The effects of past, present and future climate change on range-wide genetic diversity in northern North Atlantic marine species

It is now accepted that changes in the Earth’s climate are having a profound effect on the distributions of a wide variety of species. One aspect of these changes that has only recently received any attention, however, is their potential effect on levels of within-species genetic diversity. Theoretical, empirical and modelling studies suggest that the impact of trailing-edge population extirpation on range-wide intraspecific diversity will be most pronounced in species that harbour the majority of their genetic variation at low latitudes as a result of changes during the Quaternary glaciations. In the present review, I describe the historical factors that have determined current patterns of genetic variation across the ranges of Northern North Atlantic species, highlight the fact that the majority of these species do indeed harbour a disproportionate level of genetic diversity in rear-edge populations, and outline how combined species distribution modelling and genetic analyses can provide insights into the potential effects of climate change on their overall genetic diversity.

Magnetic short-range order in the new ternary phase Mn8Pd15Si7

A new compound, Mn8Pd15Si7, is reported to crystallize in a face centered cubic unit cell of dimension a = 12.0141(2) angstrom, space groupFm (3) over barm, and can thus be classified as a G-phase. The crystal structure was studied by single crystal X-ray diffraction, X-ray and neutron powder diffraction and electron diffraction. A filled Mg6Cu16Si7 type structure was found, corresponding to the Sc11Ir4 type structure. The magnetic properties were investigated by magnetization measurements and Reverse Monte Carlo modeling of low temperature magnetic short-range order (SRO). Dominating near neighbor antiferromagnetic correlations were found between the Mn atoms and geometric frustration in combination with random magnetic interactions via metal sites with partial Mn occupancy were suggested to hinder formation of long-range magnetic order. 

Altered Long-Range Phase Synchronization and Cortical Activation in Children Born Very Preterm

Children born very preterm, even with broadly normal IQ, commonly show selective difficulties in visuospatial processing and executive functioning. Very little, however, is known what alterations in cortical processing underlie these deficits. We recorded MEG while eight children born very preterm (=32 weeks gestational age) and eight full-term controls performed a visual short-term memory task at mean age 7.5 years (range 6.4 - 8.4). Previously, we demonstrated increased long-range alpha and beta band phase synchronization between MEG sensors during STM retention in a group of 17 full-term children age 6-10 years. Here we present preliminary evidence that long-range phase synchronization in very preterm children, relative to controls, is reduced in the alpha-band but increased in the theta-band. In addition, we investigated cortical activation during STM retention employing synthetic aperture magnetometry (SAM) beamformer to localize changes in gamma-band power. Preliminary results indicate sequential activation of occipital, parietal and frontal cortex in control children, as well as reduced activation in very preterm children relative to controls. These preliminary results suggest that children born very preterm exhibit altered inter-regional functional connectivity and cortical activation during cognitive processing.

Altered long-range alpha-band synchronization during visual short-term memory retention in children born very preterm

Children born very preterm, even when intelligence is broadly normal, often experience selective difficulties in executive function and visual-spatial processing. Development of structural cortical connectivity is known to be altered in this group, and functional magnetic resonance imaging (fMRI) evidence indicates that very preterm children recruit different patterns of functional connectivity between cortical regions during cognition. Synchronization of neural oscillations across brain areas has been proposed as a mechanism for dynamically assigning functional coupling to support perceptual and cognitive processing, but little is known about what role oscillatory synchronization may play in the altered neurocognitive development of very preterm children. To investigate this, we recorded magnetoencephalographic (MEG) activity while 7-8 year old children born very preterm and age-matched full-term controls performed a visual short-term memory task. Very preterm children exhibited reduced long-range synchronization in the alpha-band during visual short-term memory retention, indicating that cortical alpha rhythms may play a critical role in altered patterns functional connectivity expressed by this population during cognitive and perceptual processing. Long-range alpha-band synchronization was also correlated with task performance and visual-perceptual ability within the very preterm group, indicating that altered alpha oscillatory mechanisms mediating transient functional integration between cortical regions may be relevant to selective problems in neurocognitive development in this vulnerable population at school age.

Long-range synchronization and local desynchronization of alpha oscillations during visual short-term memory retention in children

Local alpha-band synchronization has been associated with both cortical idling and active inhibition. Recent evidence, however, suggests that long-range alpha synchronization increases functional coupling between cortical regions. We demonstrate increased long-range alpha and beta band phase synchronization during short-term memory retention in children 6-10 years of age. Furthermore, whereas alpha-band synchronization between posterior cortex and other regions is increased during retention, local alpha-band synchronization over posterior cortex is reduced. This constitutes a functional dissociation for alpha synchronization across local and long-range cortical scales. We interpret long-range synchronization as reflecting functional integration within a network of frontal and visual cortical regions. Local desynchronization of alpha rhythms over posterior cortex, conversely, likely arises because of increased engagement of visual cortex during retention.

Temperature and water potential relations of tropical Trametes and other wood-decay fungi from the indigenous forests of Zimbabwe

Three isolates each, of nine different Trametes and five other wood inhabiting basidiomycetes, were collected from the indigenous forests of Zimbabwe, and the impact of temperature (20-60 degrees C), osmotic and matric potential (-0.5 to - 8.0 MPa), and their interactions on in vitro growth compared. Generally, there was no significant difference between growth of isolates of the same species in relation to temperature. Temperature relationships of the species studied correlated well with their geographic distributions. Species occurring in hot, dry regions tolerated a wide temperature range, with some showing unusually high thermotolerance (55 degrees, T. socotrana, T. cingulata and T. cervina). There were significant intra-strain differences for individual species in relation to solute potential on glycerol-modified media. Generally, growth of ail species was better on glycerol- and KCl-modified osmotic media than on a metrically-modified medium (PEG 8000) at 25, 30 and 37 degrees. The limits for growth on the osmotic media were significantly wider than matric medium, being - 4.5 to - 5.0 and - 2.5 to - 4.5 MPa, respectively. An Irpex sp. grew at lower water potentials than all other species, with good growth at - 7.0 MPa. This study suggests that the capacity of these fungi for effective growth over a range of temperatures, osmotic and matric potentials contributes to their rapid wood decay capacities in tropical climates.

Thermal conductivities of ionic liquids over the temperature range from 293 K to 353 K

The thermal conductivities of 11 ionic liquids were determined, over the temperature range from 293 K to 353 K, at atmospheric pressure, using an apparatus based on the transient hot-wire method. For each of the ionic liquids studied, the thermal conductivities were found to be between (0.1 and 0.2) W.m(-1).K-1, with a slight decrease observed on increasing temperature. The uncertainty is estimated to be less than +/- 0.002 W.m(-1).K-1. In all cases, a linear equation was found to give a good fit to the data. The effects of water content and chloride content on the thermal conductivities of some of the ionic liquids were investigated. In each case, the thermal conductivities of the water + ionic liquid and chloride + ionic liquid binary mixtures were found to be less than the weighted average of the pure component thermal conductivities. This effect was adequately modeled using the Jamieson correlation. Chloride contamination at typical postsynthesis levels was found to have no significant effect on the thermal conductivities of the ionic liquid studied.

Thomson spectrometer-microchannel plate assembly calibration for MeV-range positive and negative ions, and neutral atoms

We report on the absolute calibration of a microchannel plate (MCP) detector, used in conjunction with a Thomson parabola spectrometer. The calibration delivers the relation between a registered count numbers in the CCD camera (on which the MCP phosphor screen is imaged) and the number of ions incident on MCP. The particle response of the MCP is evaluated for positive, negative, and neutral particles at energies below 1 MeV. As the response of MCP depends on the energy and the species of the ions, the calibration is fundamental for the correct interpretation of the experimental results. The calibration method and arrangement exploits the unique emission symmetry of a specific source of fast ions and atoms driven by a high power laser.

SiGe V Band Wide Tuning-Range VCO and Frequency Divider for Phase Locked Loop

A V-band wide tuning-range VCO and high frequency divide-by-8 frequency divider using Infineon 0.35 µm SiGe HBT process are presented in this paper. An LC impedance peaking technique is introduced in the Miller divider to increase the sensitivity and operation frequency range of the frequency divider. Two static frequency dividers implemented using current mode logic are used to realize dividing by 4 in the circuit. The wide tuning range VCO operates from 51.9 to 64.1 GHz i.e. 20.3% frequency tuning range. The measured phase noise at the frequency divider output stage is around -98.5 dBc at 1 MHz. The circuit consumes 200mW and operates from a 3.5Vdc supply, and occupies 0.6×0.8 mm2 die area.

Physical activity and the rejuvenation of Connswater (PARC study): protocol for a natural experiment investigating the impact of urban regeneration on public health

Background: There is a dearth of evidence regarding the impact of urban regeneration projects on public health, particularly the nature and degree to which urban regeneration impacts upon health-related behaviour change. Natural experiment methodology enables comprehensive large-scale evaluations of such interventions. The Connswater Community Greenway in Belfast is a major urban regeneration project involving the development of a 9 km linear park, including the provision of new cycle paths and walkways. In addition to the environmental improvements, this complex intervention involves a number of programmes to promote physical activity in the regenerated area. The project affords a unique opportunity to investigate the public health impact of urban regeneration.

Methods/Design: The evaluation framework was informed by the socio-ecological model and guided by the RE-AIM Framework. Key components include: (1) a quasi-experimental before-and-after survey of the Greenway population (repeated cross-sectional design), in tandem with data from a parallel Northern Ireland-wide survey for comparison; (2) an assessment of changes in the local built environment and of walkability using geographic information systems; (3) semi-structured interviews with a purposive sample of survey respondents, and a range of community stakeholders, before and after the regeneration project; and (4) a cost-effectiveness analysis. The primary outcome is change in proportion of individuals identified as being regularly physically active, according to the current UK recommendations. The RE-AIM Framework will be used to make an overall assessment of the impact of the Greenway on the physical activity behaviour of local residents.

Discussion: The Connswater Community Greenway provides a significant opportunity to achieve long-term, population level behaviour change. We argue that urban regeneration may be conceptualised meaningfully as a complex intervention comprising multiple components with the potential, individually and interactively, to affect the behaviour of a diverse population. The development and implementation of our comprehensive evaluation framework reflects this complexity and illuminates an approach to the empirical, rigorous evaluation of urban regeneration. More specifically, this study will add to the much needed evidence-base about the impact of urban regeneration on public health as well as having important implications for the development of natural experiment methodology.

Long-Range Lateral Dopant Diffusion in Tungsten Silicide Layers

Novel diode test structures have been manufactured to characterize long-range dopant diffusion in tungsten silicide layers. A tungsten silicide to p-type silicon contact has been characterized as a Schottky barrier rectifying contact with a silicide work function of 4.8 eV. Long-range diffusion of boron for an anneal at 900 °C for 30 min has been shown to alter this contact to become ohmic. Long-range diffusion of phosphorus with a similar anneal alters the contact to become a bipolar n-p diode. Bipolar diode action is demonstrated experimentally for anneal schedules of 30 min at 900 °C, indicating long-range diffusion of phosphorus (~38 µm), SIMS analysis shows dopant redistribution is adversely affected by segregation to the silicide/oxide interface. The concept of conduit diffusion has been demonstrated experimentally for application in advanced bipolar transistor technology. © 2009 IEEE.

Fluorescence based fibre optic pH sensor for the pH 10–13 range suitable for corrosion monitoring in concrete structures

The design, development and evaluation of an optical fibre pH sensor for monitoring pH in the alkaline region are discussed in detail in this paper. The design of this specific pH sensor is based on the pH induced change in fluorescence intensity of a coumarin imidazole dye which is covalently attached to a polymer network and then fixed to the distal end of an optical fibre. The sensor provides a response over a pH range of 10.0–13.2 with an acceptable response rate of around 50 min, having shown a very good stability over a period of longer than 20 months thus far. The sensor has also demonstrated little cross-sensitivity to ionic strength (IS) and also excellent photostability through a series of laboratory tests. These features make this type of sensor potentially well suited for in situ long term monitoring of pH in concrete structures, to enhance structural monitoring in the civil engineering sector

Health status and 6 years survival of 552 90+ Italian sib-ships recruited within the EU Project GEHA (GEnetics of Healthy Ageing).

In a scenario of increasing life expectancy worldwide, it is mandatory to identify the characteristics of a healthy aging phenotype, including survival predictors, and to disentangle those related to environment/lifestyle versus those related to familiarity/genetics. To this aim we comprehensively characterised a cohort of 1,160 Italian subjects of 90 years and over (90+, mean age 93 years; age range 90-106 years) followed for 6 years survival, belonging to 552 sib-ships (familiar longevity) recruited (2005-2008) within the EU-funded GEHA project in three Italian geographic areas (Northern, Central and Southern Italy) different for urban/rural and socio-economical characteristics. On the whole, the following factors emerged as significant predictors of survival after 90 years of age: absence of cognitive impairment and physical disability, high hand grip strength scores and body mass index (BMI) values, "excellent/good" self-reported health, high haemoglobin and total cholesterol levels and low creatinine levels. These parameters, excluding BMI values, were also significantly associated within sib-ships, suggesting a strong familial/genetic component. Geographical micro-heterogeneity of survival predictors emerged, such as functional and physical status being more important in Southern than in Central and Northern Italy. In conclusion, we identified modifiable survival predictors related to specific domains, whose role and importance vary according to the geographic area considered and which can help in interpreting the genetic results obtained by the GEHA project, whose major aim is the comprehensive evaluation of phenotypic and genetic data.