840 research outputs found
Media Exposure and Internal Migration -Evidence from Indonesia
This paper investigates the impact of television on internal migration in Indonesia. We exploit the differential introduction of private television throughout the country and the variation in signal reception due to topography to estimate the causal effect of media exposure. Our estimates reveal important long and short run effects. An increase of one standard deviation in the number of private TV channels received in the area of residence reduces future inter-provincial migration by 1.7-2.7 percentage points, and all migration (inter and intra-provincial) by 4-7.4 percentage points. Short run effects are slightly smaller, but still sizeable and statistically significant. We also show that respondents less exposed to private TV are more likely to consider themselves among the poorest groups of the society. As we discuss in a stylized model of migration choice under imperfect information, these findings are consistent with Indonesia citizens over-estimating the net gains from internal migration.Information; Migration decisions; Television
Evolution of a genome-encoded bias in amino acid biosynthetic pathways is a potential indicator of amino acid dynamics in the environment.
Overcoming the stress of starvation is one of an organism's most challenging phenotypic responses. Those organisms that frequently survive the challenge, by virtue of their fitness, will have evolved genomes that are shaped by their specific environments. Understanding this genotype-environment-phenotype relationship at a deep level will require quantitative predictive models of the complex molecular systems that link these aspects of an organism's existence. Here, we treat one of the most fundamental molecular systems, protein synthesis, and the amino acid biosynthetic pathways involved in the stringent response to starvation. These systems face an inherent logical dilemma: Building an amino acid biosynthetic pathway to synthesize its product-the cognate amino acid of the pathway-may require that very amino acid when it is no longer available. To study this potential "catch-22," we have created a generic model of amino acid biosynthesis in response to sudden starvation. Our mathematical analysis and computational results indicate that there are two distinctly different outcomes: Partial recovery to a new steady state, or full system failure. Moreover, the cell's fate is dictated by the cognate bias, the number of cognate amino acids in the corresponding biosynthetic pathway relative to the average number of that amino acid in the proteome. We test these implications by analyzing the proteomes of over 1,800 sequenced microbes, which reveals statistically significant evidence of low cognate bias, a genetic trait that would avoid the biosynthetic quandary. Furthermore, these results suggest that the pattern of cognate bias, which is readily derived by genome sequencing, may provide evolutionary clues to an organism's natural environment
Unrelated toxin-antitoxin systems cooperate to induce persistence.
Persisters are drug-tolerant bacteria that account for the majority of bacterial infections. They are not mutants, rather, they are slow-growing cells in an otherwise normally growing population. It is known that the frequency of persisters in a population is correlated with the number of toxin-antitoxin systems in the organism. Our previous work provided a mechanistic link between the two by showing how multiple toxin-antitoxin systems, which are present in nearly all bacteria, can cooperate to induce bistable toxin concentrations that result in a heterogeneous population of slow- and fast-growing cells. As such, the slow-growing persisters are a bet-hedging subpopulation maintained under normal conditions. For technical reasons, the model assumed that the kinetic parameters of the various toxin-antitoxin systems in the cell are identical, but experimental data indicate that they differ, sometimes dramatically. Thus, a critical question remains: whether toxin-antitoxin systems from the diverse families, often found together in a cell, with significantly different kinetics, can cooperate in a similar manner. Here, we characterize the interaction of toxin-antitoxin systems from many families that are unrelated and kinetically diverse, and identify the essential determinant for their cooperation. The generic architecture of toxin-antitoxin systems provides the potential for bistability, and our results show that even when they do not exhibit bistability alone, unrelated systems can be coupled by the growth rate to create a strongly bistable, hysteretic switch between normal (fast-growing) and persistent (slow-growing) states. Different combinations of kinetic parameters can produce similar toxic switching thresholds, and the proximity of the thresholds is the primary determinant of bistability. Stochastic fluctuations can spontaneously switch all of the toxin-antitoxin systems in a cell at once. The spontaneous switch creates a heterogeneous population of growing and non-growing cells, typical of persisters, that exist under normal conditions, rather than only as an induced response. The frequency of persisters in the population can be tuned for a particular environmental niche by mixing and matching unrelated systems via mutation, horizontal gene transfer and selection
Crime and Immigration: Evidence from Large Immigrant Waves
This paper examines the relationship between immigration and crime in a setting where large migration flows offer an opportunity to carefully appraise whether the populist view that immigrants cause crime is borne out by rigorous evidence. We consider possible crime effects from two large waves of immigration that recently occurred in the UK. The first of these was the late 1990s/early 2000s wave of asylum seekers, and the second the large inflow of workers from EU accession countries that took place from 2004. A simple economics of crime model, when dovetailed with facts about the relative labour market position of these migrant groups, suggests net returns to criminal activity are likely to be very different for the two waves. In fact, we show that the first wave led to a small rise in property crime, whilst the second wave had no such impact. There was no observable effect on violent crime for either wave. Nor were immigrant arrest rates different to natives. Evidence from victimization data also suggests that the changes in crime rates during the immigrant waves cannot be ascribed to crimes against immigrants. Overall, our findings suggest that focusing on the limited labour market opportunities of asylum seekers could have beneficial effects on crime rates.crime, immigration
Crime and Immigration: Evidence from Large Immigrant Waves
This paper examines the relationship between immigration and crime in a setting where large migration flows offer an opportunity to carefully appraise whether the populist view that immigrants cause crime is borne out by rigorous evidence. We consider possible crime effects from two large waves of immigration that recently occurred in the UK. The first of these was the late 1990s/early 2000s wave of asylum seekers, and the second the large inflow of workers from EU accession countries that took place from 2004. A simple economics of crime model, when dovetailed with facts about the relative labour market position of these migrant groups, suggests net returns to criminal activity are likely to be very different for the two waves. In fact, we show that the first wave led to a small rise in property crime, whilst the second wave had no such impact. There was no observable effect on violent crime for either wave. Nor were immigrant arrest rates different to natives. Evidence from victimization data also suggests that the changes in crime rates during the immigrant waves cannot be ascribed to crimes against immigrants. Overall, our findings suggest that focusing on the limited labour market opportunities of asylum seekers could have beneficial effects on crime rates.crime, immigration
Synchronization propensity in networks of dynamical systems: A purely topological indicator
Synchronization in networks of identical dynamical systems is enhanced by the number of manifolds in which synchrony of groups of systems is conserved or reinforced. Since the number of these invariant manifolds depends only on the coupling architecture of the network, it can be proposed as a purely topological indicator of synchronization propensity. The proposal is empirically validated through the detailed study of an ecological application
Local stabilization and network synchronization: The case of stationary regimes
Relationships between local stability and synchronization in networks of identical dynamical systems are established through the Master Stability Function approach. First, it is shown that stable equilibria of the local dynamics correspond to stable stationary synchronous regimes of the entire network if the coupling among the systems is sufficiently weak or balanced (in other words, stationary synchronous regimes can be unstable only if the coupling is sufficiently large and unbalanced). Then, it is shown that [de]stabilizing factors at local scale are [de]synchronizing at global scale again if the coupling is sufficiently weak or balanced. These results allow one to transfer, with almost no effort, what is known for simple prototypical models in biology and engineering to complex networks composed of these models. This is shown through a series of applications ranging from networks of electrical circuits to various problems in ecology and sociology involving migrations of plants, animal and human populations
The hygiene in Buenos Aires of XVIII century
El setecientos fue una etapa de gran efervescencia intelectual en la que se destacĂł la construcciĂłn de una ciencia vinculada con el desarrollo de la burguesĂa urbana que proclamaba el progreso en todos los aspectos, tambiĂ©n en la vida práctica. Entre los actores de cambio encontramos a cientĂficos reputados, a toda una corte de figuras de indudable resonancia polĂtica y cultural, a las instituciones que favorecieron los estudios y a la difusiĂłn de las ideas que fueron alentadas por los Borbones. Este estudio se centrará en la ciudad de Buenos Aires desde mediados del siglo XVIII y hasta los primeros años de la centuria siguiente y tendrá como objeto el examinar las medidas de higiene tomadas con respecto al manejo de alimentos y otros bienes muebles. Para ello se consultaron los bandos de buen gobierno y las actas del cabildo de la ciudad.The 1700’s were a time of great intellectual effervescence. It stood out the establishing of a science linked to the development of the urban bourgeoisie, which proclaimed progress in all its aspects, including everyday life. Among the actors of change, it was to find renowned scientists, a retinue of prominent figures of the political and cultural sphere, institutions that fostered studies, and the spread of ideas supported by the Bourbons. The present study will consider the city of Buenos Aires from midst of the XVIII century until the beginning of the next century, with the purpose of examining the hygienic measures taken regarding handling of food and other consumable items. To that end, law enforcement edicts and minutes of the town council were consulted
Temporalities embedded on the intensive body during the experience of the artistic project SoundSystem
This article addresses the artistic project SoundSystem, developed by Franz Manata and Saulo Laudares since 1996. The process, in action up to the present day, consists of sharing experiences through sound installations, DJ’s performances and urban interventions. Universal signs such as heart beats and bird corners are used. The duo assumes an ethical concern to affect the participant. The main issues involved are the “good encounters”, the time-dilation and the intensity provoked by the dionysian impulses of music and dance. This text will discuss the possibility of experience the time of the event, resisting to chronopolitics
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