We study the model for holographic dark energy in a spatially closed universe, generalizing the proposal in hep-th/0403127 for a flat universe. We provide independent arguments for the choice of the parameter c = 1 in the holographic dark energy model.On the one hand, c can not be less than 1, to avoid violating the second law of thermodynamics. On the other hand, observation suggests c be very close to 1, it is hard to justify a small deviation of c from 1, if c > 1.

Human bocavirus 1 (HBoV1) has been identified as one of the etiological agents of wheezing in young children with acute respiratory-tract infections. In this study, we have obtained the sequence of a full-length HBoV1 genome (including both termini) using viral DNA extracted from a nasopharyngeal aspirate of an infected patient, cloned the full-length HBoV1 genome, and demonstrated DNA replication, encapsidation of the ssDNA genome, and release of the HBoV1 virions from human embryonic kidney 293 cells. The HBoV1 virions generated from this cell line-based production system exhibits a typical icosahedral structure of approximately 26 nm in diameter, and is capable of productively infecting polarized primary human airway epithelia (HAE) from the apical surface. Infected HAE showed hallmarks of lung airway-tract injury, including disruption of the tight junction barrier, loss of cilia and epithelial cell hypertrophy. Notably, polarized HAE cultured from an immortalized airway epithelial cell line, CuFi-8 (originally derived from a cystic fibrosis patient), also supported productive infection of HBoV1. Thus, we have established a reverse genetics system and generated the first cell line-based culture system for the study of HBoV1 infection, which will significantly advance the study of HBoV1 replication and pathogenesis.

In this paper, we use the type Ia supernova data to constrain the model of holographic dark energy. For d = 1, the best fit result is Ω 0 m = 0.25, the equation of the state of the holographic dark energy w 0 Λ = −0.91 and the transition between the decelerating expansion and the accelerating expansion happened when the cosmological red-shift was z T = 0.72.If we set d as a free parameter, the best fit results are d = 0.21, Ω 0 m = 0.46, w 0 Λ = −2.67, which sounds like a phantom today, and the transition redshift is z T = 0.28.

We study a model of inflation in which a scalar field χ is non-minimally coupled to Starobinsky's R 2 gravity. After transforming it to the Einstein frame, a new scalar field, the scalaron φ, will appear and couple to χ with a nontrivial field metric, while χ acquires a positive mass via the non-minimal coupling. Initially inflation occurs along the φ direction with χ trapped near its origin by this induced mass. After φ crosses a critical value, it starts rolling down rapidly and proceeds to damped oscillations around an effective local minimum determined by the value of χ, while inflation still continues, driven by the χ field at this second stage where the effect of the non-minimal coupling becomes negligible. The presence of the damped oscillations during the transition from the first to second stage of inflation causes enhancement and oscillation features in the power spectrum of the curvature perturbation. Assuming that the oscillations may be treated perturbatively, we calculate these features by using the δN formalism, and discuss its observational implications to large scale CMB anomalies or primordial black hole formation, depending on the scale of the features.