On the investigations of galaxy redshift periodicity

In this article we present a historical review of study of the redshift periodicity of galaxies, starting from the first works performed in the seventies of the twentieth century until the present day. We discuss the observational data and methods used, showing in which cases the discretization of redshifts was observed. We conclude that galaxy redshift periodisation is an effect which can really exist. We also discussed the redshift discretization in two different structures: the Local Group of galaxies and the Hercules Supercluster. Contrary to the previous studies we consider all galaxies which can be regarded as a structure member disregarding the accuracy of velocity measurements. We applied the power spectrum analysis using the Hann function for weighting, together with the jackknife error estimator. In both the structures we found weak effects of redshift periodisation.Comment: 10 pages, 4 figures, to be published in Part. and Nucl. Lett. 200

A quantitative study of five thousand years of volcanism on Sao Miguel, Azores

The activity of the three stratovolcanoes on the island of Sao Miguel is documented by tephrochronology, and during the past 5000 years a total of some 57 volcanic eruptions have taken place, mostly of magnitudes 4-6 on Tsuya’s scale. Approximately half were trachytic, and half basaltic. Each stratovolcano has a caldera within which each has had one historic eruption. The trachytic eruptions were predominantly explosive, and most took place from vents situated within the calderas. Isopach and isograde maps of most of the resulting pumice fall deposits are given. The basaltic eruptions produced both lava flows and pyroclastics, and isopach and isograde maps are given for some of the main fall deposits. The Agua de Pau volcano has had particularly large explosive eruptions, several of them (including Fogo A, the largest in the past 5000 years) being of plinian type. The output of the three volcanoes over the 5000 years is equivalent to 4.6 km3 of dense rock, at which rate the exposed parts of the volcanoes could have accumulated in 150000 years. At least half of the erupted material is trachytic, a proportion typical of the entire accessible parts of the volcanoes. The 50 known eruptive vents of the past 5000 years are distributed in a zone 55 km long by 8 km wide which may lie above a major fracture zone. Some eruptive fissures trend obliquely across this zone, suggesting right-lateral movement along the fracture. Basaltic eruptions were confined to a much smaller area than in the preceding millennia perhaps due to the formation, at the time of the great Fogo A eruption 5000 years ago, of a broad trachytic magma chamber underlying the Agua de Pau and Furnas volcanoes which basaltic magma has since been unable to penetrate

Multi-element survey of wild edible fungi and blackberries in the UK

International audienceA survey of 12 metals including lead (Pb), copper (Cu), cadmium (Cd), mercury (Hg), arsenic (As) and platinum(Pt) was carried out using ICP-MS in 34 samples of wild fungi and 48 samples of wild blackberries collected from sites across the UK. On a freshweight basis (mg/kg) levels of Pb were in the range 0.003-5.990, Cu 0.596-34.800, Cd <0.001-19.6, Hg <0.001-4.150, As 0.001 – 0.972 and Pt (µg/kg) 0.006 – 0.200, with higher concentrations found in fungi than in blackberries. The results of the survey showed that the concentrations of the metals were consistent with previous studies, where available. Concentrations in wild fungi of Pt, tin (Sn), and titanium(Ti) were significantly higher at urban sites than at rural sites. Urban blackberries had significantly higher levels of Pb, Ti, and Cd than rural ones, but lower levels of manganeseMn. Pb, Ti and Sn concentrations were significantly higher in blackberries sampled near main roads rather than in rural areas

Characterizing source fingerprints and ageing processes in laboratory-generated secondary organic aerosols using proton-nuclear magnetic resonance (1H-NMR) analysis and HPLC HULIS determination

The study of secondary organic aerosol (SOA) in laboratory settings has greatly increased our knowledge of the diverse chemical processes and environmental conditions responsible for the formation of particulate matter starting from biogenic and anthropogenic volatile compounds. However, characteristics of the different experimental setups and the way they impact the composition and the timescale of formation of SOA are still subject to debate. In this study, SOA samples were generated using a potential aerosol mass (PAM) oxidation flow reactor using α-pinene, naphthalene and isoprene as precursors. The PAM reactor facilitated exploration of SOA composition over atmospherically relevant photochemical ageing timescales that are unattainable in environmental chambers. The SOA samples were analyzed using two state-of-The-Art analytical techniques for SOA characterization - proton nuclear magnetic resonance (1H-NMR) spectroscopy and HPLC determination of humiclike substances (HULIS). Results were compared with previous Aerodyne aerosol mass spectrometer (AMS) measurements. The combined 1H-NMR, HPLC, and AMS datasets show that the composition of the studied SOA systems tend to converge to highly oxidized organic compounds upon prolonged OH exposures. Further, our 1H-NMR findings show that only α-pinene SOA acquires spectroscopic features comparable to those of ambient OA when exposed to at least 1×1012 molecOHcm-3 ×s OH exposure, or multiple days of equivalent atmospheric OH oxidation. Over multiple days of equivalent OH exposure, the formation of HULIS is observed in both α-pinene SOA and in naphthalene SOA (maximum yields: 16 and 30 %, respectively, of total analyzed water-soluble organic carbon, WSOC), providing evidence of the formation of humic-like polycarboxylic acids in unseeded SOA

Measurements of load transmission through grounded ice rubble

Peer reviewed: NoNRC publication: Ye

Laboratory studies of the chemical composition and cloud condensation nuclei (CCN) activity of secondary organic aerosol (SOA) and oxidized primary organic aerosol (OPOA)

Secondary organic aerosol (SOA) and oxidized primary organic aerosol (OPOA) were produced in laboratory experiments from the oxidation of fourteen precursors representing atmospherically relevant biogenic and anthropogenic sources. The SOA and OPOA particles were generated via controlled exposure of precursors to OH radicals and/or O&lt;sub&gt;3&lt;/sub&gt; in a Potential Aerosol Mass (PAM) flow reactor over timescales equivalent to 1–20 days of atmospheric aging. Aerosol mass spectra of SOA and OPOA were measured with an Aerodyne aerosol mass spectrometer (AMS). The fraction of AMS signal at &lt;i&gt;m/z&lt;/i&gt; = 43 and &lt;i&gt;m/z&lt;/i&gt; = 44 (&lt;i&gt;f&lt;/i&gt;&lt;sub&gt;43&lt;/sub&gt;, &lt;i&gt;f&lt;/i&gt;&lt;sub&gt;44&lt;/sub&gt;), the hydrogen-to-carbon (H/C) ratio, and the oxygen-to-carbon (O/C) ratio of the SOA and OPOA were obtained, which are commonly used to characterize the level of oxidation of oxygenated organic aerosol (OOA). The results show that PAM-generated SOA and OPOA can reproduce and extend the observed &lt;i&gt;f&lt;/i&gt;&lt;sub&gt;44&lt;/sub&gt;–&lt;i&gt;f&lt;/i&gt;&lt;sub&gt;43&lt;/sub&gt; composition beyond that of ambient OOA as measured by an AMS. Van Krevelen diagrams showing H/C ratio as a function of O/C ratio suggest an oxidation mechanism involving formation of carboxylic acids concurrent with fragmentation of carbon-carbon bonds. Cloud condensation nuclei (CCN) activity of PAM-generated SOA and OPOA was measured as a function of OH exposure and characterized as a function of O/C ratio. CCN activity of the SOA and OPOA, which was characterized in the form of the hygroscopicity parameter &amp;kappa;&lt;sub&gt;org&lt;/sub&gt;, ranged from 8.4×10&lt;sup&gt;&amp;minus;4&lt;/sup&gt; to 0.28 over measured O/C ratios ranging from 0.05 to 1.42. This range of &amp;kappa;&lt;sub&gt;org&lt;/sub&gt; and O/C ratio is significantly wider than has been previously obtained. To first order, the &amp;kappa;&lt;sub&gt;org&lt;/sub&gt;-to-O/C relationship is well represented by a linear function of the form &amp;kappa;&lt;sub&gt;org&lt;/sub&gt; = (0.18&amp;plusmn;0.04) &amp;times;O/C + 0.03, suggesting that a simple, semi-empirical parameterization of OOA hygroscopicity and oxidation level can be defined for use in chemistry and climate models