3,207 research outputs found
Science Models as Value-Added Services for Scholarly Information Systems
The paper introduces scholarly Information Retrieval (IR) as a further
dimension that should be considered in the science modeling debate. The IR use
case is seen as a validation model of the adequacy of science models in
representing and predicting structure and dynamics in science. Particular
conceptualizations of scholarly activity and structures in science are used as
value-added search services to improve retrieval quality: a co-word model
depicting the cognitive structure of a field (used for query expansion), the
Bradford law of information concentration, and a model of co-authorship
networks (both used for re-ranking search results). An evaluation of the
retrieval quality when science model driven services are used turned out that
the models proposed actually provide beneficial effects to retrieval quality.
From an IR perspective, the models studied are therefore verified as expressive
conceptualizations of central phenomena in science. Thus, it could be shown
that the IR perspective can significantly contribute to a better understanding
of scholarly structures and activities.Comment: 26 pages, to appear in Scientometric
Process evaluation of the Bristol girls dance project
Background: The Bristol Girls Dance Project was a cluster randomised controlled trial that aimed to increase objectively measured moderate-to-vigorous physical activity (MVPA) levels of Year 7 (age 11–12) girls through a dance-based after-school intervention. The intervention was delivered in nine schools and consisted of up to forty after-school dance sessions. This paper reports on the main findings from the detailed process evaluation that was conducted. /
Methods: Quantitative and qualitative data were collected from intervention schools. Dose and fidelity were reported by dance instructors at every session. Intervention dose was defined as attending two thirds of sessions and was measured by attendance registers. Fidelity to the intervention manual was reported by dance instructors. On four randomly-selected occasions, participants reported their perceived level of exertion and enjoyment. Reasons for non-attendance were self-reported at the end of the intervention. Semi-structured interviews were conducted with all dance instructors who delivered the intervention (n = 10) and school contacts (n = 9) in intervention schools. A focus group was conducted with girls who participated in each intervention school (n = 9). /
Results: The study did not affect girls’ MVPA. An average of 31.7 girls participated in each school, with 9.1 per school receiving the intervention dose. Mean attendance and instructors’ fidelity to the intervention manual decreased over time. The decline in attendance was largely attributed to extraneous factors common to after-school activities. Qualitative data suggest that the training and intervention manual were helpful to most instructors. Participant ratings of session enjoyment were high but perceived exertion was low, however, girls found parts of the intervention challenging. /
Conclusions: The intervention was enjoyed by participants. Attendance at the intervention sessions was low but typical of after-school activities. Participants reported that the intervention brought about numerous health and social benefits and improved their dance-based knowledge and skills. The intervention could be improved by reducing the number of girls allowed to participate in each school and providing longer and more in-depth training to those delivering the intervention. /
Trial registration: ISRCTN52882523 Registered 25th April 2013
Using self-determination theory to promote adolescent girls' physical activity: Exploring the theoretical fidelity of the Bristol Girls Dance Project
OBJECTIVES: To report the theory-based process evaluation of the Bristol Girls' Dance Project, a cluster-randomised controlled trial to increase adolescent girls' physical activity. DESIGN: A mixed-method process evaluation of the intervention's self-determination theory components comprising lesson observations, post-intervention interviews and focus groups. METHOD: Four intervention dance lessons per dance instructor were observed, audio recorded and rated to estimate the use of need-supportive teaching strategies. Intervention participants (n = 281) reported their dance instructors' provision of autonomy-support. Semi-structured interviews with the dance instructors (n = 10) explored fidelity to the theory and focus groups were conducted with participants (n = 59) in each school to explore their receipt of the intervention and views on the dance instructors' motivating style. RESULTS: Although instructors accepted the theory-based approach, intervention fidelity was variable. Relatedness support was the most commonly observed need-supportive teaching behaviour, provision of structure was moderate and autonomy-support was comparatively low. The qualitative findings identified how instructors supported competence and developed trusting relationships with participants. Fidelity was challenged where autonomy provision was limited to option choices rather than input into the pace or direction of lessons and where controlling teaching styles were adopted, often to manage disruptive behaviour. CONCLUSION: The successes and challenges to achieving theoretical fidelity in the Bristol Girls' Dance Project may help explain the intervention effects and can more broadly inform the design of theory-based complex interventions aimed at increasing young people's physical activity in after-school settings
Bristol Girls Dance Project: a cluster randomised controlled trial of an after-school dance programme to increase physical activity among 11- to 12-year-old girls
BACKGROUND: Many children do not meet UK physical activity (PA) guidelines. Girls are less active than boys, and the age-related decline in activity is steeper for girls. Dance is the favourite form of PA among adolescent girls in the UK. Participation in after-school dance classes could significantly contribute to girls’ PA. Therefore, after-school dance may be effective for increasing PA levels. OBJECTIVES: To determine the effectiveness and cost-effectiveness of a dance-based intervention to increase the objectively assessed mean weekday minutes of moderate- to vigorous-intensity physical activity (MVPA) of Year 7 girls (11- and 12-year olds) 1 year after baseline measurement. DESIGN:Two-arm cluster randomised controlled trial and economic evaluation. Year 7 girls in participant schools received a ‘taster’ session and were invited to participate. Up to 33 girls per school were able to participate. Schools were randomly assigned (equal numbers) to intervention or control arms. SETTING:A total of 18 mainstream secondary schools across greater Bristol. PARTICIPANTS: Year 7 girls in participating schools who could participate in physical education. INTERVENTION: Nine intervention schools received an after-school dance intervention (40 × 75-minute sessions) underpinned by self-determination theory, which attempts to improve intrinsic motivation for being active, and delivered by external dance instructors. Control schools continued as normal. MAIN OUTCOME MEASURES: The main outcome was accelerometer-assessed mean minutes of MVPA at T2. Measures were assessed at baseline (T0), the end of the intervention (T1) and at T0 + 52 weeks (T2). RESULTS:Baseline MVPA levels were high. A total of 508 girls were included in the primary analysis, which found no difference in weekday MVPA between trial arms. There was no effect on secondary accelerometer outcomes. Data were subjected to a per-protocol analysis and no effect was found. However, at T1, girls who attended dance classes had 4.61 minutes more of MVPA and 14.27 minutes more of light-intensity activity between 15.00 and 17.00 on the days on which they attended intervention sessions. The intervention was inexpensive at £73 per participant (£63 when excluding dance instructor travel) but was not cost-effective owing to the ineffectiveness of the intervention. The European Quality of Life-5 Dimensions Youth survey data were unresponsive to changes in the sample. The process evaluation reported that girls in attendance enjoyed the sessions, that exertion levels were low during sessions and that attendance was low and declined. Fidelity to the session-plan manual was low but theoretical fidelity (to self-determination theory) was good. Qualitative information provides information for improving future interventions. CONCLUSIONS: The intervention was enjoyed by participants. However, there was no difference in the MVPA levels (which were high at baseline) of girls allocated to receive dance compared with girls receiving the control. High baseline MVPA levels indicate that the study appealed to an already active cohort and, therefore, may not have targeted those most in need of an intervention. Dance is an enjoyable activity for adolescent girls and could be further trialled as a means by which to increase PA. Research might consider the impact of dividing the intervention period into smaller blocks. TRIAL REGISTRATION: Current Controlled Trials ISRCTN52882523. FUNDING: The National Institute for Health Research Public Health Research programme. The work was also undertaken with the support of the Centre for the Development and Evaluation of Complex Interventions for Public Health Improvement (DECIPHer), a UK Clinical Research Collaboration (UKCRC) PHR Centre of Excellence. Joint funding (MR/KO232331/1) from the British Heart Foundation, Cancer Research UK, Economic and Social Research Council, Medical Research Council, the Welsh Government and the Wellcome Trust, under the auspices of the UKCRC, is gratefully acknowledged. This study was designed and delivered in collaboration with the Bristol Randomised Trials Collaboration, a UKCRC Registered Clinical Trials Unit in receipt of NIHR Clinical Trials Unit support funding. All intervention costs were funded by the respective councils to which the participant schools were affiliated, namely North Somerset Council, Bristol City Council, and Bath and North East Somerset Council
Anti-epileptic effect of Ganoderma lucidum polysaccharides by inhibition of intracellular calcium accumulation and stimulation of expression of CaMKII a in epileptic hippocampal neurons
Purpose: To investigate the mechanism of the anti-epileptic effect of Ganoderma lucidum polysaccharides (GLP), the changes of intracellular calcium and CaMK II a expression in a model of epileptic neurons were investigated.
Method: Primary hippocampal neurons were divided into: 1) Control group, neurons were cultured with Neurobasal medium, for 3 hours; 2) Model group I: neurons were incubated with Mg2+ free medium for 3 hours; 3) Model group II: neurons were incubated with Mg2+ free medium for 3 hours then cultured with the normal medium for a further 3 hours; 4) GLP group I: neurons were incubated with Mg2+ free medium containing GLP (0.375 mg/ml) for 3 hours; 5) GLP group II: neurons were incubated with Mg2+ free medium for 3 hours then cultured with a normal culture medium containing GLP for a further 3 hours. The CaMK II a protein expression was assessed by Western-blot. Ca2+ turnover in neurons was assessed using Fluo-3/AM which was added into the replacement medium and Ca2+ turnover was observed under a laser scanning confocal microscope.
Results: The CaMK II a expression in the model groups was less than in the control groups, however, in the GLP groups, it was higher than that observed in the model group. Ca2+ fluorescence intensity in GLP group I was significantly lower than that in model group I after 30 seconds, while in GLP group II, it was reduced significantly compared to model group II after 5 minutes.
Conclusion: GLP may inhibit calcium overload and promote CaMK II a expression to protect epileptic neuron
Application of the speed-duration relationship to normalize the intensity of high-intensity interval training
The tolerable duration of continuous high-intensity exercise is determined by the hyperbolic Speed-tolerable duration (S-tLIM) relationship. However, application of the S-tLIM relationship to normalize the intensity of High-Intensity Interval Training (HIIT) has yet to be considered, with this the aim of present study. Subjects completed a ramp-incremental test, and series of 4 constant-speed tests to determine the S-tLIM relationship. A sub-group of subjects (n = 8) then repeated 4 min bouts of exercise at the speeds predicted to induce intolerance at 4 min (WR4), 6 min (WR6) and 8 min (WR8), interspersed with bouts of 4 min recovery, to the point of exercise intolerance (fixed WR HIIT) on different days, with the aim of establishing the work rate that could be sustained for 960 s (i.e. 4×4 min). A sub-group of subjects (n = 6) also completed 4 bouts of exercise interspersed with 4 min recovery, with each bout continued to the point of exercise intolerance (maximal HIIT) to determine the appropriate protocol for maximizing the amount of high-intensity work that can be completed during 4×4 min HIIT. For fixed WR HIIT tLIM of HIIT sessions was 399±81 s for WR4, 892±181 s for WR6 and 1517±346 s for WR8, with total exercise durations all significantly different from each other (P<0.050). For maximal HIIT, there was no difference in tLIM of each of the 4 bouts (Bout 1: 229±27 s; Bout 2: 262±37 s; Bout 3: 235±49 s; Bout 4: 235±53 s; P>0.050). However, there was significantly less high-intensity work completed during bouts 2 (153.5±40. 9 m), 3 (136.9±38.9 m), and 4 (136.7±39.3 m), compared with bout 1 (264.9±58.7 m; P>0.050). These data establish that WR6 provides the appropriate work rate to normalize the intensity of HIIT between subjects. Maximal HIIT provides a protocol which allows the relative contribution of the work rate profile to physiological adaptations to be considered during alternative intensity-matched HIIT protocols
Solving Navigational Uncertainty Using Grid Cells on Robots
To successfully navigate their habitats, many mammals use a combination of two mechanisms, path integration and calibration using landmarks, which together enable them to estimate their location and orientation, or pose. In large natural environments, both these mechanisms are characterized by uncertainty: the path integration process is subject to the accumulation of error, while landmark calibration is limited by perceptual ambiguity. It remains unclear how animals form coherent spatial representations in the presence of such uncertainty. Navigation research using robots has determined that uncertainty can be effectively addressed by maintaining multiple probabilistic estimates of a robot's pose. Here we show how conjunctive grid cells in dorsocaudal medial entorhinal cortex (dMEC) may maintain multiple estimates of pose using a brain-based robot navigation system known as RatSLAM. Based both on rodent spatially-responsive cells and functional engineering principles, the cells at the core of the RatSLAM computational model have similar characteristics to rodent grid cells, which we demonstrate by replicating the seminal Moser experiments. We apply the RatSLAM model to a new experimental paradigm designed to examine the responses of a robot or animal in the presence of perceptual ambiguity. Our computational approach enables us to observe short-term population coding of multiple location hypotheses, a phenomenon which would not be easily observable in rodent recordings. We present behavioral and neural evidence demonstrating that the conjunctive grid cells maintain and propagate multiple estimates of pose, enabling the correct pose estimate to be resolved over time even without uniquely identifying cues. While recent research has focused on the grid-like firing characteristics, accuracy and representational capacity of grid cells, our results identify a possible critical and unique role for conjunctive grid cells in filtering sensory uncertainty. We anticipate our study to be a starting point for animal experiments that test navigation in perceptually ambiguous environments
Classification of non-Riemannian doubled-yet-gauged spacetime
Assuming covariant fields as the `fundamental' variables,
Double Field Theory can accommodate novel geometries where a Riemannian metric
cannot be defined, even locally. Here we present a complete classification of
such non-Riemannian spacetimes in terms of two non-negative integers,
, . Upon these backgrounds, strings become
chiral and anti-chiral over and directions respectively, while
particles and strings are frozen over the directions. In
particular, we identify as Riemannian manifolds, as
non-relativistic spacetime, as Gomis-Ooguri non-relativistic string,
as ultra-relativistic Carroll geometry, and as Siegel's
chiral string. Combined with a covariant Kaluza-Klein ansatz which we further
spell, leads to Newton-Cartan gravity. Alternative to the conventional
string compactifications on small manifolds, non-Riemannian spacetime such as
, may open a new scheme of the dimensional reduction from ten to
four.Comment: 1+41 pages; v2) Refs added; v3) Published version; v4) Sign error in
(2.51) correcte
Structural and biochemical characterization of the exopolysaccharide deacetylase Agd3 required for Aspergillus fumigatus biofilm formation
The exopolysaccharide galactosaminogalactan (GAG) is an important virulence factor of the fungal pathogen Aspergillus fumigatus. Deletion of a gene encoding a putative deacetylase, Agd3, leads to defects in GAG deacetylation, biofilm formation, and virulence. Here, we show that Agd3 deacetylates GAG in a metal-dependent manner, and is the founding member of carbohydrate esterase family CE18. The active site is formed by four catalytic motifs that are essential for activity. The structure of Agd3 includes an elongated substrate-binding cleft formed by a carbohydrate binding module (CBM) that is the founding member of CBM family 87. Agd3 homologues are encoded in previously unidentified putative bacterial exopolysaccharide biosynthetic operons and in other fungal genomes. The exopolysaccharide galactosaminogalactan (GAG) is an important virulence factor of the fungal pathogen Aspergillus fumigatus. Here, the authors study an A. fumigatus enzyme that deacetylates GAG in a metal-dependent manner and constitutes a founding member of a new carbohydrate esterase family.Bio-organic Synthesi
Human Computation and Convergence
Humans are the most effective integrators and producers of information,
directly and through the use of information-processing inventions. As these
inventions become increasingly sophisticated, the substantive role of humans in
processing information will tend toward capabilities that derive from our most
complex cognitive processes, e.g., abstraction, creativity, and applied world
knowledge. Through the advancement of human computation - methods that leverage
the respective strengths of humans and machines in distributed
information-processing systems - formerly discrete processes will combine
synergistically into increasingly integrated and complex information processing
systems. These new, collective systems will exhibit an unprecedented degree of
predictive accuracy in modeling physical and techno-social processes, and may
ultimately coalesce into a single unified predictive organism, with the
capacity to address societies most wicked problems and achieve planetary
homeostasis.Comment: Pre-publication draft of chapter. 24 pages, 3 figures; added
references to page 1 and 3, and corrected typ
- …