2,513 research outputs found
Modelling the impacts of the industrial biofuels strategy on the South African agricultural and biofuel subsectors
The potential impact of the current South African industrial biofuels strategy on the economic feasibility of biofuel production in South Africa is analysed and discussed. The analysis is then taken a step further by means of a scenario to analyse the potential impacts of higher global prices on the feasibility of a local biofuel industry. The BFAP sector model, a partial equilibrium model, is used to simulate the various impacts over the period 2009 to 2017. This study shows that the incentives and commitments, as presented through the strategy, are not sufficient to get a local biofuel industry up and running and make it sustainable in the long term.Resource /Energy Economics and Policy,
Modelling the impacts of macro-economic variables on the South African biofuels industry
The production of biofuels from agricultural commodities has received much attention in recent years. Apart from a few private initiatives, biofuels have not seen a large scale, commercial production in South Africa to date. This article sketches a basic picture of the economic feasibility of biofuel production in South Africa, without any form of government support, at 2006 prices. It then takes the analysis a step further and with the aid of a set of scenarios, different potential outcomes, due to a range of possible policy implementation measures, are discussed and the results documented. The Bureau for Food and Agricultural Policy’s (BFAP) sector model is used to simulate the impact of various options on the potential biofuels industry and other related industries during the course of the 2007 to 2015 period. This study shows that a lack of government support for the local biofuels industry could seriously affect its economic viability, especially in the early stages of the industry’s development. Additional issues, such as the impact on food and feed prices, also need to be taken into consideration.Resource /Energy Economics and Policy,
Expression of the CD6 T lymphocyte differentiation antigen in normal human brain
Antigens shared by the immune and central nervous systems (CNS) have been described repeatedly.
The present study reports the expression of the CD6 lymphocyte differentiation antigen in normal human
brain evidenced by immunohistochemistry and Northern blot analysis. A panel of various anti-CD6
monoclonal antibodies (mabs) tested on serial cryostat sections identified CD6-positive cells randomly
scattered in parenchyma of all examined brain areas. Northern blot analysis with a highly sensitive cRNA
probe revealed a 3.1 kb CD6-specific mRNA in various brain regions, especially in basalganglia and cortex
cerebellum. Staining with mabs raised against different hematopoietic cell types, as well as hybridization
with probes specific for the ß- and y-T cell receptor (TCR) chains support the notion that CD6 is
expressed by original brain cells. The nature of the CD6-positive cell type and possible functions of shared
antigens in immune and nervous systems are discusse
THE CELLULAR RECEPTOR (CD4) OF THE HUMAN IMMUNODEFICIENCY VIRUS IS EXPRESSED ON NEURONS AND GLIAL CELLS IN HUMAN BRAIN
The peculiar tropism of the human immunodeficiency virus (HIV) for T
helper lymphocytes can be explained by a specific interaction between the virus
and the CD4 molecule on these cells (1, 2). The tropism for T lymphocytes,
however, can hardly account for the early brain infection observed in some AIDS
(acquired immune deficiency syndrome) patients (3, 4). Since CD4 is also expressed
on virus-susceptible non-T cell lines we wondered whether an additional
expression site of CD4 could be demonstrated in neural tissue (5). To this end,
CD4 expression in brain was analyzed with several different anti-CD4 mAbs, and
using a CD4-specific cDNA probe in Northern blot analyses . CD4' cells and
CD4-specific mRNA were found in the cerebellum, thalamus, and pons. The
reactive cells could be identified as neurons as well as glial cells
Knowledge-based Model Building with KONWERK
Modeling a real world optimization problem in a form which can be processed by a machine (computer) is usually a very difficult and complex task. Therefore, building and verifying the model is often the most time consuming part of the whole process of solving a real world problem using methods of Operations Research. Software tools, which integrate representation methods developed in the field of Artificial Intelligence (AI) and methods of OR, can facilitate and speed up the process of model development.
The paper introduces the idea of knowledge based modeling as a model development and representation technique facilitating the complex process of model building. We describe the KONWERK tool-box which combines hierarchical structured knowledge representation and object oriented methodology thus providing a framework for model building and application of different optimization methods. We want the reader to form an idea of the methodology of model development and knowledge representation with KONWERK and to understand the hierarchical structure of the knowledge base.
The model of the Nitra River Case is used to describe and explain the modeling and knowledge representation with KONWERK. A given multicriteria model of the Nitra River Case was reimplemented using KONWERK within about three weeks and later enlarged by implementation of additional fairness criteria
Simple Lattice-Models of Ion Conduction: Counter Ion Model vs. Random Energy Model
The role of Coulomb interaction between the mobile particles in ionic
conductors is still under debate. To clarify this aspect we perform Monte Carlo
simulations on two simple lattice models (Counter Ion Model and Random Energy
Model) which contain Coulomb interaction between the positively charged mobile
particles, moving on a static disordered energy landscape. We find that the
nature of static disorder plays an important role if one wishes to explore the
impact of Coulomb interaction on the microscopic dynamics. This Coulomb type
interaction impedes the dynamics in the Random Energy Model, but enhances
dynamics in the Counter Ion Model in the relevant parameter range.Comment: To be published in Phys. Rev.
Joint USA-CDAT Reply Memo in Support Mtn Set Aside and Modify (Fishing)
The United States\u27 and Coeur d\u27Alene Tribe\u27s Joint Memorandum in Reply to the State of Idaho\u27s and Hecla\u27s Memoranda Opposing Motion Re: On-Reservation Fish Habitat Claim
Mtn to Set Aside and Modify
The Joint Motion to Set Aside and Modify Partial Decree or Final Order Disallowing Water Right Clai
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