Water chemistry analysis in the sediment of Baradla Cave, Hungary

Abstract Water was observed in the sediment of Baradla Cave, located in Northeast Hungary. In order to investigate its characteristics wells were drilled. Hydrochemical samples were taken directly from the wells and from the cave stream on several occasions between November 2009 and April 2010. In February 2010 there was an opportunity to observe how the chemical composition of the waters of the creeks and the sediments altered during the snow melt. Several chemical parameters of the samples were analyzed. Based on the results of the hydrochemical analyses cluster analysis was applied to define the relationship between the sampling points. Discriminant analysis was conducted to verify the classification. As a result of the classification, the water of the observation wells in the sediment proved to be distinct from the water of the cave's creek and the springs on the surface. Research shows that there is no permanent connection between the water in the cave sediment and the water of the cave creek in the cave water system

The Lyman α forest power spectrum from the XQ-100 legacy survey

We present the Lyman α flux power spectrum measurements of the XQ-100 sample of quasar spectra obtained in the context of the European Southern Observatory Large Programme ‘Quasars and their absorption lines: a legacy survey of the high redshift universe with VLT/XSHOOTER’. Using 100 quasar spectra with medium resolution and signal-to-noise ratio, we measure the power spectrum over a range of redshifts z = 3–4.2 and over a range of scales k = 0.003–0.06 km−1 s. The results agree well with the measurements of the one-dimensional power spectrum found in the literature. The data analysis used in this paper is based on the Fourier transform and has been tested on synthetic data. Systematic and statistical uncertainties of our measurements are estimated, with a total error (statistical and systematic) comparable to the one of the BOSS data in the overlapping range of scales, and smaller by more than 50 per cent for higher redshift bins (z > 3.6) and small scales (k > 0.01 km−1 s). The XQ-100 data set has the unique feature of having signal-to-noise ratios and resolution intermediate between the two data sets that are typically used to perform cosmological studies, i.e. BOSS and high-resolution spectra (e.g. UVES/VLT or HIRES). More importantly, the measured flux power spectra span the high-redshift regime that is usually more constraining for structure formation models