2,156 research outputs found
A Novel in situ Trigger Combination Method
Searches for rare physics processes using particle detectors in
high-luminosity colliding hadronic beam environments require the use of
multi-level trigger systems to reject colossal background rates in real time.
In analyses like the search for the Higgs boson, there is a need to maximize
the signal acceptance by combining multiple different trigger chains when
forming the offline data sample. In such statistically limited searches,
datasets are often amassed over periods of several years, during which the
trigger characteristics evolve and system performance can vary significantly.
Reliable production cross-section measurements and upper limits must take into
account a detailed understanding of the effective trigger inefficiency for
every selected candidate event. We present as an example the complex situation
of three trigger chains, based on missing energy and jet energy, that were
combined in the context of the search for the Higgs (H) boson produced in
association with a boson at the Collider Detector at Fermilab (CDF). We
briefly review the existing techniques for combining triggers, namely the
inclusion, division, and exclusion methods. We introduce and describe a novel
fourth in situ method whereby, for each candidate event, only the trigger chain
with the highest a priori probability of selecting the event is considered. We
compare the inclusion and novel in situ methods for signal event yields in the
CDF search. This new combination method, by virtue of its scalability to
large numbers of differing trigger chains and insensitivity to correlations
between triggers, will benefit future long-running collider experiments,
including those currently operating on the Large Hadron Collider.Comment: 17 pages, 2 figures, 6 tables, accepted by Nuclear Instruments and
Methods in Physics Research
Tyrosine intake and cardiovascular responses in a motivated performance situation
Ingesting the catecholamine precursor tyrosine can prevent decrements in, or improve, cognitive and motor performance in demanding situations. Furthermore, the biopsychosocial model of challenge and threat specifies that adrenal medullary catecholamine release plays a central role in the occurrence of a challenge state, which has been linked to better performance under pressure than a threat state. The present study thus examined whether acute tyrosine intake impacts upon challenge and threat states or influences cognitive and motor performance independently. A double-blind randomised crossover design with 49 participants (33 males; Β΅age = 22.5 years, SD = 5.0) was used. Participants ingested tyrosine or placebo (150mg/kg body mass) 60 minutes before performing the N-Back task and a bean-bag throwing task. Cognitive self-reports and cardiovascular data before each task provided indicators of challenge and threat states. There were no significant differences between tyrosine and placebo on the cognitive and cardiovascular challenge and threat variables. Generalised Estimating Equations analyses found that tyrosine was associated with better performance than placebo on the bean-bag throwing task, but not on the N-Back task. A significant interaction effect showed that challenge and threat states were more positively related to performance in the placebo condition than in the tyrosine condition. This suggests that tyrosine may have attenuated the detrimental effect of a threat state. The present study breaks new ground in relating the impact of a dietary supplement to challenge and threat states and finding that tyrosine may in some cases attenuate the negative effects of a threat state
The relationship between challenge and threat states and performance: A systematic review
The biopsychosocial model of challenge and threat states specifies that these states engender different physiological and behavioral responses in potentially stressful situations. This model has received growing interest in the sport and performance psychology literature. The present systematic review examined whether a challenge state is associated with superior performance than a threat state. Across 38 published studies that conceptualized challenge and threat states in a manner congruent with the biopsychosocial model, support emerged for the performance benefits of a challenge state. There was, however, significant variation in the reviewed studies in terms of the measures of challenge and threat states, tasks, and research designs. The benefits of a challenge state on performance were largely consistent across studies using cognitive, physiological, and dichotomous challenge and threat measures, cognitive and behavioral tasks, and direct experimental, indirect experimental, correlational, and quasi-experimental designs. The results imply that sports coaches, company directors, and teachers might benefit from trying to promote a challenge state in their athletes, employees, and students, respectively. Future research could benefit from a greater consensus on how best to measure challenge and threat states to help synthesize the evidence across studies. Specifically, we recommend that researchers use both cognitive and physiological measures and develop stronger manipulations for experimental studies. Finally, future research should report sufficient information to enable risk of bias assessment
The Effects of Support (In)Adequacy on Self-Confidence and Performance: Two Experimental Studies
The presence of supportive relationships is crucial in health and sporting contexts. However, the actual receipt of supportive behaviors from these relationships is sometimes ineffective or even detrimental. One explanation for this inconsistency is that the amount of support individuals receive might not be congruent with what they want. Using the support adequacy model as a framework, the current article was the first to examine whether the interaction of wanted and received support influences self-confidence and performance. In two experiments, participants (ns = 88, 91) performed a golf-putting task in one of the following conditions: low wanted - control (null support), low wanted β received support (overprovision), high wanted - control (underprovision), and high wanted β received support (adequacy). There were significant interactions of wanted and received support on self-confidence (Study 1 and 2) and performance (Study 2 only). More specifically, compared to participants in both the underprovision and overprovision conditions, those in the adequate condition had better self-confidence and performance. The findings provide important experimental evidence for the support adequacy model, highlight that it is a useful framework to explain the effects of received support on self-confidence and performance, and suggest that an individualβs support network should tailor actions to the support that the individual wants
βBuying salad is a lot more expensive than going to McDonaldsβ: young adultsβ views about what influences their food choices
Young adults (18β30 years of age) are an βat-riskβ group for poor dietary behaviours and less healthy food choices. Previous research with young adults has looked at the barriers and enablers driving their food choices, focusing primarily on university and college students. However, there is less research using qualitative methods with young adults as a broader population group. This study aimed to explore the experiences of young adults in two different yet similar settings: Sydney, Australia and Glasgow, Scotland. Eight focus groups of young adult participants, ranging in size from 2β6 participants, were held in Sydney, Australia (n = 14) and Glasgow, Scotland (n = 16) to discuss, explore and compare the determinants and influences of their food choices. Focus group transcripts were coded thematically based on a process of narrative analysis. Three major narratives were identified across both locations: value of food; appeal of food; and emotional connections with food. These narratives were underpinned by a broader narrative of βperforming adulthood.β This narrative reflected a belief amongst participants that they should make rational, informed choices about food despite this conflicting with their broader food environment. Future research could examine which environment-level or policy-based interventions are most acceptable to young adults in terms of influencing their food choices and dietary behaviours
The NASA Space Communications Data Networking Architecture
The NASA Space Communications Architecture Working Group (SCAWG) has recently been developing an integrated agency-wide space communications architecture in order to provide the necessary communication and navigation capabilities to support NASA's new Exploration and Science Programs. A critical element of the space communications architecture is the end-to-end Data Networking Architecture, which must provide a wide range of services required for missions ranging from planetary rovers to human spaceflight, and from sub-orbital space to deep space. Requirements for a higher degree of user autonomy and interoperability between a variety of elements must be accommodated within an architecture that necessarily features minimum operational complexity. The architecture must also be scalable and evolvable to meet mission needs for the next 25 years. This paper will describe the recommended NASA Data Networking Architecture, present some of the rationale for the recommendations, and will illustrate an application of the architecture to example NASA missions
A system for de-identifying medical message board text
There are millions of public posts to medical message boards by users seeking support and information on a wide range of medical conditions. It has been shown that these posts can be used to gain a greater understanding of patientsβ experiences and concerns. As investigators continue to explore large corpora of medical discussion board data for research purposes, protecting the privacy of the members of these online communities becomes an important challenge that needs to be met. Extant entity recognition methods used for more structured text are not sufficient because message posts present additional challenges: the posts contain many typographical errors, larger variety of possible names, terms and abbreviations specific to Internet posts or a particular message board, and mentions of the authorsβ personal lives. The main contribution of this paper is a system to de-identify the authors of message board posts automatically, taking into account the aforementioned challenges. We demonstrate our system on two different message board corpora, one on breast cancer and another on arthritis. We show that our approach significantly outperforms other publicly available named entity recognition and de-identification systems, which have been tuned for more structured text like operative reports, pathology reports, discharge summaries, or newswire
Visual Deprojection: Probabilistic Recovery of Collapsed Dimensions
We introduce visual deprojection: the task of recovering an image or video
that has been collapsed along a dimension. Projections arise in various
contexts, such as long-exposure photography, where a dynamic scene is collapsed
in time to produce a motion-blurred image, and corner cameras, where reflected
light from a scene is collapsed along a spatial dimension because of an edge
occluder to yield a 1D video. Deprojection is ill-posed-- often there are many
plausible solutions for a given input. We first propose a probabilistic model
capturing the ambiguity of the task. We then present a variational inference
strategy using convolutional neural networks as functional approximators.
Sampling from the inference network at test time yields plausible candidates
from the distribution of original signals that are consistent with a given
input projection. We evaluate the method on several datasets for both spatial
and temporal deprojection tasks. We first demonstrate the method can recover
human gait videos and face images from spatial projections, and then show that
it can recover videos of moving digits from dramatically motion-blurred images
obtained via temporal projection.Comment: ICCV 201
Effect of information format on intentions and beliefs regarding diagnostic imaging for non-specific low back pain: A randomised controlled trial in members of the public
Objective
To evaluate the effects of information format on intentions to request diagnostic imaging for non-specific low back pain in members of the public.
Methods
We performed a three arm, 1:1:1, superiority randomised trial on members of the public. Participants were randomised to one of the three groups: a Standard Care Leaflet group (standard information on low back pain), a Neutral Leaflet group (balanced information on the benefits and harms of imaging) and a Nudge Leaflet group (with behavioural cues to emphasise the harms of unnecessary imaging). Our primary outcome was intention to request imaging for low back pain.
Results
418 participants were randomised. After reading the leaflet, intention to request imaging (measured on an 11-point scale (0 = definitely would not request to 10 = definitely would request) was lower in the Nudge Leaflet group (meanβ= 4.6, SDβ= 3.4) compared with the Standard Care Leaflet group (meanβ= 5.3, SDβ= 3.3) and the Neutral Leaflet group (meanβ= 5.3, SDβ= 3.0) (adjusted mean difference between Nudge and Neutral, β1.0 points, 95%CI β1.6 to β0.4).
Conclusion
Framing information to emphasise potential harms from overdiagnosis reduced intention to request diagnostic imaging for low back pain.
Practice implications
Nudge leaflets could help clinicians manage patient pressure for unnecessary tests.Dr Mary O'Keeffe is supported by funding from the European Union's Horizon 2020 research and innovation programme under the Marie SkΕodowska-Curie grant agreement No 75049
13b,13c-Di-2-pyridyl-5,7,12,13b,13c,14-hexaΒhydro-6H,13H-5a,6a,12a,13a-tetraΒazabenz[5,6]azuleno[2,1,8-ija]benz[f]azulene-6,13-dione methanol hemisolvate
The title compound, C30H24N6O2Β·0.5CH3OH, a glycoluril derivative with two pyridine substituents on the convex face of the glycoluril system, is an important interΒmediate for the synthesis of more complex glycoluril derivatives. The compound crystallizes with two independent molΒecules in the asymmetric unit, one of which exhibits disorder of one benzene ring over two orientations with refined site occupancy factors 0.65β
(4):0.35β
(4). The crystal structure contains several short CβHβ―O contacts, and the methanol molΒecule forms an OβHβ―O hydrogen bond to one of the glycoluril molΒecules
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