422 research outputs found
Threshold Behaviour in Gauge Boson Pair Production at LEP 2
We discuss the form of the amplitude for gauge boson pair production at or
near threshold.We show that in the case of W-pair production at LEP2 near
threshold only one anomalous electromagnetic coupling can contribute. This
anomalous coupling is CP violating and contributes to the electric dipole
moment of the . Since this coupling is likely to be small, it is important
to look for ZZgamma couplings in Zgamma production. These couplings are not
suppressed at the W-threshold
Effective-Lagrangian approach to precision measurements: the anomalous magnetic moment of the muon
We investigate the use of effective Lagrangians to describe the effects on
high-precision observables of physics beyond the Standard Model. Using the
anomalous magnetic moment of the muon as an example, we detail the use of
effective vertices in loop calculations. We then provide estimates of the
sensitivity of new experiments measuring the muon's to the scale of
physics underlying the Standard Model.Comment: 22 pages, 1 figure, PHYZZX & EPSF, report #s UCRHEP-T98, UM_TH-92-17,
and NSF-ITP-92-122I Revision: The paper will now TeX properly; the content is
unchange
From Enslavement to Emancipation: Naming Practices in the Danish West Indies
AbstractIn most contexts, personal names function as identifiers and as a locus for identity. Therefore, names can be used to trace patterns of kinship, ancestry, and belonging. The social power of naming, however, and its capacity to shape the life course of the person named, becomes most evident when it has the opposite intent: to sever connections and injure. Naming in slave society was primarily practical, an essential first step in commodifying human beings so they could be removed from their roots and social networks, bought, sold, mortgaged, and adjudicated. Such practices have long been integral to processes of colonization and enslavement. This paper discusses the implications of naming practices in the context of slavery, focusing on the names given to enslaved Africans and their descendants through baptism in the Lutheran and Moravian churches in the Danish West Indies. Drawing on historiographical accounts and a detailed analysis of plantation and parish records from the island of St. Croix, we outline and contextualize these patterns and practices of naming. We examine the extent to which the adoption of European and Christian names can be read as an effort toward resistance and self-determination on the part of the enslaved. Our account is illuminated by details from the lives of three former slaves from the Danish West Indies.This paper is part of a project (CitiGen) which has received generous funding from the European Unionâs Horizon 2020 research and innovation program, under grant agreement No. 649307
Uses and Abuses of Effective Lagrangians
Motivated by past and recent analyses we critically re-examine the use of
effective lagrangians in the literature to constrain new physics and to
determine the `physics reach' of future experiments. We demonstrate that many
calculations, such as those involving anomalous trilinear gauge-boson
couplings, either considerably overestimate loop-induced effects, or give
ambiguous answers. The source of these problems is the use of cutoffs to
evaluate the size of such operators in loop diagrams. In contrast to other
critics of these loop estimates, we prove that the inclusion of
nonlinearly-realized gauge invariance into the low-energy lagrangian is
irrelevant to this conclusion. We use an explicit example using known
multi-Higgs physics above the weak scale to underline these points. We show how
to draw conclusions regarding the nature of the unknown high-energy physics
without making reference to low-energy cutoffs.Comment: 36 page
âTurpe senex miles, turpe senilis amorâ (Amores, 1, 9, 4): Ovidio, Cranach y Cervantes
Aristotle and Flora, Virgil in the basket, Susanna and the elders⊠These are different samples of a theme which enjoyed a notorious success in Europe from the last decades of the Fifteenth-century onwards. More than a simple mockery or moral lesson, the topic appears related to decorum as a basic principle in both art and life. In his paintings, Cranach paid special attention to ill-matched couples, as shown in a series of erotic scenes where a young damsel has an old man for lover; in his Quixote, guided by the Ovidian saying âTurpe senex miles, turpe senilis amorâ (Amores, 1, 9, 4), Cervantes transforms the traditional Perceval pattern in a new one. Contrary to expectations, it is an old man, not a youngster who undertakes the double adventure of war and love.AristĂłteles y Flora, Virgilio en el cesto, Susana y los viejos⊠Por distintas vĂas, el tema del viejo lascivo se enseñorea del arte europeo, plĂĄstico y literario, desde las postrimerĂas del siglo XV en adelante. El asunto, amĂ©n de su dimensiĂłn jocosa y moral, interesa por su relaciĂłn con el principio artĂstico del decoro. En las parejas desiguales (con una joven damisela y un anciano por amante) Cranach encuentra uno de sus asuntos recurrentes; en el Quijote, Cervantes da la vuelta al patrĂłn de Perceval guiado por la mĂĄxima de Ovidio âTurpe senex miles, turpe senilis amorâ (Amores, 1, 9, 4). De ese modo, no es un joven sino un anciano quien se lanza a una doble aventura, militar y amorosa
On Non-Standard Couplings among the Electroweak Vector Bosons
Application of a Stueckelberg transformation allows one to connect various
Lagrangians which have been independently proposed for non-standard couplings.
We discuss the reduction of the number of independent parameters in the
Lagrangian and compare symmetry arguments with dimensional arguments.Comment: 11 pages LaTeX 2.0
Unravelling the and Vertices at the Linear Collider: and final states
We perform a detailed analysis of the processes and at future linear colliders and
assess their sensitivity to anomalous gauge boson couplings. We consider center
of mass energies 350, 500 and 800 GeV. We demonstrate that
significant improvements can be obtained if the phase space information for the
cross sections is used maximally. At 800 GeV the parameters
and can be constrained, at 95\% CL,
to about 0.02 and 0.01, while the parameters , and
can be probed down to about 0.009, 0.002 and 0.004 respectively.
The precision of these measurements is likely to be limited by statistical
errors at anticipated luminosities at these energies.Comment: LaTeX, 16 pages, 7 figs (embedded
Cranberry A-type proanthocyanidins selectively target acute myeloid leukemia cells
Most elderly patients affected with acute myeloid leukemia (AML) will relapse and die of their disease even after achieving complete remission, thus emphasizing the urgent need for new therapeutic approaches with minimum toxicity to normal hematopoietic cells. Cranberry (Vaccinium spp.) extracts have exhibited anticancer and chemopreventive properties that have been mostly attributed to A-type proanthocyanidin (A-PAC) compounds. A-PACs, isolated from a commercially available cranberry extract, were evaluated for their effects on leukemia cell lines, primary AML samples, and normal CD34+ cord blood specimens. Our results indicated potent and specific antileukemia activity in vitro. In addition, the antileukemia activity of A-PACs extended to malignant progenitor and stem cell populations, sparing their normal counterparts. The antileukemia effects of A-PACs were also observed in vivo using patient derived xenografts. Surprisingly, we found that the mechanism of cell death was driven by activation of NF-ÎșB. Overall, our data suggest that A-PACs could be used to improve treatments for AML by targeting leukemia stem cells through a potentially novel pathway
Rosalie nação Poulard: liberdade, direito e dignidade na era da Revolução Haitiana
Historical perspective on seismic hazard to Hispaniola and the northeast Caribbean region
This paper is not subject to U.S. copyright. The definitive version was published in Journal of Geophysical Research 116 (2011): B12318, doi:10.1029/2011JB008497.We evaluate the long-term seismic activity of the North-American/Caribbean plate boundary from 500 years of historical earthquake damage reports. The 2010 Haiti earthquakes and other earthquakes were used to derive regional attenuation relationships between earthquake intensity, magnitude, and distance from the reported damage to the epicenter, for Hispaniola and for Puerto Rico and the Virgin Islands. The attenuation relationship for Hispaniola earthquakes and northern Lesser Antilles earthquakes is similar to that for California earthquakes, indicating a relatively rapid attenuation of damage intensity with distance. Intensities in Puerto Rico and the Virgin Islands decrease less rapidly with distance. We use the intensity-magnitude relationships to systematically search for the location and intensity magnitude MI which best fit all the reported damage for historical earthquakes. Many events occurred in the 20th-century along the plate-boundary segment from central Hispaniola to the NW tip of Puerto Rico, but earlier events from this segment were not identified. The remaining plate boundary to the east to Guadeloupe is probably not associated with M > 8 historical subduction-zone earthquakes. The May 2, 1787 earthquake, previously assigned an M 8â8.25, is probably only MI 6.9 and could be located north, west or SW of Puerto Rico. An MI 6.9 earthquake on July 11, 1785 was probably located north or east of the Virgin Islands. We located MI < 8 historical earthquakes on April 5, 1690, February 8, 1843, and October 8, 1974 in the northern Lesser Antilles within the arc. We speculate that the December 2, 1562 (MI 7.7) and May 7, 1842 (MI 7.6) earthquakes ruptured the Septentrional Fault in northern Hispaniola. If so, the recurrence interval on the central Septentrional Fault is âŒ300 years, and only 170 years has elapsed since the last event. The recurrence interval of large earthquakes along the Hispaniola subduction segment is likely longer than the historical record. Intra-arc M â„ 7.0 earthquakes may occur every 75â100 years in the 410-km-long segment between the Virgin Islands and Guadeloupe
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