Promoting Entrepreneurship through a Community Learning Model – Case Study: Green Businesses

This article presents a community learning model formulated by Engineers Without Borders Colombia with the aim of providing communities with tools to create sustainable productive solutions which have relevancy for members and for potential customers. The goal of this formulation is to promote learning processes that are guided by decisions made by community members to propose sustainable and replicable initiatives. The model applicability is evidenced through a case study devoted to strengthening community-led green businesses in the Guavio Province, Colombia by collecting lessons and conclusions. Ultimately, this collection will prove useful in replicating the learning model in other similar rural communities.

     

An increased estimate of the merger rate of double neutron stars from observations of a highly relativistic system

The merger of close binary systems containing two neutron stars should produce a burst of gravitational waves, as predicted by the theory of general relativity. A reliable estimate of the double-neutron-star merger rate in the Galaxy is crucial in order to predict whether current gravity wave detectors will be successful in detecting such bursts. Present estimates of this rate are rather low, because we know of only a few double-neutron-star binaries with merger times less than the age of the Universe. Here we report the discovery of a 22-ms pulsar, PSR J0737-3039, which is a member of a highly relativistic double-neutron-star binary with an orbital period of 2.4 hours. This system will merge in about 85 Myr, a time much shorter than for any other known neutron-star binary. Together with the relatively low radio luminosity of PSR J0737-3039, this timescale implies an order-of-magnitude increase in the predicted merger rate for double-neutron-star systems in our Galaxy (and in the rest of the Universe).     

Transient radio bursts from rotating neutron stars

The radio sky is relatively unexplored for transient signals, although the potential of radio-transient searches is high. This was demonstrated recently by the discovery of a previously unknown type of source, varying on timescales of minutes to hours. Here we report a search for radio sources that vary on much shorter timescales. We found eleven objects characterized by single, dispersed bursts having durations between 2 and 30 ms. The average time intervals between bursts range from 4 min to 3 h with radio emission typically detectable for <1 s per day. From an analysis of the burst arrival times, we have identified periodicities in the range 0.4-7 s for ten of the eleven sources, suggesting origins in rotating neutron stars. Despite the small number of sources detected at present, their ephemeral nature implies a total Galactic population significantly exceeding that of the regularly pulsing radio pulsars. Five of the ten sources have periods >4 s, and the rate of change of the pulse period has been measured for three of them; for one source, we have inferred a high magnetic field strength of 5 x 10(13) G. This suggests that the new population is related to other classes of isolated neutron stars observed at X-ray and gamma-ray wavelengths.     

Participative Methodology for Local Development: The Contribution of Engineers Without Borders from Italy and Colombia: Towards the Improvement of Water Quality in Vulnerable Communities

This paper presents a systemic methodology by which engineering is put to use in vulnerable communities through applied technological research and the main results of its application. The methodology presented corresponds to one implemented and designed by two groups of Engineers without Borders in Europe and Latin America, to integrate technical know-how with local context in communities with water problems in Colombia and the Democratic Republic of Congo. The main results of this methodology are related to the improvement of the living conditions of vulnerable groups thanks to the integration of the communities?? knowledge with engineering know-how, leading to autonomous communities and engineering professors and students learning from real life problems to enrich applied sciences.     

Patterns and processes in reef fish diversity

A central aim of ecology is to explain the heterogeneous distribution of biodiversity on earth. As expectations of diversity loss grow, this understanding is also critical for effective management and conservation. Although explanations for biodiversity patterns are still a matter for intense debate, they have often been considered to be scale-dependent. At large geographical scales, biogeographers have suggested that variation in species richness results from factors such as area, temperature, environmental stability, and geological processes, among many others. From the species pools generated by these large-scale processes, community ecologists have suggested that local-scale assembly of communities is achieved through processes such as competition, predation, recruitment, disturbances and immigration. Here we analyse hypotheses on speciation and dispersal for reef fish from the Indian and Pacific oceans and show how dispersal from a major centre of origination can simultaneously account for both large-scale gradients in species richness and the structure of local communities.     

DNA damage defines sites of recurrent chromosomal translocations in B lymphocytes

Recurrent chromosomal translocations underlie both haematopoietic and solid tumours. Their origin has been ascribed to selection of random rearrangements, targeted DNA damage, or frequent nuclear interactions between translocation partners; however, the relative contribution of each of these elements has not been measured directly or on a large scale. Here we examine the role of nuclear architecture and frequency of DNA damage in the genesis of chromosomal translocations by measuring these parameters simultaneously in cultured mouse B lymphocytes. In the absence of recurrent DNA damage, translocations between Igh or Myc and all other genes are directly related to their contact frequency. Conversely, translocations associated with recurrent site-directed DNA damage are proportional to the rate of DNA break formation, as measured by replication protein A accumulation at the site of damage. Thus, non-targeted rearrangements reflect nuclear organization whereas DNA break formation governs the location and frequency of recurrent translocations, including those driving B-cell malignancies.     

A Systemic Framework to Develop Sustainable Engineering Solutions in Rural Communities in Colombia

In several rural areas in Colombia there is a serious lack of water quality supply. Thereby the problematic situation is understood as complex one that involves stakeholders with pluralistic interests, multiple variables and requires the development of sustainable and suitable solutions. In order to address this issue, this paper proposes an integration of engineering design framework (CDIO) with a systemic approach. Particularly the approach emphasizes on systemic elements such as autonomy, systems within systems, cooperation between stakeholders and cause effect relations; it also proposes a previous observing phase for engineering design framework. Thus the proposed systemic framework aims to generate projects that improve living conditions in rural communities and promote the production of knowledge between the stakeholders to ensure sustainability in the long term. To illustrate the proposal, this work contains a case study that discusses a project carried out by a research team—Ingenieros Sin Fronteras Colombia—in a rural district near to Colombia’s capital. The experience, which involved and benefited 16 families in the community, provided strong evidence to support the proposed framework. The paper concludes with a discussion about the replication of this proposal in other contexts.     

<Emphasis Type="Bold">An Engineering View for Social Systems: Agency as an Operational Principle for Designing Higher Education Access Policies</Emphasis>

Access to higher education (HE) has been a persistent concern for governments, practitioners and researchers. Access to HE has been widely studied from scientific perspectives that have focussed on the factors that contribute to the problem; however, authors have highlighted the need for systemic and design perspectives on education systems. The need to connect research with policy remains one of the most challenging issues for education researchers. In view of this gap, this paper argues that engineering thinking and methods represent an opportunity for the design of HE access policies because engineering rationality (distinct from scientific rationalities) matches the concerns and goals of any policymaking attempt. Engineers design artefacts to meet particular goals. These artefacts are artificial systems, tangible or intangible, such as hammers, bridges or whole organizations, which are designed in particular contexts to meet precise goals. Policies for access to HE are good examples of artefacts that seek to fulfil specific needs under concrete constraints inherent to a country or region. More specifically, HE systems are social systems; in other words, they are created and recreated by the interactions and decisions of diverse actors. Hence, to change, redesign or improve such types of systems involves engineering their very interactions that are the outcomes of institutional and human actions. In particular, engineering design requires operational principles. Thus, we propose agency as a fundamental design concept for the improvement of HE systems, which opens new possibilities for a distinct type of policy-making that takes excellent advantage of what engineering can offer, while at the same time expanding on traditional expectations for engineering.     

Speciation by hybridization in Heliconius butterflies

Speciation is generally regarded to result from the splitting of a single lineage. An alternative is hybrid speciation, considered to be extremely rare, in which two distinct lineages contribute genes to a daughter species. Here we show that a hybrid trait in an animal species can directly cause reproductive isolation. The butterfly species Heliconius heurippa is known to have an intermediate morphology and a hybrid genome, and we have recreated its intermediate wing colour and pattern through laboratory crosses between H. melpomene, H. cydno and their F1 hybrids. We then used mate preference experiments to show that the phenotype of H. heurippa reproductively isolates it from both parental species. There is strong assortative mating between all three species, and in H. heurippa the wing pattern and colour elements derived from H. melpomene and H. cydno are both critical for mate recognition by males.     

Chromosomal rearrangements maintain a polymorphic supergene controlling butterfly mimicry

Supergenes are tight clusters of loci that facilitate the co-segregation of adaptive variation, providing integrated control of complex adaptive phenotypes. Polymorphic supergenes, in which specific combinations of traits are maintained within a single population, were first described for 'pin' and 'thrum' floral types in Primula and Fagopyrum, but classic examples are also found in insect mimicry and snail morphology. Understanding the evolutionary mechanisms that generate these co-adapted gene sets, as well as the mode of limiting the production of unfit recombinant forms, remains a substantial challenge. Here we show that individual wing-pattern morphs in the polymorphic mimetic butterfly Heliconius numata are associated with different genomic rearrangements at the supergene locus P. These rearrangements tighten the genetic linkage between at least two colour-pattern loci that are known to recombine in closely related species, with complete suppression of recombination being observed in experimental crosses across a 400-kilobase interval containing at least 18 genes. In natural populations, notable patterns of linkage disequilibrium (LD) are observed across the entire P region. The resulting divergent haplotype clades and inversion breakpoints are found in complete association with wing-pattern morphs. Our results indicate that allelic combinations at known wing-patterning loci have become locked together in a polymorphic rearrangement at the P locus, forming a supergene that acts as a simple switch between complex adaptive phenotypes found in sympatry. These findings highlight how genomic rearrangements can have a central role in the coexistence of adaptive phenotypes involving several genes acting in concert, by locally limiting recombination and gene flow.