3,262 research outputs found
P and S Delays Beneath Intraplate Volcanic Ridges and Gravity Lineations Near the East Pacific Rise
No full textThe Gravity Lineations Intraplate Melting Petrology and Seismic Expedition (GLIMPSE) explored the origin of two intraplate, non–hot spot ridge systems associated with gravity lineations in the south central Pacific. Using the 11 month ocean bottom seismometer (OBS) deployment of the GLIMPSE experiment, we determined the average P and S station delays for the region. Across the array, station delays varied by 1.22 s for P waves and 2.13 s for S waves. The presence of ultraslow shear velocity (<400 m/s) sediment layers of variable thickness throughout the region introduced S delays, determined from P-to-S-converted phases generated at the crust-sediment boundary, of 0.08 to 0.43 s. Consequently, we corrected the S delays for these sediments to examine seismic anomalies due to crustal and mantle structure. We used the sediment delay times and the relative amplitudes of the converted phases to estimate the average regional shear velocity and thickness of the sediment layer beneath the stations. The range of sediment thickness in the region is 10–70 m, and the average shear velocity in the sediments is 140 m/s. Both the average P and sediment-corrected S delays show a positive correlation with seafloor age, with faster arrivals on older seafloor where the seismically fast lithosphere has thickened away from the spreading axis. The delay times also correlate with the residual mantle Bouguer gravity anomaly (rMBA), with slow arrivals coinciding with rMBA lows and the associated ridge systems. The delays are much too large to be caused by variations in crustal thickness and must represent anomalies within the mantle. These observations qualitatively support the either the channelized asthenospheric return flow model or the small-scale convection hypothesis for the origin of the gravity lineations. These models predict both positively correlated density and velocity anomalies caused by thermal anomalies and the pressure-release melting that migrates to the surface to form the volcanic ridges above the upwelling limbs of convection cells or channels. <br/
The cult of St Nicholas in medieval Italy
No full textSt Nicholas was one of the most popular saints in medieval Italy. His cult attracted the attention
of popes, kings and emperors, and his shrine at Bari became an important international pilgrimage
destination. This thesis asks how the cult of St Nicholas came to be so widespread and popular in
Italy, and why the saint attracted the attention of diverse groups and individuals.
This thesis is structured around four chapters. The first demonstrates that through a
process of Latinisation the cult of St Nicholas became integrated within Italian literary traditions
and within a new spiritual era. Chapter Two reveals that this Latinisation also occurred within the
saint’s iconography. Chapters Three and Four are case studies of the cult in Puglia and Venice,
locations which claimed possession of the saint’s relics. These case studies show that the general
developments that the cult of St Nicholas underwent in Italy, identified in Chapters One and Two,
did not apply universally. Instead, the presence of the saint’s relics resulted in a different profile
of the saint in Bari and Venice. Through the process of Latinisation, the cult of St Nicholas
became updated and remained relevant for its new Italian audience; Chapters Three and Four
show alternative ways that the cult of St Nicholas gained widespread popularity.
This thesis presents for the first time an iconographical study of St Nicholas in Italian art,
which develops existing research of the saint’s Byzantine iconography. Chapter Four presents a
profile of the cult of St Nicholas in Venice in the Middle Ages, which is a significant oversight in
the literature. The thesis uses a variety of visual and textual sources, in particular fresco and
altarpiece representations, archival documents from Venice and Rome (including the Apostolic
Visitations), and under-exploited contemporary and antiquarian Venetian sources
External interventions and the duration of civil wars
No full textThe authors combine an empirical model of external intervention, with a theoretical model of civil war duration. Their empirical model of intervention allows them to analyze civil war duration, using"expected"rather than"actual"external intervention as an explanatory variable in the duration model. Unlike previous studies, they find that external intervention is positively associated with the duration of civil war. They distinguish partial third-party interventions that extend the length of war, from multilateral"peace"operations, which have a mandate to restore peace without taking sides - and which typically take place at war's end, or at least when both sides have agreed to a cease-fire. In a future paper, the authors will examine whether partial third-party interventions - whatever their effect on a war's duration - increase the risk of war's recurrence. If that proves true, then even if interventions reduce the length of civil war, they may do so at the cost of further destabilizing the political system, and sowing the seeds of future rebellion.Children and Youth,Peace&Peacekeeping,Post Conflict Reconstruction,Post Conflict Reconstruction,International Affairs,Post Conflict Reconstruction,Social Conflict and Violence,Peace&Peacekeeping,Post Conflict Reconstruction,International Affairs
Talmudic Quotations in Nicholas of Lyra's Postilla Literalis
No full textThe Postilla literalis super totam Bibliam, written by Nicholas of Lyra (France, 1270- 1349) is remarkable for the extensive use of texts and oral traditions of Jewish origin made by its author. This paper deals with the place of the Talmud among the Jewish sources cited in the Postilla. For Nicholas the Talmud was a new doctrine invented by the Jews sometime in their past but believed to be divine and to be given to Moses in Sinai. When reading Nicholas' Postilla, one finds many citations from medieval Jewish sources, but very few excerpts from the Talmud except as polemic with the purpose of ridiculing and disproving them. It appears that Nicholas avoided direct Talmudic citations within the Postilla, likely due to the hostile attitudes prevalent specifically toward the Talmud within the Christian world he inhabited
Muscle strength and functional ability in recreational female golfers and less active non-golfers over the age of 80 Years
No full textMuscle strength and functional ability decline with age. Physical activity can slow the decline but whether recreational golf is associated with slower decline is unknown. This cross-sectional, observational study aimed to examine the feasibility of testing muscle strength and functional ability in older female golfers and non-golfers in community settings. Thirty-one females over aged 80, living independently (golfers n = 21, mean age 83, standard deviation (±) 2.1 years); non-golfers, n = 10 (80.8 ± 1.03 years) were studied. Maximal isometric contractions of handgrip and quadriceps were tested on the dominant side. Functional ability was assessed using the Timed Up and Go (TUG) and health-related quality of life using the Short Form-36 questionnaire. Grip strength, normalised to body mass, was greater in golfers (0.33 ± 0.06 kgF/kg) than non-golfers (0.29 ± 0.06), however, the difference was not statistically significant (p = 0.051). Quadriceps strength did not differ (golfers 2.78 ± 0.74 N/kg; non-golfers 2.69 ± 0.83; p = 0.774). TUG times were significantly faster (p = 0.027) in golfers (10.4 ± 1.9 s) than non-golfers (12.6 ± 3.21 s; within sarcopenic category). Quality of life was significantly higher in golfers for the physical categories (Physical Function p < 0.001; Physical p = 0.033; Bodily pain p = 0.028; Vitality p = 0.047) but psychosocial categories did not differ. These findings indicated that the assessment techniques were feasible in both groups and sensitive enough to detect some differences between groups. The indication that golf was associated with better physical function than non-golfers in females over 80 needs to be examined by prospective randomised controlled trials to determine whether golf can help to achieve the recommended guidelines for strengthening exercise to protect against sarcopenia
Nitric oxide signaling in pseudomonas aeruginosa biofilms mediates phosphodiesterase activity, decreased cyclic Di-GMP levels, and enhanced dispersal
No full textBacteria in biofilms often undergo active dispersal events and revert to a free-swimming, planktonic state to complete the biofilm life cycle. The signaling molecule nitric oxide (NO) was previously found to trigger biofilm dispersal in the opportunistic pathogen Pseudomonas aeruginosa at low, nontoxic concentrations (N. Barraud, D. J. Hassett, S. H. Hwang, S. A. Rice, S. Kjelleberg, and J. S. Webb, J. Bacteriol. 188:7344-7353, 2006). NO was further shown to increase cell motility and susceptibility to antimicrobials. Recently, numerous studies revealed that increased degradation of the secondary messenger cyclic di-GMP (c-di-GMP) by specific phosphodiesterases (PDEs) triggers a planktonic mode of growth in eubacteria. In this study, the potential link between NO and c-di-GMP signaling was investigated by performing (i) PDE inhibitor studies, (ii) enzymatic assays to measure PDE activity, and (iii) direct quantification of intracellular c-di-GMP levels. The results suggest a role for c-di-GMP signaling in triggering the biofilm dispersal event induced by NO, as dispersal requires PDE activity and addition of NO stimulates PDE and induces the concomitant decrease in intracellular c-di-GMP levels in P. aeruginosa. Furthermore, gene expression studies indicated global responses to low, nontoxic levels of NO in P. aeruginosa biofilms, including upregulation of genes involved in motility and energy metabolism and downregulation of adhesins and virulence factors. Finally, site-directed mutagenesis of candidate genes and physiological characterization of the corresponding mutant strains uncovered that the chemotaxis transducer BdlA is involved in the biofilm dispersal response induced by NO
sj-pdf-2-jrn-10.1177_17449871211043754 – Supplemental Material for Scarred survivors: gate keepers and gate openers to healthcare for migrants in vulnerable circumstances
No full textSupplemental Material, sj-pdf-2-jrn-10.1177_17449871211043754 for Scarred survivors: gate keepers and gate openers to healthcare for migrants in vulnerable circumstances by Emily Clark, Nicholas Steel, Tara Berger Gillam, Monica Sharman, Anne Webb, Ana-Maria Bucataru and Sarah Hanson in Journal of Research in Nursing</p
sj-pdf-1-jrn-10.1177_17449871211043754 – Supplemental Material for Scarred survivors: Gate keepers and gate openers to healthcare for migrants in vulnerable circumstances
No full textSupplemental Material, sj-pdf-1-jrn-10.1177_17449871211043754 for Scarred survivors: Gate keepers and gate openers to healthcare for migrants in vulnerable circumstances by Emily Clark, Nicholas Steel, Tara Berger Gillam, Monica Sharman, Anne Webb, Ana-Maria Bucataru and Sarah Hanson in Journal of Research in Nursing</p
sj-docx-1-tra-10.1177_14604086231201533 - Supplemental material for Bilateral lower extremity injuries in pedestrian versus motor vehicle collisions
No full textSupplemental material, sj-docx-1-tra-10.1177_14604086231201533 for Bilateral lower extremity injuries in pedestrian versus motor vehicle collisions by David T Marvin, Jesse Seilern und Aspang, Alexander Webb, Jason Shah, Nicholas Cantu, Roberto C Hernandez-Irizarry and Thomas J Moore in Trauma</p
Author(s): Ezra Brown and Nicholas Loehr Source
No full textJSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. . Why is PSL(2, 7) = GL(3, 2)? Mathematical Association of America Ezra Brown and Nicholas Loehr 1. INTRODUCTION. The groups of invertible matrices over finite fields are among the first groups we meet in a beginning course in modern algebra. Eventually, we find out about simple groups and that the unique simple group of order 168 has two representations as a group of matrices. And this is where we learn that the group of 2x2 unimodular matrices over a seven-element field, with / and -/ identified, is isomorphic to the group of invertible 3x3 matrices over a 2-element field. In short, it is a fact that PSL(2, 7) = GL(3, 2). Many of us are surprised by this fact: why should a group of 2 x 2 matrices with mod-7 integer entries be isomorphic to a group of 3 x 3 binary matrices? There are a number of proofs of this remarkable theorem. Dickson [1, p. 303] gives a proof based on his general theorem giving uniform sets of generators and relations for the family of groups SL(2, q), where q is any prime power. One checks that the relations appearing in Dickson's presentation of PSL(2, 7) are satisfied by certain generators of GL(3, 2), implying that these groups have the same presentations and are therefore isomorphic. Dummit and Foote [2, show that every simple group of order 168 is necessarily isomorphic to the automorphism group Aut(.F) of the Fano plane T. They then show that Aut(^) = GL(3, 2) and that PSL(2, 7) is a simple group of order 168; the isomorphism theorem follows. Rotman gives the result as an exercise [5, Exercise 9.26, p. 281]. A hint is to begin with a simple group G of order 168 and use the seven conjugates of a Sylow 2-subgroup P of G to construct a sevenpoint projective plane; the proof is similar to Dummit and Foote's proof. Jeurissen [4] proves the result by showing that both PSL(2, 7) and GL(3, 2) are subgroups of index 2 of the automorphism group of a Coxeter graph. Elkies The aim of this paper is to give a proof that PSL(2, 7) = GL(3, 2) that is elementary in the sense that it uses neither simplicity, nor projective geometry, nor block designs. We will not prove the fact that any two simple groups of order 168 are isomorphic, nor will we use this fact in our proof. What makes our proof work is that: (a) we can identify GL(3, 2) with the set of invertible F2-linear transformations on the finite field with eight elements; (b) 7 = 23 -1; (c) the nonzero squares mod 7 are precisely the powers of 2 mod 7; (d) squaring mod 2 is additive (the Freshman's Dream); and (e) the mapping k h+ -i/k mod 7 translates to a bit-switch mod 2 -which is linear. We begin by giving functional descriptions for both groups, determining their sizes
- …
