggle with manual dexterity required to access the tablet screen directly, further indicating the need for an external access method as part of the system. The content suggested by nurses via a previously conducted survey has been confirmed by patients as relevant to their experience. Conclusions: A novel manually operated communication system has elicited both positive reviews and helpful feedback from patients

Principles of Augmentative and Alternative Communication System Design in the ICU Setting

Introduction: The ICU as a technology design setting requires specific and thoughtful awareness of patient-, caregiver-, and environment-related constraints. Designing an ICU-specific communication system involves an even deeper understanding of patient needs and desires, building on existing work exploring available technologies for use in this setting1,2. We report our initial experience from a pilot study with a novel communication device engineered specifically to allow mechanically ventilated ICU patients to communicate with caregivers3. Methods: We used a validated survey for nurses about communication purposes to explore relevant beliefs, attitudes, and desires of nurses4. Existing technologies available for communication assistance in the ICU – e.g., letter boards, writing on paper, and mouthing words – were analyzed. Suggestions about the content for an eventual communication system were collected. ICU-specific design requirements were noted, including adherence to infection control standards, accessibility to restrained patients, and availability to patients with motor weakness, contractures, edema, tremor, and/or neuropathy. In addition, the system must include a minimal learning curve, Results: Initial testing in the ICU has revealed additional considerations for technology design. For instance, many patients have visual impairments, so displays should be large and high-contrast. Furthermore, patients benefit from a very short teaching/demo process due to their short attention span. Additionally, leveraging interfaces with significant similarities to everyday systems appears to reduce confusion. Nurses also mentioned that the system should be accessible to at least some non-English-speaking patients. Finally, physical deficits that ICU patients experience require that manually operated devices be as flexible as possible in terms of type of manipulation required. Conclusions: ICU patients are in significant need of communication systems that meet their unique needs. Building such a system requires awareness of many different constraints, including both general heterogeneity of patient needs and capabilities and the constraints of the ICU setting itself