Scale of production and choice of technique in the engineering industries in developing countries

This article examines the relationship between scale of production, optimal choice of technique and costs for three engineering industries: nuts and bolts, iron founding and machine tools. In all three industries costs of production fell as the scale of output increased. This was associated with switches of technique and the spread of fixed costs over a larger number of units. The capital-output ratio fell and labour productivity increased with increases in scale while, in most cases, the capital-labour ratio increased. The implications of these findings are briefly discussed.

Evidence for complexity at the nanometer scale of radiation-induced DNA DSBs as a determinant of rejoining kinetics

The rejoining kinetics of double-stranded DNA fragments, along with measurements of residual damage after postirradiation incubation, are often used as indicators of the biological relevance of the damage induced by ionizing radiation of different qualities. Although it is widely accepted that high-LET radiation-induced double-strand breaks (DSBs) tend to rejoin with kinetics slower than low-LET radiation-induced DSBs, possibly due to the complexity of the DSB itself, the nature of a slowly rejoining DSB-containing DNA lesion remains unknown. Using an approach that combines pulsed-field gel electrophoresis (PFGE) of fragmented DNA from human skin fibroblasts and a recently developed Monte Carlo simulation of radiation-induced DNA breakage and rejoining kinetics, we have tested the role of DSB-containing DNA lesions in the 8-kbp-5.7-Mbp fragment size range in determining the DSB rejoining kinetics. It is found that with low-LET X rays or high LET alpha particles, DSB rejoining kinetics data obtained with PFGE can be computer-simulated assuming that DSB rejoining kinetics does not depend on spacing of breaks along the chromosomes. After analysis of DNA fragmentation profiles, the rejoining kinetics of X-ray-induced DSBs could be fitted by two components: a fast component with a half-life of 0.9 +/- 0.5 h and a slow component with a half-life of 16 +/- 9 h. For a particles, a fast component with a half-life of 0.7 +/- 0.4 h and a slow component with a half-life of 12 5 h along with a residual fraction of unrepaired breaks accounting for 8% of the initial damage were observed. In summary, it is shown that genomic proximity of breaks along a chromosome does not determine the rejoining kinetics, so the slowly rejoining breaks induced with higher frequencies after exposure to high-LET radiation (0.37 +/- 0.12) relative to low-LET radiation (0.22 +/- 0.07) can be explained on the basis of lesion complexity at the nanometer scale, known as locally multiply damaged sites. (c) 2005 by Radiation Research Society.

Influence of Different European Cements (CEM) on the Hydration of Cover-Zone Concrete during the Curing and Post Curing Periods

The durability of reinforced concrete structures depends, in the main, on the performance of the cover-zone concrete as it is this which protects the steel from the external environment. This paper focusses on the use of discretised electrical property measurements to study depth-related features during both the curing and post-curing period thereby allowing an integrated assessment of the protective properties of the cover region. In the current work, use is made of a small, multi-electrode array embedded within the surface 75mm of concrete specimens. Concretes were manufactured with different European cements (CEM) and water/binder ratios representing mixes which satisfied the minimum requirements for a range of environmental exposure classes including exposure to chlorides. Electrical resistance measurements were taken over a period in excess of 300 days which showed on-going hydration, pozzolanic reaction and pore-structure refinement; in addition, in the post-curing period, when exposed to a cyclic chloride ponding regime, measurements could be used to study the convective zone and ionic enrichment of the surface layer.

Genome-wide DNA profiling of marginal zone lymphomas identifies subtype-specific lesions with an impact on the clinical outcome

Marginal zone B-cell lymphomas (MZLs) have been divided into 3 distinct subtypes (extranodal MZLs of mucosa-associated lymphoid tissue [MALT] type, nodal MZLs, and splenic MZLs). Nevertheless, the relationship between the subtypes is still unclear. We performed a comprehensive analysis of genomic DNA copy number changes in a very large series of MZL cases with the aim of addressing this question. Samples from 218 MZL patients (25 nodal, 57 MALT, 134 splenic, and 2 not better specified MZLs) were analyzed with the Affymetrix Human Mapping 250K SNP arrays, and the data combined with matched gene expression in 33 of 218 cases. MALT lymphoma presented significantly more frequently gains at 3p, 6p, 18p, and del(6q23) (TNFAIP3/A20), whereas splenic MZLs was associated with del(7q31), del(8p). Nodal MZLs did not show statistically significant differences compared with MALT lymphoma while lacking the splenic MZLs-related 7q losses. Gains of 3q and 18q were common to all 3 subtypes. del(8p) was often present together with del(17p) (TP53). Although del(17p) did not determine a worse outcome and del(8p) was only of borderline significance, the presence of both deletions had a highly significant negative impact on the outcome of splenic MZLs.

A review of the global pesticide legislation and the scale of challenge in reaching the global harmonization of food safety standards

Pesticide use is important in agriculture to protect crops and improve productivity. However, they have the potential to cause adverse human health or environmental effects, dependent on exposure levels. This review examines existing pesticide legislation worldwide, focusing on the level of harmonisation, and impacts of differing legislation on food safety and trade. Pesticide legislation varies greatly worldwide as countries have different requirements guidelines and legal limits for plant protection. Developed nations have more stringent regulations than developing countries, which lack the resources and expertise to adequately implement and enforce legislation. Global differences in pesticide legislation act as a technical barrier to trade. International parties such as the European Union (EU), Codex Alimentarius Commission (Codex), and North American Free Trade Agreement (NAFTA) have attempted to harmonise pesticide legislation by providing maximum residue limits (MRLs), but globally these limits remain variable. Globally harmonised pesticide standards would serve to increase productivity, profits and trade, and enhance the ability to protect public health and the environment.