Quantification of turbate microstructures through a subglacial till : dimensions and characteristics

Peer reviewedPublisher PD

Fuelwood Scarcity, Energy Substitution and Rural Livelihoods in Namibia

In Namibia, as in many parts of Africa, households are highly dependent on fastdegrading forest resources for their livelihoods, including energy needs. Using data originally collected for Namibia's forest resource accounts and insights from a nonseparable household model, this paper empirically estimates household fuelwood demand. In particular, the factors underlying the substitution between fuelwood collected from open access forest resources, cow dung and fuelwood purchased from the market are analysed. Heckman two-step estimates show that households respond to forest scarcity, as measured by the opportunity costs of collecting fuelwood, by increasing labour input to collection more than by reducing energy consumption. There is limited evidence for substitution from fuelwood to other energy sources, particularly with the declining availability of forest stocks. All of the estimated elasticities are low confirming observations made elsewhere, particularly in South Asia. Policy interventions including energy efficiency measures and tree planting schemes are considered in the Namibian context. --Africa,forests,fuelwood,scarcity,energy,substitution,livelihoods

'Descended from immigrants and revolutionists': how family immigration history shapes representation in Congress

Does recent immigrant lineage influence the legislative behavior of members of Congress on immigration policy? We examine the relationship between the immigrant background of legislators (i.e., their generational distance from immigration) and legislative behavior, focusing on roll-call votes for landmark immigration legislation and congressional speech on the floor. Legislators more proximate to the immigrant experience tend to support more permissive immigration legislation. Legislators with recent immigration backgrounds also speak more often about immigration in Congress, though the size of immigrant constituencies in their districts accounts for a larger share of this effect. A regression discontinuity design on close elections, which addresses selection bias concerns and holds district composition constant, confirms that legislators with recent immigrant backgrounds tend to support pro-immigration legislation. Finally, we demonstrate how a common immigrant identity can break down along narrower ethnic lines in cases where restrictive legislation targets specific places of origin. Our findings illustrate the important role of immigrant identity in legislative behavior and help illuminate the legislative dynamics of present-day immigration policy.Accepted manuscrip

The adoption of market-based instruments for resource management: Three case studies

Market-based instruments (MBIs) for resource management create financial incentives for people and businesses to use resources more efficiently, within a regulatory context designed to ensure that ecological, social and cultural objectives are also met. Three case studies were done to identify factors influencing the adoption or rejection of market-based instruments in New Zealand. Case studies included Individual Transferable Quota (ITQ) for New Zealand's inshore fisheries, Transferable Water Permits (TWPs) in Tasman District and Waikato Region, and charges for occupation of coastal space at both the national and regional levels in New Zealand. This paper provides a summary of findings from these case studies. These include: MBIs are difficult to implement if they threaten the position of existing users. It is important to have clear objectives. Norms and values can be an obstacle to MBIs, especially where they help to protect the interests of key stakeholders, but value-based opposition can be overcome if practical concerns are addressed.market-based instruments, ITQ, transferable water permits, coastal occupation charges, Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Crop Production/Industries, Environmental Economics and Policy, Farm Management,

Forest resources and rural livelihoods in the north-central regions of Namibia

Economics, Forestry, Markets, Community/Rural/Urban Development, Environmental Economics and Policy,

Bounding the Rates of Convergence Towards the Extreme Value Distributions

Extreme value theory is a branch of probability which examines the extreme outliers of probability distributions. Three extreme value distributions arise as the limits of the maxima of sequences of random variables with certain properties. In this paper, we will first give information about these three distributions and prove that they are the only limit distributions of maxima. After that, we switch to a discussion about Stein\u27s method. Stein\u27s method is commonly used to prove central limit theorems. Stein\u27s method also develops bounds on the distance between probability distributions with regards to a probability metric. There are three essential steps to Stein\u27s method: finding a characterizing operator, solving the Stein equation, and then using the solution to that equation to generate bounds on the distance to the target distribution. We will give a general overview of the method with some basic examples, and then go over various ways to find operators for any distribution. We outline the generalized density method, a recent technique for finding operators, and apply it to the extreme value distributions to end a particularly good operator. Next, we work with two operators simultaneously in an attempt to bound the distance between maxima and the extreme value distributions. Specifically, we apply this idea to the convergence of the exponential distribution to the Gumbel

A communication program for television

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