547 research outputs found
Digital Infrastructures, Higher Education and the Net-Generation of Students
Students currently in higher education in the industrialised world have unprecedented access to web-based technologies and tools, and are likely to have engaged with online activities throughout their educational experiences. More widely, there is increasing pressure on universities to provide flexible learning environments and access to resources. This is keenly felt in the computer laboratory, where once dedicated, stand-alone machines provided software packages for students to work on during timetabled sessions. In recognising the move away from such patterns, Macquarie University is developing software and infrastructure to enable distributed access at any time to students, thus making a conceptual and physical shift from so-called ‘Local Area Networking’ to ‘Wide Area Networking’ and enabling greater freedom of access. The initiative is from within the Division of Economics and Financial Studies (EFS), but is applicable to students of any discipline in any university. This paper describes the development and discusses some of the implications for learning and teaching.8 page(s
Wakefulness affects synaptic and network activity by increasing extracellular astrocyte-derived adenosine
Loss of sleep causes an increase in sleep drive and deficits in hippocampal-dependent memory. Both of these responses are thought to require activation of adenosine A1 receptors (adorA1Rs) and release of transmitter molecules including ATP, which is rapidly converted to adenosine in the extracellular space, from astrocytes in a process termed gliotransmission. Although it is increasingly clear that astrocyte-derived adenosine plays an important role in driving the homeostatic sleep response and the effects of sleep loss on memory (Halassa et al., 2009; Florian et al., 2011), previous studies have not determined whether the concentration of this signaling molecule increases in response to wakefulness. Here, we show that the level of adorA1R activation increases in response to wakefulness in mice (Mus musculus). We found that this increase affected synaptic transmission in the hippocampus and modulated network activity in the cortex. Direct biosensor-based measurement of adenosine showed that the net extracellular concentration of this transmitter increased in response to normal wakefulness and sleep deprivation. Genetic inhibition of gliotransmission prevented this increase and attenuated the wakefulness-dependent changes in synaptic and network regulation by adorA1R. Consequently, we conclude that wakefulness increases the level of extracellular adenosine in the hippocampus and that this increase requires the release of transmitters from astroctyes
Benzonitrile as a Proxy for Benzene in the Cold ISM: Low-temperature Rate Coefficients for CN + C₆H₆
The low-temperature reaction between CN and benzene (C₆H₆) is of significant interest in the astrochemical community due to the recent detection of benzonitrile, the first aromatic molecule identified in the interstellar medium (ISM) using radio astronomy. Benzonitrile is suggested to be a low-temperature proxy for benzene, one of the simplest aromatic molecules, which may be a precursor to polycyclic aromatic hydrocarbons. In order to assess the robustness of benzonitrile as a proxy for benzene, low-temperature kinetics measurements are required to confirm whether the reaction remains rapid at the low gas temperatures found in cold dense clouds. Here, we study the C₆H₆ + CN reaction in the temperature range 15–295 K, using the well-established CRESU technique (a French acronym standing for Reaction Kinetics in Uniform Supersonic Flow) combined with pulsed-laser photolysis-laser-induced fluorescence. We obtain rate coefficients, k(T), in the range (3.6–5.4) × 10⁻¹⁰ cm³ s⁻¹ with no obvious temperature dependence between 15 and 295 K, confirming that the CN + C₆H₆ reaction remains rapid at temperatures relevant to the cold ISM
The genome sequence of the Round-winged Muslin, Thumatha senex (Hübner, 1804)
We present a genome assembly from an individual female Thumatha senex (the Round-winged Muslin; Arthropoda; Insecta; Lepidoptera; Erebidae). The genome sequence is 810.3 megabases in span. Most of the assembly is scaffolded into 30 chromosomal pseudomolecules, including the W and Z sex chromosomes. The mitochondrial genome has also been assembled and is 15.5 kilobases in length
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The importance of including habitat-specific behaviour in models of butterfly movement
Dispersal is a key process affecting population persistence and major factors affecting dispersal rates are the amounts, connectedness and properties of habitats in landscapes. We present new data on the butterfly Maniola jurtina in flower-rich and flower-poor habitats that demonstrates how movement and behaviour differ between sexes and habitat types, and how this effects consequent dispersal rates. Females had higher flight speeds than males but their total time in flight was four times less. The effect of habitat type was strong for both sexes, flight speeds were ~2.5x and ~1.7x faster on resource-poor habitats for males and females respectively, and flights were approximately 50% longer. With few exceptions females oviposited in the mown grass habitat, likely because growing grass offers better food for emerging caterpillars, but they foraged in the resource-rich habitat. It seems that females faced a trade-off between ovipositing without foraging in the mown grass or foraging without ovipositing where flowers were abundant. We show that taking account of habitat-dependent differences in activity, here categorised as flight or non-flight, is crucial to obtaining good fits of an individual-based model to observed movement. An important implication of this finding is that incorporating habitat-specific activity budgets is likely necessary for predicting longer-term dispersal in heterogeneous habitats as habitat-specific behaviour substantially influences the mean (>30% difference) and kurtosis (1.4x difference) of dispersal kernels. The presented IBMs provide a simple method to explicitly incorporate known activity and movement rates when predicting dispersal in changing and heterogeneous landscapes
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Beagle 2: Seeking the signatures of life on Mars
ESA's Beagle 2 lander will land on Mars to search for signatures of present and past life. A Gas Analysis Package (GAP) with a mass spectrometer, XRF, Mossbauer, stereo cameras, microscope, environmental sensors, rock corer/grinder, and a Mole attachment are on the lander
Implementing the use of operational data in buildings
This paper considers how Operational Data might address both legislative and operational requirements from the viewpoint of an operational estate. It is framed within the context of the IEE iSERVcmb project procedures for describing operational energy data against the building activities and assets. The observations and findings from the paper show that there appear no practical reasons why the same operational data should not be used to show compliance with legislative procedures, if these were to be framed appropriately, and to provide the detailed information needed to enable action to achieve efficiency improvements in an Estate. The paper shows the significant measured energy savings possible from the use of Operational Data, as well as the ability to understand the physical estate more accurately. The work is based on characterizing utility use in an Operational Estate by reference to performance achieved in other operational buildings, but the procedure could be used to characterize any efficiency measure with practical derived metrics
The genome sequence of the Black-tipped Ermine, Yponomeuta plumbella (Denis & Schiffermüller, 1775)
We present a genome assembly from an individual male Yponomeuta plumbella (the Black-tipped Ermine; Arthropoda; Insecta; Lepidoptera; Yponomeutidae). The genome sequence is 636.6 megabases in span. Most of the assembly is scaffolded into 31 chromosomal pseudomolecules, including the Z sex chromosome. The mitochondrial genome has also been assembled and is 16.5 kilobases in length
Low-temperature reactions: Tunnelling in space.
International audienceChemical reactions with activation barriers generally slow to a halt in the extreme cold of dense interstellar clouds. Low-temperature experiments on the reaction of OH with methanol have now shown that below 200 K there is a major acceleration in the rate that can only be explained by enhanced quantum mechanical tunnelling through the barrier
Benzonitrile as a Proxy for Benzene in the Cold ISM: Low-temperature Rate Coefficients for CN + C₆H₆
The low-temperature reaction between CN and benzene (C₆H₆) is of significant interest in the astrochemical community due to the recent detection of benzonitrile, the first aromatic molecule identified in the interstellar medium (ISM) using radio astronomy. Benzonitrile is suggested to be a low-temperature proxy for benzene, one of the simplest aromatic molecules, which may be a precursor to polycyclic aromatic hydrocarbons. In order to assess the robustness of benzonitrile as a proxy for benzene, low-temperature kinetics measurements are required to confirm whether the reaction remains rapid at the low gas temperatures found in cold dense clouds. Here, we study the C₆H₆ + CN reaction in the temperature range 15–295 K, using the well-established CRESU technique (a French acronym standing for Reaction Kinetics in Uniform Supersonic Flow) combined with pulsed-laser photolysis-laser-induced fluorescence. We obtain rate coefficients, k(T), in the range (3.6–5.4) × 10⁻¹⁰ cm³ s⁻¹ with no obvious temperature dependence between 15 and 295 K, confirming that the CN + C₆H₆ reaction remains rapid at temperatures relevant to the cold ISM
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