Inapproximability results for the lateral gene transfer problem

This paper concerns the Lateral Gene Transfer Problem. This minimization problem, defined by Hallett and Lagergren (2001), is that of finding the most parsimonious lateral gene transfer scenario for a given pair of gene and species trees. Our main results are the following:

The Sonoran Desert’s Domestic Bracero Programme: Institutional Actors and the Creation of Labour Migration Streams

This paper traces the journeys of male migrants to Empalme, Sonora, Mexico to uncover the development of the often overlooked domestic bracero programme that operated in conjunction with its well‐known international equivalent. Drawing on interviews and observations with ex‐braceros who met at a park near the Mexico‐US border, I examine their experiences and participation in Mexico’s domestic bracero program, an unintended and unexplored consequence of its international counterpart. The study shows how regulation and control were constantly reinvented at every step of the selection process by state actors and their affiliates in Mexico. The paper reveals how the oversupply of labour and modernization of agriculture in Sonora resulted in the development of a migration industry where local municipal leaders, coyotes, the state, and Mexican agribusiness capitalized from men’s displacement. The migration industry during the bracero selection process controlled who gained access to the United States labour market by capturing migrant labour en route to the United States in the process fueling a thriving cotton industry in the otherwise stagnant Sonoran Desert economy. The study concludes by taking the lessons from the historic domestic bracero programme to show one instance in which internal and international labour markets were closely interwoven. In the end, I call for more research that examines the relationship between markets on both sides of the border that uncovers how networks are not only structured by personal ties but also by state and market relations.     

Exposure to Violence,Coping Strategies,and Diagnosed Mental Health Problems Among Adults in a Migrant-Sending Community in Central Mexico

Deadly violence has spread throughout Mexico, affecting the well-being of citizens. What is the impact of this violence on the daily lives of Mexican adults? Building upon the stress process model, we used a mixed-methods approach to examine relationships between multiple indicators of exposure to and fear of violence and four diagnosed mental health outcomes, as well as self-rated mental health, in a Mexican community using the Survey of Health and Mexican Migration (456 surveys; 49 interviews). The multivariate models provide evidence that perceptions of insecurity are associated with diagnosed depressive episode, agoraphobia, alcohol abuse, a total count of mental health conditions, and poor self-rated mental health. Past victimization is associated with anxiety. Stress and coping behaviors did not formally mediate these violence–mental illness associations. The qualitative results confirm that residents fear violence and cope by adjusting their personal behaviors. These results foreshadow the emergence of mental health conditions as a critical public health concern for Mexicans living under the threat of violence.     

Urban park area and age determine the richness of native and exotic plants in parks of a Latin American city: Santiago as a case study

Plant diversity and composition in urban parks is determined by socio-economics, environmental, and ecological drivers. These drivers give rise to urban spaces with unique compositions of flora, consisting of planted and spontaneous species. The present study aimed to determine the contribution of native and exotic species in urban parks of a Latin American city, and to assess the related role of park area, age and socio-economic status. We also evaluated administration type (public or private) and the effect of environmental factors on plant richness. We hypothesized that the composition of park vegetation differs according to urban-rural gradient. To determine flora composition, two transects (100 m long by 1–3 m wide) per park were selected in 49 parks. In each of these, we identified all the vascular plants found (woody and herbs, planted and spontaneous), which were then classified as native or exotic. We conducted ANCOVAs in order to determine the effect of five independent variables and one factor, on native and exotic plant richness. Of 550 recorded species, 16.2% were native and 83.8% exotic. Number of plant species per park varied between 42 and 146. The parks are known urban habitats containing the highest planted and spontaneously occurring exotic diversity in the city of Santiago, contrasting with other types of habitats. Likewise, parks in Santiago are habitats with low levels of planted and spontaneously occurring native diversity, compared to the parks of Europe, America North and Asia. Ours results show that park area and age affected native plant richness, while exotic plant richness was determined only by park age. We rejected all other possible drivers. Finally, according to the low frequency of native species, we propose that Santiago’s parks could be gradually reoriented towards ex-situ conservation of native plants.     

The influence of the elites’ discourse in political attitudes: evidence from the Basque Country

Do parties’ position shifts matter for public opinion? In this paper, we would like to compare the discourses of the Basque elites with the Basque public opinion regarding the reinforcement of the Autonomy. So, combining content analysis methodology and survey data we aim to test if a mainstream political party (specifically, the Basque Nationalist Party [Partido Nacionalista Vasco]) cause the public view to shift on one of the most important policy issues in the Basque Country, that is, the territorial dimension. This study validates the top-down model and concludes that elite political discourses actually affect popular opinion.     

Micro-Flexibility and Macro-Rigidity: Some Notes on Expectations and the Dynamics of Aggregate Supply

ABSTRACT: The high macro supply elasticity experienced by industrialised countries during the second post-war boom is not explainable as the aggregate effect of current variations of companies’output in response to current variations of demand. A firm cannot adapt rapidly its output to higher demand unless it has decided fairly in advance to expand its productive capacity. Macro elasticity depends thus on the existence of ex ante excess capacity, built on the basis of expectations. The post-war boom is thus explained in terms of a virtuous sequence expectations-decisions-events. This approach helps in understanding the inversion of the expansionary phase to one of stag-flation, the failure of Keynesian policies and the subsequent industrial restructuring which gave rise to the present employment squeeze. Flexibility is something which depends on the relationships between individual expectations and decisions and their systemic results; the presently pursued micro-flexibility is at high risk of producing increasing macro-rigidity.     

Healthy, educated and wealthy: A primer on the impact of public and private welfare expenditures on economic growth

In this paper, we provide first evidence of the impact of public and private expenditures in health and education on economic growth, via their influence on people's health, skills and knowledge. We consider a growth accounting framework in order to test whether countries that devote a larger amount of resources to the consumption of health and educational services experience higher growth rates. We also test whether the effects on economic growth of public expenditure in health and education differ from those of private expenditure. Our empirical analysis is based on a panel of 19 OECD countries observed between 1971 and 1998. The results are consistent with the hypothesis that health and education expenditure affects positively growth. The estimated impact is stronger for health than for education. More importantly, we find some evidence that public expenditure influences GDP growth more than private expenditure.     

Sense of Community and the Perception of the Socio-Physical Environment: A Comparison Between Urban Centers of Different Sizes Across Europe

Measures of subjective well-being, and especially life evaluations, or judgments about how happy people are with their lives as a whole, enrich and empower social indicators research. They do this by requiring other social indicators as explanatory variables and providing a coherent encompassing framework within which the relative importance of other social indicators can be established.     

Influence of substrate depth and vegetation type on temperature and water runoff mitigation by extensive green roofs: shrubs versus herbaceous plants

The relative contribution of substrate depth and vegetation type on temperature mitigation and stormwater runoff reduction was studied in an experimental green roof in North eastern Italy. Two substrate depths (120 and 200?mm) and two vegetation types (herbaceous plants and shrubs, respectively) were used, and compared to control modules with similar substrate depths but left bare of vegetation. Experimental observations showed that: a) green roofs substantially reduce thermal load over the rooftop, with significant effects of substrate depth and no apparent impact of vegetation type; b) thermal effects are strongly influenced by substrate water content; c) green roofs strongly reduce water runoff with significant substrate x vegetation effects. Our data suggest that green roof design addressed to optimization of the thermal functions should take into account adequate planning of substrate depth. Moreover, our data show that vegetated modules out-competed medium-only ones in terms of runoff reduction capacity, in accordance with some previous studies. Both shrub-vegetated and herbaceous modules intercepted and stored more than 90% rainfall during intense precipitation events, with no significant difference between the two vegetation types despite different substrate depths.