Artigos de revistas: "Extension de cycles"

1

Reed, Richard. "Fashion Life Cycles and Extension Theory". European Journal of Marketing 21, n.º 3 (março de 1987): 52–62. http://dx.doi.org/10.1108/eum0000000004686.

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2

Coupechoux, Pierre. "Extension of universal cycles for globally identifying colorings of cycles". Discrete Mathematics 340, n.º 7 (julho de 2017): 1456–66. http://dx.doi.org/10.1016/j.disc.2017.02.002.

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3

Boumasmoud, Réda, Ernest Hunter Brooks e Dimitar P. Jetchev. "Vertical Distribution Relations for Special Cycles on Unitary Shimura Varieties". International Mathematics Research Notices 2020, n.º 13 (14 de junho de 2018): 3902–26. http://dx.doi.org/10.1093/imrn/rny119.

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Abstract We consider cycles on three-dimensional Shimura varieties attached to unitary groups, defined over extensions of a complex multiplication (CM) field $E$, which appear in the context of the conjectures of Gan et al. [6]. We establish a vertical distribution relation for these cycles over an anticyclotomic extension of $E$, complementing the horizontal distribution relation of [8], and use this to define a family of norm-compatible cycles over these fields, thus obtaining a universal norm construction similar to the Heegner $\Lambda $-module constructed from Heegner points.

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4

Katona, Gyula Y. "Extension of paths and cycles for hypergraphs". Electronic Notes in Discrete Mathematics 45 (janeiro de 2014): 3–7. http://dx.doi.org/10.1016/j.endm.2013.11.002.

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5

Gehrlein, William V., e Peter C. Fishburn. "Linear extension majority cycles on partial orders". Annals of Operations Research 23, n.º 1 (dezembro de 1990): 311–22. http://dx.doi.org/10.1007/bf02204855.

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6

Bernhardt, Chris. "Time-symmetric cycles". International Journal of Mathematics and Mathematical Sciences 2003, n.º 26 (2003): 1683–92. http://dx.doi.org/10.1155/s0161171203208097.

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The main result of this note is that given any two time-symmetric cycles, one can find a time-symmetric extension of one by the other. This means that given a time-symmetric cycle, both time-symmetric doubles and square roots can be found.

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7

COLACCHIO, GIORGIO, MARCO SPARRO e CLAUDIO TEBALDI. "SEQUENCES OF CYCLES AND TRANSITIONS TO CHAOS IN A MODIFIED GOODWIN'S GROWTH CYCLE MODEL". International Journal of Bifurcation and Chaos 17, n.º 06 (junho de 2007): 1911–32. http://dx.doi.org/10.1142/s0218127407018117.

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The model introduced by Goodwin [1967] in "A Growth Cycle" represents a milestone in the nonlinear modeling of economic dynamics. On the basis of a few simple assumptions, the Goodwin Model (GM) is formulated exactly as the well-known Lotka–Volterra system, in terms of the two variables "wage share" and "employment rate". A number of extensions have been proposed with the aim to make the model more robust, in particular, to obtain structural stability, lacking in GM original formulation. We propose a new extension that: (a) removes the limiting hypothesis of "Harrod-neutral" technical progress: (b) on the line of Lotka–Volterra models with adaptation, introduces the concept of "memory", which plays a relevant role in the dynamics of economic systems. As a consequence, an additional equation appears, the validity of the model is substantially extended and a rich phenomenology is obtained, in particular, transition to chaotic behavior via period-doubling bifurcations.

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8

Ewacha, Kevin, Peter C. Fishburn e W. V. Gehrlein. "Linear extension majority cycles in height-1 orders". Order 6, n.º 4 (1990): 313–18. http://dx.doi.org/10.1007/bf00346127.

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9

Wang, Kailong, Yuxi Ling, Yanjun Zhang, Zhou Yu, Haoyu Wang, Guangdong Bai, Beng Chin Ooi e Jin Song Dong. "Characterizing Cryptocurrency-themed Malicious Browser Extensions". Proceedings of the ACM on Measurement and Analysis of Computing Systems 6, n.º 3 (dezembro de 2022): 1–31. http://dx.doi.org/10.1145/3570603.

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Due to the surging popularity of various cryptocurrencies in recent years, a large number of browser extensions have been developed as portals to access relevant services, such as cryptocurrency exchanges and wallets. This has stimulated a wild growth of cryptocurrency themed malicious extensions that cause heavy financial losses to the users and legitimate service providers. They have shown their capability of evading the stringent vetting processes of the extension stores, highlighting a lack of understanding of this emerging type of malware in our community. In this work, we conduct the first systematic study to identify and characterize cryptocurrency-themed malicious extensions. We monitor seven official and third-party extension distribution venues for 18 months (December 2020 to June 2022) and have collected around 3600 unique cryptocurrency-themed extensions. Leveraging a hybrid analysis, we have identified 186 malicious extensions that belong to five categories. We then characterize those extensions from various perspectives including their distribution channels, life cycles, developers, illicit behaviors, and illegal gains. Our work unveils the status quo of the cryptocurrency-themed malicious extensions and reveals their disguises and programmatic features on which detection techniques can be based. Our work serves as a warning to extension users, and an appeal to extension store operators to enact dedicated countermeasures. To facilitate future research in this area, we release our dataset of the identified malicious extensions and open-source our analyzer.

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10

Wang, Kailong, Yuxi Ling, Yanjun Zhang, Zhou Yu, Haoyu Wang, Guangdong Bai, Beng Chin Ooi e Jin Song Dong. "Characterizing Cryptocurrency-themed Malicious Browser Extensions". ACM SIGMETRICS Performance Evaluation Review 51, n.º 1 (26 de junho de 2023): 91–92. http://dx.doi.org/10.1145/3606376.3593529.

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Due to the surging popularity of various cryptocurrencies in recent years, a large number of browser extensions have been developed as portals to access relevant services, such as cryptocurrency exchanges and wallets. This has stimulated a wild growth of cryptocurrency-themed malicious extensions that cause heavy financial losses to the users and legitimate service providers. They have shown their capability of evading the stringent vetting processes of the extension stores, highlighting a lack of understanding of this emerging type of malware in our community. In this work, we conduct the first systematic study to identify and characterize cryptocurrency-themed malicious extensions. We monitor seven official and third-party extension distribution venues for 18 months (December 2020 to June 2022) and have collected around 3600 unique cryptocurrency-themed extensions. Leveraging a hybrid analysis, we have identified 186 malicious extensions that belong to five categories. We then characterize those extensions from various perspectives including their distribution channels, life cycles, developers, illicit behaviors, and illegal gains. Our work unveils the status quo of the cryptocurrency-themed malicious extensions and reveals their disguises and programmatic features on which detection techniques can be based. Our work serves as a warning to extension users, and an appeal to extension store operators to enact dedicated countermeasures. To facilitate future research in this area, we release our dataset of the identified malicious extensions and open-source our analyzer.

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11

Herman, JoAnne. "Valsalva Response During Progressive Relaxation: An Extension Study". Scholarly Inquiry for Nursing Practice 3, n.º 3 (janeiro de 1989): 217–26. http://dx.doi.org/10.1891/0889-7182.3.3.217.

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This was the second study in a series to investigate the impact of muscle-tension time and breathing pattern on initiation of the Valsalva response during four tense/relax cycles of progressive relaxation. Thirty-three healthy adult subjects performed the hand, upper arm, forehead, and abdomen tense/relax cycles of a standard progressive relaxation procedure while their heart rate and breathing patterns were monitored. Occurrence of the Valsalva response was determined by dividing peak tachycardia during tension by maximum bradycardia following release of the tension. A Valsalva ratio greater than 1.5 indicates presence of the Valsalva response. Eighteen percent of the sample exhibited a Valsalva ratio score > 1.5 in one or more of the tense/ relax cycles. In a previous study, 43% of the subjects exhibited the Valsalva response. When compared with the findings of the previous study, these present findings indicate that controlling breathing pattern and decreasing tensing time may decrease the occurrence of the Valsalva response during progressive relaxation.

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12

Crook, Carolyn, e Roger Alex Clapp. "Ecosystem structure, economic cycles and market-oriented conservation". Environmental Conservation 28, n.º 3 (setembro de 2001): 194–98. http://dx.doi.org/10.1017/s0376892901000200.

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Whether market-oriented conservation, by which we mean the promotion of markets for the products of intact ecosystems, protects biodiversity, and under what conditions, has been a subject of much research and debate. Our evaluation of three strategies of the market-oriented use of natural resources led us to conclude that, at least for these three strategies, market-oriented mechanisms of conservation are often socially, economically, or ecologically unsustainable, and that proposals for market-oriented conservation should be approached with caution (Crook & Clapp 1998). Shackleton's (2001) critique and extension of the conditions for market-oriented conservation offers many useful insights, although we question some of his interpretations. Herein we examine some of those extensions, and revisit the criteria for successful market-oriented conservation.

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13

Burungale, Ashay A. "ON THE NON-TRIVIALITY OF THE -ADIC ABEL–JACOBI IMAGE OF GENERALISED HEEGNER CYCLES MODULO , II: SHIMURA CURVES". Journal of the Institute of Mathematics of Jussieu 16, n.º 1 (7 de maio de 2015): 189–222. http://dx.doi.org/10.1017/s147474801500016x.

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Generalised Heegner cycles are associated to a pair of an elliptic newform and a Hecke character over an imaginary quadratic extension $K/\mathbf{Q}$. The cycles live in a middle-dimensional Chow group of a Kuga–Sato variety arising from an indefinite Shimura curve over the rationals and a self-product of a CM abelian surface. Let $p$ be an odd prime split in $K/\mathbf{Q}$. We prove the non-triviality of the $p$-adic Abel–Jacobi image of generalised Heegner cycles modulo $p$ over the $\mathbf{Z}_{p}$-anticyclotomic extension of $K$. The result implies the non-triviality of the generalised Heegner cycles in the top graded piece of the coniveau filtration on the Chow group, and proves a higher weight analogue of Mazur’s conjecture. In the case of weight 2, the result provides a refinement of the results of Cornut–Vatsal and Aflalo–Nekovář on the non-triviality of Heegner points over the $\mathbf{Z}_{p}$-anticyclotomic extension of $K$.

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14

Peters, James Francis, e Tane Vergili. "Good coverings of proximal Alexandrov spaces. Path cycles in the extension of the Mitsuishi-Yamaguchi good covering and Jordan Curve Theorems". Applied General Topology 24, n.º 1 (5 de abril de 2023): 25–45. http://dx.doi.org/10.4995/agt.2023.17046.

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This paper introduces proximal path cycles, which lead to the main results in this paper, namely, extensions of the Mitsuishi-Yamaguchi Good Coverning Theorem with different forms of Tanaka good cover of an Alexandrov space equipped with a proximity relation as well as extension of the Jordan curve theorem. In this work, a path cycle is a sequence of maps h1,...,hi,...,hn-1 mod n in which hi : [ 0,1 ] → X and hi(1) = hi+1(0) provide the structure of a path-connected cycle that has no end path. An application of these results is also given for the persistence of proximal video frame shapes that appear in path cycles.

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15

Kar, Kamal K., e Anil K. Bhowmick. "High Strain Hysteresis Loss of Rubber Vulcanizates under Pure Shear and Constrained Extension and Influence of Filler". Rubber Chemistry and Technology 73, n.º 1 (1 de março de 2000): 56–73. http://dx.doi.org/10.5254/1.3547580.

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Abstract An experimental analysis of hysteresis loss, hysteresis loss ratio and input energy of natural rubber (NR) and styrene-butadiene rubber (SBR) vulcanizates having variations of loading of carbon black, precipitated silica and clay has been carried out under uniaxial, pure shear and constrained extension modes over a range of extension ratios (1.0 to 2.2 and 1.2 to 4.0 in X and Y directions, respectively), number of cycles (1 to 8) and temperatures (25 to 125 °C). Hysteresis loss, hysteresis loss ratio and input energy increase with an increase in filler loading, extension ratio (in both directions) and reinforcement. These parameters decrease with an increase of temperature and number of stretch cycle. Hysteresis loss, loss ratio and input energy under constrained extension are higher than those under pure shear and uniaxial modes. NR and SBR vulcanizates show similar behavior. Universal expressions relating energy input at any extension ratio, W1, to the hysteresis loss (Hy) as well as hysteresis loss ratio (Hy)r under uniaxial, pure shear and constrained extensions have been developed.

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16

Maher, Harmon Droge. "The Role of Extension in Mountain-Belt Life Cycles". Journal of Geological Education 42, n.º 3 (maio de 1994): 212–19. http://dx.doi.org/10.5408/0022-1368-42.3.212.

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17

Osipov, D. U. "T-irreducible Extension for Union of Paths and Cycles". Izvestiya of Saratov University. New Series. Series: Mathematics. Mechanics. Informatics 13, n.º 2(1) (2013): 100–105. http://dx.doi.org/10.18500/1816-9791-2013-13-2-1-100-105.

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18

Rössler, Damian, e Tamás Szamuely. "Cohomology and torsion cycles over the maximal cyclotomic extension". Journal für die reine und angewandte Mathematik (Crelles Journal) 2019, n.º 752 (1 de julho de 2019): 211–27. http://dx.doi.org/10.1515/crelle-2016-0070.

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Abstract A classical theorem by K. Ribet asserts that an abelian variety defined over the maximal cyclotomic extension K of a number field has only finitely many torsion points. We show that this statement can be viewed as a particular case of a much more general one, namely that the absolute Galois group of K acts with finitely many fixed points on the étale cohomology with {\mathbf{Q}/\mathbf{Z}} -coefficients of a smooth proper {\overline{K}} -variety defined over K. We also present a conjectural generalization of Ribet’s theorem to torsion cycles of higher codimension. We offer supporting evidence for the conjecture in codimension 2, as well as an analogue in positive characteristic.

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19

Zhang, Wei, Xue Zheng Chen, Peng Fei Yin, Zheng Kai Xu, Bing Han e Jia Wang. "EIS Study on the Deterioration Process of Organic Coatings under Immersion and Different Cyclic Wet-Dry Ratios". Applied Mechanics and Materials 161 (março de 2012): 58–66. http://dx.doi.org/10.4028/www.scientific.net/amm.161.58.

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Under immersed and we-dry cyclic conditions, the deterioration processes of the organic coating on carbon steel surface have been comparatively studied using electrochemical techniques. The wet-dry cycles were carried out by exposure to 4 h immersion and 4h dryness (4-4h cycles) and 12h immersion and 12h dryness (12-12h cycles) conditions, respectively. The immersion condition was carry out in a 3.5% NaCl solution and drying at 298K and 50% RH. According to the EIS characteristics, the entire deterioration processes under above three mentioned conditions can be divided into three main stages, consisting of the medium penetration, corrosion initiation and corrosion extension. Comparing with the immersed, the 4-4h wet-dry cycles greatly accelerated the entire deterioration process; especially during the corrosion initiation and the corrosion extension periods, leading the paint system lose its anti-corrosive performance in a short period. However, the 12-12h wet-dry cycles decelerated the entire deterioration process, prolonging the coatings anticorrosive ability. The acceleration mechanism of the coatings and underlying metal corrosion under wet-dry cycles was discussed based on the above results.

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20

SINDEE, SUTTHIPONG, PARINYA SA NGIAMSUNTHORN e SONGPON SRIWONGSA. "Periodic cycles for an extension of generalized $3x + 1$ functions". Carpathian Journal of Mathematics 40, n.º 3 (17 de abril de 2024): 727–36. http://dx.doi.org/10.37193/cjm.2024.03.12.

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The Collatz conjecture is an open problem involving the $3x + 1$ function. The function belongs to a class of generalized $3x + 1$ functions of relatively prime type. This paper focuses on exploring periodic cycles for an extension of a generalized $3x + 1$ function of relatively prime type. By extending its domain to $\mathbb{R}$, the result shows that every integer periodic point is isolated in the usual topology on $\mathbb{R}$. Moreover, every positive integer periodic cycle for the extension is attracting if the generalized $3x + 1$ function is specified by parameters under some conditions.

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21

Gehrlein, W. V. "Frequency estimates for linear extension majority cycles on partial orders". RAIRO - Operations Research 25, n.º 4 (1991): 359–64. http://dx.doi.org/10.1051/ro/1991250403591.

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22

Gehrlein, W. V., e P. C. Fishburn. "Linear extension majority cycles for small (n⩽9) partial orders". Computers & Mathematics with Applications 20, n.º 2 (1990): 41–44. http://dx.doi.org/10.1016/0898-1221(90)90239-g.

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23

Wimmer, Markus A., William Nechtow, Thorsten Schwenke e Kirsten C. Moisio. "Knee Flexion and Daily Activities in Patients following Total Knee Replacement: A Comparison with ISO Standard 14243". BioMed Research International 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/157541.

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Walking is only one of many daily activities performed by patients following total knee replacement (TKR). The purpose of this study was to examine the hypotheses (a) that subject activity characteristics are correlated with knee flexion range of motion (ROM) and (b) that there is a significant difference between the subject’s flexion/extension excursion throughout the day and the ISO specified input for knee wear testing. In order to characterize activity, the number of walking and stair stepping cycles, the time spent with dynamic and stationary activities, the number of activity sequences, and the knee flexion/extension excursion of 32 TKR subjects were collected during daily activity. Flexion/extension profiles were compared with the ISO 14243 simulator input profile using a level crossing classification algorithm. Subjects took an average of 3102 (range: 343–5857) walking cycles including 65 (range: 0–319) stair stepping cycles. Active and passive ROMs were positively correlated with stair walking time, stair step counts, and stair walking sequences. Simulated knee motion according to ISO showed significantly fewer level crossings at the flexion angles 20–40° and beyond 50° than those measured with the monitor. This suggests that implant wear testing protocols should contain more cycles and a variety of activities requiring higher knee flexion angles with incorporated resting/transition periods to account for the many activity sequences.

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24

Koch, Matthias D., Chenyi Fei, Ned S. Wingreen, Joshua W. Shaevitz e Zemer Gitai. "Competitive binding of independent extension and retraction motors explains the quantitative dynamics of type IV pili". Proceedings of the National Academy of Sciences 118, n.º 8 (16 de fevereiro de 2021): e2014926118. http://dx.doi.org/10.1073/pnas.2014926118.

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Type IV pili (TFP) function through cycles of extension and retraction. The coordination of these cycles remains mysterious due to a lack of quantitative measurements of multiple features of TFP dynamics. Here, we fluorescently label TFP in the pathogen Pseudomonas aeruginosa and track full extension and retraction cycles of individual filaments. Polymerization and depolymerization dynamics are stochastic; TFP are made at random times and extend, pause, and retract for random lengths of time. TFP can also pause for extended periods between two extension or two retraction events in both wild-type cells and a slowly retracting PilT mutant. We developed a biophysical model based on the stochastic binding of two dedicated extension and retraction motors to the same pilus machine that predicts the observed features of the data with no free parameters. We show that only a model in which both motors stochastically bind and unbind to the pilus machine independent of the piliation state of the machine quantitatively explains the experimentally observed pilus production rate. In experimental support of this model, we show that the abundance of the retraction motor dictates the pilus production rate and that PilT is bound to pilus machines even in their unpiliated state. Together, the strong quantitative agreement of our model with a variety of experiments suggests that the entire repetitive cycle of pilus extension and retraction is coordinated by the competition of stochastic motor binding to the pilus machine, and that the retraction motor is the major throttle for pilus production.

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Acosta-Rodriguez, Victoria, Filipa Rijo-Ferreira, Mariko Izumo, Pin Xu, Carla Green e Joseph Takahashi. "Circadian Alignment of Feeding Regulates Lifespan Extension by Caloric Restriction". Innovation in Aging 5, Supplement_1 (1 de dezembro de 2021): 115–16. http://dx.doi.org/10.1093/geroni/igab046.442.

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Abstract Caloric restriction (CR) promotes longevity in several species. Classic CR protocols often lead to chronic cycles of 2h-feeding/22h-fasting, raising the question whether calories, fasting or time of day are causal. To address this, we tested an AL control group and five CR protocols with different timing and duration of feeding/fasting cycles. C57BL/6J male mice were subjected to 30% CR as one single meal a day at the beginning of the day or night (classical protocols with < 2h feeding, CR-day and CR-night), or smaller meals distributed for 12h (CR-day-12h and CR-night-12h), or evenly spread out throughout 24h (CR-spread) to abolish the otherwise daily feeding pattern adopted by nocturnal animals. We found that CR alone is sufficient to extend lifespan without fasting. However, the benefits are enhanced if feeding/fasting cycles are present and match their normal nocturnal activity. Circadian alignment of feeding with at least 12h fasting boosts CR-mediated increase on survival in mice, independently body weight. Aging leads to widespread upregulation of inflammation-related genes and downregulation of metabolic pathways in liver from ad lib fed mice; whereas CR at night ameliorates these aging-related changes and preserves circadian oscillations in gene expression. Overall, our results demonstrate that circadian interventions promote longevity and provide a novel perspective for elucidating mechanisms of aging.

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Davidson*, Victoria L., Dean A. Kopsell e James E. Pollard. "The Effect of Interrupting Short Day Cycles with Day-length Extension on Floral Bud Initiation in Strawberry (Fragaria × ananasa)". HortScience 39, n.º 4 (julho de 2004): 849C—849. http://dx.doi.org/10.21273/hortsci.39.4.849c.

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Experiments were conducted to investigate the potential effect on floral bud initiation in strawberry (Fragaria × ananasa, cv. Chandler) by interrupting inductive short day cycles with a day-length extension treatment. Vegetative plants were exposed to 10-, 15-, or 20-day cycles of inductive short days in growth chambers. After receiving an inductive short day treatment plants were transferred to a greenhouse where they were exposed to non-inductive long days, which stimulated panicle elongation. Dissections of apical meristems immediately following each cycle of short days revealed that cycles of 20 days resulted in detectable floral bud formation. After 15 days in the greenhouse, all short day treatments had initiated floral buds. In the greenhouse, under long days, subsequent flowering in cohorts of plants which had previously received inductive short days showed a positive correlation between interruption of short days with day length extension and reduction in the number of floral buds initiated on earliest emerging panicles. These results suggest potential for manipulation of floral bud induction and potentially fruit size in Chandler, and perhaps other cultivars by interruption of a cycle of inductive short days with a day length extension treatment.

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Al-Yahyai, Rashid, Bruce Schaffer, Jonathan H. Crane e Frederick S. Davies. "Four Levels of Soil Water Depletion Minimally Affect Carambola Phenological Cycles". HortTechnology 15, n.º 3 (janeiro de 2005): 623–30. http://dx.doi.org/10.21273/horttech.15.3.0623.

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Phenological cycles were determined for carambola (Averrhoa carambola) trees in a gravelly loam soil at four different soil water depletion (SWD) levels in containers and in an orchard in southern Florida. The phenological cycles of young trees grown in containers were not as well defined as those of mature trees in an orchard. Shoot extension of trees in the orchard and containers was observed from the first week of March until the third week of December. Two peak flowering periods occurred during the first week of March, and from mid-September to mid-October. The major fruit harvest periods were August and December. Shoot flushing, extension shoot growth, flowering, and fruiting showed little response to irrigation at four SWD levels. This lack of response was likely caused by sufficient soil water due to precipitation and capillary rise from the high water table located about 1–2 m below the soil surface. Regardless of the lack of SWD effects on phenological cycles of carambola, the periodicity of shoot flushing, extension shoot growth, flowering, and fruiting and the intensity of these phenological events elucidated in this study should provide useful guidelines for carambola orchard management in southern Florida.

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Du, Tanghuizi, Ikumi Narita e Toshimasa Yanai. "Three-Dimensional Torso Motion in Tethered Front Crawl Stroke and its Implications on Low Back Pain". Journal of Applied Biomechanics 32, n.º 1 (fevereiro de 2016): 50–58. http://dx.doi.org/10.1123/jab.2015-0024.

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Low back pain is a common problem among competitive swimmers, and repeated torso hyperextension is claimed to be an etiological factor. The purpose of this study was to describe the three-dimensional torso configurations in the front crawl stroke and to test the hypothesis that swimmers experience torso hyperextension consistently across the stroke cycles. Nineteen collegiate swimmers underwent 2 measurements: a measurement of the active range of motion in 3 dimensions and a measurement of tethered front crawl stroke at their maximal effort. Torso extension beyond the active range of torso motion was defined as torso hyperextension. The largest torso extension angle exhibited during the stroke cycles was 9 ± 11° and it was recorded at or around 0.02 ± 0.08 s, the instant at which the torso attained the largest twist angle. No participant hyperextended the torso consistently across the stroke cycles and subjects exhibited torso extension angles during tethered front crawl swimming that were much less than their active range of motion. Therefore, our hypothesis was rejected, and the data suggest that repeated torso hyperextension during front crawl strokes should not be claimed to be the major cause of the high incidence of low back pain in swimmers.

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Noyes, Frank R., Lauren E. Huser, Brad Ashman e Michael Palmer. "Anterior Cruciate Ligament Graft Conditioning Required to Prevent an Abnormal Lachman and Pivot Shift After ACL Reconstruction: A Robotic Study of 3 ACL Graft Constructs". American Journal of Sports Medicine 47, n.º 6 (15 de abril de 2019): 1376–84. http://dx.doi.org/10.1177/0363546519835796.

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Background: Anterior cruciate ligament (ACL) graft conditioning protocols to decrease postoperative increases in anterior tibial translation and pivot-shift instability have not been established. Purpose: To determine what ACL graft conditioning protocols should be performed at surgery to decrease postoperative graft elongation after ACL reconstruction. Study Design: Controlled laboratory study. Methods: A 6 degrees of freedom robotic simulator evaluated 3 ACL graft constructs in 7 cadaver knees for a total of 19 graft specimens. Knees were tested before and after ACL sectioning and after ACL graft conditioning protocols before reconstruction. The ACL grafts consisted of a 6-strand semitendinosus-gracilis TightRope, bone–patellar tendon–bone TightRope, and bone–patellar tendon–bone with interference screws. Two graft conditioning protocols were used: (1) graft board tensioning (20 minutes, 80 N) and (2) cyclic conditioning (5°-120° of flexion, 90-N anterior tibial load) after graft reconstruction to determine the number of cycles needed to obtain a steady state with no graft elongation. After conditioning, the grafts were cycled a second time under anterior-posterior loading (100 N, 25° of flexion) and under pivot-shift loading (100 N anterior, 5-N·m internal rotation, 7 N·m valgus) to verify that the ACL flexion-extension conditioning protocol was effective. Results: Graft board tensioning did not produce a steady-state graft. Major increases in anterior tibial translation occurred in the flexion-extension graft-loading protocol at 25° of flexion (mean ± SD: semitendinosus-gracilis TightRope, 3.4 ± 1.1 mm; bone–patellar tendon–bone TightRope, 3.2 ± 1.0 mm; bone–patellar tendon–bone with interference screws, 2.4 ± 1.5 mm). The second method of graft conditioning (40 cycles, 5°-120° of flexion, 90-N anterior load) produced a stable conditioned state for all grafts, as the anterior translations of the anterior-posterior and pivot-shift cycles were statistically equivalent ( P < .05, 1-20 cycles). Conclusion: ACL graft board conditioning protocols are not effective, leading to deleterious ACL graft elongations after reconstruction. A secondary ACL graft conditioning protocol of 40 flexion-extension cycles under 90-N graft loading was required for a well-conditioned graft, preventing further elongation and restoring normal anterior-posterior and pivot-shift translations. Clinical Relevance: There is a combined need for graft board tensioning and robust cyclic ACL graft loading before final graft fixation to restore knee stability.

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Lanza, A. F. "Stellar magnetic cycles". Proceedings of the International Astronomical Union 5, S264 (agosto de 2009): 120–29. http://dx.doi.org/10.1017/s1743921309992523.

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AbstractThe solar activity cycle is a manifestation of the hydromagnetic dynamo working inside our star. The detection of activity cycles in solar-like stars and the study of their properties allow us to put the solar dynamo in perspective, investigating how dynamo action depends on stellar parameters and stellar structure. Nevertheless, the lack of spatial resolution and the limited time extension of stellar data pose limitations to our understanding of stellar cycles and the possibility to constrain dynamo models. I briefly review some results obtained from disc-integrated proxies of stellar magnetic fields and discuss the new opportunities opened by space-borne photometry made available by MOST, CoRoT, Kepler, and GAIA, and by new ground-based spectroscopic or spectropolarimetric observations. Stellar cycles have a significant impact on the energetic output and circumstellar magnetic fields of late-type active stars which affects the interaction between stars and their planets. On the other hand, a close-in massive planet could affect the activity of its host star. Recent observations provide circumstantial evidence of such an interaction with possible consequences for stellar activity cycles.

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Binda, Federico, e Amalendu Krishna. "Zero cycles with modulus and zero cycles on singular varieties". Compositio Mathematica 154, n.º 1 (9 de outubro de 2017): 120–87. http://dx.doi.org/10.1112/s0010437x17007503.

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Given a smooth variety$X$and an effective Cartier divisor$D\subset X$, we show that the cohomological Chow group of 0-cycles on the double of$X$along$D$has a canonical decomposition in terms of the Chow group of 0-cycles$\text{CH}_{0}(X)$and the Chow group of 0-cycles with modulus$\text{CH}_{0}(X|D)$on$X$. When$X$is projective, we construct an Albanese variety with modulus and show that this is the universal regular quotient of$\text{CH}_{0}(X|D)$. As a consequence of the above decomposition, we prove the Roitman torsion theorem for the 0-cycles with modulus. We show that$\text{CH}_{0}(X|D)$is torsion-free and there is an injective cycle class map$\text{CH}_{0}(X|D){\hookrightarrow}K_{0}(X,D)$if$X$is affine. For a smooth affine surface$X$, this is strengthened to show that$K_{0}(X,D)$is an extension of$\text{CH}_{1}(X|D)$by$\text{CH}_{0}(X|D)$.

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Venteris, E. R., I. M. Whillans e C. J. Van der Veen. "Effect of extension rate on terminus position, Columbia Glacier, Alaska, U.S.A." Annals of Glaciology 24 (1997): 49–53. http://dx.doi.org/10.3189/s0260305500011927.

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The relations between seasonal changes in ice speed, longitudinal extension rate and terminus position are investigated for Columbia Glacier, Alaska, over the period 1977–87. The lower reach of the glacier is studied using repeat aerial photography, which extends from the terminus to the base of an icefall about 14 km up-glacier. There are regular seasonal cycles in speed and stretching rate. These cycles continue after the glacier retreats off the shoal at the end of the fjord (in about 1983), indicating that factors other than backstress, such as seasonal changes in subglacial water, control the speed of the glacier. Terminus position appears to be linked with thinning induced by longitudinal extension, as predicted by the calving model proposed by Van der Veen (1996).

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Venteris, E. R., I. M. Whillans e C. J. Van der Veen. "Effect of extension rate on terminus position, Columbia Glacier, Alaska, U.S.A." Annals of Glaciology 24 (1997): 49–53. http://dx.doi.org/10.1017/s0260305500011927.

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The relations between seasonal changes in ice speed, longitudinal extension rate and terminus position are investigated for Columbia Glacier, Alaska, over the period 1977–87. The lower reach of the glacier is studied using repeat aerial photography, which extends from the terminus to the base of an icefall about 14 km up-glacier. There are regular seasonal cycles in speed and stretching rate. These cycles continue after the glacier retreats off the shoal at the end of the fjord (in about 1983), indicating that factors other than backstress, such as seasonal changes in subglacial water, control the speed of the glacier. Terminus position appears to be linked with thinning induced by longitudinal extension, as predicted by the calving model proposed by Van der Veen (1996).

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Hill, Callum, Mark Hughes e Daniel Gudsell. "Environmental Impact of Wood Modification". Coatings 11, n.º 3 (23 de março de 2021): 366. http://dx.doi.org/10.3390/coatings11030366.

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The modification of wood involves extra processing over and above what is associated with un-modified material and this will involve an associated environmental impact. There is now a body of information on this due to the presence in the public domain of a number of environmental product declarations (EPDs). Using these data, it is possible to determine what the extra impact associated with the modification is. The process of modification results in a life extension of the product, which has implications regarding the storage of sequestered atmospheric carbon in the harvested wood products (HWP) materials’ pool and also extended maintenance cycles (e.g., longer periods between applying coatings). Furthermore, the life extension benefits imparted by wood modification need to be compared with the use of other technologies, such as conventional wood preservatives. This paper analysed the published data from a number of sources (peer-reviewed literature, published EPDs, databases) to compare the impacts associated with different modification technologies. The effect of life extension was examined by modelling the carbon flow dynamics of the HWP pool and determining the effect of different life extension scenarios. Finally, the paper examined the impact of different coating periods, and the extensions thereof, imparted by the use of different modified wood substrates.

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Waldron, L. J., N. Terry e J. A. Nemson. "Diurnal cycles of leaf extension in unsalinized and salinized Beta vulgaris." Plant, Cell and Environment 8, n.º 3 (abril de 1985): 207–11. http://dx.doi.org/10.1111/1365-3040.ep11604611.

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WALDRON, L. J., N. TERRY e J. A. NEMSON. "Diurnal cycles of leaf extension in unsalinized and salinized Beta vulgaris". Plant, Cell and Environment 8, n.º 3 (abril de 1985): 207–11. http://dx.doi.org/10.1111/j.1365-3040.1985.tb01388.x.

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Ishigami, Yoshiyas, e Hong Wang. "An extension of a theorem on cycles containing specified independent edges". Discrete Mathematics 245, n.º 1-3 (fevereiro de 2002): 127–37. http://dx.doi.org/10.1016/s0012-365x(01)00137-6.

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Kocay, William. "An extension of the multi-path algorithm for finding hamilton cycles". Discrete Mathematics 101, n.º 1-3 (maio de 1992): 171–88. http://dx.doi.org/10.1016/0012-365x(92)90601-b.

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Tong, Ke, Yan Ping Zeng, Xin Li Han, Yao Rong Feng e Xiao Dong He. "SEM In Situ Investigation on Fatigue Cracking Behavior of X80 Pipeline Steel with Inclusions". Advanced Materials Research 284-286 (julho de 2011): 1096–100. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.1096.

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The micro-mechanical behavior of inclusions in X80 pipeline steel under fatigue loading was investigated by means of SEM in situ observation. The influence of sizes and shapes of inclusion on crack initiation and propagation was analyzed. The result shows that for large-size single-particle inclusion, cracks initiate from the interior under the fatigue loading. When a certain circulation cycles are reached, cracks initiate at the matrix near the sharp corner of the inclusion. The cracks extend at the matrix during the stable extension period and unstable extension period following the crack initiation, until fracture occurred. For chain inclusion, cracks first initiate at the interface between inclusion and matrix within the chain area, and the circulation cycles needed for initiation are far less than single inclusion. Cracks steadily extend after the initiation, and then fracture after very short circulation cycles. A chain of inclusion with the shape corners is serious harmful to the fatigue properties.

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KAYSER, MARK ANDREAS. "Trade and the Timing of Elections". British Journal of Political Science 36, n.º 3 (17 de maio de 2006): 437–57. http://dx.doi.org/10.1017/s0007123406000238.

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Do trade-transmitted international business cycles affect the timing of national elections? This article shows that export expansions do not differ substantively from booms in aggregate output in inviting opportunistic governments to call elections, especially as their terms mature. Further analysis confirms two ancillary implications of this relationship: (a) that clusters of countries tend to hold elections in periods of international economic expansion and (b) that national election cycles, much like business cycles, have become more correlated over time, most prominently in Europe. The findings in this article raise implications for continued economic integration: freer movement of goods, services and capital may imply more correlated business cycles and, by extension, election cycles.

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Arnold, Markus P., Denny T. T. Lie, Nico Verdonschot, Ruurd de Graaf, Andrew A. Amis e Albert van Kampen. "The Remains of Anterior Cruciate Ligament Graft Tension after Cyclic Knee Motion". American Journal of Sports Medicine 33, n.º 4 (abril de 2005): 536–42. http://dx.doi.org/10.1177/0363546504269938.

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Background There is sometimes a return of excess knee laxity after anterior cruciate ligament reconstruction. One of the contributing factors might be a loss in graft tension. It is unknown whether the tension imposed on an anterior cruciate ligament graft degrades with time and, if so, the effect of that loss of tension on knee laxity. Hypotheses The pretension in the anterior cruciate ligament graft reduces significantly within the first 500 motion cycles, and this decrease in graft tension causes an increase in knee laxity. Study Design Controlled laboratory study. Methods This study measured the remains of bone-patellar tendon-bone graft pretension after cyclical flexion-extension and the effect of any tension loss on knee laxity, using 8 cadaveric knees. A tension transducer was inserted into the graft and calibrated in situ. The reconstruction tension was 40 N at 20° of flexion. In test 1, the graft tension was measured under cyclical flexion-extension in a motorized rig up to 1500 cycles. Test 2, with a new graft, also included anteroposterior and internal-external rotational knee laxity measurements at 0, 500, and 1500 cycles. Results The graft tension at 0° of flexion dropped from 208 N, by 25% after 50 cycles, 41% by 500, and 46% by 1500 cycles. Anterior laxity increased from +1.4 to +2.8 mm by 500 cycles, and performing these laxity tests also caused significant tension losses. Clinical Relevance These results provide one possible explanation for early slackening of anterior cruciate ligament reconstructions.

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Zhao, Ding Ding, Ping Cai e Wei Qi. "Research on Unbalance Signal Extraction under the Constraints of Low Operation Speed and Limited Acquisition Time". Key Engineering Materials 516 (junho de 2012): 618–23. http://dx.doi.org/10.4028/www.scientific.net/kem.516.618.

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Aiming at extracting sinusoidal signals from strong background noise and disturbance under the constraint of limited cycles of samples, the spectral feature of the picked unbalance vibration signal of a hard bearing balancing machine was analyzed and an analogue filter was designed to eliminate the main disturbance components in the frequency domain, and a signal extension method based on the AR model was introduced and investigated. Simulation and field experiments demonstrated the feasibility of the presented extension method and an improvement in accuracy was achieved by extension of the AR model.

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Fostel, Ana, e John Geanakoplos. "Leverage Cycles and the Anxious Economy". American Economic Review 98, n.º 4 (1 de agosto de 2008): 1211–44. http://dx.doi.org/10.1257/aer.98.4.1211.

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We provide a pricing theory for emerging asset classes, like emerging markets, that are not yet mature enough to be attractive to the general public. We show how leverage cycles can cause contagion, flight to collateral, and issuance rationing in a frequently recurring phase we call the anxious economy. Our model provides an explanation for the volatile access of emerging economies to international financial markets, and for three stylized facts we identify in emerging markets and high yield data since the late 1990s. Our analytical framework is a general equilibrium model with heterogeneous agents, incomplete markets, and endogenous collateral, plus an extension encompassing adverse selection. (JEL D53, G12, G14, G15)

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Šećerović, A., A. Ristaniemi, F. Crivelli, S. Heub, G. Weder, S. J. Ferguson, D. Ledroit e S. Grad. "ADVANCED BIOREACTOR STUDIES OF REGION-SPECIFIC RESPONSE IN THE INTERVERTEBRAL DISC TO COMPRESSION, FLEXION/EXTENSION, AND TORSION". Orthopaedic Proceedings 106-B, SUPP_2 (2 de janeiro de 2024): 116. http://dx.doi.org/10.1302/1358-992x.2024.2.116.

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Intervertebral disc (IVD) degeneration is inadequately understood due to the lack of in vitro systems that fully mimic the mechanical and biological complexity of this organ. We have recently made an advancement by developing a bioreactor able to simulate physiological, multiaxial IVD loading and maintain the biological environment in ex vivo IVD models [1].To validate this new bioreactor system, we simulated natural spine movement by loading 12 bovine IVDs under a combination of static compression (0.1 MPa), cyclic flexion/extension (±3˚, ±6˚ or 0-6˚) and cyclic torsion (±2˚, ±4˚ or 0-4˚) for more than 10’000 (0.2 Hz) or 100’000 (1 Hz) cycles over 14 days. A higher number of cycles increased the release of glycosaminoglycans and nitric oxide, as an inflammation marker, whereas fewer cycles maintained these two factors at physiological levels. All applied protocols upregulated the expression of MMP13 in the outermost annulus fibrosus (AF), indicating a collagen degradation response. This was supported by fissures observed in the AF after a longer loading duration. Increasing loading cycles induced high cell death in the nucleus pulposus and inner AF, while with fewer cycles, high cell viability was maintained in all IVD regions, irrespective of the magnitude of rotation.Less frequent multiaxial loading maintains IVD homeostasis while more frequent loading initiates an IVD degenerative profile. Specifically, the morphological and molecular changes were localized in the AF, which can be associated with combined flexion/extension and torsion. More loading cycles induced region-specific cell death and a higher release of extracellular matrix molecules from the innermost IVD regions, likely associated with longer exposure to static compression. Altogether, we demonstrated the advantages of the multiaxial bioreactor to study region-specific response in the IVD, which will allow a more profound investigation of IVD degeneration under different combinations of motions.

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Kayama, Kotetsu, Hibiki Hashizume, Gerry Amor Camer e Daiji Endoh. "An improved gene synthesis method with asymmetric directions of oligonucleotides designed using a simulation program". BioTechniques 69, n.º 3 (setembro de 2020): 211–19. http://dx.doi.org/10.2144/btn-2020-0062.

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Artificial gene synthesis based on oligonucleotide augmentation is known as overlap extension PCR which generates a variety of intermediate synthetic products. The orientation and concentration of oligomers can be adjusted to reduce the synthesis of intermediates and optimize the full-length process of DNA synthesis, using a simulation program for serial oligomer extension. The efficiency of the serial oligomer extension process is predicted to be greatest when oligomers are in a ‘forward-reverse-reverse-reverse’ direction. Oligomers with such designed directions demonstrated generation of the desired product in the shortest time (number of cycles) by repeated annealing and elongation. This method, named Asymmetric Extension supported by a Simulator for Oligonucleotide Extension (AESOE), has shown efficiency and effectiveness with potentials for future improvements and optimal usage in DNA synthesis.

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Moore, Virginia M., e William F. Tracy. "Recurrent Full-sib Family Selection for Husk Extension in Sweet Corn". Journal of the American Society for Horticultural Science 144, n.º 1 (janeiro de 2019): 63–69. http://dx.doi.org/10.21273/jashs04559-18.

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Corn earworm (Helicoverpa zea) is a costly and destructive pest in sweet corn (Zea mays) production. A recurrent selection experiment was conducted to assess the feasibility of selecting a sweet corn population for longer husks without shortening the ears and to determine whether direct selection for longer husks confers improved resistance to the corn earworm. The initial population was derived from crosses between long- and tight-husked inbred lines (A684su, A685su, and A686su) originally selected for resistance to the european corn borer (Ostrinia nubilalis) and a high-quality commercial hybrid parent (‘Super Sweet Jubilee Plus’). Three cycles of recurrent full-sib family selection were conducted from 2014 to 2016, with a selection intensity of ≈10% per cycle. In 2017, the cycles of selection were evaluated and compared with common commercial cultivars for husk extension, ear length, rate of corn earworm infestation, and extent of corn earworm damage. Ears were artificially infested with corn earworm eggs suspended in an agar solution. The population was successfully selected for longer husk extension without shortening the ears, but the increase in husk extension did not correspond to an increase in corn earworm resistance. Further evaluation is needed to determine whether long husk extension is ineffective as a source of corn earworm resistance, whether it is more effective in combination with other resistance traits, whether greater differences in husk extension are needed to confer biologically significant differences in corn earworm resistance, or whether improved inoculation methods could improve differentiation between genotypes.

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SOMIA, N., G. S. RASH, M. WACHOWIAK e A. GUPTA. "The Initiation and Sequence of Digital Joint Motion". Journal of Hand Surgery 23, n.º 6 (dezembro de 1998): 792–95. http://dx.doi.org/10.1016/s0266-7681(98)80099-5.

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We studied the initiation and sequence of digital joint motion during unrestricted flexion and extension using a 3-D motion analysis of all fingers moving simultaneously. Our results showed that motion started in a single joint in 83% of flexion and 80% of extension cycles. The DIP joint initiated flexion and extension in the index, middle, and ring fingers, but in the little finger, flexion started in the PIP joint, and extension in the MP joint. The two most frequent sequences of joint movement during flexion of the three radial fingers were DIP-PIP-MP and PIP-DIP-MP. The two most frequent sequences during extension of the three radial fingers were DIP-MP-PIP followed by DIP-MP/PIP. In the little finger, however, the most frequent sequences during flexion were PIP-DIP-MP followed by DIP-PIP-MP and during extension, DIP-MP/PIP followed by PIP/DIP-MP

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Cook, Daniel J., Matthew S. Yeager, Michael Y. Oh e Boyle C. Cheng. "Lumbar Intrafacet Bone Dowel Fixation". Neurosurgery 76, n.º 4 (23 de janeiro de 2015): 470–78. http://dx.doi.org/10.1227/neu.0000000000000652.

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Abstract BACKGROUND: The efficacy of intrafacet bone dowels in promoting lumbar fusion has not been established. A recently published study indicates a low fusion rate, along with device migration. OBJECTIVE: To evaluate the mechanical stability of 2 lumbar facet fixation technologies before and after repeated cyclic loading. METHODS: Six human lumbar specimens were implanted with both types of allograft, one at L2-3 and the other at L4-5, on a randomized basis. All specimens were subjected to pure-moment flexibility testing before and after implantation and after 2500 and 5000 cycles of flexion-extension bending. Each specimen was scanned with computed tomography before and after cyclic loading to measure device migration. RESULTS: Only dowel 1 resulted in a statistically significant reduction in flexion-extension range of motion at the treatment level. This reduction was significant at baseline testing (P = .03) and after 2500 cycles of flexion-extension loading (P = .048) but was not significant after 5000 cycles of loading. One of the bone dowels extruded posteriorly out of the joint space during baseline axial torsion flexibility testing, which was before any cyclic loading. CONCLUSION: The data obtained in this study do not indicate efficacy of fixation for cylindrical bone dowels in the lumbar facet joint. Significant fixation was detected only for one of the devices and was no longer present after a relatively short duration of repeated loading. Furthermore, considerable magnitudes of device migration were detected.

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Menaceur, Amour, e Salah Boulaaras. "A number of limit cycle of sextic polynomial differential systems via the averaging theory". Boletim da Sociedade Paranaense de Matemática 39, n.º 4 (1 de janeiro de 2021): 181–97. http://dx.doi.org/10.5269/bspm.41922.

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The main purpose of this paper is to study the number of limit cycles of sextic polynomial differential systems (SPDS) via the averaging theory which is an extension to the study of cubic polynomial vector fields in (Nonlinear Analysis 66 (2007), 1707--1721), where we provide an accurate upper bound of the maximum number of limit cycles that SPDS can have bifurcating from the period annulus surrounding the origin of a class of cubic system.

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Kim, Jaehong, Mark Puder e Roy J. Soberman. "Joining of DNA Fragments by Repeated Cycles of Denaturation, Annealing and Extension". BioTechniques 20, n.º 6 (junho de 1996): 954–55. http://dx.doi.org/10.2144/96206bm01.

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