1,721 research outputs found
Leptogenesis, Z' bosons, and the reheating temperature of the Universe
We study the impact for leptogenesis of new U(1) gauge bosons coupled to the
heavy Majorana neutrinos. They can significantly enhance the efficiency of
thermal scenarios in the weak washout regime as long as the Z' masses are not
much larger than the reheating temperature (), with the
highest efficiencies obtained for Z' bosons considerably heavier than the heavy
neutrinos (). We show how the allowed region of the parameter
space is modified in the presence of a Z' and we also obtain the minimum
reheating temperature that is required for these models to be successful.Comment: 14 pages, 6 figures; One figure added, discussion on the reheating
temperature extende
Complete CKM quark mixing via dimensional deconstruction
It is shown that the deconstruction of into
is capable of providing all necessary ingredients to
completely impliment the complex CKM mixing of quark flavors. The hierarchical
structure of quark masses originates from the difference in the deconstructed
chiral zero-mode distribution in theory space, while the CP-violating phase
comes from the genuinely complex vacuum expectation value of link fields. The
mixing is constructed in a specific model to satisfy experimental bounds on
quarks' masses and CP violation.Comment: RevTex4, 25 pages, typos in section IIC corrected, published versio
The dual equivalence of equations and coequations for automata
Because of the isomorphism (X x A) -> X = X -> (A -> X), the transition structure t: X -> (A -> X) of a deterministic automaton with state set X and with inputs from an alphabet A can be viewed both as an algebra and as a coalgebra. Here we will use this algebra-coalgebra duality of automata as a common perspective for the study of equations and coequations. Equations are sets of pairs of words (v,w) tha
Las complicaciones de la resonancia magnética nuclear en la exploración de la articulación temporomandibular
La presencia de ciertos materiales ferromagnéticos , implantes y aparatos metálicos en el organismo se considera una contraindicación relativa para la práctica de una resonancia magnética nuclear, debido a los riesgos asociados al desplazamiento o dislocación de los mismos al ser atraÃdos en el campo magnético a que se les somete. Se presenta un resumen sobre los materiales con un riesgo potencial de complicaciones durante la práctica de la resonancia magnética nuclear de la articulación temporomandibular y se destaca la importancia de la detección previa de los mismos mediante la anamnesis y la exploración fisica de los pacientes que precisan dicha técnica. En algunos casos, se precisará asesoramiento especializado
Primary intraosseous squamous cell carcinoma arising in dentigerous cyst : report of 2 cases and review of the literature
Dentigerous cysts are one of the most common odontogenic cysts of the oral cavity. Odontogenic cysts can give
rise to a variety of neoplasms. Carcinoma arising in a dentigerous cyst is extremely rare, with a review of literature showing near 30 cases. The present report describes 2 cases of primary intraosseous squamous cell carcinoma
originated from a dentigerous cyst. The first one refers to a 57-year old female with a persistent lesion in the left
retromolarregion and diagnosed with squamous cell carcinoma originated fromthe incomplete excision of the lower
third molar follicle during its surgical extraction. The second case describes the case of an 18-year old male with
an impacted upper canine with previous history of infection and swelling of the oral cavity. The histopathological
study revealed the malignization of the follicle surrounding the dental crown. These two cases confirmed the importance of the histopathological study of all the tissue samples obtained from surgical procedures. Although the
development of a malignant lesion from a dentigerous cyst is rare and its clinical-radiological features are apparently innocuous, this entity should be considered as a differential diagnosis
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