Cost and benefits of rent control in Kumasi, Ghana

Over the past forty years, rent control has been a feature of housing in Ghana. This study focusses on the housing market in Kumasi, the second largest city in Ghana. The authors examine the characteristics of the rent control regime in force there, and assess the costs and benefits of rent control, on landlords and on tenants, and its effect on the housing stock. Rent control has been successful in ensuring that housing is very inexpensive for most households, in both absolute terms and in the proportion of income devoted to rent. Thesecontrols have deprived landlords of economic returns on their property, causing them to withdraw stock from renting to use for their own family members and to reduce maintenance. However, rent control is not the only constraint on the housing market, in Kumasi or in Ghana. The paper also describes other supply side and regulatory constraints; such as those affecting land, finance, and choice of building design and materials. A number of options for relaxation/decontrol are studied with the aid of a simple present value model. Along with decontrol of new construction it is recommended that floating up and out of controls over a five year period should be considered, along with policy changes to ensure ready supplies of land, finance, and building materials. Such policies are essential, given that private housing investment provides the great majority of rooms in Ghanaian urban areas.Non Bank Financial Institutions,Banks&Banking Reform,Housing Finance,Housing&Human Habitats,Economic Theory&Research

The possibility of the non-perturbative an-harmonic correction to Mehler's formula for propagator of the harmonic oscillator

We find the possibility of the non-perturbative an-harmonic correction to Mehler's formula for propagator of the harmonic oscillator. We evaluate the conditional Wiener measure functional integral with a term of the fourth order in the exponent by an alternative method as in the conventional perturbative approach. In contrast to the conventional perturbation theory, we expand into power series the term linear in the integration variable in the exponent. We discuss the case, when the starting point of the propagator is zero. We present the results in analytical form for positive and negative frequency.Comment: The detailed "pedagogical" evaluations are postponed to appendices, 1 figur

Kinetic separation of CO2 and CH4 on Carbon Molecular Sieves: Study of the internal diffusion and surface resistance of pure gases and binary gas mixtures Introduction and objectives

International audienceCarbon Molecular Sieves (CMS) adsorbents appear to be good candidates for gas kinetic separations by using Pressure Swing Adsorption (PSA) processes: their pore morphologies could imply diffusion rate variations depending on their nature and the size of the gas adsorbate. We studied the separation of CO2 and CH4 with a CMS material in PSA processes experimentally and by using the Linear Driving Force (LDF) theory. The results show a high kinetic selectivity for CO2. But there are lacks in the understanding of the involved diffusion phenomena. Thus, we propose to distinguish the different involved phenomena of diffusion by measuring the diffusion coefficients of CO2 and CH4 on the CMS using the Zero Length Column (ZLC) method [1]: this macroscopic method allows to separate the diffusion mechanisms by adjusting the gas velocities in the column containing the adsorbent material. The conclusion of these measurements is that the CH4 diffusion is only controlled by surface resistance diffusion whereas both internal and surface diffusion resistances are involved in CO2 diffusion as already showed by Liu and Ruthven on others CMS materials [2]. In addition of these evaluations, we propose to focus on the binary diffusion of CH4 and CO2 and then to study the influence on the kinetic selectivity of a residual adsorption of CO2 or CH4 on the CMS adsorbent when separating the CO2-CH4 mixture. The results of the binary diffusion rate measurements will be presented and qualitatively linked to the textural properties of the studied CMS

Deciding Quantifier-Free Presburger Formulas Using Parameterized Solution Bounds

Given a formula in quantifier-free Presburger arithmetic, if it has a satisfying solution, there is one whose size, measured in bits, is polynomially bounded in the size of the formula. In this paper, we consider a special class of quantifier-free Presburger formulas in which most linear constraints are difference (separation) constraints, and the non-difference constraints are sparse. This class has been observed to commonly occur in software verification. We derive a new solution bound in terms of parameters characterizing the sparseness of linear constraints and the number of non-difference constraints, in addition to traditional measures of formula size. In particular, we show that the number of bits needed per integer variable is linear in the number of non-difference constraints and logarithmic in the number and size of non-zero coefficients in them, but is otherwise independent of the total number of linear constraints in the formula. The derived bound can be used in a decision procedure based on instantiating integer variables over a finite domain and translating the input quantifier-free Presburger formula to an equi-satisfiable Boolean formula, which is then checked using a Boolean satisfiability solver. In addition to our main theoretical result, we discuss several optimizations for deriving tighter bounds in practice. Empirical evidence indicates that our decision procedure can greatly outperform other decision procedures.Comment: 26 page

Low-dose calcium supplementation for preventing pre-eclampsia: a systematic review and commentary.

BACKGROUND: Epidemiological data link low dietary calcium with pre-eclampsia. Current recommendations are for 1.5-2 g/day calcium supplementation for low-intake pregnant women, based on randomised controlled trials of ≥1 g/day calcium supplementation from 20 weeks of gestation. This is problematic logistically in low-resource settings; excessive calcium may be harmful; and 20 weeks may be too late to alter outcomes. OBJECTIVES: To review the impact of lower dose calcium supplementation on pre-eclampsia risk. SEARCH STRATEGY AND SELECTION CRITERIA: We searched PubMed and the Cochrane Pregnancy and Childbirth Group trials register. DATA COLLECTION AND ANALYSIS: Two authors extracted data from eligible randomised and quasi-randomised trials of low-dose calcium (LDC, <1 g/day), with or without other supplements. MAIN RESULTS: Pre-eclampsia was reduced consistently with LDC with or without co-supplements (nine trials, 2234 women, relative risk [RR] 0.38; 95% confidence interval [95% CI] 0.28-0.52), as well as for subgroups: LDC alone (four trials, 980 women, RR 0.36; 95% CI 0.23-0.57]); LDC plus linoleic acid (two trials, 134 women, RR 0.23; 95% CI 0.09-0.60); LDC plus vitamin D (two trials, 1060 women, RR 0.49; 0.31-0.78) and a trend for LDC plus antioxidants (one trial, 60 women, RR 0.24; 95% CI 0.06-1.01). Overall results were consistent with the single quality trial of LDC alone (171 women, RR 0.30; 95% CI 0.06-1.38). LDC plus antioxidants commencing at 8-12 weeks tended to reduce miscarriage (one trial, 60 women, RR 0.06; 95% CI 0.00-1.04). CONCLUSIONS: These limited data are consistent with LDC reducing the risk of pre-eclampsia; confirming this in sufficiently powered randomised controlled trials would have implications for current guidelines and their global implementation

Financialisation in the green economy: material connections, markets-in-the-making and Foucauldian organising actions

This paper explores the connections between financialisation in the green economy and the material commodification processes that underpin this economy. It argues that these connections are important and can be usefully conceived in terms of spaces of mutuality. These spaces of mutuality direct attention to the material processes of value creation at the level of real environmental assets. That these material processes appear thin, sluggish, fractured, hybridised or stalled in practice invites new modes of analytical engagement. One important mode of analysing these emergent green projects is to emphasise their status as durable processes of becoming or what could be called markets-in-the-making, by going beyond forms of market and economic reductionism. Michel Foucault's analysis of neoliberalism and his idea of ‘organising actions’ prove useful in this regard. Foucauldian organising actions render markets-in-the-making projects visible as durable governmental apparatuses made of disparate elements that are geographically specific, historically contingent and are aligned with an overarching market telos. Drawing on an empirical case of Reducing Emissions from Deforestation and Forest Degradation plus carbon stock enhancement and sustainable forest management (REDD+) in Nigeria’s Cross River, the paper analyses organising actions along four meta-processes – problematisations, visions, implementation and stabilisation. It concludes by highlighting the wider implications for work on environmental financialisation