Search results for "rock"

Models of the population playing the Rock-Paper-Scissors game

2018

We consider discrete dynamical systems coming from the models of evolution of populations playing rock - paper - scissors game . Asymptotic behaviour of trajectories of these systems is described, occurrence of the Neimark-Sacker bifurcation and nonexistence of time averages are proved.

Population dynamics and tolerance to desiccation in a crustacean ostracod adapted to life in small ephemeral water bodies

2011

AbstractGiven their small size, isolation and unpredictability, temporary rockpools present high environmental stress and impoverished communities of species that have adapted to such stressful conditions. Special adaptations of the invertebrates living in these habitats include tolerance to desiccation and fast ontogenetic development in order to maintain stable populations and face high risk of extinction. Dozens of small rockpools (mostly with Ø<1m) can be found in east Spain on limestone substrate, where the only known Iberian populations of Heterocypris bosniaca Petkovski et al. (2000), an ostracod species with geographic parthenogenesis, have been recently found. In this survey, two o…

Ancient xenocrystic zircon in young volcanic rocks of the southern Lesser Antilles island arc

2017

Abstract The Lesser Antilles arc is one of the best global examples in which to examine the effects of the involvement of subducted sediment and crustal assimilation in the generation of arc crust. Most of the zircon recovered in our study of igneous and volcaniclastic rocks from Grenada and Carriacou (part of the Grenadines chain) is younger than 2 Ma. Within some late Paleogene to Neogene (~ 34–0.2 Ma) lavas and volcaniclastic sediments however, there are Paleozoic to Paleoarchean (~ 250–3469 Ma) xenocrysts, and Late Jurassic to Precambrian zircon (~ 158–2667 Ma) are found in beach and river sands. The trace element characteristics of zircon clearly differentiate between different types o…

MAJOR AND TRACE ELEMENTS GEOCHEMISTRY IN THE GROUND WATERS OF A VOLCANIC AREA: MOUNT ETNA (SICILY, ITALY)

1998

Thirty-five ground-water samples have been collected from wells, springs and drainage galleries on Mt Etna volcano for the determination of major, minor and trace elements in solution. Attention has been focused in particular on dissolved minor and trace elements, for most of which no data were available in the studied area. In general, dissolution of solids into Etna's ground waters follows from strong interaction between water of meteoric origin, CO2 gas of magmatic origin and the volcanic rocks of the aquifers. However, the R-mode analysis allowed to distinguish several sources of solutes: Al, Co, Ni, Fe, Si, As would derive mainly from alteration of the volcanic rocks of Etna; SO4=, K, …

Source Mechanisms of Laboratory Earthquakes During Fault Nucleation and Formation

2021

Identifying deformation and pre-failure mechanisms preceding faulting is key for fault mechanics and for interpreting precursors to fault rupture. This study presents the results of a new and robust derivation of first motion polarity focal mechanism solutions (FMS) applied to acoustic emission (AE). FMS are solved using a least squares minimization of the fit between projected polarity measurements and the deviatoric stress field induced by dilatational (T-type), shearing (S-type), and compressional (C-type) sources. 4 × 10 cm cylindrical samples of Alzo Granite (AG, porosity &lt;1%) and Darley Dale Sandstone (DDS, porosity ≈14%) underwent conventional triaxial tests in order to investigat…

Dix ans d'archéologie forestière dans le Châtillonnais (Côte-d'Or) : enclos, habitats, parcellaires

2010

National audience; Ces recherches sur les ensembles de structures de pierre sous forêt sont mises en œuvre depuis dix ans et sont inté- grées depuis 2003 dans le P.C.R. ‘Vix et son Environnement', dirigé par C. Mordant, S. Wirth et B. Chaume. Les vestiges étudiés sont implantés dans deux milieux géographiques distincts mais contigus : le plateau calcaire recouvert par la forêt domaniale de Châtillon, et les rebords de la Digeanne et du Brevon qui entaillent ce plateau à l'est et au sud. La prospection présente ici des caractères particuliers liés au couvert forestier. Les relevés G.P.S. sont intégrés dans un S.I.G. et constituent la base de cette étude, dans un va et vient…

Duurin ♭VII asteen soinnun funktiot populaarimusiikin harmoniassa

2017

Tutkimuksen tavoitteena on selvittää ♭VII asteen soinnun funktioita modaalisessa populaarimusiikin harmoniassa. Yhtenäistä ja yksimielistä tapaa tulkita duurin ♭VII asteen sointua tai koko populaarimusiikin harmoniaa ei näytä olevan, vaan sen sijaan erilaisia modaalisen harmonian ja funktioiden tulkintapoja on monenlaisia, joita hyödynnän tässä tutkimuksessa. Keskeistä näissä tulkintatavoissa näyttää olevan konteksti eli ♭VII asteen sointua edeltävät ja seuraavat soinnut. Tutkimukseni avulla pyrinkin jäsentämään tätä hajanaista teoriaa oman aineistoni kautta. Aineistoni koostuu vuosien 1960 ja 1999 välillä Billboard-listalle päätyneistä popkappaleista. Koska funktion määrittelyssä konteksti…

Systematics and phylogeography of the genus Tigriopus (Copepoda, Harpacticoida, Harpacticidae) in the basin of the Mediterranean Sea

2020

[ES] El género de copépodos Tigriopus Norman, 1869 se distribuye en todo el mundo en piscinas costeras de rocas y actualmente se considera que incluye 15 especies válidas. Tigriopus fulvus (Fischer, 1860), con su subespecie Tigriopus fulvus adriaticus Van Douwe 1913 y Tigriopus fulvus algiricus Monard 1935, actualmente se informa que ocurren en el área mediterránea, pero actualmente se desconoce la diversidad real del género. Nuestro objetivo fue evaluar la identidad real de las poblaciones mediterráneas de Tigriopus y dilucidar su taxonomía y patrón de diversidad genética. Para alcanzar estos objetivos, utilizamos dos enfoques diferentes. El primero, basado en la morfología, donde las posi…

On the formation of laminated sediments on the continental margin off Pakistan: the effects of sediment provenance and sediment redistribution

2001

Abstract The sedimentary processes and sediment sources contributing to the formation of laminated sediments along the upper slope off Pakistan are unravelled using inorganic bulk sediment geochemistry of 43 surface cores from the Pakistani continental margin and additional geochemical and Pb and Nd-isotope data for different types of layers. An important process everywhere along the margin is redeposition of fluvial-derived detritus from the shelf onto the slope. This process is of considerably higher intensity along the Makran margin than on the Indus margin. Trace element enrichment related to early diagenesis or surface productivity, which is commonly detectable in bulk sediment composi…

2020

Although volcanic eruptions represent short periods in the whole history of a volcano, the large amount of loose pyroclastic material produced, combined with aeolian processes, can lead to continuous, long-lasting reworking of volcanic products. Driven by wind, these processes significantly influence the geomorphology and prolong the impacts of eruptions on exposed communities and ecosystems. Since such phenomena are of interest to scientists from a range of disciplines (e.g. volcanology, atmospheric and soil sciences), a well-defined, common nomenclature is necessary to optimize the multidisciplinary characterisation of both processes and deposits. We, therefore, first describe ash wind-re…