3,869 research outputs found
Charge and CP symmetry breaking in two Higgs doublet models
We show that, for the most generic model with two Higgs doublets possessing a
minimum that preserves the symmetry, charge breaking (CB) cannot
occur. If CB does not occur, the potential could have two different minima, and
there is in principle no general argument to show which one is the deepest. The
depth of the potential at a stationary point that breaks CB or CP, relative to
the preserving minimum, is proportional to the squared mass of the
charged or pseudoscalar Higgs, respectively
Integro-differential IBVP versus differential IBVP: stability analysis
The aim of this paper is the qualitative analysis from theoretical and
numerical points of view of an integro-di erential initial boundary value problem
where the reaction term presents a certain memory e ect. Stability results are
established in both cases. As in certain cases the integro-di erential initial boundary value problem can be seen as a di erential initial boundary value problem,
the results obtained for the integro-di erential formulation are compared with the
correspondent results stated for the di erential initial boundary value problem. Numerical results illustrating the theoretical results are also included
A Complex Case of Cholestasis in a Patient with ABCB4 and ABCB11 Mutations
The low-phospholipid-associated cholelithiasis (LPAC) syndrome is a form of symptomatic cholelithiasis occurring in young adults, characterized by recurrence of symptoms after cholecystectomy and presence of hepatolithiasis. The case refers to a healthy 39-year-old Caucasian male who presented with abdominal pain and jaundice. His blood tests showed conjugated hyperbilirubinemia and elevated liver enzymes (total bilirubin 6.65 mg/dL, γ-glutamyltransferase 699 IU/L) and abdominal computed tomography revealed dilation of common bile duct and left intrahepatic ducts. Magnetic resonance cholangiopancreatography identified choledocholithiasis, retrieved by endoscopic retrograde cholangiopancreatography, after which there was a worsening of jaundice (total bilirubin 23 mg/dL), which persisted for several weeks, possibly due to ciprofloxacin toxicity. After an extensive workup including liver biopsy, the identification of two foci of hepatolithiasis on reevaluation abdominal ultrasound raised the hypothesis of LPAC syndrome and the patient was started on ursodeoxycholic acid, with remarkable improvement. Genetic testing identified the mutation c.1954A>G (p.Arg652Gly) in ABCB4 gene (homozygous) and c.1331T>C (p.Val444Ala) in ABCB11 gene (heterozygous). In conclusion, we describe the unique case of an adult male with choledocholithiasis, hepatolithiasis, and persistent conjugated hyperbilirubinemia after retrieval of stones, fulfilling the criteria for LPAC syndrome and with possible superimposed drug-induced liver injury, in whom ABCB4 and ABCB11 mutations were found, both of which had not been previously described in association with LPAC.info:eu-repo/semantics/publishedVersio
Hierarchy plus anarchy in quark masses and mixings
We introduce a new parameterisation of the effect of unknown corrections from
new physics on quark and lepton mass matrices. This parameterisation is used in
order to study how the hierarchies of quark masses and mixing angles are
modified by random perturbations of the Yukawa matrices. We discuss several
examples of flavour relations predicted by different textures, analysing how
these relations are influenced by the random perturbations. We also comment on
the unlikely possibility that unknown corrections contribute significantly to
the hierarchy of masses and mixings.Comment: LaTeX, 18 pages, 16 PS figure
High overtones of Dirac perturbations of a Schwarzschild black hole
Using the Frobenius method, we find high overtones of the Dirac quasinormal
spectrum for the Schwarzschild black hole. At high overtones, the spacing for
imaginary part of is equidistant and equals to
, ( is the black hole mass), which
is twice less than that for fields of integer spin. At high overtones, the real
part of goes to zero. This supports the suggestion that the
expected correspondence between quasinormal modes and Barbero-Immirzi parameter
in Loop Quantum Gravity is just a numerical coincidence.Comment: 5 pages, Latex, 3 figures, Physical Review D.,at pres
Cognitive Control of Escape Behaviour
When faced with potential predators, animals instinctively decide whether there is a threat they should escape from, and also when, how, and where to take evasive action. While escape is often viewed in classical ethology as an action that is released upon presentation of specific stimuli, successful and adaptive escape behaviour relies on integrating information from sensory systems, stored knowledge, and internal states. From a neuroscience perspective, escape is an incredibly rich model that provides opportunities for investigating processes such as perceptual and value-based decision-making, or action selection, in an ethological setting. We review recent research from laboratory and field studies that explore, at the behavioural and mechanistic levels, how elements from multiple information streams are integrated to generate flexible escape behaviour
Work disability benefits due to musculoskeletal disorders among Brazilian private sector workers
Objective: To evaluate the prevalence and characteristics of disability benefits due to musculoskeletal disorders (MSD) granted to Brazilian private sector workers. Methods: This was a population-based epidemiological study of MSD-related benefits among registered private sector workers (n¼32 959 329). The prevalence (benefits/10 000 workers/year) of work disability benefits was calculated by gender, age, state, Human Development Index (HDI), economic activity, MSD type and work-relatedness. Results: The prevalence of MSD-related benefits in Brazil among registered private sector workers in 2008 was 93.6/10 000 workers. The prevalence increased with age, and was higher for women (112.2) than for men (88.1), although the former had shorter benefit duration. The gender-adjusted prevalence by state varied from 16.6 to 90.3 for non-work-related, and from 7.8 to 59.6 for work-related benefits. The Brazilian states with a highevery high HDI had the highest prevalence. The top four most common types of MSD-related benefits were due to back pain, intervertebral disc disorders, sinovitis/tenosynovitis and shoulder disorders. Conclusion: MSD is a frequent cause of work disability in Brazil. There were differences in prevalence among economic activities and between states grouped by HDI. This study demonstrates that further evaluation of the contributing factors associated with MSD-related disability benefits is required. Factors that should be considered include production processes, political organisation, socioeconomic and educational characteristics, the compensation and recording systems, and employeeeemployer power relationships. These factors may play an important role in the prevalence of MSD-related disability benefits, especially in countries with large socioeconomic iniquities such as Brazil
Heat conduction in the hollow sphere with a power-law variation of the external heat transfer coefficient
The conduction phenomenon in an insulated sphere is re-worked through a dimensionless approach, where the heat transfer coefficient dependence on the external radius and on the surface temperature, as in the case of forced and free convection, is taken into account. Assuming a power law variation of the convection coefficient [1, 2], and using the results of Sparrow [3], equations and graphs for the most important dimensionless parameters are presented. The developed equations show, for example, that as the insulation thickness increases the heat transfer rate tends to a positive value, independent of the considered case: constant convection coefficient, forced or free convection.http://www.sciencedirect.com/science/article/B6V3J-42MP1M2-3/1/6228c6d77bbaac53e7833e6cd67d8ef
Heat conduction in the hollow sphere with a power-law variation of the external heat transfer coefficient
The conduction phenomenon in an insulated sphere is re-worked through a dimensionless approach, where the heat transfer coefficient dependence on the external radius and on the surface temperature, as in the case of forced and free convection, is taken into account. Assuming a power law variation of the convection coefficient [1, 2], and using the results of Sparrow [3], equations and graphs for the most important dimensionless parameters are presented. The developed equations show, for example, that as the insulation thickness increases the heat transfer rate tends to a positive value, independent of the considered case: constant convection coefficient, forced or free convection.http://www.sciencedirect.com/science/article/B6V3J-42MP1M2-3/1/6228c6d77bbaac53e7833e6cd67d8ef
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