Untriggered di-hadron correlations in Pb-Pb collisions at sNN=\sqrt{s_{NN}} = 2.76 TeV from ALICE

We present measurements of untriggered di-hadron correlations as a function of centrality in Pb-Pb \sNN collisions, for charged hadrons with $p_{T} > 0.15$ GeV$/c$. These measurements provide a map of the bulk correlation structures in heavy-ion collisions. Contributions to these structures may come from jets, initial density fluctuations, elliptic flow, resonances, and/or momentum conservation. We decompose the measured correlation functions via a multi-parameter fit in order to extract the nearside Gaussian, the longer range $\Delta \eta$ correlation often referred to as the soft ridge. The effect of including higher harmonics ($v_{3}$ and $v_{4}$) in this procedure will be discussed. We investigate how the nearside Gaussian scales with the number of binary collisions. Finally, we show the charge dependence of the nearside Gaussian.Comment: 4 pages, QM 2011 proceeding

A study of total space life performance of GSFC spacecraft

The space life performance of 57 Goddard Space Flight Center spacecraft is given. The time distribution of 449 malfunctions, of which 248 were classified as failures, is presented. Test data were available for 39 of the spacecraft and permitted a comparison of system test performance with the first-day, first-month, and total space life performance. The failures per spacecraft for the system environmental tests and the three time periods in space were 12, 0.9, 1.7, and 5.0, respectively. Relevance of the data to the pre-shuttle and shuttle eras is discussed. Classifications of failures by type of device and spacecraft subsystem are included. A continuation of the Goddard philosophy of requiring a system-level environmental test program is justified

Moving to Jobs?

This paper examines whether New Zealand residents move from low-growth to high-growth regions, using New Zealand census data from the past three inter-censal periods (covering 1986-2001). We focus on the relationship between employment growth and migration flows to gauge the strength of the relationship and the stability of the relationship over the business cycle. We find that people move to areas of high employment growth, but that the probability of leaving a region is less strongly related to that region's fortunes. We also find that migration flows to the metropolitan regions of Auckland, Canterbury and Wellington include a higher proportion of international immigrants compared with the rest of New Zealand.employment growth, migration, regional development

Economic Geography and Spatial Statistics: Theory and Empirics of New Zealand Regions

This paper sets the stage for current Treasury research on New Zealand regional socio-economic issues by: - Outlining a basic theoretical framework; - Introducing a regional database and Geographic Information Systems, a new empirical tool for data analysis; and - Illustrating the potential of this data and tools for analysing policy relevant issues by testing some empirical hypotheses derived from the theoretical framework.

A Revealed Preference Approach to the Measurement of Congestion in Travel Cost Models

Travel cost models are regularly used to determine the value of recreational sites or particular site characteristics, yet a key site attribute, congestion, is often excluded from such analyses. One of several reasons is that congestion (unlike many other site attributes) is determined in equilibrium by the process of individuals sorting across sites, and thus presents significant endogeneity problems. This paper illustrates this source of endogeneity, describes how previous research has dealt with it by way of stated preference techniques, and describes an instrumental variables approach to address it in a revealed preference context. We demonstrate that failing to address the endogeneity of congestion will likely lead to the understatement of its costs, and possibly to the mistaken recovery of agglomeration benefits. We apply our technique to the valuation of a large recreational fishing site in Wisconsin (Lake Winnebago) which, if eliminated, would induce significant re-sorting of anglers amongst remaining sites. In our application, ignoring congestion leads to an understatement of the lake’s value by more than 50 percent.Congestion, Random Utility Model, Site Valuation, Travel Cost, Discrete Choice, Instrumental Variables, Quantile Regression

Estimating Equilibrium Models of Sorting across Locations

With the growing recognition of the role played by geography in all sorts of economic problems, there is strong interest in measuring the size and scope of local spillovers (i.e., simple anonymous agglomeration or congestion effects, or more complicated interactions between individuals or firms of specific types). It is well-understood, however, that such spillovers cannot be distinguished from unobservable local attributes using just the observed location decisions of individuals or firms. We propose an empirical strategy for recovering estimates of spillovers in the presence of unobserved local attributes for a broadly applicable class of equilibrium sorting models. This approach relies on an instrumental variables strategy derived from the internal logic of the sorting model itself. We show practically how the strategy is implemented, provide intuition for our instrumental variables, and discuss the role of effective choice-set variation in identifying the model, and carry-out a series of Monte Carlo experiments to demonstrate the instruments' performance in small samples.Local Spillovers, Location Choice, Economic Geography, Natural Advantage, Social Interactions, Network Effects, Endogenous Sorting, Discrete Choice Models, Agglomeration, Congestion

Experience in Thermal-vacuum Testing Earth Satellites at Goddard Space Flight Center

Thermal-vacuum environmental testing of satellite

Event by event di-hadron correlations in Pb-Pb 2.76 TeV collisions from the ALICE experiment

The large multiplicities at the LHC may permit flow harmonics to be determined on an event by event basis in Pb-Pb collisions. We extract these harmonics from event by event di-hadron correlations. Within a fine centrality bin, we find the correlation function varies substantially on an event by event basis, indicating large fluctuations in the initial conditions for a given impact parameter. Such large fluctuations lead to some events being highly triangular or highly elliptical, where the angular correlation function is completely dominated by the respective second and third Fourier harmonics. We will show unfolded $v_{2}$ distributions for various centralities, and implications for our understanding of the initial conditions.Comment: 4 pages, Hot Quarks 201

Hedonic Prices and Implicit Markets: Estimating Marginal Willingness to Pay for Differentiated Products Without Instrumental Variables

The hedonic model of Rosen (1974) has become a workhorse for valuing the characteristics of differentiated products despite a number of well-documented econometric problems. For example, Bartik (1987) and Epple (1987) each describe a source of endogeneity in the second stage of Rosen's procedure that has proven difficult to overcome. In this paper, we propose a new approach for recovering the marginal willingness-to-pay function that altogether avoids these endogeneity problems. Applying this estimator to data on large changes in violent crime rates, we find that marginal willingness-to-pay increases by ten cents with each additional violent crime per 100,000 residents.