Job quality in Europe

Promoting job quality and gender equality are objectives of the European Employment Strategy (EES) in spite of a downgrading of the attention given to both in the revised employment guidelines and the re-launch of the Lisbon Process. However, advances on both of these objectives may be important complements to the employment rate targets of the EES, as access to good quality jobs for both sexes is likely to help sustain higher employment rates. While the European Commission has a broad view of the concept of job quality in practice, it relies on a selection of labour market type indicators that say little about the quality of the actual jobs people do. Using data from the 2005 European Working Conditions survey, we analyse job quality along three dimensions: job content, autonomy and working conditions. We conclude that gender and occupational status, along with other job characteristics such as working time and sector, have more influence on an individual’s job quality than the country or ‘national model’ they are situated in. Our results also demonstrate the value of developing indicators of job quality that are both gender sensitive and derived at the level of the job rather than the labour market in order to advance EU policy and academic debate on this topic

Identification by Raman spectroscopy of Mg–Fe content of olivine samples after impact at 6kms?1 onto aluminium foil and aerogel: In the laboratory and in Wild-2 cometary samples

AbstractOlivine, (Mg, Fe)2[SiO4], is a common mineral in extraterrestrial materials, whose Mg–Fe content varies from the end-members Forsterite (Mg2SiO4: denoted ‘Fo’) to Fayalite (Fe2SiO4: denoted ‘Fa’), together with minor quantities of Ca, Cr, Mn and Ni. Olivine is readily identified by Raman spectroscopy, and the Mg–Fe content can be obtained by precise measurements of the position of the two strongest Raman peaks. Here we show that this is not only true for pristine and highly crystalline olivine, but also for grains which have undergone high pressure shock processing during hypervelocity impact. We demonstrate that there are subtle changes to the Raman spectra in grains impacted at 6.1kms−1 onto aluminium foil and into low density aerogel. We quantify these changes, and also show that if no correction is made for the impact effects, the Fe:Mg molar ratio of the olivine can be significantly misinterpreted. This study was stimulated by NASA’s Stardust mission to comet 81P/Wild-2, since freshly ejected cometary dust particles were collected (via impact) onto aluminium foil and into aerogel cells at 6.1kms−1 and these samples are being investigated with Raman spectroscopy. We identify the residue in one Stardust impact crater on aluminium foil as arising from an olivine with a composition of Fo97–100

Survival of fossils under extreme shocks induced by hypervelocity impacts

Experimental data are shown for survival of fossilized diatoms undergoing shocks in the GPa range. The results were obtained from hypervelocity impact experiments which fired fossilized diatoms frozen in ice into water targets. After the shots, the material recovered from the target water was inspected for diatom fossils. Nine shots were carried out, at speeds from 0.388 to 5.34?km?s?1, corresponding to mean peak pressures of 0.2–19?GPa. In all cases, fragmented fossilized diatoms were recovered, but both the mean and the maximum fragment size decreased with increasing impact speed and hence peak pressure. Examples of intact diatoms were found after the impacts, even in some of the higher speed shots, but their frequency and size decreased significantly at the higher speeds. This is the first demonstration that fossils can survive and be transferred from projectile to target in hypervelocity impacts, implying that it is possible that, as suggested by other authors, terrestrial rocks ejected from the Earth by giant impacts from space, and which then strike the Moon, may successfully transfer terrestrial fossils to the Moon

Catastrophic Disruption of Hollow Ice Spheres

Catastrophic disruption is a possible outcome of high-speed collisions in the solar system. The critical energy density Q* (impact energy/mass of the target), which is taken to mark the onset of catastrophic disruption, occurs when the largest intact fragment post-impact is 50% of the original target mass. Studies of Q* usually suppose the target body is a solid, rigid object. However, what if the body has a rigid shell and a hollow interior? Here, hollow ice spheres (a diameter of 19–20 cm with an ice thickness of 2.5–3.6 cm) were impacted at speeds up to ∼5 km/s. Catastrophic disruption occurred at Q* ∼ 25.5 ± 0.5 J kg−1, greater than that for similar size solid, or water-filled ice spheres (16–18 J kg−1). However, while the Q* value has increased, the actual impact energy associated with the new value of Q* has not, and the change in Q* arises due to the lower mass of the hollow target bodie

Survival of Organic Materials in Hypervelocity Impacts of Ice on Sand, Ice, and Water in the Laboratory

The survival of organic molecules in shock impact events has been investigated in the laboratory. A frozen mixture of anthracene and stearic acid, solvated in dimethylsulfoxide (DMSO), was fired in a two-stage light gas gun at speeds of ?2 and ?4?km s?1 at targets that included water ice, water, and sand. This involved shock pressures in the range of 2–12 GPa. It was found that the projectile materials were present in elevated quantities in the targets after impact and in some cases in the crater ejecta as well. For DMSO impacting water at 1.9?km s?1 and 45° incidence, we quantify the surviving fraction after impact as 0.44±0.05. This demonstrates successful transfer of organic compounds from projectile to target in high-speed impacts. The range of impact speeds used covers that involved in impacts of terrestrial meteorites on the Moon, as well as impacts in the outer Solar System on icy bodies such as Pluto. The results provide laboratory evidence that suggests that exogenous delivery of complex organic molecules from icy impactors is a viable source of such material on target bodies

Hypervelocity impacts into ice?topped layered targets: Investigating the effects of ice crust thickness and subsurface density on crater morphology

Many bodies in the outer solar system are theorized to have an ice shell with a different subsurface material below, be it chondritic, regolith, or a subsurface ocean. This layering can have a significant influence on the morphology of impact craters. Accordingly, we have undertaken laboratory hypervelocity impact experiments on a range of multilayered targets, with interiors of water, sand, and basalt. Impact experiments were undertaken using impact speeds in the range of 0.8–5.3 km s?1, a 1.5 mm Al ball bearing projectile, and an impact incidence of 45°. The surface ice crust had a thickness between 5 and 50 mm, i.e., some 3–30 times the projectile diameter. The thickness of the ice crust as well as the nature of the subsurface layer (liquid, well consolidated, etc.) have a marked effect on the morphology of the resulting impact crater, with thicker ice producing a larger crater diameter (at a given impact velocity), and the crater diameter scaling with impact speed to the power 0.72 for semi-infinite ice, but with 0.37 for thin ice. The density of the subsurface material changes the structure of the crater, with flat crater floors if there is a dense, well-consolidated subsurface layer (basalt) or steep, narrow craters if there is a less cohesive subsurface (sand). The associated faulting in the ice surface is also dependent on ice thickness and the substrate material. We find that the ice layer (in impacts at 5 km s?1) is effectively semi-infinite if its thickness is more than 15.5 times the projectile diameter. Below this, the crater diameter is reduced by 4% for each reduction in ice layer thickness equal to the impactor diameter. Crater depth is also affected. In the ice thickness region, 7–15.5 times the projectile diameter, the crater shape in the ice is modified even when the subsurface layer is not penetrated. For ice thicknesses, <7 times the projectile diameter, the ice layer is breached, but the nature of the resulting crater depends heavily on the subsurface material. If the subsurface is noncohesive (loose) material, a crater forms in it. If it is dense, well-consolidated basalt, no crater forms in the exposed subsurface layer

Impact of Multi-layered Spherical Ice Targets

The catastrophic disruption of tri-layered spherical icy bodies is reported. The bodies are 19 cm in total diameter, with a central core, an intermediate water layer and an icy surface (each layer respectively approximately 25, 55 and 20% of the total radius). Their response to high-speed impact is investigated at laboratory scales by firing 1.5 mm diameter glass spheres at the targets at speeds in the range 0.9 – 3.2 km s−1 and an ice layer thickness normalised to projectile diameter of typically 20 – 30. The energy density to just break apart such a body (defined as an event where the mass of the largest fragment post-impact is ½ the original target mass) is (3.1±0.1) J kg−1. This is significantly less than that found for similar sized solid ice spheres (18 ± 0.7) J kg−1, water filled ice spheres (16.25 ± 1.35) J kg−1 or hollow ice spheres (25.5 ± 0.5) J kg−1 indicating that the presence of a solid layer beneath an internal ocean, can influence disruption, effectively weakening the body

Space Dust and Debris Near the Earth

Penny J Wozniakiewicz and Mark J Burchell survey the dust environment around our planet, now and in the future, as discussed at an RAS Specialist Discussion meeting

Salt grains in hypervelocity impacts in the laboratory: Methods to sample plumes from the ice worlds Enceladus and Europa

The plumes naturally erupting from the icy satellite Enceladus were sampled by the Cassini spacecraft in high-speed fly-bys, which gave evidence of salt. This raises the question of how salt behaves under high-speed impact, and how it can best be sampled in future missions to such plumes. We present the results of 35 impacts onto aluminum targets by a variety of salts (NaCl, NaHCO3, MgSO4, and MgSO4·7H2O) at speeds from 0.26 to 7.3 km s−1. Using SEM-EDX, identifiable projectile residue was found in craters at all speeds. It was possible to distinguish NaCl and NaHCO3 from each other, and from the magnesium sulfates, but not to separate the hydrous from anhydrous magnesium sulfates. Raman spectroscopy on the magnesium sulfates and NaHCO3 residues failed to find a signal at low impact speeds (<0.5 km s−1) where there was insufficient projectile material deposited at the impact sites. At intermediate speeds (0.5 to 2–3 km s−1), identifiable Raman spectra were found in the impact craters, but not at higher impact speeds, indicating a loss of structure during the high speed impacts. Thus, intact capture of identifiable salt residues on solid metal surfaces requires impact speeds between 0.75 and 2 km s−1

Tardigrade Survival Limits in High-Speed Impacts—Implications for Panspermia and Collection of Samples from Plumes Emitted by Ice Worlds

The ability of tardigrades to survive impact shocks in the kilometer per second and gigapascal range was investigated. When rocks impact planetary surfaces, the impact speeds and shock pressures are in the kilometer per second and gigapascal range. This investigation tested whether tardigrades can survive in impacts typical of those that occur naturally in the Solar System. We found that they can survive impacts up to 0.9 km s-1, which is equivalent to 1.14 GPa shock pressure, but cannot survive impacts above this. This is significantly less than the static pressure limit and has implications for tardigrade survival in panspermia models. The potential survival of tardigrades in impacts of terrestrial impact ejecta on the Moon is shown to be impossible for the average lunar impact speed of such ejecta. However, a notable fraction (around 40%) of such ejecta impact at vertical speeds low enough to permit survival. Similarly, martian impact ejecta striking Phobos, for example, at a typical im�pact speed will not permit viable transfer of tardigrade-like organisms, but if a fraction of such material had a lower impact speed, survival may be possible. We also consider the implications of this for the collection of viable samples by spacecraft transiting the plumes of icy water worlds such as Europa and Enceladus. We have found the limit on survival of shocks to be around 1 GPa, which is instrumental in determining appropriate mission scenarios and collection methods for the acquisition of viable materials