Structural changes in water and Ar-water clusters under high pressure

1 pág.; 1 fig.; XXIX International Conference on Photonic, Electronic, and Atomic Collisions (ICPEAC2015); Open Access funded by Creative Commons Atribution Licence 3.0Specific size gas-water clusters are currently receiving considerable attention, as models for inclusion compounds of different type of clathrate hydrates. As model microsolutions they retain many characteristics of the bulk, are theoretically tractable, and can be used to probe the relevant guest/host interactions, as well as to derive and to test intermolecular potentials that can be also used under different thermodynamic conditions.Peer Reviewe

Heavy Metal Contamination of the Loučka River Water Ecosystem

Heavy metal contamination of the Loučka River water ecosystem was assessed in July 2005. We analyzed concentrations of T-Hg (total mercury), Cd, Pb, Cr, Cu, Zn, and Ni in water, sediments, zoobenthos, and in the brown trout (Salmo trutta m. fario) muscle and liver tissues (a total of 28 individuals) at four sampling sites. The highest Pb and Ni concentrations (4.634-12.050 and 0.689-24.980 mg kg-1) were found in sediments. The zoobenthos was most contaminated by Zn and Cu (0.556-1.505 and 2.925-74.300 mg kg-1). The heavy metal contamination of river water was highest in Ni and Cr (0.1-6.8 and 0.5-10.0 mg l-1). Concentrations of heavy metals in the brown trout muscle were following (in mg kg-1): Pb 0.108 ± 0.073 - 1.010 ± 0.506, Cd 0.003 ± 0.002 - 0.026 ± 0.022, Zn 3.956 ± 0.371 - 5.801 ± 1.718, Ni 0.058 ± 0.018 - 0.102 ± 0.046, Cr 0.028 ± 0.005 - 0.073 ± 0.039, Cu 0.329 ± 0.079 - 0.437 ± 0.064 and Hg 0.065 ± 0.008 - 0.106 ± 0.047. Statistical differences (P -1). Humans of 60 kg body mass may consume 1.5 kg of brown trout muscle from the Loučka River weekly without any risk. Adverse influence of the Uniglas distillery on the Loučka River environment contamination by heavy metals was not confirmed

The bright optical flash from GRB 060117

We present a discovery and observation of an extraordinarily bright prompt optical emission of the GRB 060117 obtained by a wide-field camera atop the robotic telescope FRAM of the Pierre Auger Observatory from 2 to 10 minutes after the GRB. We found rapid average temporal flux decay of alpha = -1.7 +- 0.1 and a peak brightness R = 10.1 mag. Later observations by other instruments set a strong limit on the optical and radio transient fluxes, unveiling an unexpectedly rapid further decay. We present an interpretation featuring a relatively steep electron-distribution parameter p ~ 3.0 and providing a straightforward solution for the overall fast decay of this optical transient as a transition between reverse and forward shock.Comment: Accepted to A&A, 4 pages, corected few typos pointed out by X.F. W

A decade of GRB follow-up by BOOTES in Spain (2003-2013)

This article covers ten years of GRB follow-ups by the Spanish BOOTES stations: 71 follow-ups providing 23 detections. Follow-ups by BOOTES-1B from 2005 to 2008 were given in the previous article, and are here reviewed, updated, and include additional detection data points as the former article merely stated their existence. The all-sky cameras CASSANDRA have not yet detected any GRB optical afterglows, but limits are reported where available

Double diffractive cross-section measurement in the forward region at LHC

The first double diffractive cross-section measurement in the very forward region has been carried out by the TOTEM experiment at the LHC with center-of-mass energy of sqrt(s)=7 TeV. By utilizing the very forward TOTEM tracking detectors T1 and T2, which extend up to |eta|=6.5, a clean sample of double diffractive pp events was extracted. From these events, we measured the cross-section sigma_DD =(116 +- 25) mub for events where both diffractive systems have 4.7 <|eta|_min < 6.5 .Comment: 5 pages, 1 figure, submitted for publicatio

Performance of the TOTEM Detectors at the LHC

The TOTEM Experiment is designed to measure the total proton-proton cross-section with the luminosity-independent method and to study elastic and diffractive pp scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the interaction point IP5, two tracking telescopes, T1 and T2, are installed on each side of the IP in the pseudorapidity region 3.1 < = |eta | < = 6.5, and special movable beam-pipe insertions - called Roman Pots (RP) - are placed at distances of +- 147 m and +- 220 m from IP5. This article describes in detail the working of the TOTEM detector to produce physics results in the first three years of operation and data taking at the LHC.Comment: 40 pages, 31 figures, submitted to Int. J. Mod. Phys.

Relationship between serum bilirubin and uric acid to oxidative stress markers in Italian and Czech populations

Summary Recently, a South-to-North oxidative stress marker gradient has been reported; consistent with known differences in the incidence of coronary heart disease between southern and northern European countries. The aim of the present study was to compare the plasma concentrations of 7-oxocholesterol (7OxCH) and 7β-hydroxycholesterol (7BCH) with systemic antioxidants in healthy Italian and Czech subjects. The study was performed in healthy subjects of Italian (n=131) and Czech (n=84) origins. In all subjects routine biochemistry work-ups were performed; additionally, plasma oxysterols and the peroxyl radicals scavenging activity (PERSA) of the sera were determined. Close relationship of serum bilirubin and uric acid to markers of oxidative stress was observed in both examined populations. Compared to the Czechs, the Italian population showed higher plasma concentrations of both oxysterols (7OxCH: 3.6 vs. 6.0 ng/ml, p −6 ; 7BCH: 5.3 vs. 8.6 ng/ml, p −6 ), lower PERSA (p −6 ), and lower serum concentrations of bilirubin and uric acid (p −6 in both cases). The dietary patterns of the Italian population did not match the Mediterranean style, but was more similar to the Continental type of diet, presumably due to non-adherence to a Mediterranean diet

Elastic Scattering and Total Cross-Section in p+p reactions measured by the LHC Experiment TOTEM at sqrt(s) = 7 TeV

Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at $\sqrt{s} = 7$ TeV in special runs with the Roman Pot detectors placed as close to the outgoing beam as seven times the transverse beam size. The differential cross-section measurements are reported in the |t|-range of 0.36 to 2.5 GeV^2. Extending the range of data to low t values from 0.02 to 0.33 GeV^2,and utilizing the luminosity measurements of CMS, the total proton-proton cross section at sqrt(s) = 7 TeV is measured to be (98.3 +- 0.2(stat) +- 2.8(syst)) mb.Comment: Proceedings of the XLI International Symposium on Multiparticle Dynamics. Accepted for publication in Prog. Theor. Phy

A millennium-long 'Blue Ring' chronology from the Spanish Pyrenees reveals severe ephemeral summer cooling after volcanic eruptions

Abstract ‘Blue Rings’ (BRs) are distinct wood anatomical anomalies recently discovered in several tree species from different sites. While it is evident that they are associated with a cooling-induced lack of cell wall lignification, BRs have yet to be evaluated systematically in paleoclimate studies. Here, we present a continuous wood anatomical assessment of 31 living and relict pine samples from a high-elevation site in the central Spanish Pyrenees that span the period 1150–2017 CE at annual resolution. While most BR years coincide with cold summer temperatures and many BRs follow large volcanic eruptions, some were formed during overall warm summers. We also see a differential response between eruptions: the Samalas eruption is followed by 80% BRs in 1258, but only a modest signal is evident after the 1815 Tambora eruption, and there are no wood anatomical effects of the Laki eruption in 1783–1784. Apparently linked to a cluster of tropical eruptions in 1695 and 1696 CE, 85% BRs occurred in 1698. This new wood anatomical evidence is corroborated by the record of sulphur deposition in polar ice cores, and corresponds with catastrophic famine and unprecedented mortality in Scotland. The extremely rare occurrence of consecutive BRs in 1345 and 1346 marks the onset and spread of the Black Death, Europe’s most devastating plague pandemic. In their ability to capture severe ephemeral cold spells, as short as several days or weeks, BR chronologies can help to investigate and understand the impacts of volcanism on climate and society.</jats:p

Defining Multiple Characteristic Raman Bands of α-Amino Acids as Biomarkers for Planetary Missions Using a Statistical Method

Biomarker molecules, such as amino acids, are key to discovering whether life exists elsewhere in the Solar System. Raman spectroscopy, a technique capable of detecting biomarkers, will be on board future planetary missions including the ExoMars rover. Generally, the position of the strongest band in the spectra of amino acids is reported as the identifying band. However, for an unknown sample, it is desirable to define multiple characteristic bands for molecules to avoid any ambiguous identification. To date, there has been no definition of multiple characteristic bands for amino acids of interest to astrobiology. This study examinedL-alanine, L-aspartic acid, L-cysteine, L-glutamine and glycine and defined several Raman bands per molecule for reference as characteristic identifiers. Per amino acid, 240 spectra were recorded and compared using established statistical tests including ANOVA. The number of characteristic bands defined were 10, 12, 12, 14 and 19 for L-alanine (strongest intensity band: 832 cm-1), L-aspartic acid (938 cm-1), L-cysteine (679 cm-1),L-glutamine (1090 cm−1) and glycine (875 cm-1), respectively. The intensity of bands differed by up to six times when several points on the crystal sample were rotated through 360 °; to reduce this effect when defining characteristic bands for other molecules, we find that spectra should be recorded at a statistically significant number of points per sample to remove the effect of sample rotation. It is crucial that sets of characteristic Raman bands are defined for biomarkers that are targets for future planetary missions to ensure a positive identification can be made