11,003 research outputs found
Nonclassical Light in Interferometric Measurements
It is shown that the even and odd coherent light and other nonclassical
states of light like superposition of coherent states with different phases may
replace the squeezed light in interferometric gravitational wave detector to
increase its sensitivity. (Contribution to the Second Workshop on Harmonic
Oscillator, Cocoyoc, Mexico, March 1994)Comment: 8 pages,LATEX,preprint of Naples University,
INFN-NA-IV-94/30,DSF-T-94/3
An exploratory study of the hard X-ray variability properties of PG quasars with RXTE
We have monitored with the RXTE PCA the variability pattern of the 2-20 keV
flux in four PG quasars (QSOs) from the Laor et al. (1994) sample. Six
observations of each target at regular intervals of 1 day were performed. The
sample comprises objects with extreme values of Balmer line width (and hence
soft X-ray steepness) and spans about one order of magnitude in luminosity. The
most robust result is that the variability amplitude decreases as energy
increases. Several options for a possible ultimate driver of the soft and hard
X-ray variability, such as the influx rate of Comptonizing relativistic
particles, instabilities in the accretion flow or the number of X-ray active
sites, are consistent with our results.Comment: Contributed talk presented at the Joint MPE,AIP,ESO workshop on
NLS1s, Bad Honnef, Dec. 1999, to appear in New Astronomy Reviews; also
available at http://wave.xray.mpe.mpg.de/conferences/nls1-worksho
THE IMPORTANCE OF DYNAMIC EFFECTS ON THE ENZYME ACTIVITY: X-RAY STRUCTURE AND MOLECULAR DYNAMICS OF ONCONASE MUTANTS.
Onconase (ONC), a member of the RNase A superfamily extracted from oocytes of Rana pipiens, is an effective cancer killer. It is currently used in treatment of various forms of cancer. ONC antitumor properties depend on its ribonucleolytic activity that is low in comparison with other members of the superfamily. The most damaging side effect from Onconase treatment is renal toxicity, which seems to be caused by the unusual stability of the enzyme. Therefore, mutants with reduced thermal stability and/or increased catalytic activity may have significant implications for human cancer chemotherapy. In this context, we have determined the crystal structures of two Onconase mutants (M23L-ONC and C87S,des103-104-ONC) and performed molecular dynamic simulations of ONC and C87S,des103-104-ONC with the aim of explaining on structural grounds the modifications of the activity and thermal stability of the mutants. The results also provide the molecular bases to explain the lower catalytic activity of Onconase compared with RNase A and the unusually high thermal stability of the amphibian enzyme
Prestress and experimental tests on fractional viscoelastic materials
Creep and/or Relaxation tests on viscoelastic materials show a power-law trend. Based upon Boltzmann superposition principle the constitutive law with a power-law kernel is ruled by the Caputo's fractional derivative. Fractional constitutive law posses a long memory and then the parameters obtained by best fitting procedures on experimental data are strongly influenced by the prestress on the specimen. As in fact during the relaxation test the imposed history of deformation is not instantaneously applied, since a unit step function may not be realized by the test machine. Aim of this paper, it is shown that, the experimental procedure, and in particular the initial ramp to reach the constant stress (or strain) strongly influences the best fitting procedure and the coefficients of the power-law
Gratitude at work works! A mix-method study on different dimensions of gratitude, job satisfaction, and job performance
Proton induced Dark Count Rate degradation in 150-nm CMOS Single-Photon Avalanche Diodes
Proton irradiation effects on a Single-Photon Avalanche Diodes (SPADs) device
manufactured using a 150-nm CMOS process are presented. An irradiation campaign
has been carried out with protons of 20 MeV and 24 MeV on several samples of a
test chip containing SPADs arrays with two different junction layouts. The dark
count rate distributions have been analyzed as a function of the displacement
damage dose. Annealing and cooling have been investigated as possible damage
mitigation approaches. We also discuss, through a space radiation simulation,
the suitability of such devices on several space mission case-studies.Comment: This is an author-created, un-copyedited version of an article
accepted for publication/published in Nuclear Instruments and Methods in
Physics Research Section A. The Version of Record is available online at
https://doi.org/10.1016/j.nima.2019.16272
Cold asphalt contaning 100% reclamed asphalt. A sustainable technology for cycle paths and maintenance intervations
Both the National Recovery and Resilience Plan (Next Generation EU Program) and the development strategies for Smart Cities focus on cycle and pedestrian paths. Their pavements must be safe, durable and sustainable and considering the need to preserve the resources that Planet Earth offers to humans, it is essential to opt for innovative construction technologies that allow recycling methods without necessarily involving the addition of first-use materials. In the field of road infrastructure, the recovery of material deriving from the demolition of old pavements (RA - Reclaimed Asphalt) is only possible thanks to the use of specific products. A state-of-the-art rejuvenator is currently being used for the construction of cycling paths with 100% cold-mixed RA. This product is currently being studied for the INFRAROB project: âMaintaining integrity, performance and safety of the road infrastructure through autonomous robotized solutions and modularizationâ (Horizon 2020) with particular reference to âpotholes patchingâ materials. Some technical data of the experiences developed to date are shown below
Effect of Toothpaste on the Surface Roughness of the Resin-Contained CAD/CAM Dental Materials: A Systematic Review
Background: The purpose of this review is to describe the possible effect of toothbrushing on surface roughness of resin-contained CAD/CAM materials. Methods: Systematic literature search for articles published in peer-reviewed journals between January 2000 and February 2020 has been conducted, which evaluated the effect of brushing on surface roughness of resin-contained CAD/CAM dental materials. The research was conducted in Scopus, PubMed/Medline, Web of Science, Embase, and Science Direct using a combination of the following MeSH/Emtree terms: âbrushingâ, âresin-basedâ, âdentalâ, âCAD/CAMâ, and âsurface roughnessâ. Results: A total of 249 articles were found in the search during initial screening. Fifty-five articles were selected for the full-text evaluation after the steps of reading of abstract/title and remotion of duplicate. Only six articles fulfilled the inclusion criteria. The Cohenâs Kappa agreement test showed an index of 0.91 for full-text. Discussion: Four of five selected articles identified an increase of surface roughness on resin-contained CAD/CAM materials after toothbrushing. Although all the articles examined used different toothpastes with no homogeneous relative dentine abrasivity (RDA) and cycles of brushing, the findings are about the same. The possible reason is attributable to the compositions of the resin-contained CAD/CAM materials. Conclusions: The surface roughness of most resin-contained CAD/CAM materials was affected by artificial toothbrushing. Correct knowledge of the composition of the dental material and toothpastes is fundamental to avoid an increase of surface roughness on prosthetic rehabilitation
Exon 3 of the NUMB Gene Emerged in the Chordate Lineage Coopting the NUMB Protein to the Regulation of MDM2
MDM2 regulates a variety of cellular processes through its dual protein:protein interaction and ubiquitin ligase activities. One major function of MDM2 is to bind and ubiquitinate P53, thereby regulating its proteasomal degradation. This function is in turn controlled by the cell fate determinant NUMB, which binds to and inhibits MDM2 via a short stretch of 11 amino acids, contained in its phosphotyrosine-binding (PTB) domain, encoded by exon 3 of the NUMB gene. The NUMB-MDM2-P53 circuitry is relevant to the specification of the stem cell fate and its subversion has been shown to be causal in breast cancer leading to the emergence of cancer stem cells. While extensive work on the evolutionary aspects of the MDM2/P53 circuitry has provided hints as to how these two proteins have evolved together to maintain conserved and linked functions, little is known about the evolution of the NUMB gene and, in particular, how it developed the ability to regulate MDM2 function. Here, we show that NUMB is a metazoan gene, which acquired exon 3 in the common ancestor of the Chordate lineage, first being present in the Cephalochordate and Tunicate subphyla, but absent in invertebrates. We provide experimental evidence showing that since its emergence, exon 3 conferred to the PTB domain of NUMB the ability to bind and to regulate MDM2 functions
Earth modeling and estimation of the local seismic ground motion due to site geology in complex volcanoclastic areas
Volcanic areas often show complex behaviour as far as seismic waves propagation and seismic motion at surface are concerned. In fact, the finite lateral extent of surface layers such as lava flows, blocks, differential welding and/or zeolitization within pyroclastic deposits, introduces in the propagation of seismic waves effects such as the generation of surface waves at the edge, resonance in lateral direction, diffractions and scattering of energy, which tend to modify the amplitude as well as the duration of the ground motion. The irregular topographic surface, typical of volcanic areas, also strongly influences the seismic site response. Despite this heterogeneity, it is unfortunately a common geophysical and engineering practice to evaluate even in volcanic environments the subsurface velocity field with monodimensional investigation method (i.e. geognostic soundings, refraction survey, down-hole, etc.) prior to the seismic site response computation which in a such cases is obviously also made with 1D algorithms. This approach often leads to highly inaccurate results. In this paper we use a different approach, i.e. a fully 2D P-wave Ăturning rayĂ tomographic survey followed by 2D seismic site response modeling. We report here the results of this approach in three sites located at short distance from Mt. Vesuvius and Campi Flegrei and characterized by overburdens constituted by volcanoclastic deposits with large lateral and vertical variations of their elastic properties. Comparison between 1D and 2D Dynamic Amplification Factor shows in all reported cases entirely different results, both in terms of peak period and spectral contents, as expected from the clear bidimensionality of the geological section. Therefore, these studies suggest evaluating carefully the subsoil geological structures in areas characterized by possible large lateral and vertical variations of the elastic properties in order to reach correct seismic site response curves to be used for engineering projects
- âŠ