The momentum constraint equation in parameterised post-Newtonian cosmology

We derive a theory-independent version of the momentum constraint equation for use in cosmology, as a part of the Parameterised Post-Newtonian Cosmology (PPNC) framework. Our equations are constructed by adapting the corresponding quantities from formalisms devised for testing and constraining gravity in isolated astrophysical systems, thereby extending the domain of applicability of these approaches up to cosmological scales. Our parameterised equations include both scalar and divergenceless-vector gravitational potentials, and can be applied to both conservative and non-conservative theories of gravity. They can also be used to describe the gravitational fields of both non-linear structures and super-horizon perturbations. We apply the parameterised equations we propose to quintessence models of dark energy, as well as to scalar-tensor and vector-tensor theories of gravity. We find them to work well in each case. Our equations are highly compact, and are intended to be useful for constraining gravity in a theory-independent fashion in cosmology.Comment: 26 pages, 2 figure

Calcium isotopic composition of high-latitude proxy carrier Neogloboquadrina pachyderma (sin.)

The accurate reconstruction of sea surface temperature (SST) history in climate-sensitive regions (e.g. tropical and polar oceans) became a challenging task in palaeoceanographic research. Biogenic shell carbonate SST proxies successfully developed for tropical regions often fail in cool water environments. Their major regional shortcomings and the cryptic diversity now found within the major high latitude proxy carrier Neogloboquadrina pachyderma (sin.) highlight an urgent need to explore complementary SST proxies for these cool-water regions. Here we incorporate the genetic component into a calibration study of a new SST proxy for the high latitudes. We found that the calcium isotopic composition (δ44/40Ca) of calcite from genotyped net catches and core-top samples of the planktonic foraminifera Neogloboquadrina pachyderma (sin.) is related to temperature and unaffected by genetic variations. The temperature sensitivity has been found to be 0.17 (±0.02)‰ per 1°C, highlighting its potential for downcore applications in open marine cool-water environments. Our results further indicate that in extreme polar environments, below a critical threshold temperature of 2.0 (±0.5)°C associated with salinities below 33.0 (±0.5)‰, a prominent shift in biomineralization affects the δ44/40Ca of genotyped and core-top N. pachyderma (sin.), becoming insensitive to temperature. These findings highlight the need of more systematic calibration studies on single planktonic foraminiferal species in order to unravel species-specific factors influencing the temperature sensitivity of Ca isotope fractionation and to validate the proxies' applicability

Pengaruh E-Service Quality dan E-Recovery Service Quality terhadap E-Satisifaction Serta Implikasinya pada E-Loyalty Pelanggan Maskapai Penerbangan Air Asia

The research objective is to be achieved (1) To determine the relationship E-service quality, E-recovery service quality customer Airlines Air Asia and (2) To determine the effect of E-service quality, E-recovery service quality of the customer E-Satisfaction Customer Airlines Air Asia and its impact on customer E-Loyalty. The study population is customer Air Aviation Services Asia which are members of the backpacker communitys and the study sample was taken as many as 349 people. This sample was taken by random sampling. Data processing technique using path analysis. The results showed that in fact the electronic-based services after the transaction should be further improved. Therefore it is proven that the electronic-based services in theory and research results proved able to satisfy customers who eventually become loyal customers, however there are still some elements of the service that should be improved by the company. Keywords: e-service quality; e-recovery; e-satisfaction; e-loyalit

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