On the inevitability of reionization: implications for cosmic microwave background fluctuations

Early photoionization of the intergalactic medium is discussed in a nearly model-independent way, in order to investigate whether early structures corresponding to rare Gaussian peaks in a CDM model can photoionize the intergalactic medium sufficiently early to appreciably smooth out the microwave background fluctuations. We conclude that this is indeed possible for a broad range of CDM normalizations and is almost inevitable for unbiased CDM, provided that the bulk of these early structures are quite small, no more massive than about 10^8 solar masses. Typical parameter values predict that reionization occurs around z=50, thereby suppressing fluctuations on degree scales while leaving the larger angular scales probed by COBE reasonably unaffected. However, for non-standard CDM, incorporating mixed dark matter, vacuum density or a tilted primordial power spectrum, early reionization plays no significant role.Comment: 32 pages, incl 10 figures. Stone-age postscript replaced by LATeX. Latest version at http://www.sns.ias.edu/~max/reion.html (faster from the US), from http://www.mpa-garching.mpg.de/~max/reion.html (faster from Europe) or from [email protected]

Mechanical and electrical interrelations in normal and ischaemic heart

Imperial Users onl

Dynamical Properties of the Mukhanov-Sasaki Hamiltonian in the context of adiabatic vacua and the Lewis-Riesenfeld invariant

We use the method of the Lewis-Riesenfeld invariant to analyze the dynamical properties of the Mukhanov-Sasaki Hamiltonian and, following this approach, investigate whether we can obtain possible candidates for initial states in the context of inflation considering a quasi-de Sitter spacetime. Our main interest lies in the question to which extent these already well-established methods at the classical and quantum level for finitely many degrees of freedom can be generalized to field theory. As our results show, a straightforward generalization does in general not lead to a unitary operator on Fock space that implements the corresponding time-dependent canonical transformation associated with the Lewis-Riesenfeld invariant. The action of this operator can be rewritten as a time-dependent Bogoliubov transformation and we show that its generalization to Fock space has to be chosen appropriately in order that the Shale-Stinespring condition is not violated, where we also compare our results to already existing ones in the literature. Furthermore, our analysis relates the Ermakov differential equation that plays the role of an auxiliary equation, whose solution is necessary to construct the Lewis-Riesenfeld invariant, as well as the corresponding time-dependent canonical transformation to the defining differential equation for adiabatic vacua. Therefore, a given solution of the Ermakov equation directly yields a full solution to the differential equation for adiabatic vacua involving no truncation at some adiabatic order. As a consequence, we can interpret our result obtained here as a kind of non-squeezed Bunch-Davies mode, where the term non-squeezed refers to a possible residual squeezing that can be involved in the unitary operator for certain choices of the Bogoliubov map.Comment: 40 pages, 5 figures, minor changes: slightly rewrote the introduction, extended the discussion on the infrared modes, corrected typos and added reference

Inflation, Human Capital and Tobin's q

A pervasive empirical finding for the US economy is that inflation is negatively correlated with the normalized market price of capital (Tobin's q) and growth. A dynamic stochastic general equilibrium model of endogenous growth is developed to explain these stylized facts. In this model, human capital is the principal driver of self-sustained growth. Long run comparative statics analysis suggests that inflation diverts scarce time resource to leisure which lowers human capital utilization. This impacts growth adversely and modulates cap¬ital adjustment cost downward resulting in a decline in Tobin's q. For the short run, a Tobin effect of inflation on growth weakens the negative association between inflation and q.

Inflation, Human Capital and Tobin's q

A less well-known empirical finding for the US and UK is a pronounced low frequency negative relationship between inflation and Tobin's q; a normalized market price of capital. This stylized fact is explained within a dynamic stochastic general equilibrium model using three key features: (i) a Lucas and Prescott (1971) physical capital adjustment cost with a rising marginal cost of investment, (ii) production of human capital with endogenous growth and (iii) an inflation tax cash-in-advance economy. The baseline endogenous growth model matches the US inflation and q long term correlation, while comparable exogenous growth are unable to do this, and it outperforms the exogenous growth models in explaining business cycle volatilities of q and of stock returns.Low frequency, Tobin's q; inflation tax, endogenous growth

The Libyan civil conflict : selected case series of orthopaedic trauma managed in Malta in 2014

Aim: The purpose of this series of cases was to analyse our management of orthopaedic trauma casualties in the Libyan civil war crisis in the European summer of 2014. We looked at both damage control orthopaedics and for case variety of war trauma at a civilian hospital. Due to our geographical proximity to Libya, Malta was the closest European tertiary referral centre. Having only one Level 1 trauma care hospital in our country, our Trauma and Orthopaedics department played a pivotal role in the management of Libyan battlefield injuries. Our aims were to assess acute outcomes and short term mortality of surgery within the perspective of a damage control orthopaedic strategy whereby aggressive wound management, early fixation using relative stability principles, antibiotic cover with adequate soft tissue cover are paramount. We also aim to describe the variety of war injuries we came across, with a goal for future improvement in regards to service providing.Methods: Prospective collection of six interesting cases with severe limb and spinal injuries sustained in Libya during the Libyan civil war between June and November 2014.Conclusions: We applied current trends in the treatment of war injuries, specifically in damage control orthopaedic strategy and converting to definitive treatment where permissible. The majority of our cases were classified as most severe (Type IIIB/C) according to the Gustilo-Anderson classification of open fractures. The injuries treated reflected the type of standard and improved weaponry available in modern warfare affecting both militants and civilians alike with increasing severity and extent of damage. Due to this fact, multidisciplinary team approach to patient centred care was utilised with an ultimate aim of swift recovery and early mobilisation. It also highlighted the difficulties and complex issues required on a hospital management level as a neighbouring country to war zone countries in transforming care of civil trauma to military trauma.peer-reviewe