One laptop per child, local refurbishment or overseas donations? Sustainability assessment of computer supply scenarios for schools in Colombia.

With the intention of bridging the 'digital divide' many programmes have been launched to provide computers for educational institutions, ranging from refurbishing second hand computers to delivering low cost new computers. The fast and economical provision of large quantities of equipment is one of the many challenges faced by such programmes. If an increase is to be achieved in the sustainability of computer supplies for schools, not only must equipment be provided, but also suitable training and maintenance delivered. Furthermore, appropriate recycling has to be ensured, so that end-of-life equipment can be dealt with properly. This study has evaluated the suitability of three computer supply scenarios to schools in Colombia: (i) 'Colombian refurbishment', -refurbishment of computers donated in Colombia, (ii) 'Overseas refurbishment', -import of computers which were donated and refurbished abroad, and (iii) 'XO Laptop', -purchase of low cost computers manufactured in Korea. The methods applied were: Material Flow Assessment, -to assess the quantities-, Life Cycle Assessment, -to assess the environmental impacts, and the application of the Multiple Attribute Utility Theory, -to analyse, evaluate and compare different scenarios. The most sustainable solution proved to be the local refurbishment of second hand computers of Colombian origin to an appropriate technical standard. The environmental impacts of such practices need to be evaluated carefully, as second hand appliances have to be maintained, require spare parts and sometimes use more energy than newer equipment. Providing schools with second hand computers from overseas and through programmes such as 'One Laptop Per Child' has the disadvantage that the potential for social improvements - such as creation of jobs and local industry involvement - is very low.

HLA-DQB1, -DQA1, -DRB1 linkage disequilibrium and haplotype diversity in a Mestizo population from Guadalajara, Mexico.

HLA-DQB1, -DQA1, and -DRB1 genes were typed by polymerase chain reaction with sequence-specific primer (PCR-SSP) in 159 healthy volunteers from 32 families living in Guadalajara, Mexico. Three-locus genotype data from all family members were used to infer haplotypes in 54 unrelated individuals of the sample, from which estimate of segregating haplotype frequencies and linkage disequilibrium (LD) between loci were computed. Genotype distributions were concordant with Hardy-Weinberg expectations (HWE) for all three loci, and allele distributions were similar to the ones observed in other Latin-American populations. Of the 56 distinct three-site (DQB1-DQA1-DRB1) haplotypes observed in the sample, the five most common (i.e., with frequencies of five counts or more) were: *0302-*0301-*04, *0201-*0201-*07, *0301-*0501-*14, *0402-*0401-*08, and *0501-*0101-*01. These common three-locus haplotypes also contributed to the majority of the significant two-locus linkage disequilibria of these three sites.