1,070 research outputs found
Emblemata: The emblem books of Andrea Alciato
A study of the life and works of the legal scholar and humanist, Andrea Alciato (1492-1550), the originator of the emblem book. The nature of the emblem is elucidated and placed in its historical, intellectual and artistic contexts, with special attention paid to the many and varied published manifestations of Alciato???s emblems from 1531 to 1621.published or submitted for publicationnot peer reviewe
The coupling between internal waves and shear-induced turbulence in stellar radiation zones: the critical layer
Internal gravity waves (hereafter IGWs) are known as one of the candidates
for explaining the angular velocity profile in the Sun and in solar-type
main-sequence and evolved stars, due to their role in the transport of angular
momentum. Our bringing concerns critical layers, a process poorly explored in
stellar physics, defined as the location where the local relative frequency of
a given wave to the rotational frequency of the fluid tends to zero (i.e that
corresponds to co-rotation resonances). IGW propagate through stably-stratified
radiative regions, where they extract or deposit angular momentum through two
processes: radiative and viscous dampings and critical layers. Our goal is to
obtain a complete picture of the effects of this latters. First, we expose a
mathematical resolution of the equation of propagation for IGWs in adiabatic
and non-adiabatic cases near critical layers. Then, the use of a dynamical
stellar evolution code, which treats the secular transport of angular momentum,
allows us to apply these results to the case of a solar-like star.The analysis
reveals two cases depending on the value of the Richardson number at critical
layers: a stable one, where IGWs are attenuated as they pass through a critical
level, and an unstable turbulent case where they can be reflected/transmitted
by the critical level with a coefficient larger than one. Such
over-reflection/transmission can have strong implications on our vision of
angular momentum transport in stellar interiors. This paper highlights the
existence of two regimes defining the interaction between an IGW and a critical
layer. An application exposes the effect of the first regime, showing a
strengthening of the damping of the wave. Moreover, this work opens new ways
concerning the coupling between IGWs and shear instabilities in stellar
interiors.Comment: 17 pages, 8 figure
Theoretical seismology in 3D : nonlinear simulations of internal gravity waves in solar-like stars
Internal gravity waves (hereafter IGWs) are studied for their impact on the
angular momentum transport in stellar radiation zones and the information they
provide about the structure and dynamics of deep stellar interiors. We here
present the first 3D nonlinear numerical simulations of IGWs excitation and
propagation in a solar-like star. The aim is to study the behavior of waves in
a realistic 3D nonlinear time dependent model of the Sun and to characterize
their properties. We compare our results with theoretical and 1D predictions.
It allows us to point out the complementarity between theory and simulation and
to highlight the convenience but also the limits of the asymptotic and linear
theories. We show that a rich spectrum of IGWs is excited by the convection,
representing about 0.4% of the total solar luminosity. We study the spatial and
temporal properties of this spectrum, the effect of thermal damping and
nonlinear interactions between waves. We give quantitative results about the
modes frequencies, evolution with time and rotational splitting and we discuss
the amplitude of IGWs considering different regimes of parameters. This work
points out the importance of high performance simulation for its
complementarity with observation and theory. It opens a large field of
investigation concerning IGWs propagating nonlinearly in 3D spherical
structures. The extension of this work to other types of stars, with different
masses, structures and rotation rates will lead to a deeper and more accurate
comprehension of IGWs in stars.Comment: 27 pages, 29 figures, accepted for publication in A&A (13/03/2014
The Commentary on ‘Na’t’ Written by Itrî
Buhûrîzâde Mustafa Itrî Efendi (ö.1711?) eşsiz besteleriyle Türk Musıkîsi’nde çığır
açan ve çağları aşan bir şöhrete sahiptir. Kaynaklar Itrî Efendi’nin başarılı bir şair olduğunu
belirtiyorsa da elimizde dîvânı yoktur ve şiirleri kimi tezkirelerde ve mecmualarda
dağınık bir hâldedir. Güfte mecmualarındaki bestekârı olduğu şiirlerin ise hangilerinin
kendisine ait olduğunun tespit edilemeyişi ve aynı dönemde yaşamış Itrî mahlaslı başka
bir şairin varlığı onun şiirlerinin incelenmesini güçleştirmektedir. Çalışmamızda bu nedenle kendisinin yazdığını ve bestelediğini bildiğimiz tek na‘tını şerh etmek istedik. Bu
sayede Itrî’nin edebî ve tasavvufî kimliği kimliği değerlendirilecektir. Bu çalışmada ayrıca
tarafımızdan UNESCO’nun ilan ettiği 2012 yılını bestekâr Itrî’yi Anma etkinliklerine
katkı ve yeni bir bilgi olarak bugüne dek bestesinin anonim sanıldığı “Şem-i ruhuna
cismimi pervâne düşürdüm” adlı eserin bestesinin Itrî’ye ait olduğu tespit edilmiştir
Geodynamic significance of the Cenozoic deposits in the southern Peruvian forearc (16°25’S to 17°15’S): constraints by facies analysis and sediment provenance.
Los sedimentos de edad Cenozoico en el sur de Peru, son respuestas de una compleja interaccion de geodinamica activa y sedimentacion, de los cuales es conspicuo de la tectonica de los Andes Centrales. Mediante la combinacion de analisis multi-metodos en minerales pesados detriticos, es posible restringir la historia de levantamiento y exhumacion de los bordes de cuencas sedimentarias en el sur de Peru. Los resultados revelan que los sedimentos cenozoicos en el sur de Peru son deltas de grano grueso depositados desde hace 30 Ma, y son consecuencia de levantamientos simultaneos de la Cordillera de la Costa y la Cordillera Occidental
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