Spatial concentration in institutional industrial real estate investment in the England and Wales

In two recent papers Byrne and Lee (2006, 2007) examined the geographical concentration of institutional office and retail investment in England and Wales at two points in time; 1998 and 2003. The findings indicate that commercial office portfolios are concentrated in a very few urban areas, whereas retail holdings correlate more closely with the urban hierarchy of England and Wales and consequently are essentially ubiquitous. Research into the industrial sector is very much less developed, and this paper therefore makes a significant contribution to understanding the structure of industrial property investment in the UK. It shows that industrial investment concentration is between that of retail and office and is focussed on LAs with high levels of manual workers in areas with smaller industrial units. It also shows that during the period studied the structure of the sector changed, with greater emphasis on the distributional element, for which location is a principal consideration

Risk reduction and real estate portfolio size

Despite a number of papers that discuss the advantages of increased size on risk levels in real estate portfolios there is remarkably little empirical evidence based on actual portfolios. The objective of this paper is to remedy this deficiency by examining the portfolio risk of a large sample of actual property data over the period 1981 to 1996. The results show that all that can be said is that portfolios of properties of a large size, on the average, tend to have lower risks than small sized portfolios. More importantly portfolios of a few properties can have very high or very low risk

On the "Poisson Trick" and its Extensions for Fitting Multinomial Regression Models

This article is concerned with the fitting of multinomial regression models using the so-called "Poisson Trick". The work is motivated by Chen & Kuo (2001) and Malchow-M{\o}ller & Svarer (2003) which have been criticized for being computationally inefficient and sometimes producing nonsense results. We first discuss the case of independent data and offer a parsimonious fitting strategy when all covariates are categorical. We then propose a new approach for modelling correlated responses based on an extension of the Gamma-Poisson model, where the likelihood can be expressed in closed-form. The parameters are estimated via an Expectation/Conditional Maximization (ECM) algorithm, which can be implemented using functions for fitting generalized linear models readily available in standard statistical software packages. Compared to existing methods, our approach avoids the need to approximate the intractable integrals and thus the inference is exact with respect to the approximating Gamma-Poisson model. The proposed method is illustrated via a reanalysis of the yogurt data discussed by Chen & Kuo (2001)

Adipocyte mTORC1 Signaling Separately Regulates Metabolic Homeostasis and Adipose Tissue Mass, Independent of RagGTPase Activity

Metabolic disorders are commonly associated with obesity, a condition where excess caloric intake leads to massive adipose tissue (AT) expansion and eventual dysfunction. When adipose tissue loses its ability to store excess energy properly, lipids accumulate in non-adipose tissues such as liver, and muscle. This ectopic lipid deposition is a significant risk factor in the development of a collection of disorders described as metabolic syndrome. While metabolic syndrome is typically linked with obesity, patients who have an inability to develop adipose tissue depots (lipodystrophy) develop similar clinical outcomes. There is evidence that aberrant mTORC1 signaling may occur in both settings, and may be a factor that contributes to adipose dysfunction. I find that adipocyte specific loss of Raptor, a key mTORC1 subunit, leads to progressive lipoatrophy, and associated metabolic dysfunction including AT inflammation, hepatosteatosis, and insulin resistance. Interestingly, inhibition of autophagy, a pathway upregulated during Raptordeletion, prevents lipoatrophy but does not protect from ectopic lipid deposition and AT inflammation. These results suggest that outputs of mTORC1 in adipocytes individually regulate adipocyte storage capacity, and AT health. Furthermore, ablation of the amino acid sensing RagGTPases, thought to be necessary for mTORC1 activity, does not phenocopy Raptor KO, suggesting RagGTPase independent functions of mTORC1 in adipocytes. RagA/B deletion, however, did consistently increase Ucp1 expression in WAT, indicating a possible noncanonical role of the Rags in regulating Ucp1. Overall, these studies advance our understanding of regulation of adipose tissue metabolism, and shed light on previously unstudied nutrient specific signaling pathways in adipocytes

Jet-like correlations between Forward- and Mid- rapidity in p+p, d+Au and Au+Au collisions from STAR at 200 GeV

In this proceedings we present STAR measurements of two particle azimuthal correlations between trigger particles at mid-rapidity ($|\eta|<$ 1) and associated particles at forward rapidities (2.7 $<|\eta|<$ 3.9) in p+p, d+Au and Au+Au collisions at $\sqrt{s_{NN}}$= 200 GeV. Two particle azimuthal correlations between a mid-rapidity trigger particle and forward-rapidity associated particles preferably probe large-x quarks scattered off small-x gluons in RHIC collisions. Comparison of the separate d- and Au-side measurements in d+Au collisions may potentially probe gluon saturation and the presence of Color Glass Condensate. In Au+Au collisions quark energy loss can be probed at large rapidities, which may be different from gluon energy loss measured at mid-rapidity.Comment: Quark Matter 06 Conference proceedings, submitted to Journal of Phys.

Physics with Identified Particles at STAR

New physics results with identified particles at STAR are presented. Measurements at low $p_T$ address bulk properties of the collision, while those at high $p_T$ address jet energy loss in the bulk matter produced. Between these extremes, measurements at intermediate $p_T$ address the interplay between jets and the bulk. We highlight: measurements of $v_2$ fluctuations as a new, sensitive probe of the initial conditions and the equation of state; correlations involving multi-strange particles, along with ratios of identified particles to test coalescence as a mechanism of particle production at intermediate $p_T$; three particle azimuthal correlation to search for conical emission; and the energy and particle-type dependence of hadron production at high $p_T$ to study quark and gluon jet energy loss.Comment: 9 pages, 7 figures. To appear in the proceedings of the 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (Quark Matter 2006), Shanghai, China, November 14-20, 200

π,K,p\pi, K, p and pˉ\bar{p} production from Au+Au collisions at sNN=62.4\sqrt{s_{_{NN}}} = 62.4 GeV

The preliminary results of $\pi^{\pm}, K^{\pm}, p$ and $\bar{p}$ spectra are reported from Au+Au collisions at $\sqrt{s_{_{NN}}} = 62.4$ GeV. Particle identification is from the Time Projection Chamber and Time-of-Flight system at STAR. The nuclear modification factor $R_{CP}$ for mesons ($\pi^{\pm}, K^{\pm}$) and baryons ($p, \bar{p}$) will also be discussed.Comment: 5 pages, 4 figures, Contributed to 8th International Conference on Strangeness in Quark Matter (SQM 2004),to be published in Journal of Physics