Rayleigh-wave dispersion curve: a proxy for site effect estimation?

One of the open issues on the effects of surface geology regards the estimation of site response when limited resources are available. In that restrictive context, one solution is to use soil characteristics as proxy. Despite its extensive use, the most common proxy, Vs30, is presently criticized because it cannot carry alone the main physics of site response. We propose here a statistical investigation of the capabilities of another proxy, the Rayleigh-wave dispersion curve, DC. When considered over a broad enough frequency band, it can provide deeper information missing in the single Vs30 parameter. A set of shear-wave velocity profiles measured for more than 600 Japanese KiK-net stations is used to compute theoretical dispersion curves (DC) and theoretical SH transfer functions (SH), while instrumental surface/downhole spectral ratios were calculated in a previous work (Cadet et al., 2011a). Canonical correlation techniques are applied to this large data set to analyze the relationship between DC and theoretical or empirical site responses. The results indicate very encouraging qualitative statistical relationships between DC and site amplification for numerically derived SH transfer functions, showing significant canonical couples with correlations up to 0.95. Results for instrumental surface/downhole transfer functions correspond to lower correlations (up to 0.73) but still allow the development of quantitative relationships

Statistical investigation of site ef f ects with emphasis on sedimentary basins, using earthquake and ambient noise recordings

During the last two decades, three empirical methods for assessing site effects have been widely used: the Standard Spectral Ratio (SSR), the Horizontal-to-Vertical Spectral Ratio from earthquake recordings (HVSR) and the Horizontal-to-Vertical Spectral Ratio from ambient noise recordings (HVN). The SSR is considered the reference empirical method to detect amplification as a function of frequency, while the HVSR and the HVN realistically indicate fundamental frequency but, for the majority of the worldwide examined sites, they cannot give reliable amplification curves as a function of frequency. Given the fact that HVSR and especially HVN can be easily obtained, it is challenging to search for any correlation with SSR amplification functions. We used recordings from 168 sites worldwide, for which all three types of spectral ratios were homogeneously processed (Haghsenas et al., Bull. Earthquake Eng. 2008). On this data set we applied standard multivariate statistical analyses, namely, factor analysis and canonical correlation, to investigate and quantify -where it is possible- any correlation between spectral ratios for a certain number of the examined frequency bins. Results show that the correlation between HVN and HVSR is very good. Moreover, their correlation with broad band SSR can be statistically quantified and receive a satisfactory physical explanation. In addition, we looked for the correlation of SSR, HVSR and HVN collected in sedimentary basins (a subset of the previous database) with geometrical and geophysical parameters. T hese attempts were constrained by the limited amount of reliable in-situ data. Among many, we select 5 parameters: Vs30, Hb, Vs_average/Hb, Hb/W_valley, Hb/W_edge (where Hb is the bedrock’s depth below the station; Vs_average is the average Vs from surface to bedrock; W_valley is 2D-width of the valley; W_edge is the distance from the closest valley’s edge). T he analysis assesses that larger are the first 4 parameters, larger is the low-frequency amplification in HVSR and HVN, and lower the high-frequency contribution. Although additional data would improve our statistical investigation and better establish quantitative correlation between spectral ratios and geophysical or/and geometrical characteristics of sedimentary basins, our results clearly show that statistical correlation between SSR and HVN-HVSR is present and modulated in specific frequency domains. T his study has been performed in the framework of the T oK IT SAK-GR EC project (2006-2010)

Analisi statistica degli effetti di sito da dati di terremoti e di rumore ambientale.

L’ultimo ventennio ha visto lo sviluppo e l’uso di tre metodi empirici per l’analisi degli effetti di sito: Standard Spectral Ratio (SSR), Horizontal-to-Vertical Spectral Ratio da registrazioni sismiche (HVSR) e Horizontal-to-Vertical Spectral Ratio da registrazioni di rumore ambientale (HVN). SSR è considerato il metodo empirico di riferimento per rilevare le amplificazioni in funzione della frequenza. HVSR e HVN, invece, danno una stima realistica della frequenza fondamentale ma, generalmente, non riescono a fornire valori affidabili di amplificazione. Nel presente lavoro sono state utilizzate le registrazioni sismiche effettuate in 168 siti provenienti da diverse aree geografiche e per cui sono stati calcolati tutti e tre i tipi di rapporti spettrali (Haghsenas et al., 2008). Su questi dati abbiamo applicato delle analisi statistiche multivariate quali la correlazione canonica (Davis, 2002), con lo scopo di mettere in evidenza e quantificare le correlazioni tra i differenti rapporti spettrali nell’intero intervallo di frequenza compreso tra 0.2Hz e 10Hz. Questo tipo di analisi permette inoltre di associare alle correlazioni una stima della loro significatività ed è stata già utilizzata da Theodulidis et al. (2008) per studiare la relazione tra HVN e danneggiamento in aree urbane. I risultati mostrano che la correlazione tra HVN e HVSR è molto buona ad esclusione delle basse frequenze e che, per entrambe le tecniche, la presenza di un picco di amplificazione nell’intervallo 0.6-2 Hz è correlato ad un minimo per frequenze 3-10Hz. I picchi di amplificazione evidenziati da queste due tecniche sono inoltre correlabili con un più largo intervallo di frequenze nei rapporti SSR. Abbiamo quindi esteso l’analisi per correlare SSR, HVSR e HVN in bacini sedimentari (un subset dei dati utilizzati) con parametri geofisici e geometrici. La riduzione del numero dei dati deriva dall’esigenza di avere siti con una buona qualità di informazioni geofisiche e geometriche. Sono stati scelti cinque parametri indicatori delle velocità medie delle onde S e delle caratteristiche geometriche 2D della valle. Sebbene un più esteso data-set migliorerebbe l’analisi statistica, stabilendo migliori stime quantitative della correlazione tra rapporti spettrali e le caratteristiche geofisiche e geometriche dei bacini sedimentari, i nostri risultati mostrano chiaramente che le correlazioni tra SSR e HVN-HVSR esistono e si modulano in specifici intervalli di frequenza. Questo studio è stato condotto nell’ambito del progetto ToK ITSAK-GR EC (2006-2010)

Statistical estimation of earthquake site response from noise recordings

Standard spectral ratio from earthquake recordings (SSR) is considered the reference empirical method for assessing site effects as a function of frequency. However, other estimates can be easily obtained from noise measurements (i.e., Horizontal-to-Vertical Spectral Ratio, HVN), even though their reliability in terms of amplitude is controversial. In the framework of the ToK ITSAK-GR (2006-2010) EC project, Cultrera et al. (2010) analyzed recordings from 64 sites worldwide, founding that it is possible to have linear combinations of the HVN amplitudes significantly correlated to linear combinations of the SSR. In the present paper we show how to estimate the SSR spectral ratios when only noise measurements are available, using the results of the canonical correlation analysis between SSR and HVN recorded at several sites. The SSR evaluation has been tested by a cross validation procedure: the expected SSR at each validation site are in turn estimated by a weighted average of the SSR values measured at the other sites; the weights are properly set to account more for the sites with similar behavior in terms of the canonical correlation between HVN and SSR. To evaluate the goodness of the estimation, we compared all the inferred and original SSR, and we performed a critical analysis on the spectral characteristics of earthquake site response that can be easily recovered from noise measurements

Cloning, Expression and Purification of an Acetoacetyl CoA Thiolase from Sunflower Cotyledon

Thiolase I and II coexist as part of the glyoxysomal β-oxidation system in sunflower (Helianthus annuus L.) cotyledons, the only system shown to have both forms. The importance of thiolases can be underscored not only by their ubiquity, but also by their involvement in a wide variety of processes in plants, animals and bacteria. Here we describe the cloning, expression and purification of acetoacetyl CoA thiolase (AACT) in enzymatically active form. Use of the extensive amount of sequence information from the databases facilitated the efficient generation of the gene-specific primers used in the RACE protocols. The recombinant AACT (1233 bp) shares 75% similarity with other plant AACTs. Comparison of specific activity of this recombinant AACT to a previously reported enzyme purified from primary sunflower cotyledon tissue was very similar (263 nkat/mg protein vs 220 nkat/mg protein, respectively). Combining the most pure fractions from the affinity column, the enzyme was purified 88-fold with a 55% yield of the enzymatically active, 47 kDa AACT

Site effect estimation through site characterization from ambient noise recordings,

Site effect assessment is an important step in seismic risk mitigation. There is therefore a drastic need for co proxies to site effects estimates. In that context, a new promising approach was proposed, using the time-avera over the top z meters with z varying form 5, 10, 20 and 30 meters (Vsz) and the fundamental resonance frequen two-parameters characterization of a site. Then to assess site effect, a Site Amplification Prediction Equat completely defined by these two parameters was build-up based on Japanese data from the KiK-Net network. Thu to be validated using other dataset. For that aim the EUROSEIS-test data is a suitable one. The EUROSE sedimentary basin in northern-Greece that has been thoroughly investigated through grants from the European C mainly to study site effects. Fourteen accelerometric stations have been installed since 1995, that to date recorded 100 events. After a review of the main available information over the EUROSEIS-test, we end up with a poor Vs for some of the accelerometric stations. Thus eight accelerometric stations were selected for noise array me surveys to provide more details information about Vsz and f0 parameters. The noise array technique has been pro decades ago but its development is still in progress, particularly regarding the inversion step. Different approaches el al. 2009, Renalier et al. 2009) were tested in this study to provide Vsz. These two inversion strategies provide Vsz for z equals to 10, 20 and 30 meters. With the resulting Vsz and f0 from noise analysis, a validation-test of th SAPE was realized. The results of such a comparison are encouraging and indicate as well limitations of the SAP It is a promising tool for engineering and seismic risk management

A theoretical insight into the photophysics of psoralen

Psoralen photophysics has been studied on quantum chemistry grounds using the multiconfigurational second-order perturbation method CASPT2. Absorption and emission spectra of the system have been rationalized by computing the energies and properties of the low-lying singlet and triplet excited states. The S1 ππ* state has been determined to be responsible of the lowest absorption and fluorescence bands and to initially carry the population in the photophysical processes related to the phototherapeutic properties of psoralen derivatives. The low-lying T1 ππ* state is, on the other hand, protagonist of the phosphorescence, and its prevalent role in the reactivity of psoralen is suggested to be related to the elongation of the pyrone ring C3–C4 bond, where the spin density is distributed on both carbon atoms. Analysis of energy gaps and spin-orbit coupling elements indicates that the efficient photophysical process leading to the population of the lowest triplet state does not take place at the Franck-Condon region but along the S1 relaxation [email protected] [email protected] [email protected]

Decontamination of MDA Reagents for Single Cell Whole Genome Amplification

Single cell genomics is a powerful and increasingly popular tool for studying the genetic make-up of uncultured microbes. A key challenge for successful single cell sequencing and analysis is the removal of exogenous DNA from whole genome amplification reagents. We found that UV irradiation of the multiple displacement amplification (MDA) reagents, including the Phi29 polymerase and random hexamer primers, effectively eliminates the amplification of contaminating DNA. The methodology is quick, simple, and highly effective, thus significantly improving whole genome amplification from single cells

Methamphetamine Preconditioning Alters Midbrain Transcriptional Responses to Methamphetamine-Induced Injury in the Rat Striatum

Methamphetamine (METH) is an illicit drug which is neurotoxic to the mammalian brain. Numerous studies have revealed significant decreases in dopamine and serotonin levels in the brains of animals exposed to moderate-to-large METH doses given within short intervals of time. In contrast, repeated injections of small nontoxic doses of the drug followed by a challenge with toxic METH doses afford significant protection against monoamine depletion. The present study was undertaken to test the possibility that repeated injections of the drug might be accompanied by transcriptional changes involved in rendering the nigrostriatal dopaminergic system refractory to METH toxicity. Our results confirm that METH preconditioning can provide significant protection against METH-induced striatal dopamine depletion. In addition, the presence and absence of METH preconditioning were associated with substantial differences in the identity of the genes whose expression was affected by a toxic METH challenge. Quantitative PCR confirmed METH-induced changes in genes of interest and identified additional genes that were differentially impacted by the toxic METH challenge in the presence of METH preconditioning. These genes include small heat shock 27 kD 27 protein 2 (HspB2), thyrotropin-releasing hormone (TRH), brain derived neurotrophic factor (BDNF), c-fos, and some encoding antioxidant proteins including CuZn superoxide dismutase (CuZnSOD), glutathione peroxidase (GPx)-1, and heme oxygenase-1 (Hmox-1). These observations are consistent, in part, with the transcriptional alterations reported in models of lethal ischemic injuries which are preceded by ischemic or pharmacological preconditioning. Our findings suggest that multiple molecular pathways might work in tandem to protect the nigrostriatal dopaminergic pathway against the deleterious effects of the toxic psychostimulant. Further analysis of the molecular and cellular pathways regulated by these genes should help to provide some insight into the neuroadaptive potentials of the brain when repeatedly exposed to drugs of abuse