Adaptive and demographic responses of plankton populations to environmental change

Because of their large population sizes, short generation times, and clonal mode of propagation, microorganisms should often be the first members of a community to respond evolutionarily to temporal changes in the environment. Because the planktonic microbial community directly or indirectly influences all other members of aquatic ecosystems, it is useful to have a general theory for the magnitude and limits of such response. Models are presented for the expected dynamics of evolutionary change for the mean and variance of a quantitative character under natural selection toward a fixed or a moving optimum. It is also shown how the rate of population growth is related to the phenotypic composition of the population and the selective aspects of the environment. These models, which lead to the identification of extinction thresholds for the rate of environmental change beyond which a population cannot maintain itself, provide a heuristic basis for understand-ing the response of ecosystems to environmental perturbations. The analyses also indicate that clones of microorganisms isolated into novel laboratory environments are likely to undergo sub-stantial evolutionary change over periods of a few hundred days, which raises questions about the utility of such cultures for inferring ecological properties of natural populations

Late-onset Lafora disease with prominent parkinsonism due to a rare mutation in EPM2A

Lafora disease (LD) is an autosomal recessive form of progressive myoclonic epilepsy that is caused by mutations in EPM2A, encoding laforin, and NHLRC1 (EPM2B), encoding malin.(1) LD is classically described with onset in early teenage years. Patients develop myoclonus, epilepsy, visual hallucinations, and psychosis. Dementia is a prominent feature and often occurs in the late teenage years. LD typically progresses quickly, and patients become bedridden and dependent within 10 years of symptom onset, with life expectancy in the early 20s.(2,3) Only a small number of late-onset cases of LD have been described. Even then, these so-called late-onset cases have typically presented in the 20s, with dementia occurring in the early 30s. We describe a patient with extremely late onset and extended survival with prominent parkinsonism due to a novel EPM2A variant

Measuring transport-associated urban inequalities: Where are we and where do we go from here?

Reducing urban inequalities is at the forefront of the global sustainable development agenda, as well as national and local policies. While existing measures of inequality are mostly focused on income and wealth, it is widely recognised that non-monetary disparities such as in health, education, and housing play a crucial role in creating and reinforcing inequalities. Transport plays a central role in mitigating inequalities by enhancing access to employment, education, and essential services. It is also directly and indirectly related to disparities in housing, neighbourhoods, and health. Policymakers increasingly recognize the potential of transport policies in addressing inequalities; however, the effects of interventions need to be understood beyond the transport sector only and should consider wider impacts. In this review, we concentrate on three interlinked sectors – housing, land-use, and transportation – where local governments possess some capacity to influence the processes by which inequalities are created and exacerbated. Currently, empirical research on inequalities within these domains is fragmented. Models and datasets used for scenario testing, planning, and intervention evaluation are often disjointed, sector-focused, and rarely consider distributional effects. Our aim is to critically review the literature across different disciplines and perspectives and propose future interdisciplinary directions towards better measurement and modelling of transport-associated inequalities

Concern and counter-concern : the challenge of fragmented fears for the reguation of hydraulic fracturing

Proposals to use the process of hydraulic fracturing (fracking) to extract natural gas in the United Kingdom has been met with both opposition and support as has often been the case for new extractive industries exploring new techniques or applications thereof. An idiosyncratic feature of the debate surrounding hydraulic fracturing is however the seeming lack of congruence of the concerns raised by experts and civic opposition. The authors consider the potential implications of this fragmentation of fears surrounding the process for its future regulation

Composition Structure of Interplanetary Coronal Mass Ejections From Multispacecraft Observations, Modeling, and Comparison with Numerical Simulations

We present an analysis of the ionic composition of iron for two interplanetary coronal mass ejections observed in May 21-23 2007 by the ACE and STEREO spacecraft in the context of the magnetic structure of the ejecta flux rope, sheath region, and surrounding solar wind flow. This analysis is made possible due to recent advances in multispacecraft data interpolation, reconstruction, and visualization as well as results from recent modeling of ionic charge states in MHD simulations of magnetic breakout and flux cancellation CME initiation. We use these advances to interpret specific features of the ICME plasma composition resulting from the magnetic topology and evolution of the CME. We find that in both the data and our MHD simulations, the flux ropes centers are relatively cool, while charge state enhancements surround and trail the flux ropes. The magnetic orientation of the ICMEs are suggestive of magnetic breakout-like reconnection during the eruption process, which could explain the spatial location of the observed iron enhancements just outside the traditional flux rope magnetic signatures and between the two ICMEs. Detailed comparisons between the simulations and data were more complicated, but a sharp increase in high iron charge states in the ACE and STEREO-A data during the second flux rope corresponds well to similar features in the flux cancellation results. We discuss the prospects of this integrated in-situ data analysis and modeling approach to advancing our understanding of the unified CME-to-ICME evolution.Comment: Accepted for submission to The Astrophysical Journa

Polarization effects in metallic films perforated with a bidimensional array of subwavelength rectangular holes

For several years, periodical arrays of subwavelength cylindrical holes in thin metallic layers have taken a crucial importance in the context of the results reported by Ebbesen et al, on particularly attractive optical transmission experiments. It had been underlined that the zeroth order transmission pattern does not depend on the polarization of the incident light at normal incidence. In the present paper, we show that it is not the case for rectangular holes, by contrast to the case of circular holes. In this context, we suggest a new kind of polarizer that present the advantages brought by the original Ebbesen devices. Assuming the recent technological interest for these kinds of metallic gratings, such a kind of polarizer could lead to new technological applications.Comment: 5 pages, 7 figures. Published versio