Catalysis by alkali and alkaline-earth metal ions in nucleophilic attack of methoxide ion on crown ethers bearing an intra-annular acetoxy group

Rates of reaction of methoxide ion with crown ethers bearing an intra-annular acetoxy group are markedly enhanced by alkali and alkaline-earth metal bromides as a result of much stronger interactions of the metal ions with transition states than with reactants.\ud \ud Rates of reactions of methoxide ion with crown ethers bearing an intra-annular acetoxy group markedly enhanced by alkali and alkaline-earth metal bromides as a result of much stronger interactions of the metal ion with transition state than with reactants

INFLUENZA DELLA SALDATURA LASER SUL COMPORTAMENTO A MEMORIA DI FORMA A DUE VIE DI UNA LEGA NiTi

Nel presente lavoro è riportato lo studio del comportamento funzionale di un giunto saldato in lega NiTi a memoria di forma. In particolare, sono stati analizzati gli effetti della saldatura laser Nd:YAG sul comportamento a memoria di forma a due vie (Two Way Shape Memory Effect, TWSME) di una lega Ni- 51 at.% Ti, attraverso un confronto sistematico con i risultati relativi al materiale non saldato. Il TWSME è stato indotto nel materiale attraverso un opportuna procedura di training, che consiste nella ripetizione di cicli termomeccanici; successivamente, sono stati misurati i cicli di isteresi (temperatura-deformazione) caratteristici del TWSME. Sono stati valutati, inoltre, gli effetti del numero di cicli di training e delle deformazioni plastiche, che si generano nel materiale durante il processo di training, sul comportamento a memoria di forma del materiale. I risultati mostrano come il comportamento funzionale, e in particolare il TWSME, sia parzialmente preservato nel materiale saldato che, comunque, presenta valori di deformazioni plastiche maggiori rispetto al materiale base

Localization of 102 exons to a 2.5 Mb region involved in Down syndrome

Exon amplification has been applied to a 2.5 Mb region of chromosome 21 that has been associated with some features of Down syndrome (DS). Identification of the majority of genes from this region will facilitate the correlation of the over-expression of particular genes with specific phenotypes of DS. Over 100 gene fragments have been isolated from this 2.5 Mb segment. The exons have been characterized by sequence analysis, comparison with public databases and expansion to cDNA clones. Localization of the exons to chromosome 21 has been determined by hybridization to genomic Southern blots and to YAC and cosmid clones representing the region. This has resulted in a higher resolution physical map with a marker approximately every 25 kb. This integrated physical and transcript map will be valuable for fine mapping of DNA from individuals with partial aneuploidy of chromosome 21 as well as for assessing and ultimately generating a complete gene map of this segment of the genom

Measurement of the quality factor of a new low-frequency differential accelerometer for testing the equivalence principle

A cryogenic differential accelerometer has been developed to test the weak equivalence principle to a few parts in 1015 within the framework of the general relativity accuracy test in an Einstein elevator experiment. The prototype sensor was designed to identify, address, and solve the major issues associated with various aspects of the experiment. This paper illustrates the measurements conducted on this prototype sensor to attain a high quality factor (Q ∼ 105) at low frequencies (<20 Hz). Such a value is necessary for reducing the Brownian noise to match the target acceleration noise of 10−14 g/√Hz, hence providing the desired experimental accuracy.AstronomyPhysic

Natural bovine coronavirus infection in a calf persistently infected with bovine viral diarrhea virus: Viral shedding, immunological features and s gene variations

The evolution of a bovine coronavirus (BCoV) natural infection in a calf persistently infected with bovine viral diarrhea virus (BVDV) was described. The infected calf developed intermittent nasal discharge, diarrhea and hyperthermia. The total number of leukocytes/mL and the absolute differential number of neutrophils and lymphocytes resulted within the normal range, but monocytes increased at T28 (time 28 post‐infection). Flow‐cytometry analysis evidenced that the CD8+ subpopulation increased at T7 and between T28 and T35. BCoV shedding in nasal discharges and feces was detected up to three weeks post infection and high antibody titers persisted up to T56. The RNA BCoV load increased until T14, contrary to what was observed in a previous study where the fecal excretion of BCoV was significantly lower in the co‐infected (BCoV/BVDV) calves than in the calves infected with BCoV only. We can suppose that BVDV may have modulated the BCoV infection exacerbating the long viral excretion, as well as favoring the onset of mutations in the genome of BCoV detected in fecal samples at T21. An extensive study was performed to verify if the selective pressure in the S gene could be a natural mode of variation of BCoV, providing data for the identification of new epidemic strains, genotypes or recombinant betacoronaviruses

Quantum Holographic Encoding in a Two-dimensional Electron Gas

The advent of bottom-up atomic manipulation heralded a new horizon for attainable information density, as it allowed a bit of information to be represented by a single atom. The discrete spacing between atoms in condensed matter has thus set a rigid limit on the maximum possible information density. While modern technologies are still far from this scale, all theoretical downscaling of devices terminates at this spatial limit. Here, however, we break this barrier with electronic quantum encoding scaled to subatomic densities. We use atomic manipulation to first construct open nanostructures--"molecular holograms"--which in turn concentrate information into a medium free of lattice constraints: the quantum states of a two-dimensional degenerate Fermi gas of electrons. The information embedded in the holograms is transcoded at even smaller length scales into an atomically uniform area of a copper surface, where it is densely projected into both two spatial degrees of freedom and a third holographic dimension mapped to energy. In analogy to optical volume holography, this requires precise amplitude and phase engineering of electron wavefunctions to assemble pages of information volumetrically. This data is read out by mapping the energy-resolved electron density of states with a scanning tunnelling microscope. As the projection and readout are both extremely near-field, and because we use native quantum states rather than an external beam, we are not limited by lensing or collimation and can create electronically projected objects with features as small as ~0.3 nm. These techniques reach unprecedented densities exceeding 20 bits/nm2 and place tens of bits into a single fermionic state.Comment: Published online 25 January 2009 in Nature Nanotechnology; 12 page manuscript (including 4 figures) + 2 page supplement (including 1 figure); supplementary movie available at http://mota.stanford.ed

SEISMIC SWARM vs MAINSHOCK‐AFTERSHOCKS SEQUENCE: REFINED HYPOCENTERS LOCATIONS AT THE APENNINES‐CALABRIAN ARC BOUNDARY (SOUTHERN ITALY)

In the last years the Apennines-Calabrian arc boundary has been affected by intense seismicity concentrated in the Pollino mountain region. The Pollino is located at the northernmost edge of the Calabrian Arc, the last remnant of subduction along the Africa- Eurasian boundary. The area is subject to Northeast- Southwest extension, which results in a complex system of normal faults striking Northwest-Southeast, nearly parallel to the Apenninic mountain range. The Italian Seismic Network between 2010 and 2014 detected more than 5500 earthquakes in the area (Italian Seismological Instrumental and Parametric Data- Base; http:// iside .rm .ingv .it). In 2010 and 2011 the earthquake rate has been variable, with increasing and decreasing phases and maximum magnitudes below M=4. On May 28th 2012, a shallow event with local magnitude of 4.3 struck, about 5 kilometers east of the previous swarm. The seismic activity remained concentrated in the M=4.3 source region until early August. At that time seismicity jumped back westward to the previous area, with several earthquakes of magnitude larger than 3, culminating with a M=5.0 earthquake on 25 October 2012. The seismic rate remained high for some months, but aftershock magnitudes did not exceed magnitude 3.7. The seismic rate then suddenly decreased at the beginning of 2013 and stayed quite low for the rest of the year up to the beginning of 2014. During these years several temporary seismic stations were deployed in the area, improving the detecting threshold of the Italian Seismic Network and giving us the opportunity to refine the location of the earthquakes hypocenters. A combined dataset, including three-component seismic waveforms recorded by both permanent and temporary stations, has been analyzed in order to obtain an appropriate 1-D and 3D velocity model for earthquake location in the study area. Here we describe the main seismological characteristics of this seismic sequence and, relying on refined earthquakes location, we make inferences on the geometry of the fault system responsible for the two strongest shocks. Swarm activity seems to occur on a diffuse crustal volume more than on fault planes. To yield a better understanding of the origin of the ongoing seismic activity in the Pollino area, using thousand of seismograms, we analyze vp and vp/vs models and anisotropic parameters in the crust. The main goal of this study is to increase the understanding of the physical mechanisms behind the seismic swarm and its influence on the seismic hazard of the Apennines- Calabrian arc boundary region.EAEE - ESCPublishedIstanbul - August 24-29 20142T. Tettonica attivaope

The 2012 Emilia seismic sequence (Northern Italy): Imaging the thrust fault system by accurate aftershock location

Starting from late May 2012, the Emilia region (Northern Italy) was severely shaken by an intense seismic sequence, originated from a ML 5.9 earthquake on May 20th, at a hypocentral depth of 6.3 km, with thrusttype focal mechanism. In the following days, the seismic rate remained high, counting 50 ML ≥ 2.0 earthquakes a day, on average. Seismicity spreads along a 30 km east–west elongated area, in the Po river alluvial plain, in the nearby of the cities Ferrara and Modena. Nine days after the first shock, another destructive thrust-type earthquake (ML 5.8) hit the area to the west, causing further damage and fatalities. Aftershocks following this second destructive event extended along the same east-westerly trend for further 20 km to the west, thus illuminating an area of about 50 km in length, on thewhole. After the first shock struck, on May 20th, a dense network of temporary seismic stations, in addition to the permanent ones, was deployed in the meizoseismal area, leading to a sensible improvement of the earthquake monitoring capability there. A combined dataset, including threecomponent seismic waveforms recorded by both permanent and temporary stations, has been analyzed in order to obtain an appropriate 1-D velocity model for earthquake location in the study area. Here we describe the main seismological characteristics of this seismic sequence and, relying on refined earthquakes location, we make inferences on the geometry of the thrust system responsible for the two strongest shocks

U and Th content in the Central Apennines continental crust: a contribution to the determination of the geo-neutrinos flux at LNGS

The regional contribution to the geo-neutrino signal at Gran Sasso National Laboratory (LNGS) was determined based on a detailed geological, geochemical and geophysical study of the region. U and Th abundances of more than 50 samples representative of the main lithotypes belonging to the Mesozoic and Cenozoic sedimentary cover were analyzed. Sedimentary rocks were grouped into four main "Reservoirs" based on similar paleogeographic conditions and mineralogy. Basement rocks do not outcrop in the area. Thus U and Th in the Upper and Lower Crust of Valsugana and Ivrea-Verbano areas were analyzed. Based on geological and geophysical properties, relative abundances of the various reservoirs were calculated and used to obtain the weighted U and Th abundances for each of the three geological layers (Sedimentary Cover, Upper and Lower Crust). Using the available seismic profile as well as the stratigraphic records from a number of exploration wells, a 3D modelling was developed over an area of 2^{\circ}x2^{\circ} down to the Moho depth, for a total volume of about 1.2x10^6 km^3. This model allowed us to determine the volume of the various geological layers and eventually integrate the Th and U contents of the whole crust beneath LNGS. On this base the local contribution to the geo-neutrino flux (S) was calculated and added to the contribution given by the rest of the world, yielding a Refined Reference Model prediction for the geo-neutrino signal in the Borexino detector at LNGS: S(U) = (28.7 \pm 3.9) TNU and S(Th) = (7.5 \pm 1.0) TNU. An excess over the total flux of about 4 TNU was previously obtained by Mantovani et al. (2004) who calculated, based on general worldwide assumptions, a signal of 40.5 TNU. The considerable thickness of the sedimentary rocks, almost predominantly represented by U- and Th- poor carbonatic rocks in the area near LNGS, is responsible for this difference.Comment: 45 pages, 5 figures, 12 tables; accepted for publication in GC