42 research outputs found

    Základy půdní úrodnosti

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    Zvyšování půdní úrodnosti bylo pro průkopníky ekologického zemědělství základem veškerého jejich úsilí. Přesto zachování úrodné půdy mnohdy nebyla věnována dostatečná pozornost. Ekologické zemědělství je však na přirozené půdní úrodnosti závislé. Oslabená a poškozená půda nám nemůže poskytnout to, co od ní očekáváme. Udržet úrodnost půdy vyžaduje velkou péči. Předkládaná brožura ukazuje půdní úrodnost z různých úhlů pohledu. Naším záměrem však nebylo vytvořit obecně platný „návod k použití“. Informace mají být mnohem spíše podnětem k tomu, aby se o vztahu člověka k půdě smýšlelo jinak a aby se tento vztah utvářel ve prospěch budoucnosti

    Grundlagen zur Bodenfruchtbarkeit - Die Beziehung zum Boden gestalten

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    Die Broschüre beleuchtet die Bodenfruchtbarkeit aus verschiedenen wissenschaftlichen und bäuerlichen Blickwinkeln. Die Informationen wollen praktische Beobachtungen der Landwirte ergänzen und dazu anregen, die Beziehung zum Boden zu überdenken und eine wirklich nachhaltige Bodenkultur zu praktizieren

    From the biological model to a 3D universe: 3D Printing in Biology

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    Die Anfertigung von Anschauungs- und Funktionsprototypen biologischer Objekte trägt maßgeblich zum Verständnis der komplexen Welt des Lebendigen bei. In den letzten Jahrzehnten werden zur Erfassung von biologischen Objekten zunehmend 3D-Techniken eingesetzt. Bei der Additiven Fertigung von dreidimensionalen Anschauungsmodellen ergeben sich einzigartige Einblicke in die dreidimensionale Struktur und die Funktion der untersuchten Objekte. Die digitale Transformation von biologischen Objekten in ein virtuelles 3D-Universum eröffnet vollkommen neue Möglichkeiten von der Erfassung der Biodiversität bis hin zur Produktion von Prothesen oder Organen.The creation of visual and functional prototypes of biological objects contributes signifcantly to the understanding of the complex world of living things. In recent decades, 3D techniques have been increasingly used to capture biological objects. Additive manufacturing of three-dimensional visual models provides unique insights into the threedimensional structure and function of the objects under investigation. The digital transformation of biological objects into a virtual 3D universe opens up completely new possibilities from capturing biodiversity to the production of prostheses or organs

    Activity of Command Fibres in Free-Ranging Crayfish, Orconectes limosus Raf.

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    Using a 3D asymmetry index as a novel form for capturing complex three-dimensionality in positional plagiocephaly

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    Abstract Positional plagiocephaly (PP) is the most common skull deformity in infants. Different classification systems exist for graduating the degree of PP, but all of these systems are based on two-dimensional (2D) parameters. This limitation leads to several problems stemming from the fact that 2D parameters are used to classify the three-dimensional (3D) shape of the head. We therefore evaluate existing measurement parameters and validate a newly developed 3D parameter for quantifying PP. Additionally, we present a new classification of PP based on a 3D parameter. 210 patients with PP and 50 patients without PP were included in this study. Existing parameters (2D and 3D) and newly developed volume parameters based on a 3D stereophotogrammetry scan were validated using ROC curves. Additionally, thresholds for the new 3D parameter of a 3D asymmetry index were assessed. The volume parameter 3D asymmetry index quantifies PP equally as well as the gold standard of 30° diagonal difference. Moreover, a 3D asymmetry index allows for a 3D-based classification of PP. The 3D asymmetry index can be used to define the degree of PP. It is easily applicable in stereophotogrammetric datasets and allows for comparability both intra- and inter-individually as well as for scientific analysis

    Subjective perception of craniofacial growth asymmetries in patients with deformational plagiocephaly

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    Objectives The present investigation aimed to evaluate the subjective perception of deformational cranial asymmetries by different observer groups and to compare these subjective perceptions with objective parameters. Materials and methods The 3D datasets of ten infants with different severities of deformational plagiocephaly (DP) were presented to 203 observers, who had been subdivided into five different groups (specialists, pediatricians, medical doctors (not pediatricians), parents of infants with DP, and laypersons). The observers rated their subjective perception of the infants’ cranial asymmetries using a 4-point Likert-type scale. The ratings from the observer groups were compared with one another using a multilevel modelling linear regression analysis and were correlated with four commonly used parameters to objectively quantify the cranial asymmetries. Results No significant differences were found between the ratings of the specialists and those of the parents of infants with DP, but both groups provided significantly more asymmetric ratings than did pediatricians, medical doctors, or laypersons. Moreover, the subjective perception of cranial asymmetries correlated significantly with commonly used parameters for objectively quantifying cranial asymmetries. Conclusions Our results demonstrate that different observer groups perceive the severity of cranial asymmetries differently. Pediatricians’ more moderate perception of cranial asymmetries may reduce the likelihood of parents to seek therapeutic interventions for their infants. Moreover, we identified some objective symmetry-related parameters that correlated strongly with the observers’ subjective perceptions. Clinical relevance Knowledge about these findings is important for clinicians when educating parents of infants with DP about the deformity

    Acoustic Crystallization of 2D Colloidal Crystals

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    2D colloidal crystallization provides a simple strategy to produce defined nanostructure arrays over macroscopic areas. Regularity and long-range order of such crystals is essential to ensure functionality, but difficult to achieve in self-assembling systems. Here, a simple loudspeaker setup for the acoustic crystallization of 2D colloidal crystals (ACDC) of polystyrene, microgels, and core–shell particles at liquid interfaces is introduced. This setup anneals an interfacial colloidal monolayer and affords an increase in average grain size by almost two orders of magnitude. The order is characterized via the structural color of the colloidal crystal, the acoustic annealing process is optimized via the frequency and the amplitude of the applied sound wave, and its efficiency is rationalized via the surface coverage-dependent interactions within the interfacial colloidal monolayer. Computer simulations show that multiple rearrangement mechanisms at different length scales, from the local motion around voids to grain boundary movements via consecutive particle rotations around common centers, collude to remove defects. The experimentally simple ACDC process, paired with the demonstrated applicability toward complex particle systems, provides access to highly defined nanostructure arrays for a wide range of research communities
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