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Predicting college readiness in STEM: a longitudinal study of Iowa studentsRickels, Heather Anne 01 May 2017 (has links)
The demand for STEM college graduates is increasing. However, recent studies show there are not enough STEM majors to fulfill this need. This deficiency can be partially attributed to a gender discrepancy in the number of female STEM graduates and to the high rate of attrition of STEM majors. As STEM attrition has been associated with students being unprepared for STEM coursework, it is important to understand how STEM graduates change in achievement levels from middle school through high school and to have accurate readiness indicators for first-year STEM coursework. This study aimed to address these issues by comparing the achievement growth of STEM majors to non-STEM majors by gender in Science, Math, and Reading from Grade 6 to Grade 11 through latent growth models (LGMs). Then STEM Readiness Benchmarks were established in Science and Math on the Iowas (IAs) for typical first-year STEM courses and validity evidence was provided for the benchmarks.
Results from the LGM analyses indicated that STEM graduates start at higher achievement levels in Grade 6 and maintain higher achievement levels through Grade 11 in all subjects. In addition, gender differences were examined. The findings indicate that students with high achievement levels self-select as STEM majors, regardless of gender. In addition, they suggest that students who are not on-track for a STEM degree may need to begin remediation prior to high school. Results from the benchmark analyses indicate that STEM coursework is more demanding and that students need to be better prepared academically in science and math if planning to pursue a STEM degree. In addition, the STEM Readiness Benchmarks were more accurate in predicting success in STEM courses than if general college readiness benchmarks were utilized. Also, students who met the STEM Readiness Benchmarks were more likely to graduate with a STEM degree.
This study provides valuable information on STEM readiness to students, educators, and college admissions officers. Findings from this study can be used to better understand the level of academic achievement necessary to be successful as a STEM major and to provide guidance for students considering STEM majors in college. If students are being encouraged to purse STEM majors, it is important they have accurate information regarding their chances of success in STEM coursework.
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Bayesian statistical modeling in epidemics and the contact networks that transmit themYin, Jun 01 May 2014 (has links)
Infectious diseases, including influenza, measles, and sexually transmitted diseases, spread from person to person. Different attempts have been made to modify or extend traditional epidemic models to relax homogeneity assumptions, so as to handle more complex and realistic situations. We propose a network-based approach to the modeling and prediction of infectious disease outbreaks.
Our focus is on heterogeneous populations where there is variation in individual susceptibility, infectivity, and person-to-person contact patterns. To address the complexity of disease propagation over a contact network, we develop a Bayesian survival model that maps the network onto a latent space and uses latent positions to predict disease transmission.
We present an R package (`epinet') implementation of our methods and an application to a high school contact network. The package uses C code to implement an MCMC algorithm to efficiently estimate parameters and predict disease outcomes. Our application involves contact data collected by mobile sensors distributed to individuals, and provides estimates of disease transmission in line with the network structure. In it, we address issues that are of direct interest to public health professionals, such as prediction of future outbreaks of diseases. Questions such as whether quarantine will help mitigate an outbreak can also be explored using our proposed model.
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Musical utterance as a way of knowing : a contemporary epistemology of musicBignell, B, University of Western Sydney, Hawkesbury, Faculty of Social Inquiry, School of Social Ecology January 2000 (has links)
This thesis takes its start from the identification of a gap in knowledge between the act of musical utterance and its significance for human being. Based on the proposition that music education could benefit from what it most appears to lack, a deep epistemology, the study first examines the knowledge gap as an epistemological omission in music curriculum and discourse, and then argues the case for retrieval of a logos epistemology to rectify the omission. The recovery of the meaning of the musical act, it is argued, is an ethical, biographical initiative taken up by the individual who senses the need to strive towards freedom of moral decision. Recovery consists in developing an epistemology specific to human utterance, namely, a logos epistemology. Since the logos is an original form-bestowing power whose sanctuary is the human being, it seeks and finds expression in uttered forms, and it is through fully conscious observation of one's own contribution to the emergence of these forms that one can find oneself as knower. It is significant that it is characteristic of the logos in the current era, however, that it is hidden from the (dual) perspective which humanity has taken up in its cognitive evolution. The condition of its recovery, then, is that it must be 'unconcealed' for it is obscured by its own forms, and consequently, by aesthetic and linguistic theory derived, not from efforts made towards enhanced musical experience, but inferred from the sense-perceptible elements of experience. It is argued that it is educationally responsible to cultivate the individual's latent epistemic resources, namely, self-observed, consciously directed intentionally, so that the meaning of the original experience of musical phenomena, tone and interval, can be raised to awareness, and musical culture renewed. / Doctor of Philosophy (PhD)
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Molecular interactions of latent transforming growth Factor-β binding Protein-2 (LTBP-2) with fibrillins and other extracellular matrix macromolecules [electronic resource]: LTBP-2 competes with LTBP-1 for binding to Fibrillin-1 suggesting that LTBP-2 may modulate latent TGF-β storageHirani, Rena M January 2006 (has links)
Elastic fibres, a major component of many connective tissues, are composed of an amorphous elastin core surrounded by fibrillin - containing microfibrils. The function of these microfibrils appears to require the co - ordinated interactions of fibrillins with a range of extracellular matrix ( ECM ) macromolecules including, latent transforming growth factor - β ( TGF - β ) binding proteins ( LTBPs ). LTBPs share a high degree of structural similarity to fibrillins, since they both contain unique 8 - cysteine motifs. Of the four members of the LTBP family, LTBPs - 1, - 3 and - 4 covalently bind to latent forms of TGF - β. LTBP - 1 has been shown to interact with the N - terminal domains of fibrillin - 1 and - 2 and LTBP - 4 interacts with the N - terminal domains of fibrillin - 1, suggesting that fibrillin - containing microfibrils may act as TGF - β stores and localise latent TGF - β complexes to the ECM. LTBP - 2 differs from other members of the LTBP family since it does not covalently bind latent TGF - β. However, LTBP - 2 strongly co - localises with fibrillin - containing microfibrils in a number of tissues suggesting that LTBP - 2 could have a structural role associated with these elements presumably independent of TGF - β storage, or could act to mediate specific microfibril - ECM interactions. To understand more about the function of LTBP - 2, this study involved screening for potentially important molecular interactions of LTBP - 2 with fibrillins and a variety of ECM proteins. Human recombinant LTBP - 2 ( r - LTBP - 2 ) was cloned, expressed and purified using a mammalian cell culture system. Solid phase binding assays were used to screen for interactions between r - LTBP - 2 and continguous fragments of fibrillin - 1 and - 2 as well as MAGPs, tropoelastin, collagens and proteoglycans. A cation dependant interaction was found between the C - terminal domains of LTBP - 2 and the N - terminal domains of fibrillin - 1, but not with the analogous region of fibrillin - 2. Thus, LTBP - 2 seems to have an exclusive role associated with fibrillin - 1 - containing microfibrils. Further studies found that the C - terminal region of LTBP - 2 competes with LTBP - 1 for binding to fibrillin - 1, suggesting that the binding site for LTBP - 2 on fibrillin - 1 is the same or in close proximity to that for LTBP - 1. Immunohistochemical analysis of LTBP - 1 and - 2 within developing human aorta indicated that both LTBPs co - localised with fibrillin - 1. However, the two LTBPs did have distinct distribution patterns in relation to each other, in that LTBP - 2 was found throughout the medial layer whereas LTBP - 1 was mainly located in patches of the outer medial layer. No regions of strong co - localisation of the two LTBPs were found. Thus, these findings suggest that LTBP - 2 could indirectly modulate the presence of TGF - β upon the fibrillin - containing microfibrils by competing for binding with the LTBP- 1 / TGF - β complex to these structures. Other binding studies showed a cation independent interaction between r - LTBP - 2 and an as yet unidentified component of a crude bovine collagen - IV extract. Since collagen - IV is a major component of basement membranes, an interaction between r - LTBP - 2 and a protein within this bovine collagen - IV preparation suggests LTBP - 2 may have a further function involving a basement membrane component. It will be interesting to determine if LTBP - 2 acts as a bridging molecule between basement membrane structures and fibrillin - containing microfibrils or if it has another function independent of these microfibrils. / Thesis (Ph.D.)--School of Medical Sciences, 2006.
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The Effects of Latent Myofascial Trigger Points on Muscle Activation Patterns During Scapular Plane ElevationLucas, Karen Rae, karen.lucas@rmit.edu.au January 2007 (has links)
Despite a paucity of experimental evidence, clinical opinion remains that though LTrPs allow pain-free movement, they are primarily associated with deleterious motor effects and occur commonly in 'healthy' muscles. The primary aim of this study was to investigate the effects of LTrPs on the muscle activation patterns (MAPs) of key shoulder girdle muscles during scapular plane elevation of the arm in the unloaded, loaded and fatigued states. In connection with the main aim, a preliminary study was carried out to examine the frequency with which LTrPs occur in the scapular positioning muscles in a group of normal subjects. After establishing intra-examiner reliability for the clinical examination process, 154 healthy subjects volunteered to be screened for normal shoulder girdle function, then undergo a physical examination for LTrPs in the trapezius, rhomboids, levator scapulae, serratus anterior and the pectoralis minor muscles bilaterally. Of these 'healthy' subjects, 89.8% had at least one LTrP in the scapular positioning muscles (mean=10.65 ± 6.8, range=1-27), with serratus anterior and upper trapezius harbouring the most LTrPs on average (2.46 ± 1.8 and 2.36 ± 1.3 respectively). Consistent with clinical opinion, this study found that LTrPs occur commonly in the scapular positioning muscles. To investigate the motor effects of LTrPs, surface electromyography (sEMG) was used to measure the timing of muscle activation of the upper and lower trapezius and serratus anterior (upward scapular rotators), the infraspinatus (rotator cuff) and middle deltoid (arm abductor). These studies found that LTrPs housed in the scapular upward rotator muscles affected the timing of activation and increased the variability of the activation times of this muscle group and were also associated with altered timing of activation in the functionally related but LTrP-free infraspinatus and middle deltoid. Compared with the control group (all muscles LTrP-free), the MAPs of the LTrP group appeared to be sub-optimal, particularly in relation to preserving the subacromial space and the loading of the rotator cuff muscles. After the initial sEMG evaluations, the LTrP subjects were randomly assigned to one of two interventions: superficial dry needling (SDN) followed by post-isometric relaxation (PIR) stretching to remove LTrP s or sham ultrasound, to act as a placebo treatment where LTrPs remained. Where LTrPs were removed, a subsequent sEMG evaluation found MAPs to be similar to the control group in most of the experimental conditions investigated. Of particular note, when LTrPs had been treated and the subjects repeated the fatiguing protocol, the resultant MAP showed no significant difference with that of the control group in the rested state, suggesting treating LTrPs was associated with an improved response to fatigue induced by repetitive overhead movements. In conclusion, the findings indicate that LTrPs commonly occur in scapular positioning muscles and have deleterious effects on MAPs employed to perform scapular plane elevation and thus affect motor control mechanisms. Treating LTrPs with SDN and PIR stretching increases pressure-pain thresholds, removes associated taut bands and at least transiently optimises the MAP during scapular plane elevation. Discussion includes possible neuromuscular pathophysiology that might explain these results.
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A reliability study of electronic components and electret foils, including latent failures due to submission to electrostatic discharges in a historical retrospectiveHellström, Sten January 2003 (has links)
This thesis deals with the reliability and life-time ofelectronic components and ways to determine these factors.Plastic encapsulated and open test circuits were assessed atdifferent humidity and temperature conditions. From the resultsan acceleration factor could be derived using the Arrheniusrelation. This factor is used to determine failure rates atdifferent drift conditions under accelerated test conditions. Aformula for the factor containing both relative humidity andtemperature could be established and was found to hold also formeasurements published by others. Electrostatic discharge (ESD) transients were studiedexperimentally and by simulation with good agreement. A verysensitive method to detect latent failures of two kinds wasintroduced by nonlinearity measurements utilizing the thirdharmonic of a test signal. The ESD-susceptibility dependence ondesign and technology is shown and can be used to improvebuilt-in reliability. Influences in the performance of semiconductor devices fromdefects like fixed charges and ions were interpreted for thefirst time by simulation using a 2D- finite element componentprogram. Significant results gave an application to a MOSFETdevice showing parameter derating, especially the change of thethreshold value. A short description of later development insimulation methods with new, more powerful tools improvingcomponent performance and reliability is given. Charged thin films of Teflon, so calledelectrets, are used as microphone membranes. Theelectret voltage is a suitable reliability factor. Fromexperimental results a mathematical relation including thetemperature was established for the rate of decay of theelectret voltage with time. A method to charge the electretswith radioactive sources is outlined and described in apatent. Finally an attempt was done to analyze the reliability ofthin film circuits by mathematical methods. Bell LabsintroducedRC-feedback filters realized in tantalum thin filmtechnology. The phase shift of the filter is about π or180°. A mathematical apparatus was developed to calculatethe change in frequency and attenuation from small componentvariations in resistors and capacitors. First and higher ordercorrections were derived, using expansion by the Taylor seriesfor the higher order. <b>Keywords:</b>reliability, failure mechanism, accelerationtests, ESD, latent failure, plastic encapsulation, electret,thin film
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Standby citizens : diverse faces of political passivityAmnå, Erik, Ekman, Joakim January 2013 (has links)
Political socialization and human agency
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Political participation and civic engagement : towards a new typologyEkman, Joakim, Amnå, Erik January 2012 (has links)
Reviewing the literature on political participation and civic engagement, the articleoffers a critical examination of different conceptual frameworks. Drawing on previousdefinitions and operationalisations, a new typology for political participation and civicengagement is developed, highlighting the multidimensionality of both concepts. Inparticular, it makes a clear distinction between manifest 'political participation'(including formal political behaviour as well as protest or extra-parliamentary politicalaction) and less direct or 'latent' forms of participation, conceptualized here as 'civicengagement' and 'social involvement'. The article argues that the notion of 'latent'forms of participation is crucial to understand new forms of political behaviour and theprospects for political participation in different countries. Due to these innovations itcontributes to a much-needed theoretical development within the literature on politicalparticipation and citizen engagement.
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Social Tag-based Community Recommendation Using Latent Semantic AnalysisAkther, Aysha 07 September 2012 (has links)
Collaboration and sharing of information are the basis of modern social web system. Users in the social web systems are establishing and joining online communities, in order to collectively share their content with a group of people having common topic of interest. Group or community activities have increased exponentially in modern social Web systems. With the explosive growth of social communities, users of social Web systems have experienced considerable difficulty with discovering communities relevant to their interests. In this study, we address the problem of recommending communities to individual users. Recommender techniques that are based solely on community affiliation, may fail to find a wide range of proper communities for users when their available data are insufficient. We regard this problem as tag-based personalized searches. Based on social tags used by members of communities, we first represent communities in a low-dimensional space, the so-called latent semantic space, by using Latent Semantic Analysis. Then, for recommending communities to a given user, we capture how each community is relevant to both user’s personal tag usage and other community members’ tagging patterns in the latent space. We specially focus on the challenging problem of recommending communities to users who have joined very few communities or having no prior community membership. Our evaluation on two heterogeneous datasets shows that our approach can significantly improve the recommendation quality.
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Functionality Classification Filter for WebsitesJärvstråt, Lotta January 2013 (has links)
The objective of this thesis is to evaluate different models and methods for website classification. The websites are classified based on their functionality, in this case specifically whether they are forums, news sites or blogs. The analysis aims at solving a search engine problem, which means that it is interesting to know from which categories in a information search the results come. The data consists of two datasets, extracted from the web in January and April 2013. Together these data sets consist of approximately 40.000 observations, with each observation being the extracted text from the website. Approximately 7.000 new word variables were subsequently created from this text, as were variables based on Latent Dirichlet Allocation. One variable (the number of links) was created using the HTML-code for the web site. These data sets are used both in multinomial logistic regression with Lasso regularization, and to create a Naive Bayes classifier. The best classifier for the data material studied was achieved when using Lasso for all variables with multinomial logistic regression to reduce the number of variables. The accuracy of this model is 99.70 %. When time dependency of the models is considered, using the first data to make the model and the second data for testing, the accuracy, however, is only 90.74 %. This indicates that the data is time dependent and that websites topics change over time.
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