457 research outputs found
Seismic constraints on the three-dimensional geometry of low-angle intracrustal reflectors in the Southern Iberia Abyssal Plain
Several lines of evidence suggest that simple shear rifting of the continental crust, in the formof low-angle detachment faulting, occurred during the final stages of continental breakupbetween West Iberia and the Grand Banks. The primary evidence for such faulting is theoccurrence of low-angle, high amplitude reflectors within the basement adjacent to the oceanâcontinent transition zone. Here we present a series of intersecting, depth migrated seismicreflection profiles that image one such reflector, the H-reflector, located on the southern edgeof Galicia Bank. âHâ lies beneath several boreholes drilled during ODP Legs 149 and 173,in a region where the oceanward extent of extended continental crust steps at least 150 kmwestward from its location in the southern Iberia Abyssal Plain to its location off the relativelyshallow Galicia Bank. In our profiles âHâ appears to define a surface that extends over a regionof at least 200 km2 and that dips down ?19? to the north, towards Galicia Bank. The profilesshow that a close affinity exists between âHâ and the most seaward continental crust. Based ongeophysical data and ODP drilling results, we infer that the basement above âHâ is composedof continental crust deformed by extensional faults into a series of wedge-shaped blocks andthin slivers. These basement wedges have a complex 3-D geometry. âHâ rises to the basementsurface on a number of the seismic profiles and appears to define locally the oceanward extentof continental fault blocks
Generalized seniority from random Hamiltonians
We investigate the generic pairing properties of shell-model many-body
Hamiltonians drawn from ensembles of random two-body matrix elements. Many
features of pairing that are commonly attributed to the interaction are in fact
seen in a large part of the ensemble space. Not only do the spectra show
evidence of pairing with favored J=0 ground states and an energy gap, but the
relationship between ground state wave functions of neighboring nuclei show
signatures of pairing as well. Matrix elements of pair creation/annihilation
operators between ground states tend to be strongly enhanced. Furthermore, the
same or similar pair operators connect several ground states along an isotopic
chain. This algebraic structure is reminiscent of the generalized seniority
model. Thus pairing may be encoded to a certain extent in the Fock space
connectivity of the interacting shell model even without specific features of
the interaction required.Comment: 10 pages, 7 figure
World Workshop on Oral Medicine VII : Relative frequency of oral mucosal lesions in children, a scoping review
Objective: To detail a scoping review on the global and regional relative frequencies of oral mucosal disorders in the children based on both clinical studies and those reported from biopsy records. Materials and Methods: A literature search was completed from 1 January 1990 to 31 December 2018 using PubMed and EMBASE. Results: Twenty clinical studies (sample size: 85,976) and 34 studies from biopsy services (40,522 biopsies) were included. Clinically, the most frequent conditions were aphthous ulcerations (1.82%), trauma-associated lesions (1.33%) and herpes simplex virus (HSV)-associated lesions (1.33%). Overall, the most commonly biopsied lesions were mucoceles (17.12%), fibrous lesions (9.06%) and pyogenic granuloma (4.87%). By WHO geographic region, the pooled relative frequencies of the most common oral lesions were similar between regions in both clinical and biopsy studies. Across regions, geographic tongue (migratory glossitis), HSV lesions, fissured tongue and trauma-associated ulcers were the most commonly reported paediatric oral mucosal lesions in clinical studies, while mucoceles, fibrous lesions and pyogenic granuloma were the most commonly biopsied lesions. Conclusions: The scoping review suggests data from the clinical studies and biopsy records shared similarities in the most commonly observed mucosal lesions in children across regions. In addition, the majority of lesions were benign in nature
Regular spectra in the vibron model with random interactions
The phenomenom of emerging regular spectral features from random interactions
is addressed in the context of the vibron model. A mean-field analysis links
different regions of the parameter space with definite geometric shapes. The
results that are, to a large extent, obtained in closed analytic form, provide
a clear and transparent interpretation of the high degree of order that has
been observed in numerical studies.Comment: 19 pages, 8 figures, 2 tables. Physical Review C, in pres
Study of Effect on Teeth of Intermittent Fluoridation of a Community Water Supply
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67913/2/10.1177_00220345530320011601.pd
Minimal muscle damage after a marathon and no influence of beetroot juice on inflammation and recovery
This study examined whether beetroot juice (BTJ) would attenuate inflammation and muscle
damage following a marathon. Using a double blind, independent groupâs design, 34 runners
(~16 previous marathons completed) consumed either BTJ or an isocaloric placebo (PLA) for
3 days following a marathon. Maximal isometric voluntary contractions (MIVC),
countermovement jumps (CMJ), muscle soreness, serum cytokines, leucocytosis, creatine
kinase (CK), high sensitivity C-reactive protein (hs-CRP) and aspartate aminotransferase
(AST) were measured pre, post, and on the 2 days after the marathon. CMJ and MIVC were
reduced after the marathon (P0.05).
Muscle soreness was increased in the day after the marathon (BTJ; 45±48 vs. PLA; 46±39
mm) and had returned to baseline by day 2, irrespective of supplementation (P=0.694).
Cytokines (Interleukin-6; IL-6, interleukin-8, tumour necrosis factor-α) were increased
immediately post-marathon but apart from IL-6 had returned to baseline values by day 1 post.
No interaction effects were evident for IL-6 (P=0.213). Leucocytes increased 1.7 fold after
the race and remained elevated 2 days post, irrespective of supplement (P<0.0001). CK
peaked at 1 day post marathon (BTJ: 965±967 & PLA: 1141±979 IU·L-1) and like AST and
hs-CRP, was still elevated 2 days after the marathon (P<0.05); however, no group differences
were present for these variables. Beetroot juice did not attenuate inflammation or reduce
muscle damage following a marathon, possibly because most of these indices were not
markedly different from baseline values in the days after the marathon
Lorentz breaking Effective Field Theory and observational tests
Analogue models of gravity have provided an experimentally realizable test
field for our ideas on quantum field theory in curved spacetimes but they have
also inspired the investigation of possible departures from exact Lorentz
invariance at microscopic scales. In this role they have joined, and sometime
anticipated, several quantum gravity models characterized by Lorentz breaking
phenomenology. A crucial difference between these speculations and other ones
associated to quantum gravity scenarios, is the possibility to carry out
observational and experimental tests which have nowadays led to a broad range
of constraints on departures from Lorentz invariance. We shall review here the
effective field theory approach to Lorentz breaking in the matter sector,
present the constraints provided by the available observations and finally
discuss the implications of the persisting uncertainty on the composition of
the ultra high energy cosmic rays for the constraints on the higher order,
analogue gravity inspired, Lorentz violations.Comment: 47 pages, 4 figures. Lecture Notes for the IX SIGRAV School on
"Analogue Gravity", Como (Italy), May 2011. V.3. Typo corrected, references
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Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Lepton + Jets Events with Lifetime b-tagging
We present a measurement of the top quark pair () production cross
section () in collisions at TeV
using 230 pb of data collected by the D0 experiment at the Fermilab
Tevatron Collider. We select events with one charged lepton (electron or muon),
missing transverse energy, and jets in the final state. We employ
lifetime-based b-jet identification techniques to further enhance the
purity of the selected sample. For a top quark mass of 175 GeV, we
measure pb, in
agreement with the standard model expectation.Comment: 7 pages, 2 figures, 3 tables Submitted to Phys.Rev.Let
Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt{s} = 1.96 TeV using Kinematic Characteristics of Lepton + Jets Events
We present a measurement of the top quark pair ttbar production cross section
in ppbar collisions at a center-of-mass energy of 1.96 TeV using 230 pb**{-1}
of data collected by the DO detector at the Fermilab Tevatron Collider. We
select events with one charged lepton (electron or muon), large missing
transverse energy, and at least four jets, and extract the ttbar content of the
sample based on the kinematic characteristics of the events. For a top quark
mass of 175 GeV, we measure sigma(ttbar) = 6.7 {+1.4-1.3} (stat) {+1.6- 1.1}
(syst) +/-0.4 (lumi) pb, in good agreement with the standard model prediction.Comment: submitted to Phys.Rev.Let
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