115 research outputs found

    A class of loss functions of catenary form

    Full text link
    The catenary form of loss function is considered in the framework of Bayesian decision theory. The mathematical tractability of this form seems to be unrecognized; it contains quadratic loss as a limiting case. For various probability distributions expressions are given for posterior analysis, and limiting properties are investigated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45167/1/10955_2005_Article_BF01030302.pd

    The level scheme of 134Ba

    Full text link
    The gamma-ray spectrum associated with the beta decay of 134Cs has been studied with curved-crystal and Ge(Li) spectrometers. The data provide energy and intensity measurements of 11 gamma rays. Coincidence spectra were taken using a Ge(Li)---NaI(Tl) combination. The data fail to support the previously proposed levels at 1570 and 1773 keV.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33329/1/0000725.pd

    Dynamic liquefaction of shear zones in intact loess during simulated earthquake loading

    Get PDF
    The 2010-2011 Canterbury earthquake sequence in New Zealand exposed loess-mantled slopes in the area to very high levels of seismic excitation (locally measured as >2 g). Few loess slopes showed permanent local downslope deformation, and most of these showed only limited accumulated displacement. A series of innovative dynamic back pressured shear-box tests were undertaken on intact and remoulded loess samples collected from one of the recently active slopes replicating field conditions under different simplified horizontal seismic excitations. During each test, the strength reduction and excess pore water pressures generated were measured as the sample failed. Test results suggest that although dynamic liquefaction could have occurred, a key factor was likely to have been that the loess was largely unsaturated at the times of the large earthquake events. The failure of intact loess samples in the tests was complex and variable due to the highly variable geotechnical characteristics of the material. Some loess samples failed rapidly as a result of dynamic liquefaction as seismic excitation generated an increase in pore-water pressure, triggering rapid loss of strength and thus of shear resistance. Following initial failure, pore pressure dissipated with continued seismic excitation and the sample consolidated, resulting in partial shear-strength recovery. Once excess pore-water pressures had dissipated, deformation continued in a critical effective stress state with no further change in volume. Remoulded and weaker samples, however, did not liquefy, and instead immediately reduced in volume with an accompanying slower and more sustained increase in pore pressure as the sample consolidated. Thereafter excess pressures dissipated and deformation continued at a critical state. The complex behaviour explained why, despite exceptionally strong ground shaking, there was only limited displacement and lack of run-out: dynamic liquefaction was unlikely to occur in the freely draining slopes. Dynamic liquefaction however remained a plausible mechanism to explain loess failure in some of the low-angle toe slopes, where a permanent water table was present in the loess

    A Simultaneous Dual-site Technosignature Search Using International LOFAR Stations

    Get PDF
    The Search for Extraterrestrial Intelligence aims to find evidence of technosignatures, which can point toward the possible existence of technologically advanced extraterrestrial life. Radio signals similar to those engineered on Earth may be transmitted by other civilizations, motivating technosignature searches across the entire radio spectrum. In this endeavor, the low-frequency radio band has remained largely unexplored; with prior radio searches primarily above 1 GHz. In this survey at 110-190 MHz, observations of 1,631,198 targets from TESS and Gaia are reported. Observations took place simultaneously with two international stations (noninterferometric) of the Low Frequency Array in Ireland and Sweden. We can reject the presence of any Doppler drifting narrowband transmissions in the barycentric frame of reference, with equivalent isotropic radiated power of 10 17 W, for 0.4 million (or 1.3 million) stellar systems at 110 (or 190) MHz. This work demonstrates the effectiveness of using multisite simultaneous observations for rejecting anthropogenic signals in the search for technosignatures.Comment: 15 Pages, 16 Figures, 2 Machine Readable Table

    Diastereoselective Synthesis of C60/Steroid Conjugates

    Get PDF
    The design and synthesis of fullerene–steroid hybrids by using Prato’s protocol has afforded new fullerene derivatives endowed with epiandrosterone, an important naturally occurring steroid hormone. Since the formation of the pyrrolidine ring resulting from the 1,3-dipolar cyloaddition reaction takes place with generation of a new stereogenic center on the C2 of the five-membered ring, the reaction proceeds with formation of a diastereomeric mixture [compounds 6 and 7 in 70:30 ratio, 8 and 9 in 26:74 ratio (HPLC)] in which the formation of the major diasteroisomers 6 and 9 is consistent with an electrophilic attack of [60]fullerene on the Re face of the azomethine ylide directed by the steroidic unit. The chiroptical properties of these conjugates reveal typical Cotton effects in CD spectra that have been used to assign the absolute configuration of the new fulleropyrrolidines. The electrochemical study of the new compounds reveals the presence of four quasi-reversible reduction waves which are cathodically shifted in comparison with the parent C60, thus ascertaining the proposed structures.Financial support by the Ministerio de Ciencia e Innovación (MINECO) of Spain (CTQ2011-24652, CTQ2011-27253, PIB2010JP-00196, and CSD2007-00010 projects) and CAM (Madrisolar-2) is acknowledged; A.R. thanks UCM for financial support; M.S. is indebted to Programa del Grupo Santander 2012

    Job search information behaviours: An ego-net study of networking amongst young job-seekers

    Get PDF
    Networking is considered an integral feature of job search, yet its behavioural manifestation has received little attention in the extant literature. Here this is addressed in a study of young job-seekers that adopted an egocentric network approach underpinned by Information Behaviour theory, with specific reference to Wilson's model of information needs and seeking. The analysis of data from semi-structured interviews reveals that job-seekers acquire a broad range of job search information from contacts in their networks, and that the contributions of such contacts extend beyond the sharing of job vacancy alerts. In addition, in cases where social media platforms are accessed by job-seekers, these facilitate crucial ties to industry contacts, and provide valuable informational opportunities to those who adopt them. These findings contribute to a widened understanding of the information behaviours that support the effective mobilisation of contacts within social networks during job search, and are of particula
    • 

    corecore