21838 research outputs found
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Improving topological cluster reconstruction using calorimeter cell timing in ATLAS
No full textAbstract
Clusters of topologically connected calorimeter cells around cells with large absolute signal-to-noise ratio (topo-clusters) are the basis for calorimeter signal reconstruction in the ATLAS experiment. Topological cell clustering has proven performant in LHC Runs 1 and 2. It is, however, susceptible to out-of-time pile-up of signals from soft collisions outside the 25 ns proton-bunch-crossing window associated with the event’s hard collision. To reduce this effect, a calorimeter-cell timing criterion was added to the signal-to-noise ratio requirement in the clustering algorithm. Multiple versions of this criterion were tested by reconstructing hadronic signals in simulated events and Run 2 ATLAS data. The preferred version is found to reduce the out-of-time pile-up jet multiplicity by
∼
50
%
for jet
p
T
∼
20
GeV and by
∼
80
%
for jet
p
T
≳
50
GeV, while not disrupting the reconstruction of hadronic signals of interest, and improving the jet energy resolution by up to 5% for
20
<
p
T
<
30
GeV. Pile-up is also suppressed for other physics objects based on topo-clusters (electrons, photons,
τ
-leptons), reducing the overall event size on disk by about
6
%
in early Run 3 pile-up conditions. Offline reconstruction for Run 3 includes the timing requirement
Observation of electroweak production of W+W− in association with jets in proton-proton collisions at s = 13 TeV with the ATLAS detector
No full textAbstract
A measurement of the production of W bosons with opposite electric charges in association with two jets is presented based on 140 fb−1 of data collected by the ATLAS detector in proton-proton collisions at
s
= 13 TeV. The analysis is sensitive to the scattering of W bosons, which is of particular interest in the ATLAS physics programme as it can be used to probe the electroweak symmetry breaking mechanism of the Standard Model. This signal is observed with a significance of 7.1 standard deviations above the background expectation, while 6.2 standard deviations were expected. The measured cross-section is determined in a signal-enriched fiducial volume and is found to be 2.7 ± 0.5 fb, which is consistent with the theoretical prediction of
2.20
−
0.13
+
0.14
fb
A comparison of place attachment as a cultural ecosystem service in South African National Parks: an adaptive management strategy
Get PDFEcotourism is one of the essential and fast-growing sub-sectors of tourism globally. The COVID-19 pandemic and its accompanying confinements have renewed the interest and importance of nature for the general well-being of people. This research focuses on the intangible benefits of visitors’ subjective experiences within selected national parks in South Africa and highlights the benefits of these experiences to management. Research conducted in these national parks mainly considered the general motivations of visitors and focused on market segmentation. The South African National Parks’ (SANParks) vision statement and aim are to be a world-class system of sustainable national parks reconnecting and inspiring society. This research proposes consecutive subjective experience stages with inter-relationships when people visit natural areas, ultimately leading to attachment. These could assist in SANParks’ vision. The study found that the preferred parks were Kgalagadi Transfrontier Park (KTP) and Kruger National Park (KNP). These parks also receive ample tourists and are successful. The less preferred parks selected were Golden Gate Highlands National Park (GGHNP), Mapungubwe National Park (MapNP), Marakele National Park (MarNP) and Mountain Zebra National Park (MZNP). There was a mandate from SANParks to elevate the tourism potential of the smaller parks.
The research design for this research was a mixed-method, multiple case study approach that consisted of three phases. The population consisted of adult visitors to the parks. Simple random sampling was used for questionnaires, and convenience and purposive sampling was used for the semi-structured interviews. Quantitative data analysis consisted of basic descriptive and inferential statistics, while qualitative data were analysed using content analysis. The results were obtained from 1 895 questionnaires from phase one, 23 semi-structured interviews in phase two and 2 023 questionnaires from phase three.
Results showed that respondents had unique motivations to visit the respective parks, and these differed between the preferred (e.g. loyalty) and less preferred parks (e.g. accessibility and novelty-seeking). The attributes of each park were unique. Preferred park respondents focused on the iconic species and animal
v
interactions, while the less preferred parks’ included aesthetics, unique species and other natural features. Cultural ecosystem services were deemed most important to the preferred park respondents overall. The existence value is the most important value to all respondents. KNP respondents had the highest level of place attachment, followed by KTP. All respondents indicated a strong connection to nature. Environmental problems overall were considered the most threatening to KNP respondents. The loss of wilderness was most threatening to KTP and GGHNP respondents, while wildlife poaching was most threatening to KNP, MapNP, MarNP and MZNP respondents. The most pressing future threats and current hindrances in all parks are increased commercialisation and tourism and the accompanying bad behaviour displayed (e.g. drinking, littering, speeding, noise, vandalisation, etc.).
This research adds value to the respective parks’ strategic adaptive management, and the results could be incorporated into their desired strategic direction for each park. The less preferred park managers should aim to improve the profiles of these parks by developing authentic activities that will attract and enhance visitors’ recreational experiences, improving their loyalty and attachment. Furthermore, pro-environment behaviours could be encouraged by social marketing campaigns, environmental education programs, and the creation of infographics to increase awareness of intangible benefits.D. Phil. (Environmental Science)Environmental Science
How using English as the medium of instruction affects teaching and learning at a TVET college: lecturers and students’ experiences
Get PDFThe purpose of this study was to explore the experiences and challenges of lecturers and students using English as the medium of instruction (EMI) for teaching and learning at a public technical and vocational education and training (TVET) college in South Africa. The study focused on two campuses of a TVET college in Free State Province where English is the only medium of instruction. A qualitative case study approach and purposeful method with in-depth interviews and analysis were employed to understand the experiences of these participants. The findings of the study revealed that the challenges of using EMI which impeded academic performance resulted from a variety of factors. Trends, including restricted comprehension, insufficient English proficiency and limited English vocabulary and academic literacy, emerged as the barriers that posed challenges to the academic performance of students. Based on the study’s findings, it is clear that the college lacks interventions to strengthen language capabilities, enhance professional skills and provide academic support services such as multilingual educational contexts. Further research is needed to understand the underlined mechanisms and develop strategies to mitigate their impact.M. A. (English Studies)English Studie
Differential evolution optimization algorithms and its application in machine learning based disease detection
No full textText in EnglishMachine learning (ML) in healthcare is crucial for establishing and enhancing performant automated disease detection systems that can be used in medical practice. This dissertation aims to improve ML classifiers for disease detection through three main objectives: optimising hyperparameters using Differential Evolution (DE), comparing the performance of DE-optimised classifiers (Random Forest, AdaBoost, Gradient Boosting) against traditional methods, and exploring DE's application in automating triage systems in healthcare. Research employed datasets from the UC Irvine Machine Learning Repository, focusing on heart disease and thyroid cancer due to their prevalence. Data analysis involved optimising classifiers with DE and assessing their performance. The study identified the DE-optimised Random Forest classifier as particularly effective, achieving 98.7% accuracy and a 97.2% F1-score in thyroid cancer recurrence, and 93.3% accuracy with a 90.9% F1-score for heart disease. These results underscore DE's potential in enhancing accuracy and efficiency of ML classifiers. The findings also suggest significant implications for DE in healthcare, especially in automated triage systems, indicating a transformative impact on predictive diagnostics. The dissertation concludes with recommendations for integrating DE-optimised ML classifiers in healthcare settings and suggestions for future research.M. Sc. (Engineering)Electrical and Mining Engineerin
Physiological and behavioural effects of imidacloprid on Culex sp.
No full textResearch into the toxicological risks posed by pesticides and other chemicals to non-target aquatic species, which are crucial components of the food chain, is paramount for safeguarding the biosphere. This study aims to evaluate the effects of the insecticide, imidacloprid on the behaviour, physiology and survival of larvae of the mosquito Culex sp. Resting, swimming and respiration were selected as behavioural assessment endpoints when organisms were exposed to concentrations ranging between 0 – 2 ppm of imidacloprid while recording for 600 seconds. Survival was assessed after 24 hours, while the physiological changes were assessed using catalase and acetylcholinesterase activity. Based on the results, imidacloprid has a negative effect on Culex sp. Among the assessed behaviours, respiration and resting were significantly (p < 0,05) affected by imidacloprid exposure. There was a significant increase in resting behaviour and a decrease in the breathing behaviour as the concentrations of IMI increased.As concentrations increased, the survival rate decreased. Additionally, there was a significant decrease in catalase activity (p < 0,05) and a significant increase in acetylcholine activity (p < 0,05). The changes in behaviour and physiology noted in this study indicate the possible effects that imidacloprid can have on different aquatic species within ecosystems in the biosphere.M. Sc. (Environmental Science)Environmental Science
Pentecostal theology regarding disability in African neo-Pentecostalism
No full textThe Pentecostal approach to disability is currently informed by the imposed healing,
deliverance, and performance of other miracles, particularly among neo-Pentecostals in Africa. This is also informed by the neo-Pentecostal pastor’s radical approach to the aspect of healing in Pentecostal theology. Therefore, instead of addressing disability from the point of environmental, social, and technological aspects, neo-Pentecostal pastors either impose healing on the disabled body, or blame them for a lack of faith. This in a way presents some power dynamics between the abled neo-Pentecostal pastors’ bodies and the disabled congregant bodies. This article uses a critical theory, to argue that the development of the
Pentecostal theology of disability should take cognisance of the environmental, social, and technological factors. When this is done, a Pentecostal setting in the form of a church service, crusade, or revival will not become a place of imposed healing and deliverance, but an environmentally, socially, and technologically friendly one, that is conducive to those living with a disability.Christian Spirituality, Church History and Missiolog
The influence of learner discipline on learning in Ekurhuleni primary schools, Gauteng Province
No full textIn South African schools, especially in Gauteng province, learner discipline problems are a worrying phenomenon. In many schools in the Ekurhuleni region of the Gauteng Department of Education, teachers are battling to deal with learner indiscipline in the post-corporal punishment era. Due to the prohibition of corporal discipline and the proclamation of the new disciplinary system, public schools in this district seem to be in a chaotic state. Prior to their appointment, teachers generally have little or no training in the use of alternative methods of maintaining discipline, yet they have to deal with the worsening levels of learner discipline. This study sought to find out possible ways in which effective discipline can be maintained and identify strategies to overcome poor discipline challenges in Ekurhuleni primary schools. This study followed a qualitative research approach and used semi-structured interviews to collect data. The investigation focused on three primary schools which were purposefully sampled to participate in the study. The research concentrated only on the views of the educators and the principals. The findings revealed that maintaining learner discipline in schools is a difficult undertaking for both principals and teachers as they lack proper training on the use of alternatives to corporal punishment, a lack of clarity on the alternatives to corporal punishment, a lack of administrative and stakeholder support for most teachers, particularly from the Department of Basic Education. To address these shortcomings, it is recommended that all stakeholders be involved in the discussion of learner discipline and policies guiding it. In this sense, it is critical to include the entire community in maintaining learner discipline in a bid to support learning. The community could devise innovative approaches and mechanisms that could assist principals and teachers in maintaining learner discipline in schools. All these strategies could engender good learner discipline in schools, which is essential for effective teaching and learning.M. Ed. (Education Management)Educational Studie
Combination of searches for heavy spin-1 resonances using 139 fb−1 of proton-proton collision data at s = 13 TeV with the ATLAS detector
No full textAbstract
A combination of searches for new heavy spin-1 resonances decaying into different pairings of W, Z, or Higgs bosons, as well as directly into leptons or quarks, is presented. The data sample used corresponds to 139 fb−1 of proton-proton collisions at
s
= 13 TeV collected during 2015–2018 with the ATLAS detector at the CERN Large Hadron Collider. Analyses selecting quark pairs (qq, bb,
t
t
¯
, and tb) or third-generation leptons (τν and ττ) are included in this kind of combination for the first time. A simplified model predicting a spin-1 heavy vector-boson triplet is used. Cross-section limits are set at the 95% confidence level and are compared with predictions for the benchmark model. These limits are also expressed in terms of constraints on couplings of the heavy vector-boson triplet to quarks, leptons, and the Higgs boson. The complementarity of the various analyses increases the sensitivity to new physics, and the resulting constraints are stronger than those from any individual analysis considered. The data exclude a heavy vector-boson triplet with mass below 5.8 TeV in a weakly coupled scenario, below 4.4 TeV in a strongly coupled scenario, and up to 1.5 TeV in the case of production via vector-boson fusion
The perception of primary school teachers on school leadership during the implementation of fourth industrial revolution in rural primary schools in Limpopo Province
No full textAbstracts in English, Sepedi and TshivendaThe study investigated how primary school teachers perceived their empowerment as leaders during the implementation of the Fourth Industrial Revolution. This study made use of a qualitative approach. A purposeful sampling approach was used to select participants for this study. The participants were limited to primary school principals and teachers from selected schools in rural areas of the Mopani West District. Data were gathered using semi-structured and focus group interviews. The findings disclosed that rural primary schools lack resources, therefore, they need financial support to implement the Fourth Industrial Revolution successfully. Educational government departments should provide financial support to the schools as well as provide 4IR training to all the teachers. The findings verified that these recommendations would ensure the successful implementation of the Fourth Industrial Revolution.Thuto ye ebe e nyakišiša mokgwa woo barutiši ba dikolo tša phoraemari ba kwešišago hlohleletšo bjale ka baetapele magareng ga go phethagatša intasteri ya bone ya phetogo. Thuto ye e šomišitše mokgwa wa boleng.Sampole ya goba le morero e šomišitšwe go kgetha batšea karolo mo thutong ye. Go kgetha batšea karolo, gobe go lebeletšwe feela barutiši le dihlogo tša dikolo gotšwa dikong tša diphoraemari tša dinaga magaeng tšeo di kgethilweng ka Mopani West district. Poledišano ya batho ba ba bedi mmogo le ya sehlopha e šomišitšwe go kgoboketša dinthla. Dipoelo di tšweletšitše gore dikolo tša diphoraemari tša dinaga magaeng di na le tlhaelelo ya ditšhomišo, ka gore yalo, di hloka thekgo ya mašeleng go phethagatša intasteri ya bone ya phethogo ka katlego. Lefapa la mmušo le swanetše go fana ka thušo ya mašeleng mo dikolong, mmogo le go ruta barutiši ka moka ka intasteri ya bone ya phetogo. Dipoelo tše di kgonthišišitše gore dikeletšo tše di tlo netefatša katlego ya phethagatšo ya intasteri ya bone ya phetogo.Tsenguluso ino yo ṱoḓisisa ku pfesesele kwa vhadededzi vha zwikolo zwa phuraimari kha u maanḓafhadziwa havho zwi tshi ḓa kha u shumisiwa ha 4IR zwikoloni. Tsenguluso ino yo shumisa u toḓisisa hau tou vhudzisa vhathu dzimbudziso, ho topolwa vhathu vho teaho u itela u ṱola ngudo edzi . Vho topolwaho ndi vhadededzi vha phuraimari na ṱhoho dza zwikoloni zwa phuraimari fhedzi kha tshiṱiriki tsha Mopani Vhukovhela . Ho shumisiwa nyambedzano yo vuleaho na mbudziso dzo to livhiswaho kha zwigwadazwa, vhathu u kuvhanganya vhuṱanzi na mawanwa a tsenguluso. Mawanwa a heyi tsenguluso ndia uri vhadededzi vha zwikoloni zwa vha na zwishumiswa ,zwo ralo vha khou ṱhoga thuso ya masheleni uri vha kone u shumisa 4IR nga ndila yone i no vhuedza .Muhasho wa zwa pfunzo ukhou tea u fha thikhedzo ya masheleni zwikoloni na u pfumbudza vhadededzi nga 4IR . Mawana a khou tikedza uri zwo themendelwaho afha kha, tsenguluso zwi do ita uri u zwi konadzee u shumisa 4IR nga nḓila i no vhuedza zwikoloni.M. Ed. (Education Management)Educational Leadership and Managemen