22 research outputs found
The effect of neck strength and anthropometric properties of academy football players on the linear and rotational accelerations experienced during heading
Introduction and purpose: Research on heading a football ball has gained interest in recent years due to the proposed association with long-term brain health and rule changes at a governing body level. Currently, evidence exploring linear and rotational accelerations is largely limited to standardised and lab-based headers and use of a hand-held dynamometer to assess neck strength, thus potentially lack ecological and concurrent validity. Therefore, this study examined the association between anthropometric properties and neck strength with linear and rotational accelerations during typical football activity. Materials and Methods: Eleven football players from a single category one academy underwent an anthropometric assessment (stature, body mass, neck length, neck circumference, and estimated head mass) and had isometric neck strength (allometrically scaled forward, lateral flexion, and extension force) determined using a fixed dynamometer. Linear and rotational accelerations were measured using instrumented mouthguards. To assess the associations, two separate linear mixed models were constructed. Results: A total of 259 âplayer observationsâ were included. A small negative association was observed between neck length, head-neck segment mass and side flexion strength with linear acceleration. A positive association was observed between neck circumference, head mass, and strength in forward flexion and extension. Neck length, neck circumference and side flexion strength were negatively associated with rotational accelerations whilst head mass, head-neck segment mass, and strength in forward flexion and extension was positively associated. The magnitude of the association and effect on the estimate for a one standard deviation change is presented in Figure 1 and 2. Conclusion: The findings in this study highlight an association between anthropometric and neck strength properties with linear and rotational accelerations experienced by players during typical football activity. These findings could have important implications when managing young athlete returning to heading activity as they progress and when developing individualised neck strengthening programmes
Focusing and Calibration of Large Scale Network Sensors using GraphBLAS Anonymized Hypersparse Matrices
Defending community-owned cyber space requires community-based efforts.
Large-scale network observations that uphold the highest regard for privacy are
key to protecting our shared cyberspace. Deployment of the necessary network
sensors requires careful sensor placement, focusing, and calibration with
significant volumes of network observations. This paper demonstrates novel
focusing and calibration procedures on a multi-billion packet dataset using
high-performance GraphBLAS anonymized hypersparse matrices. The run-time
performance on a real-world data set confirms previously observed real-time
processing rates for high-bandwidth links while achieving significant data
compression. The output of the analysis demonstrates the effectiveness of these
procedures at focusing the traffic matrix and revealing the underlying stable
heavy-tail statistical distributions that are necessary for anomaly detection.
A simple model of the corresponding probability of detection () and
probability of false alarm () for these distributions highlights
the criticality of network sensor focusing and calibration. Once a sensor is
properly focused and calibrated it is then in a position to carry out two of
the central tenets of good cybersecurity: (1) continuous observation of the
network and (2) minimizing unbrokered network connections.Comment: Accepted to IEEE HPEC, 9 pages, 12 figures, 1 table, 63 references, 2
appendice
Conserved ancestral tropical niche but different continental histories explain the latitudinal diversity gradient in brush-footed butterflies.
The global increase in species richness toward the tropics across continents and taxonomic groups, referred to as the latitudinal diversity gradient, stimulated the formulation of many hypotheses to explain the underlying mechanisms of this pattern. We evaluate several of these hypotheses to explain spatial diversity patterns in a butterfly family, the Nymphalidae, by assessing the contributions of speciation, extinction, and dispersal, and also the extent to which these processes differ among regions at the same latitude. We generate a time-calibrated phylogeny containing 2,866 nymphalid species (~45% of extant diversity). Neither speciation nor extinction rate variations consistently explain the latitudinal diversity gradient among regions because temporal diversification dynamics differ greatly across longitude. The Neotropical diversity results from low extinction rates, not high speciation rates, and biotic interchanges with other regions are rare. Southeast Asia is also characterized by a low speciation rate but, unlike the Neotropics, is the main source of dispersal events through time. Our results suggest that global climate change throughout the Cenozoic, combined with tropical niche conservatism, played a major role in generating the modern latitudinal diversity gradient of nymphalid butterflies
The 13th Southern Hemisphere Conference on the Teaching and Learning of Undergraduate Mathematics and Statistics
NgÄ mihi aroha ki ngÄ tangata katoa and warm greetings to you all. Welcome to Herenga
Delta 2021, the Thirteenth Southern Hemisphere Conference on the Teaching and Learning
of Undergraduate Mathematics and Statistics.
It has been ten years since the Volcanic Delta Conference in Rotorua, and we are excited to
have the Delta community return to Aotearoa New Zealand, if not in person, then by virtual
means. Although the limits imposed by the pandemic mean that most of this yearâs 2021
participants are unable to set foot in TÄmaki Makaurau Auckland, this has certainly not
stopped interest in this event. Participants have been invited to draw on the concept of
herenga, in Te Reo MÄori usually a mooring place where people from afar come to share
their knowledge and experiences. Although many of the participants are still some distance
away, the submissions that have been sent in will continue to stimulate discussion on
mathematics and statistics undergraduate education in the Delta tradition.
The conference invited papers, abstracts and posters, working within the initial themes of
Values and Variables. The range of submissions is diverse, and will provide participants with
many opportunities to engage, discuss, and network with colleagues across the Delta
community. The publications for this thirteenth Delta Conference include publications in the
International Journal of Mathematical Education in Science and Technology, iJMEST,
(available at https://www.tandfonline.com/journals/tmes20/collections/Herenga-Delta-2021),
the Conference Proceedings, and the Programme (which has created some interesting
challenges around time-zones), by the Local Organizing Committee. Papers in the iJMEST
issue and the Proceedings were peer reviewed by at least two reviewers per paper. Of the
ten submissions to the Proceedings, three were accepted.
We are pleased to now be at the business end of the conference and hope that this event will
carry on the special atmosphere of the many Deltas which have preceded this one. We hope
that you will enjoy this conference, the virtual and social experiences that accompany it, and
take the opportunity to contribute to further enhancing mathematics and statistics
undergraduate education.
NgÄ manaakitanga,
Phil Kane (The University of Auckland | Waipapa Taumata Rau) on behalf of the Local
Organising Committ
Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo
Meeting Abstracts: Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo Clearwater Beach, FL, USA. 9-11 June 201
William Faulkner and Mac Reed during filming of a Ford Foundation documentary
https://egrove.olemiss.edu/cofield/1396/thumbnail.jp