441 research outputs found
The new radiation-hard optical links for the ATLAS pixel detector
The ATLAS detector is currently being upgraded with a new layer of pixel
based charged particle tracking and a new arrangement of the services for the
pixel detector. These upgrades require the replacement of the opto-boards
previously used by the pixel detector. In this report we give details on the
design and production of the new opto-boards.Comment: Presentation at the DPF 2013 Meeting of the American Physical Society
Division of Particles and Fields, Santa Cruz, California, August 13-17, 201
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Development of a low-power, low-cost front end electronics module for large scale distributed neutrino detectors
A number of concepts have been presented for distributed neutrino detectors formed of large numbers of autonomous detectors. Examples include the Antarctic Ross Ice Shelf Antenna Neutrino Array (ARIANNA) [Barwick 2006], as well as proposed radio extensions to the IceCube detector at South Pole Station such as AURA and IceRay. [Besson 2008]. We have focused on key enabling technical developments required by this class of experiments. The radio Cherenkov signal, generated by the Askaryan mechanism [Askaryan 1962, 1965], is impulsive and coherent up to above 1 GHz. In the frequency domain, the impulsive character of the emission results in simultaneous increase of the power detected in multiple frequency bands. This multiband triggering approach has proven fruitful, especially as anthropogenic interference often results from narrowband communications signals. A typical distributed experiment of this type consists of a station responsible for the readout of a cluster of antennas either near the surface of the ice or deployed in boreholes. Each antenna is instrumented with a broadband low-noise amplifier, followed by an array of filters to facilitate multi-band coincidence trigger schemes at the antenna level. The power in each band is detected at the output of each band filter, using either square-law diode detectors or log-power detectors developed for the cellular telephone market. The use of multiple antennas per station allows a local coincidence among antennas to be used as the next stage of the trigger. Station triggers can then be combined into an array trigger by comparing timestamps of triggers among stations and identifying space-time clusters of station triggers. Data from each station is buffered and can be requested from the individual stations when a multi-station coincidence occurs. This approach has been successfully used in distributed experiments such as the Pierre Auger Observatory. [Abraham et al. 2004] We identified the filters as being especially critical. The frequency range of interest, {approx}200 MHz to {approx}1.2 GHz, is a transitional region where the lumped circuit element approach taken at low frequencies begins to reach limitations due to component tolerances, component losses, and parasitic effects. Active circuits can help to mitigate against these effects at the cost of added power consumption that becomes prohibitive for distributed experiments across the band of interest. At higher frequency microstrip, stripline, and other microwave techniques come to the fore. We have developed designs and design tools for passive filters extending the high frequency techniques to the frequency range of interest. Microstrip and stripline techniques are not usually attractive here because of the large physical dimensions of the resulting circuits, but in this application the tradeoff of size against power consumption favors this choice. These techniques are also intrinsically low-cost, as the filter is built into the circuit boards and the cost of components and their assembly onto the board is avoided. The basic element of the filter tree is an impedance matched wideband diplexer. This consists of a pair of low pass and high pass filters with a shared cutoff frequency and complementary frequency responses. These are designing the lowpass filter as a high order LC filter, which can be implemented as a series of transmission line segments of varying width. This can be transformed in to a CL high pass filter with a complementary frequency response. When the two filters are coupled to a common input, the input impedances of the networks add in parallel to give a constant input impedance as a function of frequency, with power flowing into one leg or the other of the filter pair. These filters can be cascaded to divide the band into the frequency ranges of interest; the broadband impedance matching at the inputs makes coupling of successive stages straightforward. These circuits can be produced in quantity at low cost using standard PCB fabrication techniques. We have determined that to achieve best performance the circuits should be built on a low loss-tangent RF substrate. We are working in cooperation with our colleagues in condensed matter who also have a need for this capability to purchase the equipment for in-house fabrication of prototype quantities of these circuits. We plan to continue the work on these filtersusing internal funds, and produce and characterize the performance of prototypes. We also participated in deployment of a prototype detector station near McMurdo Station, Antarctica in collaboration with colleagues at UCLA and UC-Irvine. The prototype station includes a single-board computer, GPS receiver, ADC board, and Iridium satellite modem powered by an omnidirectional solar array. We operated this station in the austral summer of 2006-2007, and used the Iridium SMS mode to transmit the status of the station until the end of the daylight season
Assessing a commercially available sports drink on exogenous carbohydrate oxidation, fluid delivery and sustained exercise performance
Background:
Whilst exogenous carbohydrate oxidation (CHOEXO) is influenced by mono- and disaccharide combinations, debate exists whether such beverages enhance fluid delivery and exercise performance. Therefore, this study aimed to ascertain CHOEXO, fluid delivery and performance times of a commercially available maltodextrin/ fructose beverage in comparison to an isocaloric maltodextrin beverage and placebo.
Methods:
Fourteen club level cyclists (age: 31.79 ± 10.02 years; height: 1.79 ± 0.06 m; weight: 73.69 ± 9.24 kg; VO2max: 60.38 ± 9.36 mL · kg·-1 minâ1) performed three trials involving 2.5 hours continuous exercise at 50% maximum power output (Wmax: 176.71 ± 25.92 W) followed by a 60 km cycling performance test. Throughout each trial, athletes were randomly assigned, in a double-blind manner, either: (1) 1.1 g · minâ1 maltodextrin + 0.6 g · minâ1 fructose (MD + F), (2) 1.7 g · minâ1 of maltodextrin (MD) or (3) flavoured water (P). In addition, the test beverage at 60 minutes contained 5.0 g of deuterium oxide (2H2O) to assess quantification of fluid delivery. Expired air samples were analysed for CHOEXO according to the 13C/12C ratio method using gas chromatography continuous flow isotope ratio mass spectrometry.
Results:
Peak CHOEXO was significantly greater in the final 30 minutes of submaximal exercise with MD + F and MD compared to P (1.45 ± 0.09 g · minâ1, 1.07 ± 0.03 g · minâ1and 0.00 ± 0.01 g · minâ1 respectively, P < 0.0001), and significantly greater for MD + F compared to MD (P = 0.005). The overall appearance of 2H2O in plasma was significantly greater in both P and MD + F compared to MD (100.27 ± 3.57 ppm, 92.57 ± 2.94 ppm and 78.18 ± 4.07 ppm respectively, P < 0.003). There was no significant difference in fluid delivery between P and MD + F (P = 0.078). Performance times significantly improved with MD + F compared with both MD (by 7 min 22 s ± 1 min 56 s, or 7.2%) and P (by 6 min 35 s ± 2 min 33 s, or 6.5%, P < 0.05) over 60 km.
Conclusions:
A commercially available maltodextrin-fructose beverage improves CHOEXO and fluid delivery, which may benefit individuals during sustained moderate intensity exercise. The greater CHOEXO observed when consuming a maltodextrin-fructose beverage may support improved performance times
Teaching Computation in Neuroscience: Notes on the 2019 Society for Neuroscience Professional Development Workshop on Teaching
The 2019 Society for Neuroscience Professional 1Development Workshop on Teaching reviewed current tools, approaches, and examples for teaching computation in neuroscience. Robert Kass described the statistical foundations that students need to properly analyze data. Pascal Wallisch compared MATLAB and Python as programming languages for teaching students. Adrienne Fairhall discussed computational methods, training opportunities, and curricular considerations. Walt Babiec provided a view from the trenches on practical aspects of teaching computational neuroscience. Mathew Abrams concluded the session with an overview of resources for teaching and learning computational modeling in neuroscience
Genomic Signatures of Historical Allopatry and Ecological Divergence in an Island Lizard
Geographical variation amongcontiguouspopulations is frequently attributed to ecological divergence or historical isolation followed by secondary contact.Distinguishing between these effects is key to studies of incipient speciation and could be revealed by different genomic signatures. We used RAD-seq analyses to examine morphologically divergent populations of the endemic lizard (Gallotia galloti) from the volcanic island of Tenerife. Previous analyses have suggested ecological and historical causes to explain the morphological diversity. Analyses of 276,483 single nucleotide polymorphisms (SNPs) from>20 Mbp of the genome revealed one genetically divergent population from Anaga, a region associated with divergent mtDNA lineages in other Tenerife endemics. This population also has a high number of private alleles, and its divergence can be explained by historical isolation. Bayesian outlier analyses identified a small proportion of SNPs as candidates for selection (0.04%) which were strongly differentiated between xeric andmesic habitat types. Individual testing for specific xericâmesic selection using an alternative approach also supported ecological divergence in a similarly small proportion of SNPs. The study indicates the roles of both historical isolation and ecological divergence in shaping genomic diversity in G. galloti.However, northâsouthmorphological divergence appears solely associated with the latter and likely involves a relatively small proportion of the genome
UK National Ecosystem Assessment Follow-on. Work package 7: Operationalising scenarios in the UK National Ecosystem Assessment Follow-on
Summary
Study aims and approach
An aim of the UK NEA Follow-on (UK NEAFO) is to develop and communicate the evidence base of
the UK NEA and make it relevant to decision and policy making. It also provides an important
opportunity for those working on scenario methods and concepts to scrutinise the role of futures
thinking in the management of ecosystem services and so develop their effectiveness as decision
support tools. In this study we have therefore asked: how can the UK NEA scenarios help us to
understand, manage and communicate the consequences of changes in ecosystem services across all
scales?
There are many different understandings about what scenarios are, and what they should be used
for. To clarify the issues surrounding the role of scenarios, we have approached this work from two
angles. We have firstly looked at the way the storylines can support decision making processes.
Secondly, we have looked at the content of the scenarios themselves and explored how through the
use of models the UK NEA scenarios as products might be refined to enhance their value as
analytical tools.
Scenarios in Action
We used the opportunity of a series of meetings with stakeholders to develop the UK NEA scenarios
from a process perspective. These meetings took various forms, but throughout the main aim was to
find out whether people found the scenarios sufficiently believable, challenging and relevant.
In workshops organised by the scenario team in Leeds, Edinburgh and Belfast, we worked with
participants on a series of tasks designed to help them immerse themselves in the scenarios and
reflect on them critically. While those we worked with had many comments about the scenarios in
detail, the evidence we collected from these meetings suggests that the majority of people found
the scenarios to be plausible and the projections consistent. The majority also agreed with the
proposition that the suite of scenarios as a whole addressed a relevant ranges of issues.
We explored with the workshop participants several ways in which the storylines could be enriched,
by: developing the narrative about the way people might live in the different scenario worlds;
developing time-lines for the scenarios; thinking more deeply about regional and local differences;
and, exploring how the scenarios would frustrate or facilitate the embedding of the ecosystem
approach in decision making. We found that while all of these elements had value in terms of
stimulating discussion and understanding of the scenarios, they were not needed in order to address
deficiencies in the original storylines in terms of plausibility or credibility.
The evidence we collected therefore suggests that the existing narratives are probably sufficient as
an entry point for discussions about the future of ecosystem services in the UK. What was apparent
from the observations that we made in the workshops was that it would probably be a mistake to
âover-engineerâ or âover-specifyâ the narratives because there needs to be room for discussion and
probing. We were struck how people took the existing scenarios and found new features and ideas
in them than had not been identified by in the original work. For example, in one session National
Security, with its emphasis on resource efficiency, was found to be âgreenerâ than it initially looks. In
another Local Stewardship was discovered to need some degree of central control and regulation to
work efficiently. These kinds of discussion are evidence of the reflection, deliberation and social
learning that can be promoted by using the UK NEA scenarios.
UK NEAFO Work Package 7: Operationalising scenarios
7
In the workshop we organised in Belfast we found that the presentation of the scenarios could be
tailored to a specific region (i.e. Northern Ireland) and, through area-specific breakout groups during
the workshop, to specific localities within it. However, our experiences here emphasised the need
for considerable preparation, consultation with the stakeholder community, and changing of the
workshop format to make the scenarios intelligible and engaging to local stakeholders.
Work on the use of the scenarios in a more explicit decision support role will be reported via the
work on response options (WP8), which considered how they could be used to âstress-testâ policy
response options. The experience gained from the work undertaken in the early stages of UK NEAFO
was that the scenarios appeared to provide a suitable platform for the work, but that the stresstesting
methodology needed to be refined. During the follow-on we have also interviewed policy
leads in Defra, for example, to gain a better picture of policy needs, and the way scenarios might
usefully serve them. Apart from the challenge of ârelevanceâ it is clear that the time needed for
people to work with scenarios probably means that they are less useful to policy customers in the
context of their everyday work but can be useful at a very broad and strategic level. However, there
is clearly an opportunity for scenarios to be used more extensively through commissioned work. The
importance of commissioned work has been emphasised during the follow-on phase by invitations
to observe the work of the CAMERAS1 work in Scotland, and the Noise Study being undertaken for
Defra. Both are actively using the UK NEA scenarios. The outcomes of these on-going studies will be
reported elsewhere by others. Nevertheless, even though these projects are at a preliminary stage
they help us better understand how scenarios can be used to communicate the consequences of
changes in ecosystem services to different groups and individuals.
Scenarios as products: developing the model base
The UK NEA scenarios were initially used to make both qualitative and quantitative projections. The
quantitative work mainly involved modelling how land cover would change under the different
scenarios (Haines-Young et al. 2011). Although these data were used to make an analysis of the
changes in marginal economic values for some ecosystem services during the initial phase of the UK
NEA, they have not been fully exploited. At the time it was recognised that there were many gaps in
our understanding of the links between land cover and ecosystem services; UK NEAFO has provided
the opportunity to address some of these deficiencies.
Thus in the follow-on work we have sought to extend the range of models that can be used to
explore the UK NEA scenarios. The modelling work has not sought to change the scenarios
fundamentally, but to enrich the insights that can be derived from exploring the differences
between them in a systematic, and quantitative way. The goal, has been to extend the analysis that
can be built up around the narratives and hence enrich the scenarios as âproductsâ. Four topic areas
were selected as the focus for this work: flood and drought risk (based on an analysis of changes in
river flows), biodiversity (farmland birds), marine and cultural ecosystem services.
Catchment modelling
We looked at the effects of land-use change on river flows under each of the UK NEA scenarios. We
modelled hydrological discharge within 34 UK catchments and calculated four hydrological indicators
for each catchment: average annual discharge, flood hazard, and Q5 and Q95 (measures of the
magnitude of unusually high (Q5) and unusually low (Q95) flows). For our flood hazard indicator we
calculated the interval between floods of a size currently occurring every 30 years. Although we kept
climate constant in the models, as we wanted to isolate the effects of land cover change, we ran
them for both the high and low climate change land cover variants for each scenario.
1 A Coordinated Agenda for Marine, Environment and Rural Affairs Science, 2011-2016.
http://www.scotland.gov.uk/Topics/Research/About/EBAR/CAMERASsite
In general, the âgreenâ scenarios, Nature@Work and Green and Pleasant Land, as well as National
Security, were associated with lower flows than currently occur (when measured using any of the
four indicators). However, for a given scenario there was a great deal of variability between
catchments in terms of the size and statistical significance of the differences. The magnitude of
change across all scenarios and catchments ranged from -13% to 6% for average annual discharge,
-14 to 7% for Q5, -24 to 27 % for Q95 and -16 to 36 years for flood hazard. Differences were
particularly evident between Nature@Work and World Markets, with the latter associated with
higher flows than occur currently, and the majority of the statistically significant increased flows.
Some catchments showed significant changes that were different in sign between these two
scenarios.
Taken together, our results indicate that that in managing change a balance needs to be struck
between alleviating the likelihoods of increased drought and increased flooding, depending on the
likely effects of these phenomena in the catchment.
Farmland birds
We looked at the relationship between land use data produced during the first phase of the UK NEA
and models of farmland bird populations, in 1kmx1km squares covered by the Breeding Bird Survey
(BBS) and Winter Farmland Bird Survey (WFBS).
We used Functional Space Models to estimate the annual population growth rate under each
scenario of each of the 19 farmland bird species used to calculate the farmland bird index (Gregory
et al. 2004). We used this to look at the relationship between land use under the scenarios and: i)
the average population growth rate for all 19 species, and ii) a subset of 11 species showing
declining population trends under current land use. Overall we found that land use change across
the scenarios had relatively little impact. However, the only statistically significant change was for
declining species under Green and Pleasant Land, where population growth rates became
significantly more negative.
We used Mechanistic Models to estimate the number of over-winter âbird-daysâ for two types of
seed-eating farmland birds, a yellowhammer-type and linnet-type These species were chosen
because they differ in their food preferences with respect to cereal, oil and weed seeds, but
between them are representative of the diversity of seed-eating farmland birds as a whole. We
found a significant decline in the ecological value of lowland agricultural areas for these species
across all UK NEA scenarios, but the greatest impact was for scenarios with the highest monetised
values for ecosystem services, as measured by the first phase of the UK NEA (Nature@Work, Green
and Pleasant Land). This appears to be due to the fact that, compared with the baseline, the area of
arable crops declines most sharply under these scenarios, due partly to changes in land use but also
because of conversion of arable land to other habitats important for ecosystem services (e.g.
woodland).
Taken together these results imply a trade-off between overall value for ecosystem services and
conservation of farmland birds, and highlight the need to consider the specific impacts of land use
change on biodiversity, alongside other ecosystem services.
Marine ecosystem services
Only a limited attempt was made to model marine ecosystem services during the first phase of the
UK NEA. In the follow-on we have conducted preliminary work to produce spatially explicit models
for three important marine ecosystem services: fisheries landings, aquaculture production and
carbon sequestration. We made comparisons between baseline data and time slices for 2015, 2030
UK NEAFO Work Package 7: Operationalising scenarios
9
and 2060 under four of the UK NEA scenarios that were considered most relevant for the sector, and
mapped these across UK territorial waters.
There is a high degree of uncertainty associated with the models, mainly due to a lack of suitable
data and poor knowledge of the drivers of change. In many cases, in the absence of robust
quantitative models, we needed to take the qualitative descriptions of the UK NEA scenarios and
combine these with expert knowledge to estimate changes in the three types of ecosystem service.
We estimated that in three of the four scenarios: Nature@Work, Local Stewardship and National
Security, fisheries landings would be, by 2060 only slightly lower or at higher levels than they are
today. Under World Markets, however, projected landings would decline significantly by 2060, due
to a lack of regulation combined with high levels of investment from private capital. In the light of
this, it was interesting that aquaculture was at higher levels under World Markets than under any of
the other scenarios, although all of them showed higher levels than the baseline. This was because
under this scenario more investment capital would be available to invest in fish farms.
We believe that carbon sequestration would be most likely to be impacted by the World Markets
and Natural Security, due to higher CO2 emissions causing an increase in ocean acidification.
Our results, although tentative, mark a significant first step in attempts to map and project the
impact of possible future change on marine ecosystem services.
Cultural Ecosystem Services
In the first phase of the UK NEA, the relationship between the drivers of change and cultural
ecosystem services (CES) was mainly explored through the impact they had on land cover. For UK
NEAFO, we additionally used the Monitor of Engagement for the Natural Environment (MENE)
dataset. We examined how the UK NEA scenarios can be used as a framework to explore the
relationship between the supply of cultural spaces in the landscape and peoples preferences for
different types of natural spaces and practices in them. We have developed a Bayesian Belief
Network (BBN) that allows users to explore these relationships interactively and look at the potential
impacts of changes socio-demographic structure of the kind described by the UK NEA scenarios.
Our spatial analysis of the MENE data showed that people tend to select locations with higher
woodland cover than the average for the surroundings, when they travel intermediate distances
from their home, but that this tendency declines when they travel longer distances. Woodland cover
is projected to double under both Nature@Work and Green and Pleasant Land, and both provide
more opportunities to visit woodland close to home than under scenarios such as World Markets.
However, our analysis shows that on the basis of the current geography of people and woodlands,
the way planting is targeting under Green and Pleasant Land has the potential to deliver greater joint
benefits from biodiversity change and cultural ecosystem services than Nature@Work.
The BBN we have developed using the HUGIN Expert software allows the relationships within the
MENE data to be explored interactively; it is hosted on a prototype website that is open to the wider
community. By examining the relationships between socio-demographic characteristics of the MENE
respondents, the types of natural spaces they visit and the activities they do in them, this BBN tool
allows users to explore the impacts of possible future change on the supply and demand of CES.
Conclusion
How can plausible future scenarios help understand, manage and communicate the consequences of
changes in ecosystem services across all scales? In this work we have shown that they can be used to
promote understanding by the deliberative processes that they engender. The UK NEA scenarios
appear to be sufficiently rich and comprehensive to support debate across a wide range of topic
areas relevant to current policy concerns. The scenarios can also help understanding by providing a
framework in which current models can be applied and the outcome used both to test the
plausibility of the scenarios themselves and to deepen the insights that can be derived from them.
These analytical âscenario productsâ can be equally important both in terms of deepening our
understanding of the assumptions on which the scenarios are built and in stimulating debate about
their implications.
We have shown that the distinction between the âprocessâ and âproductâ dimensions of scenario
thinking is a useful one, given the many ways scenarios can be used. The distinction clarifies some of
the different purposes and problems that scenarios work seeks to address. However, our work also
demonstrates that both components have their strengths, and neither can be taken isolation. If we
are to use scenarios to understand, manage and communicate the consequences of changes in
ecosystem services across different scales and in different contexts, then targeted analytical studies
developed within the qualitative framework of the UK NEA scenarios, can enrich our understanding
of todayâs issues and how we might respond to them
Lifespan extension and the doctrine of double effect
Recent developments in biogerontologyâthe study of the biology of ageingâsuggest that it may eventually be possible to intervene in the human ageing process. This, in turn, offers the prospect of significantly postponing the onset of age-related diseases. The biogerontological project, however, has met with strong resistance, especially by deontologists. They consider the act of intervening in the ageing process impermissible on the grounds that it would (most probably) bring about an extended maximum lifespanâa state of affairs that they deem intrinsically bad. In a bid to convince their deontological opponents of the permissibility of this act, proponents of biogerontology invoke an argument which is grounded in the doctrine of double effect. Surprisingly, their argument, which we refer to as the âdouble effect argumentâ, has gone unnoticed. This article exposes and critically evaluates this âdouble effect argumentâ. To this end, we first review a series of excerpts from the ethical debate on biogerontology in order to substantiate the presence of double effect reasoning. Next, we attempt to determine the role that the âdouble effect argumentâ is meant to fulfil within this debate. Finally, we assess whether the act of intervening in ageing actually can be justified using double effect reasoning
The BASES Expert Statement on Mental Health Literacy in Elite Sport
Research demonstrates that elite athletes are not immune to poor mental health (Gorczynski et al., 2017; Rice et al., 2016), which can adversely affect their overall health and performance. Here, elite sport is defined on a continuum from semi-elite (e.g. high-performance youth development programmes) to worldclass elite (e.g. global competitions) (Swann et al., 2015). There are many reasons why elite athletes may experience poor mental
health. Training and performance demands can place considerable psychological stress on elite athletes who also face public and media scrutiny, financial concerns, sudden and prolonged injuries, and retirement, especially when unexpected. Despite these challenges, few elite athletes seek professional help for their mental health
Glycogen synthase kinase-3 mediates acetaminophen-induced apoptosis in human hepatoma cells
Abstract: 232 Introduction: 61
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