1,641 research outputs found
'Diverse mobilities': second-generation Greek-Germans engage with the homeland as children and as adults
This paper is about the children of Greek labour migrants in Germany. We focus on two life-stages of âreturnâ for this second generation: as young children brought to Greece on holidays or sent back for longer periods, and as young adults exercising an independent âreturnâ migration. We draw both on literature and on our own field interviews with 50 first- and second-generation Greek-Germans. We find the practise of sending young children back to Greece to have been surprisingly widespread yet little documented. Adult relocation to the parental homeland takes place for five reasons: (i) a âsearch for selfâ; (ii) attraction of the Greek way of life; (iii) the actualisation of the âfamily narrative of returnâ by the second, rather than the first, generation; (iv) life-stage events such as going to university or marrying a Greek; (v) escape from a traumatic event or oppressive family situation. Yet the return often brings difficulties, disillusionment, identity reappraisal, and a re-evaluation of the German context
Physical and dynamical characterisation of low Delta-V NEA (190491) 2000 FJ10
We investigated the physical properties and dynamical evolution of Near Earth
Asteroid (NEA) (190491) 2000 FJ10 in order to assess the suitability of this
accessible NEA as a space mission target. Photometry and colour determination
were carried out with the 1.54 m Kuiper Telescope and the 10 m Southern African
Large Telescope during the object's recent favourable apparition in 2011-12.
During the earlier 2008 apparition, a spectrum of the object in the 6000-9000
Angstrom region was obtained with the 4.2 m William Herschel Telescope.
Interpretation of the observational results was aided by numerical simulations
of 1000 dynamical clones of 2000 FJ10 up to 10^6 yr in the past and in the
future. The asteroid's spectrum and colours determined by our observations
suggest a taxonomic classification within the S-complex although other
classifications (V, D, E, M, P) cannot be ruled out. On this evidence, it is
unlikely to be a primitive, relatively unaltered remnant from the early history
of the solar system and thus a low priority target for robotic sample return.
Our photometry placed a lower bound of 2 hrs to the asteroid's rotation period.
Its absolute magnitude was estimated to be 21.54+-0.1 which, for a typical
S-complex albedo, translates into a diameter of 130+-20 m. Our dynamical
simulations show that it has likely been an Amor for the past 10^5 yr. Although
currently not Earth-crossing, it will likely become so during the period 50 -
100 kyr in the future. It may have arrived from the inner or central Main Belt
> 1 Myr ago as a former member of a low-inclination S-class asteroid family.
Its relatively slow rotation and large size make it a suitable destination for
a human mission. We show that ballistic Earth-190491-Earth transfer
trajectories with Delta-V < 2 km s^-1 at the asteroid exist between 2052 and
2061.Comment: 2 Tables, 11 Figures, accepted for publication in Astronomy &
Astrophysic
Material properties of the heel fat pad across strain rates
The complex structural and material behaviour of the human heel fat pad determines the transmission of plantar loading to the lower limb across a wide range of loading scenarios; from locomotion to injurious incidents. The aim of this study was to quantify the hyper-viscoelastic material properties of the human heel fat pad across strains and strain rates. An inverse finite element (FE) optimisation algorithm was developed and used, in conjunction with quasi-static and dynamic tests performed to five cadaveric heel specimens, to derive specimen-specific and mean hyper-viscoelastic material models able to predict accurately the response of the tissue at compressive loading of strain rates up to 150 sâ1. The mean behaviour was expressed by the quasi-linear viscoelastic (QLV) material formulation, combining the Yeoh material model (C10=0.1MPa, C30=7MPa, K=2GPa) and PronyŚłs terms (A1=0.06, A2=0.77, A3=0.02 for Ï1=1ms, Ï2=10ms, Ï3=10s). These new data help to understand better the functional anatomy and pathophysiology of the foot and ankle, develop biomimetic materials for tissue reconstruction, design of shoe, insole, and foot and ankle orthoses, and improve the predictive ability of computational models of the foot and ankle used to simulate daily activities or predict injuries at high rate injurious incidents such as road traffic accidents and underbody blast
Unusual polarimetric properties of (101955) Bennu: similarities with F-class asteroids and cometary bodies
We have obtained polarimetric measurements of asteroid (101955) Bennu, a
presumably primitive near-Earth object (NEO) that is the target of NASA's
sample return mission OSIRIS-REx. During our observing campaign, Bennu was
visible from Earth under a wide range of illumination conditions, with
phase-angle in the range 16 to 57 degrees. Together with (3200) Phaethon and
(152679) 1998 KU2, observed very recently, Bennu is the only existing example
of a primitive NEO observed in polarimetric mode over a wide interval of phase
angles. Based on our polarimetric data, we propose that Bennu belongs to the
unusual F taxonomic class defined in the 80s. According to previous works, the
F-class includes objects with cometary features. This fact can be of great
importance for the interpretation of the results of the exploration of this
object by OSIRIS-REx. From polarimetry we also derive an estimate of the
geometric albedo of Bennu: 0.059 +/- 0.003.Comment: Accepted by MNRAS Letter
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