Polytropic equation of state and primordial quantum fluctuations

We study the primordial Universe in a cosmological model where inflation is driven by a fluid with a polytropic equation of state $p = \alpha\rho + k\rho^{1 + 1/n}$. We calculate the dynamics of the scalar factor and build a Universe with constant density at the origin. We also find the equivalent scalar field that could create such equation of state and calculate the corresponding slow-roll parameters. We calculate the scalar perturbations, the scalar power spectrum and the spectral index.Comment: 16 pages, 4 figure

Evidência de infecção ativa por herpesvírus 6 (variante- A) em pacientes com linfadenopatia em Belém, Pará, Brasil

A total of 323 patients with lymphadenopathy were selected in Belém, Brazil, between January 1996 and December 2001, and screened for the presence of human herpesvirus-6 (HHV-6) IgM- and- IgG antibodies by enzyme-linked immunosorbent assay (ELISA). When seroprevalence is analyzed by gender, similar rates are found for female (60.6%) and male (55.7%) individuals. Seventy-seven (23.8%) patients were HHV-6-IgM-and- IgG-positive (IgM+ subgroup), with positivity rates of 29.7% and 17.7% (p = 0.0007) for female- and male individuals, respectively. Sera from a subgroup (n = 120) of these subjects, with high HHV-6 antibody levels (either IgM+ or IgG+ reactivities), were subsequently processed for the presence of HHV-6 DNA by polymerase chain reaction (PCR)/nested PCR. Active infections (IgM+ and/or IgG+ high levels specific antibodies plus detection of viral DNA) were diagnosed in 20/77 (20.0%) and 8/43 (18.6%); subgroup of the 120 individuals suspected of having HHV-6 suggestive recent infection. All (n = 28) cases of active infection were found to be associated with HHV-6 variant-A (HHV-6A), as detectable by PCR/nested PCR, using variant-specific primer that amplify regions of 195 base pairs (bp) (HHV-6A) and 423 bp (HHV-6B). Rates of HHV-6 DNA detection between female and male patients were similar (p >; 0.05) in the IgM+ and IgG+ groups: 20.4% versus 35.7% and 25.0% versus 13.0%, respectively. HHV-6 DNA was detected across ; 50 age-groups at rates that ranged from 15.4% (male, ; 0,05) em pacientes dos sexos feminino e masculino, no grupo IgM+ e IgG+ com: 20,4% versus 35,7% e 25,0% versus 13,0%, respectivamente. A detecção do DNA viral do HHV-6 ocorreu no grupo etário ; 50 anos, com taxas que variaram de 15,4% (homens, < 5 anos) a 100,0% (mulheres, 11-20 anos). O aumento dos linfonodos cervicais foi registrado como mais freqüente, ocorrendo em número de 9 (32,0%) casos, tanto entre indivíduos do sexo masculino como naqueles do feminino. Entre os pacientes (n = 28) com infecção ativa pela variante A do HHV-6, a duração dos sintomas em 35,7% deles foi de 1-5 dias, enquanto em 64,3% durou de 6-20 dias. Nossos dados sugerem ser importante investigar a infecção pelo HHV-6 entre os pacientes (crianças e adultos) portadores de linfadenopatia como manifestação clínica proeminente no curso das doenças agudas febris