103 research outputs found
Investigations on the Luminescence Properties of Quartz and Feldspars Extracted from Loess in the Canterbury Plains, New Zealand South Island
The applicability of the single-aliquot regenerative-dose (SAR) protocol, by using the optically stimulated lumi-nescence (OSL) signal of quartz as well as the post-infraredâinfrared (pIRIR) signals of polymineral fine grains, namely pIRIR225 and pIRIR290, was assessed for dating loess in New Zealand South Island. OSL signals of quartz grains displayed low sensitivity. However, the application of repeated irradiation/bleaching cycles did not result in an increase in sensitivity; annealing in the 300â500°C temperature range generated the sensitisation of both the 110°C thermoluminescence (TL) peak as well as the OSL signal, likely by activation of yet unidentified luminescence centres. After heating, the quartz signal is comparable to that of ideal samples, but the annealing is precluding successful dating. On the other hand, feldspar infrared-stimulated signals displayed satisfactory properties, al-lowing estimation of ages ranging from 14 ± 1â29 ± 3 ka for the investigated deposit. It was shown that pIRIR225 and pIRIR290 methods have potential for dating loess in the South Island of New Zealand, based on the following observations: (i) Dose recovery tests were successful with recovered-to-given dose ratios with a <10% deviation from unity, (ii) constant residual values of about 4 Gy and about 10 Gy were obtained after exposures for 48 h in the case of pIRIR225 signals and 96 h in the case of pIRIR290 signals, respectively, (iii) while a slight dose-dependence of the residual was reported, and for a dose as large as 1600 Gy the residual values are â
9 Gy and â
19 Gy for pIRIR225 and pIRIR290 signals, respectively
Wavelength-Gated Photochemical Synthesis of Phenalene Diimides
Herein, we pioneer a wavelengthâgated synthesis route to phenalene diimides. Consecutive DielsâAlder reactions of methylisophthalaldehydes and maleimides afford hexahydroâphenaleneâ1,6âdiol diimides via 5âformylâhexahydroâbenzo[f]isoindoles as the intermediate. Both photoreactions are efficient (82â99â% yield) and exhibit excellent diastereoselectivity (62â98â%â
d.r.). The wavelengthâgated nature of the stepwise reaction enables the modular construction of phenalene diimide scaffolds by choice of substrate and wavelength. Importantly, this synthetic methodology opens a facile avenue to a new class of persistent phenalenyl diimide neutral radicals, constituting a versatile route to spinâactive molecules
Seismogenic faults, landslides, and associated tsunamis off southern Italy - Cruise No. M86/2, December 27, 2011 - January 17, 2012, Cartagena (Spain) - Brindisi (Italy)
Summary
The continental margins of southern Italy are located along converging plate boundaries, which
are affected by intense seismicity and volcanic activity. Most of the coastal areas experienced
severe earthquakes, landslides, and tsunamis in historical and/or modern times. The most
prominent example is the Messina earthquake of Dec. 28, 1908 (Ms=7.3; 80,000 casualties),
which was characterized by the worst tsunami Italy experienced in the historical time (~2000
casualties). It is, however, still unclear, whether this tsunami was triggered by a sudden vertical
movement along a major fault during the earthquake or as a result of a giant marine slide
initiated by the earthquake. The recurrence rates of major landslides and therefore the risk
associated with landslides is also unknown. Based on detailed bathymetric data sets collected by
Italian colleagues in the frame of the MaGIC Project (Marine Geohazards along the Italian
Coast), we collected seismic data (2D and 3D) and gravity cores in three working areas (The
Messina Straits, off Eastern Sicily, the Gioia Basin). A dense grid of new 2D-seismic data in the
Messina Straits will allow to map fault patterns in great detail. One interesting outcome in this
context is the identification of a set of normal faults striking in an EW-direction, which is almost
perpendicular to the previously postulated faults. This EW-striking faults seem to be active. The
area off eastern Sicily is characterized by numerous landslides and a complex deformation
pattern. A 3D-seismic data set has been collected during the cruise using the so called P-cable in
order to investigate these deformation patterns in detail. The new data will be the basis for a risk
assessment in the working areas
Coupling terrestrial and marine datasets for coastal hazard assessment and risk reduction in changing environments â Un Progetto di ricerca nellâambito dellâEUR-OPA Major Hazards Agreement del Consiglio dâEuropa
Lo European and Mediterranean Major Hazards Agreement (EUR-OPA) del Consiglio dâEuropa Ăš una piattaforma per la cooperazione tra paesi europei e del Mediterraneo meridionale nel campo dei rischi naturali e tecnologici. Lâaccordo si prefigge di stimolare una piĂč stretta collaborazione tra gli stati membri ai fini della prevenzione e della protezione da possibili calamitĂ , di condividere conoscenze sulle pericolositĂ legate ai cambiamenti ambientali e di sviluppare nuove metodologie e strumenti per una gestione efficace dei rischi.peer-reviewe
A consistent global approach for morphometric characterisation of subaqueous landslides
Landslides are common in aquatic settings worldwide, from lakes and coastal environments to the deep sea. Fast-moving, large-volume landslides can potentially trigger destructive tsunamis. Landslides damage and disrupt global communication links and other critical marine infrastructure. Landslide deposits act as foci for localized, but important, deep-seafloor biological communities. Under burial, landslide deposits play an important role in a successful petroleum system. While the broad importance of understanding subaqueous landslide processes is evident, a number of important scientific questions have yet to receive the needed attention. Collecting quantitative data is a critical step to addressing questions surrounding subaqueous landslides.
Quantitative metrics of subaqueous landslides are routinely recorded, but which ones, and how they are defined, depends on the end-user focus. Differences in focus can inhibit communication of knowledge between communities, and complicate comparative analysis. This study outlines an approach specifically for consistent measurement of subaqueous landslide morphometrics to be used in the design of a broader, global open-source, peer-curated database. Examples from different settings illustrate how the approach can be applied, as well as the difficulties encountered when analysing different landslides and data types. Standardizing data collection for subaqueous landslides should result in more accurate geohazard predictions and resource estimation
Gaining Greater Insight into HCV Emergence in HIV-Infected Men Who Have Sex with Men: The HEPAIG Study
OBJECTIVES: The HEPAIG study was conducted to better understand Hepatitis C virus (HCV) transmission among human immuno-deficiency (HIV)-infected men who have sex with men (MSM) and assess incidence of HCV infection among this population in France. METHODS AND RESULTS: Acute HCV infection defined by anti-HCV or HCV ribonucleic acid (RNA) positivity within one year of documented anti-HCV negativity was notified among HIV-infected MSM followed up in HIV/AIDS clinics from a nationwide sampling frame. HIV and HCV infection characteristics, HCV potential exposures and sexual behaviour were collected by the physicians and via self-administered questionnaires. Phylogenetic analysis of the HCV-NS5B region was conducted. HCV incidence was 48/10 000 [95% Confidence Interval (CI):43-54] and 36/10 000 [95% CI: 30-42] in 2006 and 2007, respectively. Among the 80 men enrolled (median age: 40 years), 55% were HIV-diagnosed before 2000, 56% had at least one sexually transmitted infection in the year before HCV diagnosis; 55% were HCV-infected with genotype 4 (15 men in one 4d-cluster), 32.5% with genotype 1 (three 1a-clusters); five men were HCV re-infected; in the six-month preceding HCV diagnosis, 92% reported having casual sexual partners sought online (75.5%) and at sex venues (79%), unprotected anal sex (90%) and fisting (65%); using recreational drugs (62%) and bleeding during sex (55%). CONCLUSIONS: This study emphasizes the role of multiple unprotected sexual practices and recreational drugs use during sex in the HCV emergence in HIV-infected MSM. It becomes essential to adapt prevention strategies and inform HIV-infected MSM with recent acute HCV infection on risk of re-infection and on risk-reduction strategies
Towards Equitable, Diverse, and Inclusive science collaborations: The Multimessenger Diversity Network
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