Cichlid Fish Diversity Threatened by Eutrophication That Curbs Sexual Selection

Cichlid fish species of Lake Victoria can interbreed without loss of fertility but are sexually isolated by mate choice. Mate choice is determined on the basis of coloration, and strong assortative mating can quickly lead to sexual isolation of color morphs. Dull fish col- oration, few color morphs, and low species diversity are found in areas that have become turbid as a result of recent eutrophication. By constraining color vision, turbidity interferes with mate choice, relaxes sexual selection, and blocks the mechanism of reproductive isolation. In this way, human activities that increase turbidity destroy both the mechanism of diversification and that which maintains diversity.

Performing immobility / protesting immobility: The risks & rewards of public space protest performances

Though there is much interest in mobilities and performing mobilities as a characteristic of modern, urban, social life today, this is not always matched by attention to immobilities, as the flipside of mobility in modern life. In this paper, I investigate public space performances designed to draw attention to precisely this counterpoint to current discourses of mobilities – performances about the socially produced immobilities many people with disabilities find a more fundamental feature of day-to-day life, the fight for mobility, and the freedom found when accommodations for alternative mobilities are made available. Although public policy is increasingly aligned with a social model of disability, which sees disability as socially constructed through systems, institutions and infrastructure deliberately designed to exclude specific bodies – stairs, curbs, queues and so forth – and although governments in the US, UK, and to a lesser degree Australia, New Zealand and other Commonwealth nations aim to address these inequalities, the experience of immobility is still every-present for many people. This often comes not just from pain, or from impairment, or event from lack of accommodations for alternative mobilities, but from fellow social performers’ antipathy to, appropriation of, or destruction of accommodations designed to facilitate access for a range of different bodies in public space, and thus the public sphere. The archetypal instance of this tension between the mobile, and those needing accommodations to allow mobility, is, of course, the antipathy many able bodied people feel towards the provision of disabled parking spaces. A cursory search online shows thousands of accounts of antagonism, vitriol, and even violence prompted by disputes which began when a disabled person asked an able person to exit a designated disabled parking space. For many, it seems, expecting them to pass by such parks so others can experience the mobility they take for granted is too much. In this paper, I examine a number of protest performances in public space in which activist present actions – for example, placing wheelchairs in every regular parking space in a precinct – to give bystanders, passersby and spectators, as well as antagonistic fellow social performers, a sense of what socially produced immobility feels like. I examine responses to such protest performances, and what they say about the potential social, political and ethical impacts of such protests, in terms of their potential to produce new attitudes to mobility, alternative mobility, and access to alternative modes of mobility.

Les effets de l'européanisation de la lutte contre la migration irrégulière sur les droits humains des migrants

Les politiques migratoires européennes sont conçues en termes de contrôle de l’entrée et du séjour des étrangers. Depuis la mise en place des conditions de libre circulation dans les années 1980, l’Union européenne est impliquée dans le traitement des non-nationaux qui, auparavant, relevait exclusivement de la discrétion étatique. La migration et l’asile sont aujourd’hui des domaines de compétence partagée entre l’Union et ses membres. La priorité est accordée à la lutte contre la migration irrégulière, perçue non seulement comme un défi à la souveraineté, mais aussi comme une menace à l’État providence et un risque pour la sécurité. Cette recherche porte sur l’européanisation de la lutte contre la migration irrégulière et ses effets sur les droits humains des étrangers. Il est soutenu que l’européanisation définie comme un processus de construction, de diffusion et d’institutionnalisation des normes, des pratiques et des convictions partagées, permet aux États d’atteindre leur objectif de limiter le nombre d’étrangers indésirés, y compris des demandeurs d’asile, sur leur sol. L’européanisation légitime et renforce les mesures préventives et dissuasives existantes à l’encontre des migrants clandestins. De nouvelles normes communes sont produites et de nouveaux dispositifs de coopération européenne sont créés en vue de réprimer la migration irrégulière. Ce phénomène transforme le paradigme migratoire dans les États membres ainsi que les pays candidats à l’adhésion qui se trouvent désormais chargés de la sécurisation des frontières extérieures de l’Union. La recherche démontre que ces développements ont un impact négatif sur les droits fondamentaux. Ils exacerbent aussi la vulnérabilité des demandeurs d’asile assimilés aux migrants économiques. Une analyse comparative de l’européanisation du renvoi forcé en France, au Royaume-Uni et en Turquie montre que la politique européenne engendre des atteintes aux droits et libertés des étrangers et limite leur capacité de contester les violations devant les tribunaux. L’accent est mis sur la nécessité de trouver un équilibre entre la préoccupation légitime des États et de l’Union d’assurer la sécurité et le bien-être de leurs citoyens et la protection des droits des migrants irréguliers. Il revient ultimement aux tribunaux de veiller à ce que le pouvoir discrétionnaire étatique s’exerce en stricte conformité avec les normes constitutionnelles et les obligations internationales découlant du droit international des réfugiés et des droits de l’homme.

Gait termination : a review of experimental methods and the effects of aging and gait pathologies

The study of human gait has expanded and diversified to the extent that it is now possible to identify a substantive literature concerning a variety of gait tasks, such as gait initiation [Halliday SE, Winter DA, Frank JS, Patla AE, Prince F. The initiation of gait in young, elderly, and Parkinson's disease subjects. Gait Posture 1998;8:8–14; Mickelborough J, van der Linden ML, Tallis RC, Ennos AR. Muscle activity during gait initiation in normal elderly people. Gait Posture 2004;19:50–57], stepping over and across obstacles [Patla AE, Prentice SD, Robinson C, Newfold J. Visual control of locomotion: strategies for changing direction and for going over obstacles. J Exp Psych 1991;17:603–34; Chen, HC, Ashton-Miller JA, Alexander NB, Schultz AB. Effect of age and available response time on ability to step over an obstacle. J Gerontol 1994;49:227–33; Sparrow WA, Shinkfield AJ, Chow S, Begg RK. Gait characteristics in stepping over obstacles. Hum Mov Sci 1996;15:605–22; Begg RK, Sparrow WA, Lythgo ND. Time-domain analysis of foot–ground reaction forces in negotiating obstacles. Gait Posture 1998;7:99–109; Patla AE, Rietdyk S. Visual control of limb trajectory over obstacles during locomotion: effect of obstacle height and width. Gait Posture 1993;1:45–60] negotiating raised surfaces such as curbs and stairs [Begg RK, Sparrow WA. Gait characteristics of young and older individuals negotiating a raised surface: implications for the prevention of falls. J Gerontol Med Sci 2000;55A:147–54; Mcfayden BJ, Winter DA. An integrated biomechanical analysis of normal stair ascent and descent. J Biomech 1988;21:733–44]. In addition, increasing research interest in age-related declines in gait that might predispose individuals to falls has engendered a very extensive literature concerning ageing effects on gait. While rapid locomotor adjustments are common in the course of daily activities there has been no previous review of the findings concerning gait adaptations when walking is terminated both rapidly and unexpectedly. The aims of this review were first, to summarise the key research findings and methodological considerations from studies of termination. The second aim was to demonstrate the effects of ageing and gait pathologies on termination with respect to the regulation of step characteristics, lower-limb muscle activation patterns and foot–ground reaction forces.

The Limits of political compromise: debt ceilings and political competition

We study the desirability of limits on the public debt and of political competition in an economy where political parties alternate in office. Due to rent-seeking motives, incumbents have an incentive to set public expenditures above the socially optimal level. Parties cannot commit to future policies, but they can forge a political compromise where each party curbs excessive spending when in office if it expects future governments to do the same. In contrast to the received literature, we find that strict limits on government borrowing can exacerbate political-economy distortions by rendering a political compromise unsustainable. This tends to happen when political competition is limited. Conversely, a tight limit on the public debt fosters a compromise that yields the efficient outcome when political competition is vigorous, saving the economy from immiseration. Our analysis thus suggests a legislative tradeoff between restricting political competition and constraining the ability of governments to issue debt.

Dynamic control of a reconfigurable stair-climbing mobility system

Electric-powered wheelchairs improve the mobility of people with physical disabilities, but the problem to deal with certain architectural barriers has not been resolved satisfactorily. In order to solve this problem, a stair-climbing mobility system (SCMS) was developed. This paper presents a practical dynamic control system that allows the SCMS to exhibit a successful climbing process when faced with typical architectural barriers such as curbs, ramps, or staircases. The implemented control system depicts high simplicity, computational efficiency, and the possibility of an easy implementation in a microprocessor-/microcontroller-based system. Finally, experiments are included to support theoretical results.

Binding of purified multiple antibiotic-resistance repressor protein (MarR) to mar operator sequences.

Elevated expression of the marORAB multiple antibiotic-resistance operon enhances the resistance of Escherichia coli to various medically significant antibiotics. Transcription of the operon is repressed in vivo by the marR-encoded protein, MarR, and derepressed by salicylate and certain antibiotics. The possibility that repression results from MarR interacting with the marO operator-promoter region was studied in vitro using purified MarR and a DNA fragment containing marO. MarR formed at least two complexes with marO DNA, bound > 30-fold more tightly to it than to salmon sperm DNA, and protected two separate 21-bp sites within marO from digestion by DNase I. Site I abuts the downstream side of the putative -35 transcription-start signal and includes 4 bp of the -10 signal. Site II begins 13 bp downstream of site I, ending immediately before the first base pair of marR. Site II, approximately 80% homologous to site I, is not required for repression since a site II-deleted mutant (marO133) was repressed in trans by wild-type MarR. The absence of site II did not prevent MarR from complexing with the site I of marO133. Salicylate bound to MarR (Kd approximately 0.5 mM) and weakened the interaction of MarR with sites I and II. Thus, repression of the mar operon, which curbs the antibiotic resistance of E. coli, correlates with the formation of MarR-site I complexes. Salicylate appears to induce the mar operon by binding to MarR and inhibiting complex formation, whereas tetracycline and chloramphenicol, which neither bind MarR nor inhibit complex formation, must induce by an indirect mechanism.

A comparative analysis of bicycle lanes versus wide curb lanes: final report.

Federal Highway Administration, Office of Safety and Traffic Operations, Washington, D.C.

Bicycle lanes versus wide curb lanes: operational and safety findings and countermeasure recommendations.

Federal Highway Administration, Office of Safety and Traffic Operations, Washington, D.C.

An evaluation of detectable warning surfaces for sidewalk curb ramps. Final report.

Virginia Department of Transportation, Richmond

Provisions for elderly and handicapped pedestrians. Volume 2: hazards, barriers, problems and the law. Final report.

Federal Highway Administration, Office of Research and Development, Washington, D.C.

Provisions for elderly and handicapped pedestrians. Volume 3: the development and evaluation of countermeasures. Final report.

Federal Highway Administration, Office of Research and Development, Washington, D.C.

User's guide and program description for a tripped roll over vehicle simulation. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Provisions for elderly and handicapped pedestrians. Volume I: executive summary. Final report.

Federal Highway Administration, Office of Research and Development, Washington, D.C.