Transition redshift: new kinematic constraints from supernovae

The transition redshift (deceleration/acceleration) is discussed by expanding the deceleration parameter to first order around its present value. A detailed study is carried out by considering two different parametrizations, q = q(0) + q(1)z and q = q(0) + q(1)z(1 + z)(-1), and the associated free parameters (q(0), q(1)) are constrained by three different supernovae (SNe) samples. A previous analysis by Riess et al. using the first expansion is slightly improved and confirmed in light of their recent data (Gold07 sample). However, by fitting the model with the Supernova Legacy Survey (SNLS) type Ia sample, we find that the best fit to the redshift transition is z(t) = 0.61, instead of z(t) = 0.46 as derived by the High-z Supernovae Search (HZSNS) team. This result based in the SNLS sample is also in good agreement with the sample of Davis et al., z(t) = 0.60(-0.11)(+0.28) (1 sigma). Such results are in line with some independent analyses and accommodate more easily the concordance flat model (Lambda CDM). For both parametrizations, the three SNe Ia samples considered favour recent acceleration and past deceleration with a high degree of statistical confidence level. All the kinematic results presented here depend neither on the validity of general relativity nor on the matter-energy contents of the Universe.

Bayesian analysis and constraints on kinematic models from union SNIa

The kinematic expansion history of the universe is investigated by using the 307 supernovae type Ia from the Union Compilation set. Three simple model parameterizations for the deceleration parameter ( constant, linear and abrupt transition) and two different models that are explicitly parametrized by the cosmic jerk parameter ( constant and variable) are considered. Likelihood and Bayesian analyses are employed to find best fit parameters and compare models among themselves and with the flat Lambda CDM model. Analytical expressions and estimates for the deceleration and cosmic jerk parameters today (q(0) and j(0)) and for the transition redshift (z(t)) between a past phase of cosmic deceleration to a current phase of acceleration are given. All models characterize an accelerated expansion for the universe today and largely indicate that it was decelerating in the past, having a transition redshift around 0.5. The cosmic jerk is not strongly constrained by the present supernovae data. For the most realistic kinematic models the 1 sigma confidence limits imply the following ranges of values: q(0) is an element of [-0.96, -0.46], j(0) is an element of [-3.2,-0.3] and z(t) is an element of [0.36, 0.84], which are compatible with the Lambda CDM predictions, q(0) = -0.57 +/- 0.04, j(0) = -1 and z(t) = 0.71 +/- 0.08. We find that even very simple kinematic models are equally good to describe the data compared to the concordance Lambda CDM model, and that the current observations are not powerful enough to discriminate among all of them.

Observational constraints on the dark energy and dark matter mutual coupling

We examine different phenomenological interaction models for Dark Energy and Dark Matter by performing statistical joint analysis with observational data arising from the 182 Gold type la supernova samples, the shift parameter of the Cosmic Microwave Background given by the three-year Wilkinson Microwave Anisotropy Probe observations, the baryon acoustic oscillation measurement from the Sloan Digital Sky Survey and age estimates of 35 galaxies. Including the time-dependent observable, we add sensitivity of measurement and give complementary results for the fitting. The compatibility among three different data sets seem to imply that the coupling between dark energy and dark matter is a small positive value, which satisfies the requirement to solve the coincidence problem and the second law of thermodynamics, being compatible with previous estimates. (c) 2008 Elsevier B.V. All rights reserved.

Observational constraints on holographic tachyonic dark energy in interaction with dark matter

We discuss an interacting tachyonic dark energy model in the context of the holographic principle. The potential of the holographic tachyon field in interaction with dark matter is constructed. The model results are compared with CMB shift parameter, baryonic acoustic oscilations, lookback time and the Constitution supernovae sample. The coupling constant of the model is compatible with zero, but dark energy is not given by a cosmological constant.

Electroweak precision constraints on the Lee-Wick standard model

We perform an analysis of the electroweak precision observables in the Lee-Wick Standard Model. The most stringent restrictions come from the S and T parameters that receive important tree level and one loop contributions. In general the model predicts a large positive S and a negative T. To reproduce the electroweak data, if all the Lee-Wick masses are of the same order, the Lee-Wick scale is of order 5 TeV. We show that it is possible to find some regions in the parameter space with a fermionic state as light as 2.4-3.5 TeV, at the price of rising all the other masses to be larger than 5-8 TeV. To obtain a light Higgs with such heavy resonances a fine-tuning of order a few per cent, at least, is needed. We also propose a simple extension of the model including a fourth generation of Standard Model fermions with their Lee-Wick partners. We show that in this case it is possible to pass the electroweak constraints with Lee-Wick fermionic masses of order 0.4-1.5 TeV and Lee-Wick gauge masses of order 3 TeV.

Technology and marginalization: a case study of the limited adoption of the intranet at a state-owned organisation in rural Australia

Taking a critical theory approach and the pluralist view of technology, this paper examines the problems in organizational communication that arose due to the implementation of a limited intranet electronic mail system as the main channel of communication between a rural stateowned organization and its city-based Head Office, installed at the sole discretion of the latter.
The intranet was provided only to the administration division and managers of some units due to financial constraints. This required others to receive information carried via the intranet through a gatekeeper who due to information and work overload, failed to disseminate the information effectively and efficiently. Using a combination of qualitative data collection methods, this study found that the intranet had marginalized those without access to it and reinforced the privileged position of those already with higher status within the organization, contrary to the utopian predictions
of new technologies as leading to social equality.

Interest, nations, and the state in development: Instability in archipelic Southeast Asia

The Southeast Asian archipelago has become marked by divisions
within existing states, placing significant local constraints upon
the process of ‘development’. These divisions include ‘vertical’
challenges to the state, i.e. they have the capacity to split the state
into geographic divisions based on proto-nationalist identity, and
‘horizontal’ challenges to the state, defined by ethnic and
communal rivalry and conflict. This brief paper will canvas some
issues in such divisions.

Korea's developmental alliance : state, capital and the politics of rapid development

South Korea is often cited as a case of miraculous transformation from poverty to prosperity. Korea’s achievement of moving from one of the world’s poorest countries as recently as the early 1960s to the ranks of the ten biggest economies only four decades later has rightly attracted interest from policymakers and scholars alike.

This book identifies the factors that shaped relations between the state and big business in Korea, the ‘developmental alliance’. These factors offer a cogent framework in which to identify and predict changes in power relations between government and business. Rather than merely offering a means of explaining the rapid-growth phase of Korean development, the politics of the developmental alliance also help us understand how and why the Korean miracle turned to crisis in 1997 and why the subsequent recovery has been so uneven. In this way, the book highlights the political power of business, which is often underplayed in discussions of the development of Korea. It also sheds light on the constraints on policymakers during modernisation, and how power is shared among a small number of powerful parties.

Illustrating the tumultuous politics of the ‘developmental alliance’ between business and government during the rise and decline of South Korea’s economic miracle, this book is an essential read for anyone interested in Korean politcs, economics and development,

Housing service officers : agents of the state or customer service officers?

Staff employed in the Victorian Office of Housing are invariably required to exercise discretion in their day-to-day work managing housing assets and providing services to public housing tenants. Policies specify processes but they never cover all situations and do not provide guidance on competing objectives. For example, preparing a property for reletting is a process with protocols and budget constraints. However, staff can make procedural variations that compy with policy. These variations, generally learnt from peers on the job, often result in budget over runs, but do result in improved properties for new tenants. Discretion is being exercised in balancing housing asset, budget control and tenant service objectives. A housing officer sums up the enduring tension in balancing objectives in the question and statement:’ Am I an agent of the state or a customer service officer? Because I can’t be both’. Organisationally these tensions are spoken about as ‘management issues’, ‘policy reengineering’ and ‘unrealistic understandings’. Using data from an ethnographic study in the Victorian Office of Housing, the paper addresses the question: ‘What do we know about the way in which front line housing officers manage competing objectives in their daily work and how might this knowledge be usefully used in the development of operational policy?’ The paper will explore the way in which complex administrative rules are used as a device to align staff to the Office of Housing objectives and limit the exercise of discretion by frontline staff. Against the background of this analysis the paper will consider the limitations of rule making and the extent to which other organisational strategies might be important for improvements in service provision in a context of constrained resources and limited resources.

Understanding travel behavior using demographic and socioeconomic variables as travel constraints

Samdahl and Jekubovich (1997) view constraints as a subset of reasons for not engaging in a particular behavior. There is limited empirical research on the role of demographic and socioeconomic variables as travel constraints. This study investigates the relationships between a wide range of short and long trip planning and travel behaviors and sociodemographic constraints comprised of age, income and life cycle.

This research uses data generated from a cross-sectional, self-completed survey on travel and tourism which was collected during 2003 and 2004 from 49,105 Australian respondents. This paper utilizes binomial regression to find that age, income and life stage have significant differential and interactive effects on travel behavior. The results show that sociodemographic variables act in different ways to constrain/free different types of travel behavior. Implications are provided for national and state based tourism authorities. There is a need to understand these phenomena. Current research is addressing these issues.

Overcoming data constraints to create meaningful ecological models

Many techniques used to model ecosystems cannot be meaningfully applied to large-scale ecological problems due to data constraints. Disparate collection methods, data types and incomplete data sets, or limited theoretical understanding mean that a wide range of modelling techniques used to model physical processes or for problems specific to species or populations cannot be used at an ecosystem scale. In developing an ecological response model for the Coorong, a South Australian hypersaline estuary, we combined several flexible modelling approaches in a statistical framework to develop an approach we call ‘ecosystem states’. This model uses simulated hydrodynamic conditions as input to predict one of a suite of states per space and time, allowing prediction of likely ecological conditions under a variety of scenarios. Each ecosystem state has defined sets of biota and physico-chemical parameters. The existing model is limited in that its predictions have yet to be tested and, as yet, no spatial or temporal connectivity has been incorporated into simulated time series of ecosystem states. This approach can be used in a wide range of ecosystems, where enough data are available to model ecosystem states. We are in the process of applying the technique to a nearby lake system. This has been more difficult than for the Coorong as there is little overlap in the spatial and temporal coverage of biological data sets for that region. The approach is robust to low-quality biological data and missing environmental data, so should suit situations where community or management monitoring programs have occurred through time.

A Gradient-Type Method For Real-Time State Estimation Of Water Distribution Networks

Drinking water distribution networks risk exposure to malicious or accidental contamination. Several levels of responses are conceivable. One of them consists to install a sensor network to monitor the system on real time. Once a contamination has been detected, this is also important to take appropriate counter-measures. In the SMaRT-OnlineWDN project, this relies on modeling to predict both hydraulics and water quality. An online model use makes identification of the contaminant source and simulation of the contaminated area possible. The objective of this paper is to present SMaRT-OnlineWDN experience and research results for hydraulic state estimation with sampling frequency of few minutes. A least squares problem with bound constraints is formulated to adjust demand class coefficient to best fit the observed values at a given time. The criterion is a Huber function to limit the influence of outliers. A Tikhonov regularization is introduced for consideration of prior information on the parameter vector. Then the Levenberg-Marquardt algorithm is applied that use derivative information for limiting the number of iterations. Confidence intervals for the state prediction are also given. The results are presented and discussed on real networks in France and Germany.

Construction of facilities under asymmetric information: do constitutional constraints matter?

This paper studies construction of facilities in a federal state under asymmetric information. A country consists of two regions, each ruled by a local authority. The federal government plans to construct a facility in one of the regions. The facility generates a local value in the host region and has spillover effects in the other region. The federal government does not observe the local value because it is the local authority's private information. 80 the federal governrnent designs an incentive-compatible mechanism, specifying if the facility should be constructed and a balanced scheme of interregional transfers to finance its cost. The federal governrnent is constitutionally constrained to respect a given leveI of each region's welfare. We show that depending upon the facility's local value and the spillover effect, the governrnent faces different incentive problems. Moreover, their existence depends crucially on how stringent constitutional constraints are. Therefore, the optimal mechanism will also depend upon these three features of the model.

Does liquidity constraints matter for Ricardian equivalence?

The paper analysis a general equilibrium model with two periods, several households and a government that has to finance some expenditures in the first period. Households may have some private information either about their type (adverse selection) or about some action levei chosen in the first period that affects the probability of certain states of nature in the second period (moral hazard). Trade of financiai assets are intermediated by a finite collection of banks. Banks objective functions are determined in equilibrium by shareholders. Due to private information it may be optimal for the banks to introduce constraints in the set of available portfolios for each household as wellas household specific asset prices. In particular, households may face distinct interest rates for holding the risk-free asset. The government finances its expenditures either by taxing households in the first period or by issuing bonds in the first period and taxing households in the second period. Taxes may be state-dependent. Suppose government policies are neutml: i) government policies do not affect the distribution of wealth across households; and ii) if the government decides to tax a household in the second period there is a portfolio available for the banks that generates the Mme payoff in each state of nature as the household taxes. Tben, Ricardian equivalence holds if and only if an appropriate boundary condition is satisfied. Moreover, at every free-entry equilibrium the boundary condition is satisfied and thus Ricardian equivalence holds. These results do not require any particular assumption on the banks' objective function. In particular, we do not assume banks to be risk neutral.

Firm financial constraints and the impact of monetary policy: evidence from financial conglomerates

Building on recent evidence on the functioning of internal capital markets in financial conglomerates, this paper conducts a novel test of the balance sheet channel of monetary policy. It does so by comparing monetary policy responses of small banks that are affiliated with the same bank holding company, and this arguably face similar constraints in accessing internal/external sources of funds, but that operate in different geographical regions, and thus face different pools of borrowers. Because these subsidiaries typically concentrate their lending with small local businesses, we can use cross-sectional differences in state-level economic indicators at the time of changes of monetary policy to study whether or not the strength of borrowers' balance sheets influences the response of bank lending. We find evidence that the negative response of bank loan growth to a monetary contraction is significantly stronger when borrowers have 'weak balance sheets. Our evidence suggests that the monetary authority should consider the amplification effects that financial constraints play following changes in basic interest rates and the role of financial conglomerates in the transmission of monetary policy.