scholarly journals Importance of accurately quantifying internal loading in developing phosphorus reduction strategies for a chain of shallow lakes

2020 ◽  
Vol 36 (4) ◽  
pp. 391-411
Author(s):  
Dale M. Robertson ◽  
Matthew W. Diebel
2011 ◽  
Author(s):  
James MacLellan ◽  
Martin Bunch ◽  
Kaz Higuchi ◽  
Ilias Kotsireas ◽  
Roderick Melnik ◽  
...  

Hydrobiologia ◽  
2003 ◽  
Vol 506-509 (1-3) ◽  
pp. 135-145 ◽  
Author(s):  
Martin Søndergaard ◽  
Jens Peder Jensen ◽  
Erik Jeppesen

2019 ◽  
Vol 45 (4) ◽  
pp. 742-751 ◽  
Author(s):  
Awoke Dagnew ◽  
Donald Scavia ◽  
Yu-Chen Wang ◽  
Rebecca Muenich ◽  
Margaret Kalcic

2021 ◽  
Vol 36 (3) ◽  
pp. 141-149
Author(s):  
Craig Turner ◽  
Peter Visentin ◽  
Gongbing Shan

One of the greatest challenges in reducing high rates of performance injuries among musicians is in providing them usable tools to address playing-related musculoskeletal problems (PRMP) before they become disorders. Studies in biomechanics have the potential to provide such tools. In order to better understand the mechanisms through which PRMP manifest in pianists, especially in the distal segments of the upper limbs, the current study quantifies wrist internal loading (WIL) and wrist impact loading frequency. It does so while discussing pianists’ motor behaviours and observed effort-reduction strategies in the wrists as a function of anthropometry. This concept has great utility for performers. A VICON 3D motion capture system documented two expert pianists performing a B major scale, hands together, at 4, 6, 8, 9, and 10 notes/sec. Biomechanical modeling quantified WIL. Changes in motor behaviour were observed at 8 notes/sec. Individualized anthropometry influenced the range of motor strategies available to each pianist. The pianist with the larger hand span employed a flexion/extension wrist strategy as a compensatory means for effort reduction, while the pianist with the smaller hand span employed a radial/ ulnar deviation strategy. The current study provides a new perspective in addressing PRMP among pianists by rationalizing anthropometric potentials in terms of ergonomic parameters and documenting the availability and utility of effort-reduction strategies in the wrists during piano performance as performers consider PRMP risk and avoidance.


Author(s):  
H. Todokoro ◽  
S. Nomura ◽  
T. Komoda

It is interesting to observe polymers at atomic size resolution. Some works have been reported for thorium pyromellitate by using a STEM (1), or a CTEM (2,3). The results showed that this polymer forms a chain in which thorium atoms are arranged. However, the distance between adjacent thorium atoms varies over a wide range (0.4-1.3nm) according to the different authors.The present authors have also observed thorium pyromellitate specimens by means of a field emission STEM, described in reference 4. The specimen was prepared by placing a drop of thorium pyromellitate in 10-3 CH3OH solution onto an amorphous carbon film about 2nm thick. The dark field image is shown in Fig. 1A. Thorium atoms are clearly observed as regular atom rows having a spacing of 0.85nm. This lattice gradually deteriorated by successive observations. The image changed to granular structures, as shown in Fig. 1B, which was taken after four scanning frames.


Author(s):  
Eva-Maria Mandelkow ◽  
Ron Milligan

Microtubules form part of the cytoskeleton of eukaryotic cells. They are hollow libers of about 25 nm diameter made up of 13 protofilaments, each of which consists of a chain of heterodimers of α-and β-tubulin. Microtubules can be assembled in vitro at 37°C in the presence of GTP which is hydrolyzed during the reaction, and they are disassembled at 4°C. In contrast to most other polymers microtubules show the behavior of “dynamic instability”, i.e. they can switch between phases of growth and phases of shrinkage, even at an overall steady state [1]. In certain conditions an entire solution can be synchronized, leading to autonomous oscillations in the degree of assembly which can be observed by X-ray scattering (Fig. 1), light scattering, or electron microscopy [2-5]. In addition such solutions are capable of generating spontaneous spatial patterns [6].In an earlier study we have analyzed the structure of microtubules and their cold-induced disassembly by cryo-EM [7]. One result was that disassembly takes place by loss of protofilament fragments (tubulin oligomers) which fray apart at the microtubule ends. We also looked at microtubule oscillations by time-resolved X-ray scattering and proposed a reaction scheme [4] which involves a cyclic interconversion of tubulin, microtubules, and oligomers (Fig. 2). The present study was undertaken to answer two questions: (a) What is the nature of the oscillations as seen by time-resolved cryo-EM? (b) Do microtubules disassemble by fraying protofilament fragments during oscillations at 37°C?


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