Zeitschriftenartikel: „Progressive Edge Growth“

1

Chen, Lin, und Da-Zheng Feng. „Fast Implementation of the Progressive Edge-Growth Algorithm“. ETRI Journal 31, Nr. 2 (09.04.2009): 240–42. http://dx.doi.org/10.4218/etrij.09.0208.0358.

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2

Kraidy, Ghassan M. „On Progressive Edge-Growth Interleavers for Turbo Codes“. IEEE Communications Letters 20, Nr. 2 (Februar 2016): 200–203. http://dx.doi.org/10.1109/lcomm.2015.2504364.

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3

Xiao-Yu Hu, E. Eleftheriou und D. M. Arnold. „Regular and irregular progressive edge-growth tanner graphs“. IEEE Transactions on Information Theory 51, Nr. 1 (Januar 2005): 386–98. http://dx.doi.org/10.1109/tit.2004.839541.

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4

Martinez-Mateo, Jesus, Dav Elkouss und Vicente Martin. „Improved Construction of Irregular Progressive Edge-Growth Tanner Graphs“. IEEE Communications Letters 14, Nr. 12 (Dezember 2010): 1155–57. http://dx.doi.org/10.1109/lcomm.2010.101810.101384.

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5

Vukobratovic, D., und V. Senk. „Generalized ACE Constrained Progressive Edge-Growth LDPC Code Design“. IEEE Communications Letters 12, Nr. 1 (Januar 2008): 32–34. http://dx.doi.org/10.1109/lcomm.2008.071457.

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6

Anbalgan, Anand, und Senthil Kumar.P. „Progressive edge growth LDPC Encoder with spiral search algorithm“. International Journal of Engineering & Technology 7, Nr. 1.3 (31.12.2017): 198. http://dx.doi.org/10.14419/ijet.v7i1.3.10673.

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Trapping set causes the drop of performance in error floor region. Identification of TS is done by graphical method and enumerators. The lowest odd degree (minimal) TS is increasing the formation of more unsaturated nodes in iterative decoding. Progressive edge growth (PEG) Low-density parity check code (LDPC) [2] avoidance of trapping sets are mainly based on the distance and degree calculation of successive CN. This simple tool is used to eliminate TS when the encoder ensemble designs itself. Non-zero neighborhood search also made an influence on error floor. The spiral search method is used for Non-zero codeword search (NZCW) search for the first time in this research, at the decoder part. So, Non-zero codeword spiral search (NZCSS) converge fast with less number iteration, and this reduces the iteration of the decoder.

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7

Sharon, E., und S. Litsyn. „Constructing LDPC codes by error minimization progressive edge growth“. IEEE Transactions on Communications 56, Nr. 3 (März 2008): 359–68. http://dx.doi.org/10.1109/tcomm.2008.050658.

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8

Jiang, Xueqin, Yi Yang, Moon Ho Lee und Minda Zhu. „Progressive edge-growth algorithm for low-density MIMO codes“. Journal of Communications and Networks 16, Nr. 6 (Dezember 2014): 639–44. http://dx.doi.org/10.1109/jcn.2014.000110.

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9

El-Maleh, Aiman H., Mohamed Adnan Landolsi und Esa A. AlGhoneim. „Window-constrained interconnect-efficient progressive edge growth LDPC codes“. AEU - International Journal of Electronics and Communications 67, Nr. 7 (Juli 2013): 588–94. http://dx.doi.org/10.1016/j.aeue.2012.12.006.

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10

Xiao, H., und A. H. Banihashemi. „Improved Progressive-Edge-Growth (PEG) Construction of Irregular LDPC Codes“. IEEE Communications Letters 8, Nr. 12 (Dezember 2004): 715–17. http://dx.doi.org/10.1109/lcomm.2004.839612.

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11

Venkiah, A., D. Declercq und C. Poulliat. „Design of cages with a randomized progressive edge-growth algorithm“. IEEE Communications Letters 12, Nr. 4 (April 2008): 301–3. http://dx.doi.org/10.1109/lcomm.2008.071843.

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12

Jiang, Xueqin, Xiang-Gen Xia und Moon Ho Lee. „Efficient Progressive Edge-Growth Algorithm Based on Chinese Remainder Theorem“. IEEE Transactions on Communications 62, Nr. 2 (Februar 2014): 442–51. http://dx.doi.org/10.1109/tcomm.2014.011114.130285.

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13

Wang, Lina, Hang Zhang, Yaoyao Li und Tianyu An. „Partly systematic Luby transform codes based on improved progressive edge-growth algorithm for Mars communications“. Journal of Algorithms & Computational Technology 12, Nr. 3 (23.04.2018): 200–207. http://dx.doi.org/10.1177/1748301818770082.

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The Luby transform code is a forward error correction code and was originally designed for the erasure channel. In this paper, the Luby transform codes over the Mars communication channel are investigated. To guarantee the reliable data transmission over the Mars communication channel which are usually affected by fading and noises, the progressive edge-growth algorithm is improved and used in for encoding the Luby transform codes. And then a partly systematic Luby transform code with an improved progressive edge-growth algorithm is designed to improve the error propagation phenomenon in Mars communications. Performance evaluations of the designed partly systematic Luby transform code based on the random graph, PEG and improved progressive edge-growth algorithms, respectively, are conducted through a series of simulations. Simulation results show that the performance of the partly systematic Luby transform code based on the improved progressive edge-growth algorithm outperforms those of the partly systematic Luby transform code based on two other algorithms and has the lower bit error rate and overhead.

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14

Yeh, Harry H. „Nonlinear progressive edge waves: their instability and evolution“. Journal of Fluid Mechanics 152 (März 1985): 479–99. http://dx.doi.org/10.1017/s0022112085000799.

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The fundamental properties of nonlinear progressive edge waves are investigated experimentally in a physical model with a uniformly and mildly sloping beach with a straight shoreline. An evolution equation for the envelope of progressive edge waves is the nonlinear Schrödinger (NLS) equation. It is found that the timescale of viscous-dissipation effects in the experiments is comparable with the timescale of the theoretical evolution process for inviscid progressive edge waves. This lack of timescale separation indicates a major shortcoming of the NLS equation as a model of the laboratory experiments. Even with this limitation, a uniform train of edge waves is found to be unstable to a modulational perturbation as predicted by the NLS equation. However, behaviour of the evolution is both qualitatively and quantitatively different from the theoretical predictions. The evolution of the periodogram for the unstable wavetrain shows an asymmetric development of the sidebands about the fundamental frequency; instability growth is limited to the lower sideband. This behaviour leads to a sequential shift of wave energy to lower frequencies as the waves propagate. It is found that a locally soliton-shaped wave packet is unstable in the laboratory environment. It is estimated that a much-larger-scale experimental facility is required to achieve inviscid experiments for the NLS equation.

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CHEN, Xin, Ai-dong MEN, Bo YANG und Zi-yi QUAN. „Construction of LDPC codes over GF(q) with modified progressive edge growth“. Journal of China Universities of Posts and Telecommunications 16, Nr. 5 (Oktober 2009): 103–6. http://dx.doi.org/10.1016/s1005-8885(08)60275-7.

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16

Zhengang Chen und S. Bates. „Construction of low-density parity-check convolutional codes through progressive edge-growth“. IEEE Communications Letters 9, Nr. 12 (Dezember 2005): 1058–60. http://dx.doi.org/10.1109/lcomm.2005.1576587.

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17

Leng Xue-Dong, Wang Da-Ming, Ba Bin und Wang Jian-Hui. „A quasi-cyclic compressed sensing delay estimation algorithm based on progressive edge-growth“. Acta Physica Sinica 66, Nr. 9 (2017): 090703. http://dx.doi.org/10.7498/aps.66.090703.

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18

Healy, Cornelius T., und Rodrigo C. de Lamare. „Design of LDPC Codes Based on Multipath EMD Strategies for Progressive Edge Growth“. IEEE Transactions on Communications 64, Nr. 8 (August 2016): 3208–19. http://dx.doi.org/10.1109/tcomm.2016.2579641.

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19

Han, Changcai, Hui Li und Weigang Chen. „Minimum Distance Optimization with Chord Edge Growth for High Girth Non-Binary LDPC Codes“. Electronics 9, Nr. 12 (17.12.2020): 2161. http://dx.doi.org/10.3390/electronics9122161.

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Short or moderate-length non-binary low-density parity-check (NB-LDPC) codes have the potential applications in future low latency and high-reliability communication thanks to the strong error correction capability and parallel decoding. Because of the existence of the error floor, the NB-LDPC codes usually cannot satisfy very low bit error rate (BER) requirements. In this paper, a low-complexity method is proposed for optimizing the minimum distance of the NB-LDPC code in a progressive chord edge growth manner. Specifically, each chord edge connecting two non-adjacent vertices is added to the Hamiltonian cycle one-by-one. For each newly added chord edge, the configuration of non-zero entries corresponding to the chord edge is determined according to the so-called full rank condition (FRC) of all cycles that are related to the chord edge in the obtained subgraph. With minor modifications to the designed method, it can be used to construct the NB-LDPC codes with an efficient encoding structure. The analysis results show that the method for designing NB-LDPC codes while using progressive chord edge growth has lower complexity than traditional methods. The simulation results show that the proposed method can effectively improve the performance of the NB-LDPC code in the high signal-to-noise ratio (SNR) region. While using the proposed scheme, an NB-LDPC code with a quite low BER can be constructed with extremely low complexity.

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Uchoa, Andre G. D., Cornelius Healy, Rodrigo C. de Lamare und Richard D. Souza. „Design of LDPC Codes Based on Progressive Edge Growth Techniques for Block Fading Channels“. IEEE Communications Letters 15, Nr. 11 (November 2011): 1221–23. http://dx.doi.org/10.1109/lcomm.2011.092911.111520.

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21

Durcek, Viktor, Michal Kuba und Milan Dado. „Investigation of random-structure regular LDPC codes construction based on progressive edge-growth and algorithms for removal of short cycles“. Eastern-European Journal of Enterprise Technologies 4, Nr. 9(112) (31.08.2021): 46–53. http://dx.doi.org/10.15587/1729-4061.2021.225852.

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This paper investigates the construction of random-structure LDPC (low-density parity-check) codes using Progressive Edge-Growth (PEG) algorithm and two proposed algorithms for removing short cycles (CB1 and CB2 algorithm; CB stands for Cycle Break). Progressive Edge-Growth is an algorithm for computer-based design of random-structure LDPC codes, the role of which is to generate a Tanner graph (a bipartite graph, which represents a parity-check matrix of an error-correcting channel code) with as few short cycles as possible. Short cycles, especially the shortest ones with a length of 4 edges, in Tanner graphs of LDPC codes can degrade the performance of their decoding algorithm, because after certain number of decoding iterations, the information sent through its edges is no longer independent. The main contribution of this paper is the unique approach to the process of removing short cycles in the form of CB2 algorithm, which erases edges from the code's parity-check matrix without decreasing the minimum Hamming distance of the code. The two cycle-removing algorithms can be used to improve the error-correcting performance of PEG-generated (or any other) LDPC codes and achieved results are provided. All these algorithms were used to create a PEG LDPC code which rivals the best-known PEG-generated LDPC code with similar parameters provided by one of the founders of LDPC codes. The methods for generating the mentioned error-correcting codes are described along with simulations which compare the error-correcting performance of the original codes generated by the PEG algorithm, the PEG codes processed by either CB1 or CB2 algorithm and also external PEG code published by one of the founders of LDPC codes

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Healy, C. T., und R. C. de Lamare. „Decoder-Optimised Progressive Edge Growth Algorithms for the Design of LDPC Codes with Low Error Floors“. IEEE Communications Letters 16, Nr. 6 (Juni 2012): 889–92. http://dx.doi.org/10.1109/lcomm.2012.042312.112220.

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23

Tlish, M. M., N. L. Sycheva, N. A. Boyko, M. E. Shavilova und F. A. Psavok. „Progressive symmetric eritrocarotodermia Gottron: A rare case“. Vestnik dermatologii i venerologii 95, Nr. 3 (02.10.2019): 40–45. http://dx.doi.org/10.25208/0042-4609-2019-95-3-40-45.

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The article deals with ethiopathogenetic factors of origin of progredient symmetric erythrokeratodermia of Gottron which is mainly characterized by autosomal dominant mode of inheritance and is classified as a disorder of cornification with extra epidermal cellular proliferation.Clinicopathologic criteria on the basis of which this pathology can be verified are described here, such as: onset of a disease at an early age, strictly divided polycyclic, fixed, hyperkeratotic plaques with a narrow erythematic crown and a clean-cut, sometimes hyper pigmented edge, which are symmetrically located on skin on head, buttocks, limbs and are not prone to quick peripheral growth; large frequency of palmoplantar keratoderma and also histological changes typical of erythrokeratodermia.The article describes a rare clinical case of autosomal-recessive progredient symmetric erythrokeratodermia of Gottron which is distinguished by seasonal changes of skin pathological process — emergence of rash in winter and complete remissions in summer.

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Cheung, Albert Y., Prethy Rao, Yoshihiro Yonekawa, Benjamin J. Thomas, Aparna Shah, Bruce R. Garretson, Antonio Capone und Tarek S. Hassan. „Progressive Massive Choroidal Neovascularization“. Journal of VitreoRetinal Diseases 1, Nr. 3 (19.04.2017): 197–203. http://dx.doi.org/10.1177/2474126417703515.

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Purpose: A small subset of patients with neovascular age-related macular degeneration (AMD) can have relentless progression of choroidal neovascularization (CNV) and subsequent disciform scarring (DS) with extension beyond the vascular arcades to the equator. We present the clinical courses of this severe phenotype of progressive massive CNV (PM-CNV). Methods: Retrospective case series of 14 eyes of 8 patients who presented with (1) massive DS encompassing the posterior pole and extending to the equator and (2) progressive DS expansion despite treatment between 2004 and 2015 at a tertiary referral center. Demographics, clinical and ocular characteristics, fluorescein angiographic findings, and treatment regimens were reviewed. Results: Baseline characteristics included a mean age of 73.0 years (range, 65.- 86.9 years) with 7 (87.5%) women. Six (75%) patients had bilateral PM-CNV. Mean follow-up was 10.5 years (range, 0.5-18.2 years). Ten (71.4%) eyes underwent intravitreal anti-vascular endothelial growth factor therapy, 3 (21.4%) intravitreal corticosteroid injections, and 3 photodynamic therapy. Most eyes (92.9%) demonstrated subretinal hemorrhage at the edge of the DS prior to DS expansion during treatment. Of the 6 patients with bilateral PM-CNV, 5 developed DS in 1 eye earlier than the subsequent eye (mean time, 63.6 months). Final visual acuity was ≤20/400 in all eyes (20/400 [n = 1]), count fingers (n = 5), hand motions (n = 5), and no light perception (n = 3). Conclusion: Progressive massive CNV is a profound reactivation of DS in some AMD eyes and is associated with severe, often bilateral, vision loss.

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Kwon, Y. W., und C. T. Liu. „Numerical Study of Damage Growth in Particulate Composites“. Journal of Engineering Materials and Technology 121, Nr. 4 (01.10.1999): 476–82. http://dx.doi.org/10.1115/1.2812404.

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A numerical study was conducted to simulate and predict damage initiation and growth around the crack tip crack tip in particulate composite specimens made of hard particles embedded in a soft rubber-like matrix material. Therefore, damage evolution in the matrix material around crack tips was investigated. The progressive damage was modeled using a micro/macro-approach which combined two levels of analyses like the micro-level and the macro-level analyses. Damage description was undertaken at the microlevel using a simplified three-dimensional unit-cell model and an isotropic continuum damage theory. The numerical study examined both him and thick specimens with a short or long edge crack to understand the effects of specimen thickness and crack size on the damage initiation, growth, and saturation. Numerical results were compared with experimental data.

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Hosseini-Toudeshky, Hossein, und Bijan Mohammadi. „Coupling of Continuum Damage Mechanics with De-Cohesive Element for Delamination Analysis in Laminated Composites“. Advanced Materials Research 123-125 (August 2010): 527–30. http://dx.doi.org/10.4028/www.scientific.net/amr.123-125.527.

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To predict the progressive damages including the large delamination growth in composite laminates, a new interface de-cohesive constitutive law is developed which is compatible with 3D continuum damage mechanics (CDM). To avoid the difficulties of 3D mesh generation and 3D interface modeling between the layers, the interface element is implemented in the Reddy’s full layer-wise plate theory. An angle-ply laminate is analyzed to evaluate the developed CDM+Interface procedure in edge delamination initiation and evolution at final stage of CDM damage progress.

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Bonga-Bonga, Lumengo, und Martin Perold. „A CGE Simulation Of A Flat Tax As A Possibility For Tax Reform In South Africa“. Journal of Applied Business Research (JABR) 30, Nr. 6 (27.10.2014): 1693. http://dx.doi.org/10.19030/jabr.v30i6.8883.

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During recent years, there has been widespread interest in South Africa for the so-called flat tax systems that appear to have been implemented successfully in Eastern Europe. This paper applied a CGE modelling technique to compare the performance of the South African economy in case alternative tax systems, namely the progressive and the flat tax systems, are applied. The counterfactual situation whose effects are tested in this paper is a 10% decrease in the VAT rate consistent with some popular call for the reduction of the degree of the regressiveness of VAT. The key performances of the South African economy are assessed in terms of economic growth, the welfare of households, equity and employment. On the basis of this empirical investigation the flat tax has a slight edge over the current progressive system.

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Wang, Ze Xing, Jin Hua Jiang und Nan Liang Chen. „Tensile Behavior of Textile Reinforced Flexible Composites with Single Edge Notch (SEN) under Static Solicitation“. Advanced Materials Research 311-313 (August 2011): 205–9. http://dx.doi.org/10.4028/www.scientific.net/amr.311-313.205.

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For industrial applications, many of the damage of textile reinforced flexible composites are due to growth of the defects coming from manufacturing process or generation by static or dynamic load prior to failure. Hence, this work attempt to investigate on tensile behavior and damage initiation mechanisms in woven fabric reinforced flexible composite with single edge notch (SEN) subjected to mono-axial loading. Tensile tests were conducted with a notch depth of 0, 5, 10, 15 and 20mm, respectively. Damage mechanisms have been described and tensile strength, energy absorption was also expressed. Experimental results indicate that the failure progressive in the textile reinforced flexible composite was quite complex and tested material demonstrated significant notch sensitivity.

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Kahane, Nitza, Yuval Cinnamon und Chaya Kalcheim. „The roles of cell migration and myofiber intercalation in patterning formation of the postmitotic myotome“. Development 129, Nr. 11 (01.06.2002): 2675–87. http://dx.doi.org/10.1242/dev.129.11.2675.

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We have previously found that the postmitotic myotome is formed by two successive waves of myoblasts. A first wave of pioneer cells is generated from the dorsomedial region of epithelial somites. A second wave originates from all four edges of the dermomyotome but cells enter the myotome only from the rostral and caudal lips. We provide new evidence for the existence of these distinctive waves. We show for the first time that when the somite dissociates, pioneer myotomal progenitors migrate as mesenchymal cells from the medial side towards the rostral edge of the segment. Subsequently, they generate myofibers that elongate caudally. Pioneer myofiber differentiation then progresses in a medial-to-lateral direction with fibers reaching the lateralmost region of each segment. At later stages, pioneers participate in the formation of multinucleated fibers during secondary myogenesis by fusing with younger cells. We also demonstrate that subsequent to primary myotome formation by pioneers, growth occurs by uniform cell addition along the dorsoventral myotome. At this stage, the contributing cells arise from multiple sources as the myotome keeps growing even in the absence of the dorsomedial lip. Moreover, as opposed to suggestions that myotome growth is driven primarily and directly by the medial and lateral edges, we demonstrate that there is no direct fiber generation from the dorsomedial lip. Instead, we find that added fibers elongate from the extreme edges. Altogether, the integration between both myogenic waves results in an even pattern of dorsoventral growth of the myotome which is accounted for by progressive cell intercalation of second wave cells between preexisting pioneer fibers.

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Burhanuddin, Yanuar, Che Hassan Che Haron und Jaharah A. Ghani. „The Effect of Tool Edge Geometry on Tool Performance and Surface Integrity in Turning Ti-6Al-4V Alloys“. Advanced Materials Research 264-265 (Juni 2011): 1211–21. http://dx.doi.org/10.4028/www.scientific.net/amr.264-265.1211.

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This paper focuses on the influence of cutting tool edge geometry, cutting speed and feed rate on the tool performance and workpiece’s surface integrity in dry turning of Ti-6Al-4V alloy using PCBN inserts. The parameters evaluated are tool life, wear rate, wear mechanisms, surface roughness and subsurface microstructure alterations. The rate of wear growth of the insert was assessed by progressive flank wear using optical microscope by taking photographs after certain length of cut. The wear mechanism at the end of tool life was investigated in detail using scanning electron microscope (SEM) and EDAX analysis. The results show, by increasing the cutting speed and feed rate resulted in tool life reduction. Cutting with honed edge insert at cutting speed of 180 m/min has shown very little wear, even after 20 min of cutting. The honed insert proved less sensitive to increases in feed rate than the chamfered insert. In general the honed insert showed a significant improvement in tool life. All inserts failed due to attrition wear and adhesion. No flank notch wear was observed, but some crater wear occurred at the chamfer land. Microstructure alteration was not found when machining using the different edge geometry. In these trials, the subsurface micro structural deformations in the direction of cutting were deformed grain boundaries and elongation of grains. Chip smearing and debris on the surface was also found.

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Zhao, Hong Hao, Fan Bo Meng, Qing Qi Zhao und Jie Wang. „A Novel Construction Method of QC-LDPC Codes Based on Generalized ACE Constrained“. Advanced Materials Research 760-762 (September 2013): 1684–89. http://dx.doi.org/10.4028/www.scientific.net/amr.760-762.1684.

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Recently, structured LDPC codes have been focused on due to excellent performance and lower complexity. An improved construction of QC-LDPC based on a modified PEG algorithm is proposed in this paper. The modified Progressive Edge-Growth algorithm is a PEG algorithm with Approximated Cycle Extrinsic Message Degree (ACE) metric, which is used to describe the connectivity of cycles. The approach can maximize the girth of the cycles, improve the connectivity of cycles and have the advantages of QC algorithms. The simulation results demonstrate that the PEG algorithm based on ACE has lower Bit Error Rate (BER) and Frame Error Rate (FER) than the original PEG algorithm at the low Signal Noise Ratio (SNR) values, and has a relatively lower computational complexity.

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Tong, Ning Ning, Dan Feng Zhao und Yu Ping Wu. „A Kind of Improved PEG Algorithm of Q-Ary LDPC Codes“. Applied Mechanics and Materials 130-134 (Oktober 2011): 3032–35. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.3032.

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Progressive-edge-growth (PEG) algorithm is one of the best known methods for constructing LDPC codes at short and intermediate block lengths, however, the codes directly designed by such algorithm has high encoding complexity, especially for q-ary LDPC codes, encoding complexity increases with the increase of q value rapidly, which hinder the development of q-ary LDPC code’s implementation seriously. To such problem, the paper presents a improved method based on PEG algorithm which can be encoded by the iterative encoding algorithm with the liner operation complexity. The simulation results indicate: Though the error correcting capability of irregular q-ary LDPC codes constructed by the proposed methods in the paper is basically identical with the codes constructed by the PEG algorithm, but the powerful advantage makes it be easily implemented by the hardware .

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Gao, Chaohui, Sen Liu, Dong Jiang und Lijun Chen. „Constructing LDPC Codes with Any Desired Girth“. Sensors 21, Nr. 6 (12.03.2021): 2012. http://dx.doi.org/10.3390/s21062012.

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In wireless sensor networks, the reliability of communication can be greatly improved by applying low-density parity-check (LDPC) codes. Algorithms based on progressive-edge-growth (PEG) pattern and quasi-cyclic (QC) pattern are the mainstream approaches to constructing LDPC codes with good performance. However, these algorithms are not guaranteed to remove all short cycles to achieve the desired girth, and their excellent inputs are difficult to obtain. Herein, we propose an algorithm, which must be able to construct LDPC codes with the girth desired. In addition, the optimal input to the proposed algorithm is easy to find. Theoretical and experimental evidence of this study shows that the LDPC codes we construct have better decoding performance and less power consumption than the PEG-based and QC-based codes.

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Ghafari, Sepehr, und Fereidoon Moghadas Nejad. „R-Curve Characterization of Crumb Rubber Modified Asphalt Mixtures Incorporating Warm Mix Additive at Low Temperatures“. Key Engineering Materials 894 (27.07.2021): 109–14. http://dx.doi.org/10.4028/www.scientific.net/kem.894.109.

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In a previous research by authors, a methodology was developed to derive J-R curves for Hot Mix Asphalt (HMA) mixtures using an elastic-plastic approach where a comprehensive understanding of crack propagation regime could be achieved. In this research, the effect of crumb rubber modification of HMA binder is studied in terms of R-curves and crack propagation at low temperatures. Mode I Single edge notched beam (SE(B)) fracture tests were conducted in temperature levels of 0 °C, -10 °C, and -20 °C. PG58-22 and PG64-22 binders were used in the fabrication of HMA samples. Modified specimens consist of 20% crumb rubber along with the incorporation of 3% warm mix admixture. Crack growth resistance curves were obtained in SE(B) tests by means of image processing and recording of the progressive crack length. Elastic-plastic J-R curves revealed that crumb rubber modified mixtures exhibit higher crack growth resistance for each bitumen performance grade. As well, increased ductility and cohesive energy can be observed according to the R-curves as the mixtures are modified by crumb rubber.

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Galambošová, Jana, Miroslav Macák, Marek Živčák, Vladimír Rataj, Pavol Slamka und Katarína Olšovská. „Comparison of Spectral Reflectance and Multispectrally Induced Fluorescence to Determine Winter Wheat Nitrogen Deficit“. Advanced Materials Research 1059 (Dezember 2014): 127–33. http://dx.doi.org/10.4028/www.scientific.net/amr.1059.127.

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Technical and technological aspects of variable rate nitrogen fertilization receive much attention nowadays. Current commercial technology is based on the use of spectral reflectance of crop. However, these have some limitations as variety dependence, crop health effect and limited use in more developed growth stages. New parameters overcoming these problems need to be assessed and their potential in precision agriculture should be considered. Multispectrally induced fluorescence is a progressive method. In addition to chlorophyll content, it allows to determine phenolic compounds, which is a product of metabolism of the plant under nitrogen deficit and is considered as the most exact indicator of nitrogen deficit. Comparing the spectral reflectance indices (normalized difference vegetation index – NDVI and normalized difference red edge index – NDRE) and multispectral fluorescence index (nitrogen balance index – NBI), these performed similarly in terms of determining the leaves biomass and nitrogen content in %, NDRE and NBI reflected significantly also aboveground N; however, only the correlation of NDVI reflected with N uptake and with leaf area was highly significant.

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Marchand, Peter J., France L. Goulet und Thomas C. Harrington. „Death by attrition: a hypothesis for wave mortality of subalpine Abiesbalsamea“. Canadian Journal of Forest Research 16, Nr. 3 (01.06.1986): 591–96. http://dx.doi.org/10.1139/x86-102.

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Wave mortality in subalpine Abies forests of the northeastern United States is characterized by the progressive dieback of overstory dominants in a compact zone that advances systematically through mature stands and is followed by vigorous regeneration of the overstory species. The principal driving force for this dieback appears to be exposure at the edge of canopy gaps to very high winds. In this study, individual trees at the leading edge of a dieback front and trees in a thinned plot within the mature stand downwind of the advancing wave both experienced a substantial decline in foliage mass and, consequently, in prebudbreak foliar starch pool over a 2-year period. In the case of the thinned stand, this reduction was attributed to a large increase in wintertime green litter fall. Increased exposure at the wave front and in the thinned stand also resulted in a dramatic increase in root damage relative to control trees. Coincidental to breakage of roots, root xylem discoloration (attributed to wounding and invasion by root pathogens) was greater on trees at the wave front than on trees in the mature zone. Loss of active foliage and roots was accompanied by a two- to five-fold reduction in annual wood increment among dieback zone trees. These data suggest that exposed trees, which suffer a substantial reduction in crown size and foliage carbohydrate pool in an environment where growth is marginal to begin with, may not be able to keep up with the increased energy demand for root and foliage turnover and eventually suffer death by attrition of both tissues.

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Bashiri, Abdullateef H., und Abdulnaser M. Alshoaibi. „Adaptive Finite Element Prediction of Fatigue Life and Crack Path in 2D Structural Components“. Metals 10, Nr. 10 (01.10.2020): 1316. http://dx.doi.org/10.3390/met10101316.

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The existence of a hole near a growing fatigue crack can cause the crack trajectory to deviate. Unless the hole is too close to the crack, the crack is arrested at the edge of the hole and does not progress further. The purpose of this paper was to predict the crack propagation and lifetime of two-dimension geometries for linear elastic materials in mixed-mode loading using a finite element source code program written in Visual Fortran language. The finite element mesh is generated using the advancing front method. The onset criterion of crack propagation was based on the equivalent stress intensity factor which provides the most important parameter that must be accurately estimated for the mixed-mode loading condition. The maximum circumferential stress theory was used as a direction criterion. The modified compact tension (MCTS) was studied to demonstrate the influence of the hole’s presence on the direction of crack growth and fatigue life for different configurations. The Paris’ law model has been employed to evaluate the mixed-mode fatigue life for MCTS in different configurations under the linear elastic fracture mechanics (LEFMs) assumption. The framework involves a progressive crack extension study of stress intensity factors (SIFs), crack growth direction, and fatigue life estimation. The results show that the fatigue growth was attracted to the hole either changes its direction to reach the hole or floats by the hole and grows as the hole is missed. The results of the study agree with several crack propagation experiments in the literature revealing similar crack propagation trajectory observations.

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Carbognani, M., A. Piotti, S. Leonardi, L. Pasini, I. Spanu, G. G. Vendramin, M. Tomaselli und A. Petraglia. „Reproductive and genetic consequences of extreme isolation in Salix herbacea L. at the rear edge of its distribution“. Annals of Botany 124, Nr. 5 (31.07.2019): 849–60. http://dx.doi.org/10.1093/aob/mcz129.

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Abstract Background and Aims At the rear edge of the distribution of species, extreme isolation and small population size influence the genetic diversity and differentiation of plant populations. This may be particularly true for Arctic-alpine species in mid-latitude mountains, but exactly how peripherality has shaped their genetic and reproductive characteristics is poorly investigated. The present study, focused on Salix herbacea, aims at providing new insights into the causes behind ongoing demographic dynamics and their consequences for peripheral populations of Arctic-alpine species. Methods We performed a whole-population, highly detailed sampling of the only two S. herbacea populations in the northern Apennines, comparing their clonal and genetic diversity, sex ratio and spatial genetic structure with a reference population from the Alps. After inspecting ~1800 grid intersections in the three populations, 563 ramets were genotyped at 11 nuclear microsatellite markers (nSSRs). Past demography and mating patterns of Apennine populations were investigated to elucidate the possible causes of altered reproductive dynamics. Key Results Apennine populations, which experienced a Holocene bottleneck and are highly differentiated (FST = 0.15), had lower clonal and genetic diversity compared with the alpine population (RMLG = 1 and HE = 0.71), with the smaller population exhibiting the lowest diversity (RMLG = 0.03 and HE = 0.24). An unbalanced sex ratio was found in the larger (63 F:37 M) and the smaller (99 F:1 M) Apennine population. Both were characterized by the presence of extremely large clones (up to 2500 m2), which, however, did not play a dominant role in local reproductive dynamics. Conclusions Under conditions of extreme isolation and progressive size reduction, S. herbacea has experienced an alteration of genetic characteristics produced by the prevalence of clonal growth over sexual reproduction. However, our results showed that the larger Apennine population has maintained levels of sexual reproduction enough to counteract a dramatic loss of genetic and clonal diversity.

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Kukk, Villu, Targo Kalamees und Jaan Kers. „The effects of production technologies on the air permeability and crack development of cross-laminated timber“. Journal of Building Physics 43, Nr. 3 (07.08.2019): 171–86. http://dx.doi.org/10.1177/1744259119866869.

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In a building envelope, the cross-laminated timber is often used as an air barrier layer. The objective of this study was to evaluate the impact of production technologies such as edge bonding, different initial moisture content of lamination and number of lamination layers (three and five) on the air permeability properties of the cross-laminated timber. Air leakage and crack area in cross-laminated timber panels were measured after the panels were conditioned in environments with different relative humidities in progressive steps from humid to dry environments (relative humidity 75% → relative humidity 43% → relative humidity 30% → relative humidity 15%). The test results showed that the five-layer specimens combined with initially drier laminations had the most considerable effect on avoiding air leakages through the panel. The greater number of layers helps to avoid any overlapping of gaps between laminations that are possible sources of air leakages. Based on the results, it is recommended to combine the technologies of using a larger number of layers together with initially drier laminations to minimise the growth of cracks on panel surfaces and avoid air leakages during the time of use.

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Hu, Junfeng, Xi Deng, Xutong Zhang, Wen-Xue Wang und Terutake Matsubara. „Effect of Off-Axis Ply on Tensile Properties of [0/θ]ns Thin Ply Laminates by Experiments and Numerical Method“. Polymers 13, Nr. 11 (31.05.2021): 1809. http://dx.doi.org/10.3390/polym13111809.

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The effect of off-axis ply on the tensile properties of unbalanced symmetric [0/θ]ns laminates was explored through experimental and numerical analysis. Six CFRP [0/θ]2s plies with different off-axis angles θ were fabricated for tensile tests. In situ observations of the damage to the laminates were conducted to investigate the initiation and progressive growth of the laminates during the tension tests. The fiber fractures, crack initiation, and progressive propagation were analyzed by observing the free edge of the laminates, and the difference in damage behavior caused by different off-axis angles was investigated. All the six [0/θ]2s plies with off-axis angles θ ranging from 15° to 90° showed approximate linear stress–strain responses in the tensile tests. Matrix cracks were not observed prior to the final catastrophic failure in the off-axis layers of the [0/θ]2s laminates with a θ in the range of 15–60°. Finite element analysis (FEA) of the [0/θ]s plies was conducted using a 3D micromechanical model, in which matrix cracking and fiber-matrix debonding in the off-axis layer were simulated using a cohesive interface element. Three micromechanical crack-free, cohesive interface, and initial crack models were analyzed to predict the influence of the matrix cracks inside the off-axis layer on the damage behavior of the [0/θ]s laminates. The numerical results from the initial crack micromechanical model show a lower bound of the tensile strength of the [0/θ]s plies. A high stress concentration is observed adjacent to the cracked off-axis layer, inducing a tensile strength loss of about 20%.

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Searl, Alison. „Saddle dolomite: a new view of its nature and origin“. Mineralogical Magazine 53, Nr. 373 (Dezember 1989): 547–55. http://dx.doi.org/10.1180/minmag.1989.053.373.05.

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AbstractSaddle dolomite is a common product of late-stage diagenesis and hydrothermal activity. It has been suggested that during growth Ca enrichment occurs towards crystal edges leading to a lattice expansion relative to face centres. However, backscatter scanning electron microscopy of eight samples has revealed that, instead of edge associated Ca enrichment, saddle dolomites have a series of edge associated Mg enriched wedges, between 5 and 20 µm thick and 300 µm long. Wedge geometry implies development of extra lattice layers at edges relative to face centres. It is suggested that the wedges develop during rapid, transport-controlled, crystal growth. The wedges possibly reflect a switching from continuous growth across the face to edge-nucleated growth as the boundary layer solution becomes progressively depleted. Continuous growth might be reinstigated through convective turnover of the boundary layer presenting fresh solution to the growing crystal.

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Meng, Jiahui, Danfeng Zhao und Liang Zhang. „Design and Analysis of Non-Binary LDPC-CPM System for Hybrid Check Matrix Construction Algorithm of WSN“. Sensors 18, Nr. 8 (25.07.2018): 2418. http://dx.doi.org/10.3390/s18082418.

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In order to enhance the reliability and anti-interference performance of wireless sensor network (WSN) data transmission, this paper designs the low power scheme of the WSN from the angle of error correction coding and proposes the hybrid check matrix construction (HC) algorithm based on iterative coding algorithms with linear coding complexity. The algorithm first improves the traditional iterative coding algorithm, making it suitable for non-binary low-density parity check (LDPC) codes. Then, the algorithm applies the backward iteration method to change the coding scheme and uses the check matrix construction method so that the progressive edge growth (PEG) algorithm has a lower triangular structure, which is used as a base matrix. An improved quasi-cyclic LDPC (QC-LDPC) algorithm, with a lower triangular structure, is used to generate a cyclic shift matrix and a finite domain coefficient matrix. Simultaneously, the short loop is eliminated and the optimal check matrix is selected for use in the channel coding process. The non-binary LDPC-CPM system is modeled and simulated. The simulation results show that the non-binary LDPC code constructed by the HC algorithm not only has linear coding and storage complexity but also has strong error correction capability. The design of non-binary LDPC-CPM system parameters can enhance the reliability, anti-jamming capability and reduce the complexity and reduce the complexity of the WSN.

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Mackinnon, David I. „Patterns of loop development in post-Paleozoic terebratulid brachiopods and their evolutionary significance“. Paleontological Society Special Publications 6 (1992): 192. http://dx.doi.org/10.1017/s2475262200007528.

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Studies of loop ultrastructure reveal much about both the processes and patterns of loop growth in brachiopods. Such studies also provide useful insight into evolutionary relationships between various main loop-bearing brachiopod taxa. At least five different loop types, two short-looped and three long-looped, are recognisable in Cenozoic Terebratulida.Loop development in short-looped forms is relatively unspectacular and of limited value for evolutionary studies. It consists of the growth of either an undulating transverse ribbon extending between two short crura (in the Family Terebratulidae) or, where crural processes are united (as in most Cancellothyrididae), a ring. In all short-looped forms the loop is derived from, and hence supported solely by, the crura throughout ontogeny.The early stages of loop development in the great majority of post-Paleozoic long-looped brachiopods are similar. A septal pillar, located centrally in the dorsal valve floor, appears generally very early in ontogeny. Rudimentary descending branch elements are generated both from the crura and the flanks of the septal pillar. Rudimentary ascending elements develop at either the ventral or posteroventral edge of the septal pillar and consist firstly of an inverted or steeply inclined and continuously expanding cone or hood which, through resorption of its posteriorly located apex, becomes transformed into a ring. Further growth sees firstly the fusion of the anterior extremeties of adjacent ascending and descending loop elements followed by their progressive anterolateral separation from the septal pillar.Contrasting modes of growth characterise the later stages of loop development in the three main groups of long-looped brachiopods. In Dallinidae, ascending and descending elements detach from the septum to give rise to a long, reflected loop supported only by the crura. In Terebratellidae, a pair of narrow, laterally directed but anteriorly migrating struts anchor the the descending branches to the median septum. These struts, in structural continuity with the median septum, are built up entirely from secondary layer fibres. In Laqueidae, in addition to a pair of septal struts, a pair of anterolaterally migrating vertical bands spanning the gap between adjacent ascending and descending branches provide further support. Unlike the septal struts but like the remaining ascending and descending loop elements, the vertical bands are constructed from both primary and secondary shell layers. Growth line discordancies at the junctions between the vertical bands and contiguous ascending and descending elements indicate the structural integrity of the vertical bands.

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Vajedian, Sanaz, Mahdi Motagh, Zahra Mousavi, Khalil Motaghi, Eric Fielding, Bahman Akbari, Hans-Ulrich Wetzel und Aliakbar Darabi. „Coseismic Deformation Field of the Mw 7.3 12 November 2017 Sarpol-e Zahab (Iran) Earthquake: A Decoupling Horizon in the Northern Zagros Mountains Inferred from InSAR Observations“. Remote Sensing 10, Nr. 10 (03.10.2018): 1589. http://dx.doi.org/10.3390/rs10101589.

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The study of crustal deformation fields caused by earthquakes is important for a better understanding of seismic hazard and growth of geological structures in tectonically active areas. In this study, we present, using interferometric measurements constructed from Sentinel-1 Terrain Observation with Progressive Scan (TOPS) data and ALOS-2 ScanSAR, coseismic deformation and source model of the Mw 7.3, 12 November 2017 earthquake that hit northwest of the Zagros Mountains in the region between Iran–Iraq border. This was one of the strongest seismic events to hit this region in the past century, and it resulted in an uplift area of about 3500 km2 between the High Zagros Fault (HZF) and Mountain Front Fault (MFF) with a maximum amount of 70 cm south of Miringe fault. A subsidence over an area of 1200 km2 with a maximum amount of 35 cm occurred near Vanisar village at the hanging wall of the HZF. Bayesian inversion of interferometric synthetic aperture radar (InSAR) observations suggests a source model at a depth between 14 and 20 km that is consistent with the existence of a decoupling horizon southwest edge of the northern portion of the Zagros Mountains near the MFF. Moreover, we present evidence for a number of coseismically induced rockslides and landslides, the majority of them which occurred along or close to pre-existing faults, causing decorrelation in differential interferograms. Exploiting the offset-tracking technique, we estimated surface motion by up to 34 and 10 m in horizontal and vertical directions, respectively, due to lateral spreading on a big coseismic-induced landslide near Mela-Kabod. Field observations also revealed several zones of en echelon fractures and crack zones developed along a pre-existing fault passing through Qasr-e Shirin City, which exhibited secondary surface slip by up to 14 cm along its strike.

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Wang, Yingchao, Yang Liu, Yongliang Li, Wen Jiang und Yueming Wang. „Experimental Study on the Failure Mechanism of Tunnel Surrounding Rock under Different Groundwater Seepage Paths“. Geofluids 2021 (06.05.2021): 1–17. http://dx.doi.org/10.1155/2021/8856365.

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The influence of groundwater on tunnel engineering is very complicated. Due to the complexity of water flow water pressure transfer and uncertain defects in the stratum, all of which are key factors with regard to the design of tunnel engineering. Therefore, the variation of surrounding rock during excavation and the deformation and failure of soft surrounding rock under different seepage paths of underground water after excavation systematically. Experimental results showed that the stress change of surrounding rock caused by tunnel excavation can be divided into 3 stages: stress redistribution, stress adjustment, and stress rebalancing. In the process of water pressure loading, water flow rate is closely related to the experimental phenomenon. The between stable loading water pressure pore water pressure of the tunnel surrounding rock and the distance from the measuring point to the edge of the tunnel obey the exponential function of the decreasing growth gradient. With the increase of loading pressure, the pore water pressure and stress at the top of the tunnel increase, and the coupling of stress field and seepage field on both sides of surrounding rock more and more intense. The failure process of the tunnel can be divided into 6 stages according to the damage degree. The final failure pattern of the surrounding rock of the tunnel is mainly determined by the disturbed area of excavation. The arched failure area and the collapse-through failure area are composed of three regions. The surrounding rock is characterized by a dynamic pressure arch in the process of seepage failure, but it is more prone to collapse failure at low water pressure. The results of this study are the progressive failure mechanism of tunnel under different groundwater seepage paths and would be of great significance to the prevention of long-range disasters.

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Palmer, A. R., D. Jiang und D. H. Marshall. „Responses of ventral cochlear nucleus onset and chopper units as a function of signal bandwidth“. Journal of Neurophysiology 75, Nr. 2 (01.02.1996): 780–94. http://dx.doi.org/10.1152/jn.1996.75.2.780.

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1. The responses of units in the ventral cochlear nucleus in anesthetized guinea pigs have been measured to best-frequency tones, noise bands geometrically centered around the unit best frequency, and noise bands asymmetrically positioned around the best frequency. 2. Each unit isolated was characterized using peristimulus time histograms (PSTHs) to best-frequency tones at 20 and 50 dB suprathreshold, frequency-intensity response areas and rate-versus-level functions in response to best-frequency tones and wideband noise. The data reported here are derived from full analyses of 5 chopper units and 17 onset units. The onsets were divided into onset-I (OnI), onset-L (OnL), and onset-C (OnC) by the criteria described by Winter and Palmer: the PSTHs of OnI units show only an onset response, OnL units respond with a single spike at onset followed by a low level of sustained activity, and OnC units have PSTHs with one to four onset peaks and low levels of sustained discharge. 3. In response to geometrically centered noise bands of constant spectral density, the discharge of chopper units and one OnI unit increased over a relatively narrow range of bandwidths, corresponding to the equivalent rectangular bandwidth calculated from their response area, and then became constant. In contrast, OnL and OnC units showed increases in discharge rate with noise bandwidth over very wide ranges of bandwidth. The growth of the discharge rate with noise bandwidth was approximately linear on double logarithmic axes and therefore could be described by a power function with an exponent of 0.37. This relation held even for noise levels near threshold. 4. When noise bands with constant spectral density (at the input to the earphone) were presented with one edge fixed at the unit's best frequency, the discharge rate of most chopper units and the one OnI unit increased over a narrow range of bandwidths and then became constant. This pattern was observed irrespective of whether the second edge of the noise was progressively increased above, or decreased below, the best frequency. For two of the chopper units, in which lateral inhibitory sidebands could be demonstrated, increasing the noise bandwidth led first to increases and then to decreases in the discharge rate as the noise energy impinged upon the sideband. The chopper units act like energy detectors with a filter corresponding to their single tone response area, but, for some units, with the addition of inhibitory sidebands. 5. For the OnL and OnC units, increasing the noise bandwidth above or below best frequency caused progressive increases in the discharge rate over wide ranges of bandwidth. These increases occurred even for low noise spectral densities. The growth in discharge rate for these onset units was well fitted at all spectral density levels by power functions: one above best frequency and one below. At levels of the noise 40 dB above the unit threshold, the point at which the discharge rate reached 90% of its maximum was, on average, about 2 octaves below best frequency and 1 octave above. For some onset units, changes in the discharge rate were seen as the noise bandwidth was varied over about 14 kHz, which is about one-third of the total frequency hearing range of the guinea pig. 6. The data for onset units is consistent with the hypothesis that onset units in the ventral cochlear nucleus achieve their precision in the temporal domain by integration of the inputs from auditory nerve fibers with a wide range of best frequencies. The range of frequency over which onset units integrate frequency matches that of the inhibitory input to dorsal cochlear nucleus neurons, suggesting a possible role as an inhibitory interneuron.

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Ferguson, Mark W. J. „Palate development“. Development 103, Supplement (01.09.1988): 41–60. http://dx.doi.org/10.1242/dev.103.supplement.41.

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In all vertebrates, the secondary palate arises as bilateral outgrowths from the maxillary processes. In birds and most reptiles, these palatal shelves grow initially horizontally, but do not fuse with each other resulting in physiological cleft palate. In crocodilians, shelf fusion occurs resulting in an intact secondary palate. Mammalian palatal shelves initially grow vertically down the side of the tongue, but elevate at a precise time to a horizontal position above the dorsum of the tongue and fuse with each other to form an intact palate. Palatal shelf-elevation is the result of an intrinsic shelf elevating force, chiefly generated by the progressive accumulation and hydration of hyaluronic acid. In all vertebrates the nasal epithelium differentiates into pseudostratified ciliated columnar cells and the oral epithelia differentiates into stratified squamous cells, but the medial edge epithelial (MEE) phenotype differs in different groups. In mammals, the MEE of opposing shelves adhere to each other to form an epithelial seam which then disrupts by cell death and cell migration into the mesenchyme accompanied by an epitheliomesenchymal transformation. In birds, the MEE keratinize resulting in cleft palate whereas, in alligators, the MEE migrate onto the nasal aspect of the palate. In all vertebrates, this regional, temporal and species-specific epithelial differentiation is specified by the underlying mesenchyme. Signalling of this interaction is complex but involves both extracellular matrix and soluble factors e.g. minor collagen types, tenascin, EGF, TGFα, TGFβ, PDGF, FGF. These soluble growth factors have a biphasic effect: directly on the epithelia and on the mesenchyme where they stimulate or inhibit cell division and synthesis of specific extracellular matrix molecules. The extracellular matrix molecules (and bound growth factors) synthesized by the mesenchymal cells may then directly affect the epithelium. These signals cause differential gene expression via second messenger systems e.g. cAMP, cGMP, Ca2+, pH, pI etc. Molecular markers for nasal, medial and oral epithelial cell differentiation include the types of cytokeratin intermediate filaments and specific cell surface molecules recognized by monoclonal antibodies: the genes for such molecules are probably expressed in response to mesenchymal signals. Using such an approach, it is possible to go from a morphological description of palate development to a cellular analysis of the mechanisms involved and then to identification of candidate genes that may be important for screening and diagnosis of cleft palate.

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Gulbrandsen, Ørnulf. „The rise of the north-western Tswana kingdoms: on the dynamics of interaction between internal relations and external forces“. Africa 63, Nr. 4 (Oktober 1993): 550–82. http://dx.doi.org/10.2307/1161006.

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AbstractWhile southern African polities are often considered as essentially fissionary in nature, this article gives emphasis to the equally important fusionary processes. Examining the rise of the north-western kingdoms, it is focused upon the accumulation of material and symbolic capital in the royal centres. Particular attention is paid to how the rulers exploited this capital in their efforts to amalgamate the power structures surrounding their offices. The accumulation of the royal capital is related to the kingdoms' interaction with the larger world, and it is argued that the rise of the north-western Tswana kingdoms—located on the edge of the Kalahari—might profitably be seen as localised culminations of regional processes, propelled by regional and global forces. Thus the present historical approach helps to demonstrate how these kingdoms gained strength by translating ever newer types of external forces into the constructive underpinnings of a central authority: the initial conquest and incorporation of local groups gave these polities demographic strength. By virtue of virgin pastures, copper production and the natural resources of the Kalahari the centre grew in wealth and strength, attracting foreign groups and incorporating them politically through clientisation. These regional economic and ecological processes underpinned the growth of royal pastoral wealth and diversified the composition of the population, allowing the king to use particular cultural institutions to strengthen his internal control and military capacity. In particular, through several decades of military success from the later eighteenth century onwards, the resources and authority commanded by the king were institutionalised through a politico-administrative ward system.It is argued that the progressive strength of these polities involved two types of dialectical transformation: first, a socio-political dialectic at work in the interaction between internal relations and external forces, by which the king translated cattle and people into political controls; and, secondly, the reproduction and strengthening of the symbolic capital vested in the royal ancestorhood, upon which the king's legitimacy rested, was effected by the transformation of any successful ruler from being king to becoming a royal ancestor. Although the transformative operations of the rulers are thus emphasised, their successful agency in translating external forces into royal capital is attributed primarily not to their personal capacity but to the advantageous structural conditions under which they operated as the historical con-text evolved.

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Jiménez-Sánchez, Juan, Jesús J. Bosque, Germán A. Jiménez Londoño, David Molina-García, Álvaro Martínez, Julián Pérez-Beteta, Carmen Ortega-Sabater et al. „Evolutionary dynamics at the tumor edge reveal metabolic imaging biomarkers“. Proceedings of the National Academy of Sciences 118, Nr. 6 (03.02.2021): e2018110118. http://dx.doi.org/10.1073/pnas.2018110118.

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Human cancers are biologically and morphologically heterogeneous. A variety of clonal populations emerge within these neoplasms and their interaction leads to complex spatiotemporal dynamics during tumor growth. We studied the reshaping of metabolic activity in human cancers by means of continuous and discrete mathematical models and matched the results to positron emission tomography (PET) imaging data. Our models revealed that the location of increasingly active proliferative cellular spots progressively drifted from the center of the tumor to the periphery, as a result of the competition between gradually more aggressive phenotypes. This computational finding led to the development of a metric, normalized distance from 18F-fluorodeoxyglucose (18F-FDG) hotspot to centroid (NHOC), based on the separation from the location of the activity (proliferation) hotspot to the tumor centroid. The NHOC metric can be computed for patients using 18F-FDG PET–computed tomography (PET/CT) images where the voxel of maximum uptake (standardized uptake value [SUV]max) is taken as the activity hotspot. Two datasets of 18F-FDG PET/CT images were collected, one from 61 breast cancer patients and another from 161 non–small-cell lung cancer patients. In both cohorts, survival analyses were carried out for the NHOC and for other classical PET/CT-based biomarkers, finding that the former had a high prognostic value, outperforming the latter. In summary, our work offers additional insights into the evolutionary mechanisms behind tumor progression, provides a different PET/CT-based biomarker, and reveals that an activity hotspot closer to the tumor periphery is associated to a worst patient outcome.

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Stevens, R. P., und P. Heil. „The interplay of dynamic and thermodynamic processes in driving the ice-edge location in the Southern Ocean“. Annals of Glaciology 52, Nr. 57 (2011): 27–34. http://dx.doi.org/10.3189/172756411795931642.

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AbstractA stand-alone sea-ice model (CICE4) was used to investigate the physical processes affecting the ice-edge location. Particular attention is paid to the relative contributions of dynamic and thermodynamic processes in advancing the ice edge equatorward during ice growth. Results from 10 years of an 11 year numerical simulation have been verified against satellite observations from 1998 to 2007. the autumn advance of the sea-ice edge is primarily due to thermodynamic processes, with significant dynamic contributions limited to regions such as 60–70˚ E and 310–340˚ E. In the dynamically dominated regions, winds with a southerly component cause equatorward ice advection but also induce thermodynamic growth of new ice, which occurs well poleward of the 15% ice-concentration contour where air temperature is lowest. As the ice moves into warmer water it melts, hence extending equatorward the region with ocean mixed layer at freezing point. This accelerates the northward progression of the ice edge and permits thermodynamic ice growth as soon as the air temperature reaches below the ocean freezing point. In regions where thermodynamic processes are dominant (e.g. 340–40˚ E), maximum ice production occurs just poleward of the 15% ice-concentration contour, where thin sea ice is prevalent. In these longitude bands, autumn ice melt is generally absent at the ice edge due to ineffective equatorward ice advection.

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