Search results for " CRA"
showing 10 items of 611 documents
Analysis on the Time and Frequency Domains of the Acceleration in Front Crawl Stroke
2012
Analysis on the Time and Frequency Domains of the Acceleration in Front Crawl Stroke The swimming involves accelerations and decelerations in the swimmer's body. Thus, the main objective of this study is to make a temporal and frequency analysis of the acceleration in front crawl swimming, regarding the gender and the performance. The sample was composed by 31 male swimmers (15 of high-level and 16 of low-level) and 20 female swimmers (11 of high-level and 9 of low-level). The acceleration was registered from the third complete cycle during eight seconds in a 25 meters maximum velocity test. A position transducer (200Hz) was used to collect the data, and it was synchronized to an aquatic ca…
Crack dynamics and crack surfaces in elastic beam lattices
1998
The dynamics of propagating cracks is analyzed in elastic two-dimensional lattices of beams. At early times, inertia effects and static stress enhancement combine so that the crack-tip velocity is found to behave as t1/7. At late times a minimal crack-tip model reproduces the numerical simulation results. With no disorder and for fast loading, a “mirror-mist-mirror” crack-surface pattern emerges. Introduction of disorder leads, however, to the formation of the “mirror-mist-hackle”–type interface typical in many experimental situations. Peer reviewed
Roughening of a propagating planar crack front
2000
A numerical model of the front of a planar crack propagating between two connected elastic plates is investigated. The plates are modeled as square lattices of elastic beams. The plates are connected by similar but breakable beams with a randomly varying stiffness. The crack is driven by pulling both plates at one end in Mode I at a constant rate. We find $\ensuremath{\zeta}=1/3, z=4/3,$ and $\ensuremath{\beta}=1/4$ for the roughness, dynamical, and growth exponents, respectively, that describe the front behavior. This is similar to continuum limit analyses based on a perturbative stress-intensity treatment of the front [H. Gao and J. R. Rice, J. Appl. Mech. 56, 828 (1989)]. We discuss the …
Experimental evidence for chirality in the odd-A 105Rh
2004
Abstract High-spin states in 105 Rh were populated by the 96 Zr( 13 C, p3n) reaction at beam energies of 51 and 58 MeV, and studied using the EUROBALL IV γ -ray spectrometer and the DIAMANT charged particle array. A pair of nearly degenerate Δ I = 1 three-quasiparticle bands with the same spins and parity have been observed. Comparison of the experimental results with tilted axis cranking calculations confirms the chiral character of the two bands, while arguments based on the excitation of particles within the π g 9 / 2 ν ( h 11 / 2 ) 2 configuration of the yrast band and comparison with the previously observed γ band exclude the other possible interpretations. This is the first experiment…
Impact Energy Flux on Earth in the Last 150 Ma as Inferred from the Cratering Records
1998
We have used a compilation of 30 well-dated large impact craters on Earth (i.e., diameters larger than 5 km) younger than 150 Ma, their diameters, geochronologic ages, and the corresponding uncertainties to construct a graph summarizing our current knowledge on the influx of the impact energy onto the Earth as a function of time. From the crater diameters, we estimated the corresponding impact energies through suitable scaling laws. Then to each crater we associated a gaussian (bell) function of time centered at its age. Finally, all the bell functions corresponding to different craters were summed up and the resulting curve was plotted. From this curve, it is apparent that the 65 Ma old Ch…
Ernst Julius Öpik’s (1916) note on the theory of explosion cratering onthe Moon’s surface—The complex case of a long-overlooked benchmark paper
2014
High-velocity impact as a common phenomenon in planetary evolution was ignored until well into the twentieth century, mostly because of inadequate understanding of cratering processes. An eight-page note, published in Russian by the young Ernst Julius Opik, a great Estonian astronomer, was among the key selenological papers, but due to the language barrier, it was barely known and mostly incorrectly cited. This particular paper is here intended to serve as an explanatory supplement to an English translation of Opik's article, but also to document an early stage in our understanding of cratering. First, we outline the historical–biographical background of this benchmark paper, and second, a …
Brittle failure in polycrystalline RVEs by a grain-scale cohesive boundary element formulation
2013
Polycrystalline materials are commonly employed in engineering structures. For modern applica- tions a deep understanding of materials degradation is of crucial relevance. It is nowadays widely recognized that the macroscopic material properties depend on the microstructure. The polycrystalline microstructure is characterized by the features of the grains and by the phys- ical and chemical properties of the intergranular interfaces, that have a direct influence on the evolution of the microstructural damage. The experimental investigation of failure mechanisms in 3D polycrystals still remains a challenging task. A viable alternative, or complement, to the experiments is Computational Microm…
Pompéi, Pistrina : recherches sur les boulangeries de l'Italie romaine [2010]
2011
Compte-rendu des opérations de terrain à Pompéi (campagne 2010)
An individual-based dataset of carbon and nitrogen isotopic data of Callinectes sapidus in invaded Mediterranean waters
2022
The characterisation of functional traits of non-indigenous and invasive species is crucial to assess their impact within invaded habitats. Successful biological invasions are often facilitated by the generalist diet of the invaders which can modify their trophic position and adapt to new ecosystems determining changes in their structure and functioning. Invasive crustaceans are an illustrative example of such mechanisms since their trophic habits can determine important ecological impacts on aquatic food webs. The Atlantic blue crab Callinectes sapidus is currently established and considered invasive in the Mediterranean Sea where it has been recorded for the first time between 1947 and 19…
Excess of de novo variants in genes involved in chromatin remodelling in patients with marfanoid habitus and intellectual disability.
2020
PurposeMarfanoid habitus (MH) combined with intellectual disability (ID) (MHID) is a clinically and genetically heterogeneous presentation. The combination of array CGH and targeted sequencing of genes responsible for Marfan or Lujan–Fryns syndrome explain no more than 20% of subjects.MethodsTo further decipher the genetic basis of MHID, we performed exome sequencing on a combination of trio-based (33 subjects) or single probands (31 subjects), of which 61 were sporadic.ResultsWe identified eight genes with de novo variants (DNVs) in at least two unrelated individuals (ARID1B, ATP1A1, DLG4, EHMT1, NFIX, NSD1, NUP205 and ZEB2). Using simulation models, we showed that five genes (DLG4, NFIX, …