scholarly journals Flat structures on the deformations of Gepner chiral rings

2016 ◽  
Vol 2016 (10) ◽  
Author(s):  
Alexander Belavin ◽  
Vladimir Belavin
Keyword(s):  
Chiral Rings ◽  
Flat Structures

scholarly journals Determination of the modal parameters on the thin flat structures

2018 ◽  
Vol 18 ◽  
pp. 91-95 ◽  
Author(s):  
Roman Zajac ◽  
Aleš Prokop ◽  
Kamil Řehák
Keyword(s):  
Modal Parameters ◽  
Flat Structures

scholarly journals Detecting and Visualizing the Communities of Innovation in Beijing-Tianjin-Hebei Urban Agglomeration Based on the Patent Cooperation Network

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Fang Zhou ◽  
Bo Zhang
Keyword(s):  
Deep Understanding ◽  
Urban Agglomeration ◽  
Geographical Information ◽  
Single Center ◽  
Power Construction ◽  
Flat Structures ◽  
Collaborative Innovation ◽  
The Hierarchical Structure ◽  
Cooperation Network ◽  
Communities Of Innovation

For a deep understanding of Beijing-Tianjin-Hebei (BTH) collaborative innovation, we detected and visualized the communities of innovation in BTH Urban Agglomeration based on the patent cooperation network. China Patent Database was connected with Business Registration Database and the Tianyan Check to achieve the geographical information of organizational innovators. Spinglass algorithm was applied and ultimately 12 communities of innovation were detected. Based on the different structure characteristics, we further clustered the 12 communities into four typical structures that are hierarchical, single-center, polycentric, and flat structures. The hierarchical structure is usually large in scale and the cooperative intensity is relatively high. Single-center structure has a center with a high proportion of centrality and the cooperative intensity is relatively low. Polycentric structure has multiple centers with similar proportions of centrality. Flat structure is usually small in scale and has no obvious network center. In the patent cooperative network of BTH Urban Agglomeration, universities and state-owned enterprises occupied the centers and acted important roles to connect other organizations. Some communities of innovation showed significant industry characteristics, mainly involving six industry fields that are electric power, construction, petroleum, metallurgy and materials, municipal transportation, and railway. From the geographical perspective, some communities manifested local attributes and some demonstrated cooperation between regions. Beijing was the center of the Beijing-Tianjin-Hebei patent cooperation network. Compared with the pair of Beijing-Tianjin and the pair of Beijing-Hebei, Tianjin and Hebei were not closely connected. In the future, Beijing-Tianjin-Hebei collaborative innovation should strengthen cooperation between Tianjin and Hebei.

The WUSCHEL gene is required for shoot and floral meristem integrity in Arabidopsis

Development ◽  
1996 ◽  
Vol 122 (1) ◽  
pp. 87-96 ◽  
Author(s):  
T. Laux ◽  
K.F. Mayer ◽  
J. Berger ◽  
G. Jurgens
Keyword(s):  
Developmental Stages ◽  
Shoot Meristem ◽  
Wild Type ◽  
Recessive Mutations ◽  
Organ Identity ◽  
Flat Structures ◽  
Meristem Identity ◽  
Wus Gene ◽  
Floral Meristems ◽  
Shoot Meristems

Self perpetuation of the shoot meristem is essential for the repetitive initiation of shoot structures during plant development. In Arabidopsis shoot meristem maintenance is disrupted by recessive mutations in the WUSCHEL (WUS) gene. The defect is evident at all developmental stages and is restricted to shoot and floral meristems, whereas the root meristem is not affected. wus mutants fail to properly organize a shoot meristem in the embryo. Postembryonically, defective shoot meristems are initiated repetitively but terminate prematurely in aberrant flat structures. In contrast to wild-type shoot meristems, primordia initiation occurs ectopically across mutant apices, including the center, and often new shoot meristems instead of organs are initiated. The cells of wus shoot apices are larger and more vacuolated than wild-type shoot meristem cells. wus floral meristems terminate prematurely in a central stamen. Double mutant studies indicate that the number of organ primordia in the center of wus flowers is limited, irrespective of organ identity and we propose that meristem cells are allocated into floral whorl domains in a sequential manner. WUS activity also appears to be required for the formation of supernumerary organs in the center of agamous, superman or clavata1 flowers, suggesting that the WUS gene acts upstream of the corresponding genes. Our results suggest that the WUS gene is specifically required for central meristem identity of shoot and floral meristems to maintain their structural and functional integrity.

Deployability Conditions for Curved and Flat, Polygonal and Trapezoidal Deployable Structures

1993 ◽  
Vol 8 (1-2) ◽  
pp. 97-106 ◽  
Author(s):  
C.J. Gantes ◽  
R.D. Logcher ◽  
J.J. Connor ◽  
Y. Rosenfeld
Keyword(s):  
Structural Analysis ◽  
Regular Polygon ◽  
Geometric Design ◽  
Geometric Constraints ◽  
Design Criteria ◽  
Deployable Structures ◽  
Design Procedures ◽  
Curved Structures ◽  
Space Frames ◽  
Flat Structures

Prefabricated, deployable space frames that exhibit self-standing and stress-free states in both the deployed and collapsed configurations are investigated in this paper. This type of deployable structures shows considerable advantages as compared to previous designs that either required external stabilizing or had members with residual stresses in the deployed configuration. Following previous developments for flat deployable structures consisting of units with regular-polygon planviews, this study deals with flat structures made of trapezoidals, and curved structures assembled from regular-polygonal units. First, the general geometric constraints and deployability conditions for these units are formulated, and a methodology for using these constraints as geometric design criteria is presented. Furthermore, additional conditions for the assemblage of single units into larger structures are given. Then, structural analysis issues for this type of structures are discussed. The necessity of nonlinear analysis during deployment is emphasized. Finally, the above geometric design procedures are demonstrated with specific examples.

scholarly journals The Diverse Roles of Auxin in Regulating Leaf Development

Plants ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 243 ◽  
Author(s):  
Yuanyuan Xiong ◽  
Yuling Jiao
Keyword(s):  
Leaf Development ◽  
Leaf Blade ◽  
Recent Progress ◽  
Auxin Transport ◽  
Leaf Primordium ◽  
Auxin Signaling ◽  
Plant Organs ◽  
Leaf Patterning ◽  
Flat Structures ◽  
Photosynthesis And Respiration

Leaves, the primary plant organs that function in photosynthesis and respiration, have highly organized, flat structures that vary within and among species. In recent years, it has become evident that auxin plays central roles in leaf development, including leaf initiation, blade formation, and compound leaf patterning. In this review, we discuss how auxin maxima form to define leaf primordium formation. We summarize recent progress in understanding of how spatial auxin signaling promotes leaf blade formation. Finally, we discuss how spatial auxin transport and signaling regulate the patterning of compound leaves and leaf serration.

scholarly journals Bipolar H II regions

2018 ◽  
Vol 617 ◽  
pp. A67 ◽  
Author(s):  
M. R. Samal ◽  
L. Deharveng ◽  
A. Zavagno ◽  
L. D. Anderson ◽  
S. Molinari ◽  
...  
Keyword(s):  
Star Formation ◽  
Molecular Cloud ◽  
Galactic Plane ◽  
Three Dimensional ◽  
Young Stellar Objects ◽  
Formation Processes ◽  
Two Dimensional ◽  
Stellar Objects ◽  
Flat Structures ◽  
Exciting Star

Aims. We aim to identify bipolar Galactic H II regions and to understand their parental cloud structures, morphologies, evolution, and impact on the formation of new generations of stars. Methods. We use the Spitzer-GLIMPSE, Spitzer-MIPSGAL, and Herschel-Hi-GAL surveys to identify bipolar H II regions and to examine their morphologies. We search for their exciting star(s) using NIR data from the 2MASS, UKIDSS, and VISTA surveys. Massive molecular clumps are detected near these bipolar nebulae, and we estimate their temperatures, column densities, masses, and densities. We locate Class 0/I young stellar objects (YSOs) in their vicinities using the Spitzer and Herschel-PACS emission. Results. Numerical simulations suggest bipolar H II regions form and evolve in a two-dimensional flat- or sheet-like molecular cloud. We identified 16 bipolar nebulae in a zone of the Galactic plane between ℓ ± 60° and |b| < 1°. This small number, when compared with the 1377 bubble H II regions in the same area, suggests that most H II regions form and evolve in a three-dimensional medium. We present the catalogue of the 16 bipolar nebulae and a detailed investigation for six of these. Our results suggest that these regions formed in dense and flat structures that contain filaments. We find that bipolar H II regions have massive clumps in their surroundings. The most compact and massive clumps are always located at the waist of the bipolar nebula, adjacent to the ionised gas. These massive clumps are dense, with a mean density in the range of 105 cm−3 to several 106 cm−3 in their centres. Luminous Class 0/I sources of several thousand solar luminosities, many of which have associated maser emission, are embedded inside these clumps. We suggest that most, if not all, massive 0/I YSO formation has probably been triggered by the expansion of the central bipolar nebula, but the processes involved are still unknown. Modelling of such nebula is needed to understand the star formation processes at play.

scholarly journals Effects of Phosphorelay Perturbations on Architecture, Sporulation, and Spore Resistance in Biofilms of Bacillus subtilis

2006 ◽  
Vol 188 (8) ◽  
pp. 3099-3109 ◽  
Author(s):  
Jan-Willem Veening ◽  
Oscar P. Kuipers ◽  
Stanley Brul ◽  
Klaas J. Hellingwerf ◽  
Remco Kort
Keyword(s):  
Bacillus Subtilis ◽  
Fluorescent Protein ◽  
Current Model ◽  
Laboratory Strain ◽  
Time Lapse ◽  
Rich Media ◽  
Flat Structures ◽  
Reporter Strains ◽  
Green Fluorescent ◽  
Fluorescent Protein Reporter

ABSTRACT The spore-forming bacterium Bacillus subtilis is able to form highly organized multicellular communities called biofilms. This coordinated bacterial behavior is often lost in domesticated or laboratory strains as a result of planktonic growth in rich media for many generations. However, we show here that the laboratory strain B. subtilis 168 is still capable of forming spatially organized multicellular communities on minimal medium agar plates, exemplified by colonies with vein-like structures formed by elevated bundles of cells. In line with the current model for biofilm formation, we demonstrate that overproduction of the phosphorelay components KinA and Spo0A stimulates bundle formation, while overproduction of the transition state regulators AbrB and SinR leads to repression of formation of elevated bundles. Time-lapse fluorescence microscopy studies of B. subtilis green fluorescent protein reporter strains show that bundles are preferential sites for spore formation and that flat structures surrounding the bundles contain vegetative cells. The elevated bundle structures are formed prior to sporulation, in agreement with a genetic developmental program in which these processes are sequentially activated. Perturbations of the phosphorelay by disruption and overexpression of genes that lead to an increased tendency to sporulate result in the segregation of sporulation mutations and decreased heat resistance of spores in biofilms. These results stress the importance of a balanced control of the phosphorelay for biofilm and spore development.

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