RESUMEN
Extending general relativity by adding extra degrees of freedom is a popular approach for explaining the accelerated expansion of the Universe and to build high energy completions of the theory of gravity. The presence of such new degrees of freedom is, however, tightly constrained from several observations and experiments that aim to test general relativity in a wide range of scales. The viability of a given modified theory of gravity, therefore, strongly depends on the existence of a screening mechanism that suppresses the extra degrees of freedom. We perform simulations, and find that waves propagating in the new degrees of freedom can significantly impact the efficiency of some screening mechanisms, thereby threatening the viability of these modified gravity theories. Specifically, we show that the waves produced in the symmetron model can increase the amplitude of the fifth force and the parametrized post Newtonian parameters by several orders of magnitude.
RESUMEN
We have carried out an association study of a polymorphism in the 3'UTR of the dopamine transporter gene (DAT) and a polymorphism in the coding region of the D3 receptor gene (DRD3) in Spanish patients with manic depression and in controls. No significant differences in allelic and genotypic frequencies of either of these polymorphisms was found in patients compared with controls.
Asunto(s)
Trastorno Bipolar/genética , Proteínas Portadoras/genética , Glicoproteínas de Membrana , Proteínas de Transporte de Membrana , Proteínas del Tejido Nervioso , Polimorfismo Genético , Receptores de Dopamina D2/genética , Mapeo Cromosómico , Cromosomas Humanos Par 3 , Cromosomas Humanos Par 5 , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática , Frecuencia de los Genes , Ligamiento Genético , Genotipo , Humanos , Receptores de Dopamina D3 , Valores de Referencia , Secuencias Repetitivas de Ácidos Nucleicos , EspañaRESUMEN
We have carried out an association study between a dinucleotide repeat polymorphism in GABRA3 gene and manic-depressive illness in a Spanish population. This may be an important candidate gene for bipolar affective disorders since it is located in the Xq28 region, previously implicated in linkage studies. In addition, severe GABergic alterations have been reported in patients. We have not found significant differences between controls and patients in allele frequencies or genotypes.
Asunto(s)
Trastorno Bipolar/genética , Receptores de GABA/genética , Cromosoma X , Trastorno Bipolar/metabolismo , Femenino , Marcadores Genéticos , Humanos , Masculino , Polimorfismo Genético , EspañaRESUMEN
Genetic factors play an important role in the aetiology of bipolar affective disorder (BP). So far, results of linkage studies have been largely disappointing. We have searched for a possible association between polymorphic DNA markers of two candidate genes (tyrosine hydroxylase, TH; dopamine D2 receptor gene, DRD2) and BP in a population from central Spain. Our results are consistent with the existence of a weak association between these two genes and BP, in such a way that TH and DRD2 could be considered as minor genes contributing to susceptibility.
