386 resultados para Willie, Mike
Resumo:
Existing research on synchronous remote working in CSCW has highlighted the troubles that can arise because actions at one site are (partially) unavailable to remote colleagues. Such ‘local action’ is routinely characterised as a nuisance, a distraction, subordinate and the like. This paper explores interconnections between ‘local action’ and ‘distributed work’ in the case of a research team virtually collocated through ‘MiMeG’. MiMeG is an e-Social Science tool that facilitates ‘distributed data sessions’ in which social scientists are able to remotely collaborate on the real-time analysis of video data. The data are visible and controllable in a shared workspace and participants are additionally connected via audio conferencing. The findings reveal that whilst the (partial) unavailability of local action is at times problematic, it is also used as a resource for coordinating work. The paper considers how local action is interactionally managed in distributed data sessions and concludes by outlining implications of the analysis for the design and study of technologies to support group-to-group collaboration.
Resumo:
The recent solar minimum was the longest and deepest of the space age, with the lowest average sunspot numbers for nearly a century. The Sun appears to be exiting a grand solar maximum (GSM) of activity which has persisted throughout the space age, and is headed into a significantly quieter period. Indeed, initial observations of solar cycle 24 (SC24) continue to show a relatively low heliospheric magnetic field strength and sunspot number (R), despite the average latitude of sunspots and the inclination of the heliospheric current sheet showing the rise to solar maximum is well underway. We extrapolate the available SC24 observations forward in time by assuming R will continue to follow a similar form to previous cycles, despite the end of the GSM, and predict a very weak cycle 24, with R peaking at ∼65–75 around the middle/end of 2012. Similarly, we estimate the heliospheric magnetic field strength will peak around 6nT. We estimate that average galactic cosmic ray fluxes above 1GV rigidity will be ∼10% higher in SC24 than SC23 and that the probability of a large SEP event during this cycle is 0.8, compared to 0.5 for SC23. Comparison of the SC24 R estimates with previous ends of GSMs inferred from 9300 years of cosmogenic isotope data places the current evolution of the Sun and heliosphere in the lowest 5% of cases, suggesting Maunder Minimum conditions are likely within the next 40 years.
Resumo:
This study has investigated the antioxidant capacity of different woods used in cooperage and the effect of the botanical species of wood on this capacity. Quercus robur and Castanea sativa were the species with the highest antioxidant capacity, due to their relatively high content of phenolic compounds. However, the phenolic content of Prunus avium samples was very low, also reflected in its antioxidant capacity. All measurements of antioxidant capacity were consistent with the content and composition of the phenolic compounds detected in the wood samples. The major contributors to the antioxidant capacity were identified as phenolic acids, including gallic, protocatechuic, p-coumaric and ellagic acid and all the ellagitannins, due to their characteristic structure.
Resumo:
Extending previous studies, a full-circle investigation of the ring current has been made using Cluster 4-spacecraft observations near perigee, at times when the Cluster array had relatively small separations and nearly regular tetrahedral configurations, and when the Dst index was greater than −30 nT (non-storm conditions). These observations result in direct estimations of the near equatorial current density at all magnetic local times (MLT) for the first time and with sufficient accuracy, for the following observations. The results confirm that the ring current flows westward and show that the in situ average measured current density (sampled in the radial range accessed by Cluster 4–4.5RE) is asymmetric in MLT, ranging from 9 to 27 nAm−2. The direction of current is shown to be very well ordered for the whole range of MLT. Both of these results are in line with previous studies on partial ring extent. The magnitude of the current density, however, reveals a distinct asymmetry: growing from 10 to 27 nAm−2 as azimuth reduces from about 12:00MLT to 03:00 and falling from 20 to 10 nAm−2 less steadily as azimuth reduces from 24:00 to 12:00MLT. This result has not been reported before and we suggest it could reflect a number of effects. Firstly, we argue it is consistent with the operation of region-2 field aligned-currents (FACs), which are expected to flow upward into the ring current around 09:00MLT and downward out of the ring current around 14:00MLT. Secondly, we note that it is also consistent with a possible asymmetry in the radial distribution profile of current density (resulting in higher peak at 4– 4.5RE). We note that part of the enhanced current could reflect an increase in the mean AE activity (during the periods in which Cluster samples those MLT).
Resumo:
Self-pollination dominates in wheat , with a small level of out-crossing due to flowering asynchrony and male sterility. However, the timing and synchrony of male and female flowering in wheat is a crucial determinant of seed set and may be an important factor affecting gene flow and resilience to climate change. Here, a methodology is presented for assessing the timing and synchrony of flowering in wheat. From the onset of flowering until the end of anthesis, the anther and stigma activity of each floret was assessed on the first five developing ears in potted plants grown under ambient conditions and originating from cv Paragon or cvs Spark-Rialto backgrounds. At harvest maturity, seed presence, size and weight was recorded for each floret scored. The synchrony between pollen dehiscence and stigma collapse within a flower was dependent on its relative position in a spike and within a floret. Determined on the basis of synchrony within each flower, the level of pollination by pollen originating from other flowers reached approximately 30% and did not change throughout the duration of flowering. A modelling exercise parameterised by flowering observations indicated that the temporal and spatial variability of anther activity within and between spikes may influence the relative resilience of wheat to sudden, extreme climatic events which has direct relevance to predicted future climate scenarios in the UK.
Resumo:
This paper examines the ethics of the Clean Development Mechanism (CDM) in its architecture, processes and outcomes and its potential to allocate resources to the poor as ‘ethical development’. Two specific examples of CDM projects help us to explore some of the quandaries that seem to be quickly defining operating procedure for the CDM in its efforts to bring entitlementsto the poor. The paper concludes with reflections on the normative and social complications of the CDM and closes with three key areas of further investigation.
Resumo:
Cosmic rays modify current flow in the global atmospheric electrical circuit. Charging at horizontal layer cloud edges has been observed to be consistent with global circuit vertical current flow through the cloud, which can modify the properties of small and pure water droplets. Studies have been hampered by the absence of cloud edge observations, hence cloud base height information is investigated here. Cloud base height measured at the Lerwick Observatory, Shetland, UK, is analysed using threshold tests and spectral analysis. The cloud base height distributions for low cloud (cloud base less than 800 m) are found to vary with cosmic ray conditions. Further, 27 day and 1.68 year periodicities characteristic of cosmic ray variations are present, weakly, in the cloud base height data of stratiform clouds, when such periodicities are present in neutron monitor cosmic ray data. These features support the idea of propagation of heliospheric variability into layer clouds, through the global atmospheric electric circuit.
Resumo:
The recent low and prolonged minimum of the solar cycle, along with the slow growth in activity of the new cycle, has led to suggestions that the Sun is entering a Grand Solar Minimum (GSMi), potentially as deep as the Maunder Minimum (MM). This raises questions about the persistence and predictability of solar activity. We study the autocorrelation functions and predictability R^2_L(t) of solar indices, particularly group sunspot number R_G and heliospheric modulation potential phi for which we have data during the descent into the MM. For R_G and phi, R^2_L (t) > 0.5 for times into the future of t = 4 and 3 solar cycles, respectively: sufficient to allow prediction of a GSMi onset. The lower predictability of sunspot number R_Z is discussed. The current declines in peak and mean R_G are the largest since the onset of the MM and exceed those around 1800 which failed to initiate a GSMi.
Resumo:
The phenolic fractions released during hydrothermal treatment of selected feedstocks (corn cobs, eucalypt wood chips, almond shells, chestnut burs, and white grape pomace) were selectively recovered by extraction with ethyl acetate and washed with ethanol/water solutions. The crude extracts were purified by a relatively simple adsorption technique using a commercial polymeric, nonionic resin. Utilization of 96% ethanol as eluting agent resulted in 47.0-72.6% phenolic desorption, yielding refined products containing 49-60% w/w phenolics (corresponding to 30-58% enrichment with respect to the crude extracts). The refined extracts produced from grape pomace and from chestnut burs were suitable for protecting bulk oil and oil-in-water and water-in-oil emulsions. A synergistic action with bovine serum albumin in the emulsions was observed.
Resumo:
The secoiridoids 3,4-dihydroxyphenylethanol-elenolic acid (3,4-DHPEA-EA) and 3,4-dihydroxyphenylethanol-elenolic acid dialdehyde (3,4-DHPEA-EDA) account for approximately 55 % of the phenolic content of olive oil and may be partly responsible for its reported human health benefits. We have investigated the absorption and metabolism of these secoiridoids in the upper gastrointestinal tract. Both 3,4-DHPEA-EDA and 3,4-DHPEA-EA were relatively stable under gastric conditions, only undergoing limited hydrolysis. Both secoiridoids were transferred across a human cellular model of the small intestine (Caco-2 cells). However, no glucuronide conjugation was observed for either secoiridoid during transfer, although some hydroxytyrosol and homovanillic alcohol were formed. As Caco-2 cells are known to express only limited metabolic activity, we also investigated the absorption and metabolism of secoiridoids in isolated, perfused segments of the jejunum and ileum. Here, both secoiridoids underwent extensive metabolism, most notably a two-electron reduction and glucuronidation during the transfer across both the ileum and jejunum. Unlike Caco-2 cells, the intact small-intestinal segments contain NADPH-dependent aldo-keto reductases, which reduce the aldehyde carbonyl group of 3,4-DHPEA-EA and one of the two aldeydic carbonyl groups present on 3,4-DHPEA-EDA. These reduced forms are then glucuronidated and represent the major in vivo small-intestinal metabolites of the secoiridoids. In agreement with the cell studies, perfusion of the jejunum and ileum also yielded hydroxytyrosol and homovanillic alcohol and their respective glucuronides. We suggest that the reduced and glucuronidated forms represent novel physiological metabolites of the secoiridoids that should be pursued in vivo and investigated for their biological activity.
Resumo:
A UK field experiment compared a complete factorial combination of three backgrounds (cvs Mercia, Maris Huntsman and Maris Widgeon), three alleles at the Rht-B1 locus as Near Isogenic Lines (NILs: rht-B1a (tall), Rht-B1b (semi-dwarf), Rht-B1c (severe dwarf)) and four nitrogen (N) fertilizer application rates (0, 100, 200 and 350 kg N/ha). Linear+exponential functions were fitted to grain yield (GY) and nitrogen-use efficiency (NUE; GY/available N) responses to N rate. Averaged over N rate and background Rht-B1b conferred significantly (P<0.05) greater GY, NUE, N uptake efficiency (NUpE; N in above ground crop / available N) and N utilization efficiency (NUtEg; GY / N in above ground crop) compared with rht-B1a and Rht-B1c. However the economically optimal N rate (Nopt) for N:grain price ratios of 3.5:1 to 10:1 were also greater for Rht-B1b, and because NUE, NUpE and NUtE all declined with N rate, Rht-Blb failed to increase NUE or its components at Nopt. The adoption of semi-dwarf lines in temperate and humid regions, and the greater N rates that such adoption justifies economically, greatly increases land-use efficiency, but not necessarily, NUE.