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Introduction
Injury prevention programs (IPPs) are an inherent part of training in recreational and professional sports. Providing performance-enhancing benefits in addition to injury prevention may help adjust coaches and athletes’ attitudes towards implementation of injury prevention into daily routine. Conventional thinking by players and coaches alike seems to suggest that IPPs need to be specific to one’s sport to allow for performance enhancement. The systematic literature review aims to firstly determine the IPPs nature of exercises and whether they are specific to the sport or based on general conditioning. Secondly, can they demonstrate whether general, sports-specific or even mixed IPPs improve key performance indicators with the aim to better facilitate long-term implementation of these programs?
Methods
PubMed and Web of Science were electronically searched throughout March 2018. The inclusion criteria were randomized control trials, publication dates between Jan 2006 and Feb 2018, athletes (11–45 years), injury prevention programs and included predefined performance measures that could be categorized into balance, power, strength, speed/agility and endurance. The methodological quality of included articles was assessed with the Cochrane Collaboration assessment tools.
Results
Of 6619 initial findings, 22 studies met the inclusion criteria. In addition, reference lists unearthed a further 6 studies, making a total of 28. Nine studies used sports specific IPPs, eleven general and eight mixed prevention strategies. Overall, general programs ranged from 29–57% in their effectiveness across performance outcomes. Mixed IPPs improved in 80% balance outcomes but only 20–44% in others. Sports-specific programs led to larger scale improvements in balance (66%), power (83%), strength (75%), and speed/agility (62%).
Conclusion
Sports-specific IPPs have the strongest influence on most performance indices based on the significant improvement versus control groups. Other factors such as intensity, technical execution and compliance should be accounted for in future investigations in addition to exercise modality.
The foreland of the Andes in South America is characterised by distinct along strike changes in surface deformational styles. These styles are classified into two end-members, the thin-skinned and the thick-skinned style. The superficial expression of thin-skinned deformation is a succession of narrowly spaced hills and valleys, that form laterally continuous ranges on the foreland facing side of the orogen. Each of the hills is defined by a reverse fault that roots in a basal décollement surface within the sedimentary cover, and acted as thrusting ramp to stack the sedimentary pile. Thick-skinned deformation is morphologically characterised by spatially disparate, basement-cored mountain ranges. These mountain ranges are uplifted along reactivated high-angle crustal-scale discontinuities, such as suture zones between different tectonic terranes.
Amongst proposed causes for the observed variation are variations in the dip angle of the Nazca plate, variation in sediment thickness, lithospheric thickening, volcanism or compositional differences. The proposed mechanisms are predominantly based on geological observations or numerical thermomechanical modelling, but there has been no attempt to understand the mechanisms from a point of data-integrative 3D modelling. The aim of this dissertation is therefore to understand how lithospheric structure controls the deformational behaviour. The integration of independent data into a consistent model of the lithosphere allows to obtain additional evidence that helps to understand the causes for the different deformational styles. Northern Argentina encompasses the transition from the thin-skinned fold-and-thrust belt in Bolivia, to the thick-skinned Sierras Pampeanas province, which makes this area a well suited location for such a study. The general workflow followed in this study first involves data-constrained structural- and density-modelling in order to obtain a model of the study area. This model was then used to predict the steady-state thermal field, which was then used to assess the present-day rheological state in northern Argentina.
The structural configuration of the lithosphere in northern Argentina was determined by means of data-integrative, 3D density modelling verified by Bouguer gravity. The model delineates the first-order density contrasts in the lithosphere in the uppermost 200 km, and discriminates bodies for the sediments, the crystalline crust, the lithospheric mantle and the subducting Nazca plate. To obtain the intra-crustal density structure, an automated inversion approach was developed and applied to a starting structural model that assumed a homogeneously dense crust. The resulting final structural model indicates that the crustal structure can be represented by an upper crust with a density of 2800 kg/m³, and a lower crust of 3100 kg/m³. The Transbrazilian Lineament, which separates the Pampia terrane from the Río de la Plata craton, is expressed as a zone of low average crustal densities.
In an excursion, we demonstrate in another study, that the gravity inversion method developed to obtain intra-crustal density structures, is also applicable to obtain density variations in the uppermost lithospheric mantle. Densities in such sub-crustal depths are difficult to constrain from seismic tomographic models due to smearing of crustal velocities. With the application to the uppermost lithospheric mantle in the north Atlantic, we demonstrate in Tan et al. (2018) that lateral density trends of at least 125\,km width are robustly recovered by the inversion method, thereby providing an important tool for the delineation of subcrustal density trends.
Due to the genetic link between subduction, orogenesis and retroarc foreland basins the question rises whether the steady-state assumption is valid in such a dynamic setting. To answer this question, I analysed (i) the impact of subduction on the conductive thermal field of the overlying continental plate, (ii) the differences between the transient and steady-state thermal fields of a geodynamic coupled model. Both studies indicate that the assumption of a thermal steady-state is applicable in most parts of the study area. Within the orogenic wedge, where the assumption cannot be applied, I estimated the transient thermal field based on the results of the conducted analyses.
Accordingly, the structural model that had been obtained in the first step, could be used to obtain a 3D conductive steady-state thermal field. The rheological assessment based on this thermal field indicates that the lithosphere of the thin-skinned Subandean ranges is characterised by a relatively strong crust and a weak mantle. Contrarily, the adjacent foreland basin consists of a fully coupled, very strong lithosphere. Thus, shortening in northern Argentina can only be accommodated within the weak lithosphere of the orogen and the Subandean ranges. The analysis suggests that the décollements of the fold-and-thrust belt are the shallow continuation of shear zones that reside in the ductile sections of the orogenic crust. Furthermore, the localisation of the faults that provide strain transfer between the deeper ductile crust and the shallower décollement is strongly influenced by crustal weak zones such as foliation. In contrast to the northern foreland, the lithosphere of the thick-skinned Sierras Pampeanas is fully coupled and characterised by a strong crust and mantle. The high overall strength prevents the generation of crustal-scale faults by tectonic stresses. Even inherited crustal-scale discontinuities, such as sutures, cannot sufficiently reduce the strength of the lithosphere in order to be reactivated. Therefore, magmatism that had been identified to be a precursor of basement uplift in the Sierras Pampeanas, is the key factor that leads to the broken foreland of this province. Due to thermal weakening, and potentially lubrication of the inherited discontinuities, the lithosphere is locally weakened such that tectonic stresses can uplift the basement blocks. This hypothesis explains both the spatially disparate character of the broken foreland, as well as the observed temporal delay between volcanism and basement block uplift.
This dissertation provides for the first time a data-driven 3D model that is consistent with geophysical data and geological observations, and that is able to causally link the thermo-rheological structure of the lithosphere to the observed variation of surface deformation styles in the retroarc foreland of northern Argentina.
The fabrication of 1D nanostrands composed of stimuli responsive microgels has been shown in this work. Microgels are well known materials able to respond to various stimuli from outer environment. Since these microgels respond via a volume change to an external stimulus, a targeted mechanical response can be achieved. Through carefully choosing the right composition of the polymer matrix, microgels can be designed to react precisely to the targeted stimuli (e.g. drug delivery via pH and temperature changes, or selective contractions through changes in electrical current125).
In this work, it was aimed to create flexible nano-filaments which are capable of fast anisotropic contractions similar to muscle filaments. For the fabrication of such filaments or strands, nanostructured templates (PDMS wrinkles) were chosen due to a facile and low-cost fabrication and versatile tunability of their dimensions. Additionally, wrinkling is a well-known lithography-free method which enables the fabrication of nanostructures in a reproducible manner and with a high long-range periodicity.
In Chapter 2.1, it was shown for the first time that microgels as soft matter particles can be aligned to densely packed microgel arrays of various lateral dimensions. The alignment of microgels with different compositions (e.g. VCL/AAEM, NIPAAm, NIPAAm/VCL and charged microgels) was shown by using different assembly techniques (e.g. spin-coating, template confined molding). It was chosen to set one experimental parameter constant which was the SiOx surface composition of the templates and substrates (e.g. oxidized PDMS wrinkles, Si-wafers and glass slides). It was shown that the fabrication of nanoarrays was feasible with all tested microgel types. Although the microgels exhibited different deformability when aligned on a flat surface, they retained their thermo-responsivity and swelling behavior.
Towards the fabrication of 1D microgel strands interparticle connectivity was aspired. This was achieved via different cross-linking methods (i.e. cross-linking via UV-irradiation and host-guest complexation) discussed in Chapter 2.2. The microgel arrays created by different assembly methods and microgel types were tested for their cross-linking suitability. It was observed that NIPAAm based microgels cannot be cross-linked with UV light. Furthermore, it was found that these microgels exhibit a strong surface-particle-interaction and therefore could not be detached from the given substrates. In contrast to the latter, with VCL/AAEM based microgels it was possible to both UV cross-link them based on the keto-enol tautomerism of the AAEM copolymer, and to detach them from the substrate due to the lower adhesion energy towards SiOx surfaces. With VCL/AAEM microgels long, one-dimensional microgel strands could be re-dispersed in water for further analysis. It has also been shown that at least one lateral dimension of the free dispersed 1D microgel strands is easily controllable by adjusting the wavelength of the wrinkled template. For further work, only VCL/AAEM based microgels were used to focus on the main aim of this work, i.e. the fabrication of 1D microgel nanostrands.
As an alternative to the unspecific and harsh UV cross-linking, the host-guest complexation via diazobenzene cross-linkers and cyclodextrin hosts was explored. The idea behind this approach was to give means to a future construction kit-like approach by incorporation of cyclodextrin comonomers in a broad variety of particle systems (e.g. microgels, nanoparticles). For this purpose, VCL/AAEM microgels were copolymerized with different amounts of mono-acrylate functionalized β-cyclodextrin (CD). After successfully testing the cross-linking capability in solution, the cross-linking of aligned VCL/AAEM/CD microgels was tried. Although the cross-linking worked well, once the single arrays came into contact to each other, they agglomerated. As a reason for this behavior residual amounts of mono-complexed diazobenzene linkers were suspected. Thus, end-capping strategies were tried out (e.g. excess amounts of β-cyclodextrin and coverage with azobenzene functionalized AuNPs) but were unsuccessful. With deeper thought, entropy effects were taken into consideration which favor the release of complexed diazobenzene linker leading to agglomerations. To circumvent this entropy driven effect, a multifunctional polymer with 50% azobenzene groups (Harada polymer) was used. First experiments with this polymer showed promising results regarding a less pronounced agglomeration (Figure 77). Thus, this approach could be pursued in the future. In this chapter it was found out that in contrast to pearl necklace and ribbon like formations, particle alignment in zigzag formation provided the best compromise in terms of stability in dispersion (see Figure 44a and Figure 51) while maintaining sufficient flexibility.
For this reason, microgel strands in zigzag formation were used for the motion analysis described in Chapter 2.3. The aim was to observe the properties of unrestrained microgel strands in solution (e.g. diffusion behavior, rotational properties and ideally, anisotropic contraction after temperature increase). Initially, 1D microgel strands were manipulated via AFM in a liquid cell setup. It could be observed that the strands required a higher load force compared to single microgels to be detached from the surface. However, with the AFM it was not possible to detach the strands in a controllable manner but resulted in a complete removal of single microgel particles and a tearing off the strands from the surface, respectively. For this reason, to observe the motion behavior of unrestrained microgel strands in solution, confocal microscopy was used. Furthermore, to hinder an adsorption of the strands, it was found out that coating the surface of the substrates with a repulsive polymer film was beneficial. Confocal and wide-field microscopy videos showed that the microgel strands exhibit translational and rotational diffusive motion in solution without perceptible bending. Unfortunately, with these methods the detection of the anisotropic stimuli responsive contraction of the free moving microgel strands was not possible. To summarize, the flexibility of microgel strands is more comparable to the mechanical behavior of a semi flexible cable than to a yarn. The strands studied here consist of dozens or even hundreds of discrete submicron units strung together by cross-linking, having few parallels in nanotechnology.
With the insights gained in this work on microgel-surface interactions, in the future, a targeted functionalization of the template and substrate surfaces can be conducted to actively prevent unwanted microgel adsorption for a given microgel system (e.g. PVCL and polystyrene coating235). This measure would make the discussed alignment methods more diverse. As shown herein, the assembly methods enable a versatile microgel alignment (e.g. microgel meshes, double and triple strands). To go further, one could use more complex templates (e.g. ceramic rhombs and star shaped wrinkles (Figure 14) to expand the possibilities of microgel alignment and to precisely control their aspect ratios (e.g. microgel rods with homogeneous size distributions).
Introduction: Many semiarid regions around the world are presently experiencing significant changes in both climatic conditions and vegetation. This includes a disturbed coexistence between grasses and bushes also known as bush encroachment, and altered precipitation patterns with larger rain events. Fewer, more intense precipitation events might promote groundwater recharge, but depending on the structure of the vegetation also encourage further woody encroachment.
Materials and Methods: In this study, we investigated how patterns and sources of water uptake of Acacia mellifera (blackthorn), an important encroaching woody plant in southern African savannas, are associated with the intensity of rain events and the size of individual shrubs. The study was conducted at a commercial cattle farm in the semiarid Kalahari in Namibia (MAP 250 mm/a). We used soil moisture dynamics in different depths and natural stable isotopes as markers of water sources. Xylem water of fifteen differently sized individuals during eight rain events was extracted using a Scholander pressure bomb.
Results and Discussion: Results suggest the main rooting activity zone of A. mellifera in 50 and 75 cm soil depth but a reasonable water uptake from 10 and 25 cm. Any apparent uptake pattern seems to be driven by water availability, not time in the season. Bushes prefer the deeper soil layers after heavier rain events, indicating some evidence for the classical Walter’s two-layer hypothesis. However, rain events up to a threshold of 6 mm/day cause shallower depths of use and suggest several phases of intense competition with perennial grasses. The temporal uptake pattern does not depend on shrub size, suggesting a fast upwards water flow inside. d2H and d18O values in xylem water indicate that larger shrubs rely less on upper and very deep soil water than smaller shrubs. It supports the hypothesis that in environments where soil moisture is highly variable in the upper soil layers, the early investment in a deep tap-root to exploit deeper, more reliable water sources could reduce the probability of mortality during the establishment phase. Nevertheless, independent of size and time in the season, bushes do not compete with potential groundwater recharge. In a savanna encroached by A. mellifera, groundwater will most likely be affected indirectly.
In this study, we analyze the forecast accuracy and profitability of buy recommendations published in five major German financial magazines for private households based on fundamental analysis. The results show a high average forecast accuracy but with a very high standard deviation, which indicates poor forecast accuracy with regard to individual stocks. The recommendation profitability slightly exceeds the performance of the MSCI World index. Considering the involved risk, which is represented by a high standard deviation, the excess returns appear to be insufficient.
Genetic divergence is impacted by many factors, including phylogenetic history, gene flow, genetic drift, and divergent selection. Rotifers are an important component of aquatic ecosystems, and genetic variation is essential to their ongoing adaptive diversification and local adaptation. In addition to coding sequence divergence, variation in gene expression may relate to variable heat tolerance, and can impose ecological barriers within species. Temperature plays a significant role in aquatic ecosystems by affecting species abundance, spatio-temporal distribution, and habitat colonization. Recently described (formerly cryptic) species of the Brachionus calyciflorus complex exhibit different temperature tolerance both in natural and in laboratory studies, and show that B. calyciflorus sensu stricto (s.s.) is a thermotolerant species. Even within B. calyciflorus s.s., there is a tendency for further temperature specializations. Comparison of expressed genes allows us to assess the impact of stressors on both expression and sequence divergence among disparate populations within a single species. Here, we have used RNA-seq to explore expressed genetic diversity in B. calyciflorus s.s. in two mitochondrial DNA lineages with different phylogenetic histories and differences in thermotolerance. We identify a suite of candidate genes that may underlie local adaptation, with a particular focus on the response to sustained high or low temperatures. We do not find adaptive divergence in established candidate genes for thermal adaptation. Rather, we detect divergent selection among our two lineages in genes related to metabolism (lipid metabolism, metabolism of xenobiotics).
Background
Sand is an easy-to-access, cost-free resource that can be used to treat pronated feet (PF). Therefore, the aims of this study were to contrast the effects of walking on stable ground versus walking on sand on ground reaction forces (GRFs) and electromyographic (EMG) activity of selected lower limb muscles in PF individuals compared with healthy controls.
Methods
Twenty-nine controls aged 22.2±2.5 years and 30 PF individuals aged 22.2±1.9 years were enrolled in this study. Participants walked at preferred speed and in randomized order over level ground and sand. A force plate was included in the walkway to collect GRFs. Muscle activities were recorded using EMG system.
Results
No statistically significant between-group differences were found in preferred walking speed when walking on stable ground (PF: 1.33±0.12 m/s; controls: 1.35±0.14 m/s; p = 0.575; d = 0.15) and sand (PF: 1.19±0.11 m/s; controls: 1.23±0.18 m/s; p = 0.416; d = 0.27). Irrespective of the group, walking on sand (1.21±0.15 m/s) resulted in significantly lower gait speed compared with stable ground walking (1.34±0.13 m/s) (p<0.001; d = 0.93). Significant main effects of “surface” were found for peak posterior GRFs at heel contact, time to peak for peak lateral GRFs at heel contact, and peak anterior GRFs during push-off (p<0.044; d = 0.27–0.94). Pair-wise comparisons revealed significantly smaller peak posterior GRFs at heel contact (p = 0.005; d = 1.17), smaller peak anterior GRFs during push-off (p = 0.001; d = 1.14), and time to peak for peak lateral GRFs (p = 0.044; d = 0.28) when walking on sand. No significant main effects of “group” were observed for peak GRFs and their time to peak (p>0.05; d = 0.06–1.60). We could not find any significant group by surface interactions for peak GRFs and their time to peak. Significant main effects of “surface” were detected for anterior-posterior impulse and peak positive free moment amplitude (p<0.048; d = 0.54–0.71). Pair-wise comparisons revealed a significantly larger peak positive free moment amplitude (p = 0.010; d = 0.71) and a lower anterior-posterior impulse (p = 0.048; d = 0.38) when walking on sand. We observed significant main effects of “group” for the variable loading rate (p<0.030; d = 0.59). Pair-wise comparisons revealed significantly lower loading rates in PF compared with controls (p = 0.030; d = 0.61). Significant group by surface interactions were observed for the parameter peak positive free moment amplitude (p<0.030; d = 0.59). PF individuals exhibited a significantly lower peak positive free moment amplitude (p = 0.030, d = 0.41) when walking on sand. With regards to EMG, no significant main effects of “surface”, main effects of “group”, and group by surface interactions were observed for the recorded muscles during the loading and push-off phases (p>0.05; d = 0.00–0.53).
Conclusions
The observed lower velocities during walking on sand compared with stable ground were accompanied by lower peak positive free moments during the push-off phase and loading rates during the loading phase. Our findings of similar lower limb muscle activities during walking on sand compared with stable ground in PF together with lower free moment amplitudes, vertical loading rates, and lower walking velocities on sand may indicate more relative muscle activity on sand compared with stable ground. This needs to be verified in future studies.
Background: Telerehabilitation can contribute to the maintenance of successful rehabilitation regardless of location and time. The aim of this study was to investigate a specific three-month interactive telerehabilitation routine regarding its effectiveness in assisting patients with physical functionality and with returning to work compared to typical aftercare.
Objective: The aim of the study was to investigate a specific three-month interactive telerehabilitation with regard to effectiveness in functioning and return to work compared to usual aftercare.
Methods: From August 2016 to December 2017, 111 patients (mean 54.9 years old; SD 6.8; 54.3% female) with hip or knee replacement were enrolled in the randomized controlled trial. At discharge from inpatient rehabilitation and after three months, their distance in the 6-minute walk test was assessed as the primary endpoint. Other functional parameters, including health related quality of life, pain, and time to return to work, were secondary endpoints.
Results: Patients in the intervention group performed telerehabilitation for an average of 55.0 minutes (SD 9.2) per week. Adherence was high, at over 75%, until the 7th week of the three-month intervention phase. Almost all the patients and therapists used the communication options. Both the intervention group (average difference 88.3 m; SD 57.7; P=.95) and the control group (average difference 79.6 m; SD 48.7; P=.95) increased their distance in the 6-minute-walk-test. Improvements in other functional parameters, as well as in quality of life and pain, were achieved in both groups. The higher proportion of working patients in the intervention group (64.6%; P=.01) versus the control group (46.2%) is of note.
Conclusions: The effect of the investigated telerehabilitation therapy in patients following knee or hip replacement was equivalent to the usual aftercare in terms of functional testing, quality of life, and pain. Since a significantly higher return-to-work rate could be achieved, this therapy might be a promising supplement to established aftercare.
Portal Wissen = Daten
(2019)
Datenassimilation? Halt! Keine Angst, treten Sie näher! Kein Zungenbrecher, keine Raketenwissenschaft. Oder doch? Wir werden sehen. Fakt ist: Datenassimilation gibt es eigentlich schon lange und (fast) überall. Doch erst im Zeitalter der Supercomputer nimmt sie Ausmaße an, die Staunen hervorruft.
Daten, kennt jeder. Assimilation jedoch ist ein schwieriger Begriff für etwas, das rings um uns die ganze Zeit stattfindet: Anpassung. Vor allem die Natur führt uns seit Millionen von Jahren vor, wie das geht mit der evolutionären Anpassung. Vom Einzeller zum Primaten, von der Alge zum Mammutbaum, vom Dino … Wer sich nicht anpassen kann, passt schnell nicht mehr ins Bild.
Und natürlich haben auch wir gelernt, uns in neuen Situationen zu orientieren und entsprechend zu handeln. Wenn wir über die Straße wollen, haben wir dafür einen Plan: an den Bordstein treten, nach links und rechts schauen und erst gehen, sobald kein Auto mehr kommt. Machen wir all dies und passen unseren Plan an den Verkehr an, den wir sehen, kommen wir nicht nur heil drüben an, sondern haben auch noch erfolgreich Datenassimilation betrieben.
Freilich klingt das anders, wenn Wissenschaftler zu erklären versuchen, wie ihnen Datenassimilation hilft. Meteorologen zum Beispiel arbeiten schon seit Jahren mit ihr. Der Deutsche Wetterdienst schreibt: „In der Numerischen Wettervorhersage versteht man unter Datenassimilation die Angleichung eines Modelllaufes an die wirkliche Entwicklung der Atmosphäre, wie sie durch die vorhandenen Beobachtungen beschrieben wird.“ Gemeint ist, dass eine Wettervorhersage nur dann genau ist, wenn das Modell, mit dem man sie berechnet, immer wieder mit neuen Messdaten aktualisiert, also assimiliert, wird.
Seit 2017 gibt es an der Universität Potsdam einen ganzen Sonderforschungsbereich, den SFB 1294, der sich mit den mathematischen Grundlagen der Datenassimilation beschäftigt. Für Portal Wissen haben wir die beiden Mathematiker und Sprecher des SFB, Prof. Sebastian Reich und Prof. Wilhelm Huisinga, gefragt, wie Datenassimilation eigentlich genau funktioniert – und in welchen Forschungsgebieten man sie künftig noch gewinnbringend einsetzen kann. Zwei Beispiele dafür haben wir uns im SFB gleich selbst angeschaut: die Analyse von Blickbewegungen und die Erforschung des Weltraumwetters.
Daneben ist die aktuelle Ausgabe des Magazins voller Forschungsprojekte, die auf verschiedenste Weise um Daten kreisen. So wirft der Atmosphärenphysiker Markus Rex einen Blick voraus auf die spektakuläre MOSAiC-Expedition, bei der der deutsche Forschungseisbrecher „Polarstern“ ab September 2019 ein Jahr lang eingefroren durch das Nordpolarmeer driften und dabei zahlreiche Daten rund um Eis, Ozean, Bio- und Atmosphäre sammeln wird. Wir haben ein Forschungskolleg besucht, dessen Doktoranden die Datensammelwut unserer neuen technologischen Alltagsbegleiter kritisch unter die Lupe nehmen. Im Projekt „TraceAge“ wollen Ernährungswissenschaftler mithilfe der Daten von Tausenden Probanden einer Langzeitstudie mehr über die Funktion von Spurenelementen in unserem Körper herausfinden. Informatiker haben eine Methode entwickelt, mit der aus der Datenflut des WWW relevante Informationen gefiltert werden, sodass Blinde leichter im Internet surfen können. Ein Biologe untersucht anhand von über Jahrzehnte hinweg erhobenen Daten, wie sich die brandenburgischen Wälder verändern. Und eine Geoforscherin arbeitet daran, aus unscheinbar wirkenden seismischen Daten ein Frühwarnsystem für Vulkanausbrüche zu entwickeln.
Außerdem haben wir uns das neue Schülerlabor der Chemiedidaktik zeigen lassen, einen Juniorprofessor für vergleichende Literaturwissenschaft nach seiner Lust am Ungewissen befragt und mit einer Verwaltungswissenschaftlerin über die Möglichkeiten der digitalen Verwaltung gesprochen. Es geht nicht zuletzt um den märkischen Eulenspiegel, personalisierte Kosmetik und die Frage, wie man Kinder für Sport und Bewegung begeistern kann. Wir wünschen Ihnen viel Vergnügen beim Lesen – und wenn Sie uns Erfahrungsdaten ihrer Lektüre zukommen lassen, werden wir unser nächstes Heft damit assimilieren. Versprochen!
Die Redaktion
Over the last years there is an increasing awareness that historical land cover changes and associated land use legacies may be important drivers for present-day species richness and biodiversity due to time-delayed extinctions or colonizations in response to historical environmental changes. Historically altered habitat patches may therefore exhibit an extinction debt or colonization credit and can be expected to lose or gain species in the future. However, extinction debts and colonization credits are difficult to detect and their actual magnitudes or payments have rarely been quantified because species richness patterns and dynamics are also shaped by recent environmental conditions and recent environmental changes.
In this thesis we aimed to determine patterns of herb-layer species richness and recent species richness dynamics of forest herb layer plants and link those patterns and dynamics to historical land cover changes and associated land use legacies. The study was conducted in the Prignitz, NE-Germany, where the forest distribution remained stable for the last ca. 100 years but where a) the deciduous forest area had declined by more than 90 per cent (leaving only remnants of "ancient forests"), b) small new forests had been established on former agricultural land ("post-agricultural forests"). Here, we analyzed the relative importance of land use history and associated historical land cover changes for herb layer species richness compared to recent environmental factors and determined magnitudes of extinction debt and colonization credit and their payment in ancient and post-agricultural forests, respectively.
We showed that present-day species richness patterns were still shaped by historical land cover changes that ranged back to more than a century. Although recent environmental conditions were largely comparable we found significantly more forest specialists, species with short-distance dispersal capabilities and clonals in ancient forests than in post-agricultural forests. Those species richness differences were largely contingent to a colonization credit in post-agricultural forests that ranged up to 9 species (average 4.7), while the extinction debt in ancient forests had almost completely been paid. Environmental legacies from historical agricultural land use played a minor role for species richness differences. Instead, patch connectivity was most important. Species richness in ancient forests was still dependent on historical connectivity, indicating a last glimpse of an extinction debt, and the colonization credit was highest in isolated post-agricultural forests. In post-agricultural forests that were better connected or directly adjacent to ancient forest patches the colonization credit was way smaller and we were able to verify a gradual payment of the colonization credit from 2.7 species to 1.5 species over the last six decades.
Lange gab es auf der Erde Dinge, die konnte nur der Mensch. Doch diese Zeit könnte zu Ende gehen. Mithilfe des universalen Werkzeugs, das uns einzigartig macht – unserer Intelligenz –, haben wir dafür gesorgt, dass wir es nicht länger sind. Zumindest wenn es darum geht, kognitive Aufgaben zu lösen. Künstliche Intelligenz kann inzwischen Schach spielen, Sprache verstehen, Auto fahren. Vieles sogar besser als wir. Wie kam es dazu?
Der Philosoph Aristoteles schuf mit seinen Syllogismen die ersten „Gesetze des Denkens“, die Mathematiker Blaise Pascal und Wilhelm Leibniz bauten einige der frühesten Rechenmaschinen, der Mathematiker George Boole führte als erster eine formale Sprache zur Darstellung der Logik ein, der Naturwissenschaftler Alan Turing schuf mit seiner Dechiffriermaschine „Colossus“ den ersten programmierbaren Computer. Philosophen, Mathematiker, Psychologen, Linguisten – seit Jahrhunderten entwickeln Wissenschaftlerin- nen und Wissenschaftler Formeln, Maschinen und Theorien, die es möglich machen sollen, unsere wertvollste Fähigkeit zu reproduzieren und womöglich sogar zu verbessern. Aber was ist das eigentlich: „Künstliche Intelligenz“?
Schon die Bezeichnung fordert zum Vergleich auf. Ist Künstliche Intelligenz wie menschliche Intelligenz? Alan Turing formulierte 1950 einen Test, der eine befriedigende operationale Definition von Intelligenz liefern sollte: Intelligent ist eine Maschine demnach, wenn sie ein dem Menschen gleichwertiges Denkvermögen besitzt. Sie muss also bei beliebigen kognitiven Aufgaben dasselbe Niveau erreichen. Beweisen muss sie dies, indem sie einen menschlichen Fragenden glauben lässt, sie sei ein Mensch. Keine leichte Sache: Immerhin muss sie dafür natürliche Sprache verarbeiten, Wissen speichern, aus diesem Schlüsse ziehen und Neues lernen können. Tatsächlich entstanden in den vergangenen zehn Jahren etliche KI-Systeme, die in Chat- Gesprächen, mit automatisch erzeugten Texten oder Bildern den Test auf die eine oder andere Weise bestanden. Im Fokus stehen nun meist andere Fragen: Braucht KI ihre Schöpfer überhaupt noch? Wird sie den Menschen nicht nur überflügeln, sondern eines Tages sogar ersetzen – sei es in der Welt der Arbeit oder sogar darüber hinaus? Löst KI im Zeitalter der allumfassenden digitalen Vernetzung unsere Probleme – oder wird sie Teil davon?
Über Künstliche Intelligenz, ihr Wesen, ihre Beschränkungen, ihr Potenzial und ihr Verhältnis zum Menschen wird nicht erst diskutiert seitdem es sie gibt. Vor allem Literatur und Kino haben Szenarien mit verschiedenstem Ausgang kreiert. Aber wie sehen das Wissenschaftler, die mit oder zu Künstlicher Intelligenz forschen? Für die aktuelle Ausgabe des Forschungsmagazins kamen ein Kognitionswissenschaftler, eine Bildungsforscherin und ein Informatiker darüber ins Gespräch. Daneben haben wir uns in der Hochschule nach Projekten umgesehen, deren fachliche Heimat die zahlreichen Möglichkeiten offenbart, die KI für viele Disziplinen erahnen lässt. So geht die Reise in die Geowissenschaften und die Informatik ebenso wie die Wirtschafts-, Gesundheits- und Literaturwissenschaften.
Daneben haben wir die Breite der Forschung an der Universität nicht aus den Augen verloren: Ein Jurist führt ein in die gar nicht so weltferne Sphäre des Weltraumrechts, während Astrophysiker daran arbeiten, dass modernste Teleskope zum richtigen Zeitpunkt genau in die Regionen des Weltraums schauen, wo gerade etwas „los ist“. Eine Chemikerin erklärt, warum die Batterie der Zukunft aus dem Drucker kommt, und Molekularbiologen berichten, wie sie stressresistente Pflanzen züchten wollen. Mit menschlichem Stress in der Arbeitswelt beschäftigt sich nicht nur ein Forschungs-, sondern auch ein Gründerprojekt. Darüber ist in diesem Heft genauso zu lesen wie über aktuelle Studien zum Restless Legs Syndrom bei Kindern oder aber der Situation von Muslimen in Brandenburg. Nicht zuletzt machen wir Sie mit jenen Schafen bekannt, die derzeit im Park Sanssouci weiden – im Auftrag der Wissenschaft. Gar nicht so dumm! Viel Vergnügen!
Die Redaktion
With the growth of information technology, patient attitudes are shifting – away from passively receiving care towards actively taking responsibility for their well- being. Handling doctor-patient relationships collaboratively and providing patients access to their health information are crucial steps in empowering patients. In mental healthcare, the implicit consensus amongst practitioners has been that sharing medical records with patients may have an unpredictable, harmful impact on clinical practice. In order to involve patients more actively in mental healthcare processes, Tele-Board MED (TBM) allows for digital collaborative documentation in therapist-patient sessions. The TBM software system offers a whiteboard-inspired graphical user interface that allows therapist and patient to jointly take notes during the treatment session. Furthermore, it provides features to automatically reuse the digital treatment session notes for the creation of treatment session summaries and clinical case reports. This thesis presents the development of the TBM system and evaluates its effects on 1) the fulfillment of the therapist’s duties of clinical case documentation, 2) patient engagement in care processes, and 3) the therapist-patient relationship. Following the design research methodology, TBM was developed and tested in multiple evaluation studies in the domains of cognitive behavioral psychotherapy and addiction care. The results show that therapists are likely to use TBM with patients if they have a technology-friendly attitude and when its use suits the treatment context. Support in carrying out documentation duties as well as fulfilling legal requirements contributes to therapist acceptance. Furthermore, therapists value TBM as a tool to provide a discussion framework and quick access to worksheets during treatment sessions. Therapists express skepticism, however, regarding technology use in patient sessions and towards complete record transparency in general. Patients expect TBM to improve the communication with their therapist and to offer a better recall of discussed topics when taking a copy of their notes home after the session. Patients are doubtful regarding a possible distraction of the therapist and usage in situations when relationship-building is crucial. When applied in a clinical environment, collaborative note-taking with TBM encourages patient engagement and a team feeling between therapist and patient. Furthermore, it increases the patient’s acceptance of their diagnosis, which in turn is an important predictor for therapy success. In summary, TBM has a high potential to deliver more than documentation support and record transparency for patients, but also to contribute to a collaborative doctor-patient relationship. This thesis provides design implications for the development of digital collaborative documentation systems in (mental) healthcare as well as recommendations for a successful implementation in clinical practice.
Restful choreographies
(2019)
Business process management has become a key instrument to organize work as many companies represent their operations in business process models. Recently, business process choreography diagrams have been introduced as part of the Business Process Model and Notation standard to represent interactions between business processes, run by different partners. When it comes to the interactions between services on the Web, Representational State Transfer (REST) is one of the primary architectural styles employed by web services today. Ideally, the RESTful interactions between participants should implement the interactions defined at the business choreography level.
The problem, however, is the conceptual gap between the business process choreography diagrams and RESTful interactions. Choreography diagrams, on the one hand, are modeled from business domain experts with the purpose of capturing, communicating and, ideally, driving the business interactions. RESTful interactions, on the other hand, depend on RESTful interfaces that are designed by web engineers with the purpose of facilitating the interaction between participants on the internet. In most cases however, business domain experts are unaware of the technology behind web service interfaces and web engineers tend to overlook the overall business goals of web services. While there is considerable work on using process models during process implementation, there is little work on using choreography models to implement interactions between business processes. This thesis addresses this research gap by raising the following research question: How to close the conceptual gap between business process choreographies and RESTful interactions? This thesis offers several research contributions that jointly answer the research question.
The main research contribution is the design of a language that captures RESTful interactions between participants---RESTful choreography modeling language. Formal completeness properties (with respect to REST) are introduced to validate its instances, called RESTful choreographies. A systematic semi-automatic method for deriving RESTful choreographies from business process choreographies is proposed. The method employs natural language processing techniques to translate business interactions into RESTful interactions. The effectiveness of the approach is shown by developing a prototypical tool that evaluates the derivation method over a large number of choreography models.
In addition, the thesis proposes solutions towards implementing RESTful choreographies. In particular, two RESTful service specifications are introduced for aiding, respectively, the execution of choreographies' exclusive gateways and the guidance of RESTful interactions.
Portal = Wohnen
(2019)
Zuhause. Ein schönes Wort, wenn man eines hat. Ein Sehnsuchtswort, wenn man keines hat oder das eigene Zuhause nicht sicher ist. Zuhause steht auf dem Spiel, das zeigten die Nachrichten der vergangenen Monate und Jahre – in Potsdam und Berlin ebenso wie in vielen anderen Städten. Überall fehlt Wohnraum, den sich Menschen leisten können.
Seit Monaten kursiert auch in unserem Referat die Frage: Gibt es etwas Neues wegen deiner Wohnung? Streit mit dem Vermieter, Eigentümerwechsel oder eine auszehrende Wohnungssuche – was uns persönlich beschäftigt, ist derzeit überall zu hören. Deswegen möchten wir in der aktuellen Ausgabe des Universitätsmagazins Portal dem Thema Wohnen auf den Grund gehen.
Was bedeutet der Mangel an bezahlbarem Wohnraum für die soziale Mischung und wie kann die Politik hier eingreifen? Das haben wir einen Sozialwissenschaftler gefragt. Und wir haben uns umgehört, wie Studierende und Beschäftigte der Universität Potsdam eigentlich wohnen, was für sie Zuhause ist und was ihnen Sorgen bereitet. Wir haben einen Blick in die Wohnheime auf dem Campus Golm gewagt und zeigen Ihnen eine Vision des Standorts als Lebensraum nach menschlichem Maß. Aber auch das Klima lässt uns nicht kalt: Wie kann sich eine Stadt wie Potsdam, Wohnort von fast 180.000 Menschen, künftig besser auf Wetterextreme vorbereiten?
Wie Sie sicherlich schon bemerkt haben, erscheint die Portal in einem neuen Gewand. Doch wie eh und je haben wir die Menschen an der Universität besucht – in der Hoffnung, dass Sie einander an dieser großen Einrichtung mit den drei Standorten etwas besser kennenlernen. Und auch die Leserinnen und Leser, die die Uni Potsdam nicht so gut kennen, möchten wir in das Leben an unserer Hochschule einführen.
Wir haben Studierende getroffen, die sich besonders engagieren: für den Schutz des Klimas, die Gleichstellung aller Geschlechter oder im Fakultätsrat. Andere musizieren miteinander. In der Serie „Mein Arbeitstag“ fragen wir, welche Aufgaben alltäglich in der Universitätsbibliothek zu bewältigen sind. Eine Auszubildende hat ihren Praktikumsalltag im fernen Hongkong mit uns geteilt, während uns ein Seminar der Lehrerbildung in die Virtual Reality entführt. Wir lernen hyperschnelle Sterne und das beste Mittel gegen Rückenschmerzen kennen. Was die menschliche Stimme mit den Bewegungen der Erde zu tun hat, erfahren Sie in einem „Laborbesuch“. Im „Gespräch“ unterhält sich ein Klimaforscher mit einem Schüler und wir zeigen, wo sich Uni und Stadt gefunden haben. Wir nehmen Sie mit in die entstehende „European Digital UniverCity“ und erkundigen uns in einer internen „Expertenanfrage“ nach einer neuen Frauenbewegung in der Katholischen Kirche. Neugierig haben wir einem Slavisten 15 forsche Fragen gestellt. Ein Linguist erklärt uns, ob und wie wir Außerirdische verstehen können, wenn sie denn mit uns sprechen wollen. Wir haben mit einer ausgezeichneten Juristin über die Todesstrafe gesprochen und mit einer Postdoktorandin über selbstspielende Klaviere. Da auch eine junge Uni wie die unsere älter wird, schauen wir in der „Zeitreise“ zurück in die Kinderstube der Alma Mater und pusten mit Humor den Staub von den Akten. In der Serie „Es war einmal“ äußern sich zwei Forschende zu einem geschichtlichen Jubiläum. Und weil unser (und hoffentlich auch Ihr) Wissensdurst keine Grenzen kennt, haben wir ein Wissenschaftswort herumgedreht: den Turn. Was das ist und warum einem davon schwindelig werden kann – lesen Sie es selbst!
Auftrag und Möglichkeiten der Kommission für Friedenskonsolidierung im System der Vereinten Nationen
(2019)
Vor dem Hintergrund der international steigenden Zahl an Konfliktrückfällen insbesondere im Anschluss an bereits offiziell für beendet erklärte Bürgerkriege und die daraus folgende zunehmende Relevanz von Peacebuilding-Maßnahmen der internationalen Gemeinschaft, wird in diesem Beitrag die Arbeit der Kommission für Friedenskonsolidierung der Vereinten Nationen untersucht. Einerseits werden hierbei, nach einigen einführenden Erläuterungen zum Begriff der Friedenskonsolidierung an sich sowie der Zusammensetzung und Funktionsweise der Kommission, zunächst ihre einzelnen Aufträge systematisch unter Einordnung in den Kontext des Peacebuilding-Systems der Vereinten Nationen herausgearbeitet und eine auswertende Bilanz unter ihre bisherige Erfüllung gezogen. Daran anschließend erfolgt eine Darstellung der zukünftigen Möglichkeiten der Kommission im Bereich der Friedenskonsolidierung unter besonderer Berücksichtigung ihres Potenzials innerhalb des Systems der Vereinten Nationen sowie der einschlägigen völkerrechtlichen Aspekte.
PaRDeS, the journal of the German Association for Jewish Studies, aims at exploring the fruitful and multifarious cultures of Judaism as well as their relations to their environment within diverse areas of research. In addition, the journal promotes Jewish Studies within academic discourse and reflects on its historic and social responsibilities.
Transcending the conventional debate around efficiency in sustainable consumption, anti-consumption patterns leading to decreased levels of material consumption have been gaining importance. Change agents are crucial for the promotion of such patterns, so there may be lessons for governance interventions that can be learnt from the every-day experiences of those who actively implement and promote sustainability in the field of anti-consumption. Eighteen social innovation pioneers, who engage in and diffuse practices of voluntary simplicity and collaborative consumption as sustainable options of anti-consumption share their knowledge and personal insights in expert interviews for this research. Our qualitative content analysis reveals drivers, barriers, and governance strategies to strengthen anti-consumption patterns, which are negotiated between the market, the state, and civil society. Recommendations derived from the interviews concern entrepreneurship, municipal infrastructures in support of local grassroots projects, regulative policy measures, more positive communication to strengthen the visibility of initiatives and emphasize individual benefits, establishing a sense of community, anti-consumer activism, and education. We argue for complementary action between top-down strategies, bottom-up initiatives, corporate activities, and consumer behavior. The results are valuable to researchers, activists, marketers, and policymakers who seek to enhance their understanding of materially reduced consumption patterns based on the real-life experiences of active pioneers in the field.
Quantum field theory on curved spacetimes is understood as a semiclassical approximation of some quantum theory of gravitation, which models a quantum field under the influence of a classical gravitational field, that is, a curved spacetime. The most remarkable effect predicted by this approach is the creation of particles by the spacetime itself, represented, for instance, by Hawking's evaporation of black holes or the Unruh effect. On the other hand, these aspects already suggest that certain cornerstones of Minkowski quantum field theory, more precisely a preferred vacuum state and, consequently, the concept of particles, do not have sensible counterparts within a theory on general curved spacetimes. Likewise, the implementation of covariance in the model has to be reconsidered, as curved spacetimes usually lack any non-trivial global symmetry. Whereas this latter issue has been resolved by introducing the paradigm of locally covariant quantum field theory (LCQFT), the absence of a reasonable concept for distinct vacuum and particle states on general curved spacetimes has become manifest even in the form of no-go-theorems.
Within the framework of algebraic quantum field theory, one first introduces observables, while states enter the game only afterwards by assigning expectation values to them. Even though the construction of observables is based on physically motivated concepts, there is still a vast number of possible states, and many of them are not reasonable from a physical point of view. We infer that this notion is still too general, that is, further physical constraints are required. For instance, when dealing with a free quantum field theory driven by a linear field equation, it is natural to focus on so-called quasifree states. Furthermore, a suitable renormalization procedure for products of field operators is vitally important. This particularly concerns the expectation values of the energy momentum tensor, which correspond to distributional bisolutions of the field equation on the curved spacetime. J. Hadamard's theory of hyperbolic equations provides a certain class of bisolutions with fixed singular part, which therefore allow for an appropriate renormalization scheme.
By now, this specification of the singularity structure is known as the Hadamard condition and widely accepted as the natural generalization of the spectral condition of flat quantum field theory. Moreover, due to Radzikowski's celebrated results, it is equivalent to a local condition, namely on the wave front set of the bisolution. This formulation made the powerful tools of microlocal analysis, developed by Duistermaat and Hörmander, available for the verification of the Hadamard property as well as the construction of corresponding Hadamard states, which initiated much progress in this field. However, although indispensable for the investigation in the characteristics of operators and their parametrices, microlocal analyis is not practicable for the study of their non-singular features and central results are typically stated only up to smooth objects. Consequently, Radzikowski's work almost directly led to existence results and, moreover, a concrete pattern for the construction of Hadamard bidistributions via a Hadamard series. Nevertheless, the remaining properties (bisolution, causality, positivity) are ensured only modulo smooth functions.
It is the subject of this thesis to complete this construction for linear and formally self-adjoint wave operators acting on sections in a vector bundle over a globally hyperbolic Lorentzian manifold. Based on Wightman's solution of d'Alembert's equation on Minkowski space and the construction for the advanced and retarded fundamental solution, we set up a Hadamard series for local parametrices and derive global bisolutions from them. These are of Hadamard form and we show existence of smooth bisections such that the sum also satisfies the remaining properties exactly.
The lack of soil data, which are relevant, reliable, affordable, immediately available, and sufficiently detailed, is still a significant challenge in precision agriculture. A promising technology for the spatial assessment of the distribution of chemical elements within fields, without sample preparation is laser-induced breakdown spectroscopy (LIBS). Its advantages are contrasted by a strong matrix dependence of the LIBS signal which necessitates careful data evaluation. In this work, different calibration approaches for soil LIBS data are presented. The data were obtained from 139 soil samples collected on two neighboring agricultural fields in a quaternary landscape of northeast Germany with very variable soils. Reference analysis was carried out by inductively coupled plasma optical emission spectroscopy after wet digestion. The major nutrients Ca and Mg and the minor nutrient Fe were investigated. Three calibration strategies were compared. The first method was based on univariate calibration by standard addition using just one soil sample and applying the derived calibration model to the LIBS data of both fields. The second univariate model derived the calibration from the reference analytics of all samples from one field. The prediction is validated by LIBS data of the second field. The third method is a multivariate calibration approach based on partial least squares regression (PLSR). The LIBS spectra of the first field are used for training. Validation was carried out by 20-fold cross-validation using the LIBS data of the first field and independently on the second field data. The second univariate method yielded better calibration and prediction results compared to the first method, since matrix effects were better accounted for. PLSR did not strongly improve the prediction in comparison to the second univariate method.
The effects of static stretching (StS) on subsequent strength and power activities has been one of the most debated topics in sport science literature over the past decades. The aim of this review is (1) to summarize previous and current findings on the acute effects of StS on muscle strength and power performances; (2) to update readers’ knowledge related to previous caveats; and (3) to discuss the underlying physiological mechanisms of short-duration StS when performed as single-mode treatment or when integrated into a full warm-up routine. Over the last two decades, StS has been considered harmful to subsequent strength and power performances. Accordingly, it has been recommended not to apply StS before strength- and power-related activities. More recent evidence suggests that when performed as a single-mode treatment or when integrated within a full warm-up routine including aerobic activity, dynamic-stretching, and sport-specific activities, short-duration StS (≤60 s per muscle group) trivially impairs subsequent strength and power activities (∆1–2%). Yet, longer StS durations (>60 s per muscle group) appear to induce substantial and practically relevant declines in strength and power performances (∆4.0–7.5%). Moreover, recent evidence suggests that when included in a full warm-up routine, short-duration StS may even contribute to lower the risk of sustaining musculotendinous injuries especially with high-intensity activities (e.g., sprint running and change of direction speed). It seems that during short-duration StS, neuromuscular activation and musculotendinous stiffness appear not to be affected compared with long-duration StS. Among other factors, this could be due to an elevated muscle temperature induced by a dynamic warm-up program. More specifically, elevated muscle temperature leads to increased muscle fiber conduction-velocity and improved binding of contractile proteins (actin, myosin). Therefore, our previous understanding of harmful StS effects on subsequent strength and power activities has to be updated. In fact, short-duration StS should be included as an important warm-up component before the uptake of recreational sports activities due to its potential positive effect on flexibility and musculotendinous injury prevention. However, in high-performance athletes, short-duration StS has to be applied with caution due to its negligible but still prevalent negative effects on subsequent strength and power performances, which could have an impact on performance during competition.