Primeval Corrections to the CMB Anisotropies

We show that deviations of the quantum state of the inflaton from the thermal vacuum of inflation may leave an imprint in the CMB anisotropies. The quantum dynamics of the inflaton in such a state produces corrections to the inflationary fluctuations, which may be observable. Because these effects originate from IR physics below the Planck scale, they will dominate over any trans-Planckian imprints in any theory which obeys decoupling. Inflation sweeps away these initial deviations and forces its quantum state closer to the thermal vacuum. We view this as the quantum version of the cosmic no-hair theorem. Such imprints in the CMB may be a useful, independent test of the duration of inflation, or of significant features in the inflaton potential about 60 e-folds before inflation ended, instead of an unlikely discovery of the signatures of quantum gravity. The absence of any such substructure would suggest that inflation lasted uninterrupted much longer than ${\cal O}(100)$ e-folds.Comment: 17 pages, latex, no figures; v3: added references and comments, final version to appear in Phys. Rev.

Scenario of Accelerating Universe from the Phenomenological \Lambda- Models

Dark matter, the major component of the matter content of the Universe, played a significant role at early stages during structure formation. But at present the Universe is dark energy dominated as well as accelerating. Here, the presence of dark energy has been established by including a time-dependent $\Lambda$ term in the Einstein's field equations. This model is compatible with the idea of an accelerating Universe so far as the value of the deceleration parameter is concerned. Possibility of a change in sign of the deceleration parameter is also discussed. The impact of considering the speed of light as variable in the field equations has also been investigated by using a well known time-dependent $\Lambda$ model.Comment: Latex, 9 pages, Major change

Coupled oscillators as models of phantom and scalar field cosmologies

We study a toy model for phantom cosmology recently introduced in the literature and consisting of two oscillators, one of which carries negative kinetic energy. The results are compared with the exact phase space picture obtained for similar dynamical systems describing, respectively, a massive canonical scalar field conformally coupled to the spacetime curvature, and a conformally coupled massive phantom. Finally, the dynamical system describing exactly a minimally coupled phantom is studied and compared with the toy model.Comment: 18 pages, LaTeX, to appear in Physical Review

Extended Quintessence and its Late-time Domination

Various astronomical observations point towards the evidence for dark energy. One of the most mysterious problem is the coincidence problem: why dark energy becomes dominant only recently. We present a scenario based on extended quintessence models to explain the late-time domination of dark energy without severe fine-tuning of initial conditions and model parameters.Comment: 8 page

Airborne mycobiota determined in the neonatal unit of the Ege University Hospital, Bornova, Turkey

Pathogenic or opportunist fungi in hospital environments may be a source of infection in susceptible hosts. Especially for newborn intensive care units of hospitals, the control of the fungal spore and knowing the incidence of mycobiota in hospitals are of great importance in order to understand the types of infections and the problems caused by them. In this study, the level of endogenous airborne fungal concentrations and the types of fungi were determined at Ege University Hospital, Faculty of Medicine, Neonatal Unit, which is located centre of Izmir. For this purpose, air samples were collected at 14 selected stations monthly during twelve months with the Merck MAS 100 air sampler. As a result, a total of 2631 fungal colonies were counted. Sixty two fungal species belonging to 12 genera were identified. These species consisted of Aspergillus (12), Penicillium (24), Cladosporium (10), Alternaria (6) and other species (10). The 6 microfungi were identified only in genus level. The most prevalent genera were the common moulds; Aspergillus (39.33±61.43), Penicillium (23.00±23.50), Cladosporium (74.33±63.43) and Alternaria (20.17±25.09). In this study, aimed to emphasize the importance of monitoring the presence of airborne fungal biota, particularly Aspergillus spp. in the newborn intensive care units where newborns and especially premature babies were hospitalized and opportunistic pathogenic species such as A.flavus, A. fumigatus, A. niger and A. terreus were isolated. © by PSP