131,414 research outputs found
The mesostriatal system in the primate
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Brain and Cognitive Sciences, 1989.Includes bibliographical references (leaves 183-201).by Laura Feigenbaum Langer.Ph.D
Directed cartesian-product graphs have unique factorizations that can be computed in polynomial time
No full textAbstractThe cartesian product of directed, simple graphs D1 = (V1, A1) and D2 = (V2, A2) is a digraph D with V(D) = V1 × V2 and A(D) = {(ν1, ν2) → (w1, w2): ν1 = w1 and ν2 → w2 ϵA2 or ν2 = w2 and ν1 → w1ϵA1}. In this paper, we prove that directed graphs have unique prime factorizations under cartesian multiplication and that we can find the prime factorizations of weakly connected digraphs in polynomial time. This work extends recent work by Feigenbaum, Hershberger, Schäffer, and Winkler on cartesian factoring of undirected graphs
Application of Feigenbaum\u27s Cost of Quality Strategy on Engineering Firms
No full textIt has been 50+ years since Feigenbaum first conceived of the strategy for the manufacturing sector, yet quality costing strategies have not found a foothold among engineering firms. This study was aimed at constructing a theory that explains possible barriers to acceptance of the Feigenbaum strategy by analyzing the attitudes and opinions of players in an actual engineering firm. Modeled after the Feigenbaum approach and tailored to the business model of engineering and architectural firms, a system was developed to classify and record costs of quality. A local office of a large engineering firm was recruited to apply the system on a hand-picked design project. Using an inductive approach and a grounded theory methodology, records were examined and participants were interviewed. The observed concepts and emergent hypotheses begin to tell an interesting story that might be the key to the ultimate success or failure of the Feigenbaum approach to quality costing in engineering firms
On the statistical Analysis of Feigenbaum Constants
No full textWe present statistical analysis of blocks in the binary expansions of Feigenbaum constants a and d
for the logistic map. The analysis is carried out on both 1016 and 3400 bit expansions. A w2 test is
applied for lumping data and a serial test is applied on gliding data. Contrary to a previous research
by Karamanos and Kotsireas, our test results did not indicate any evidence to reject randomness of
these constants. Additional 25 randomness tests also support the conjecture of randomness of these
constants having transcendental character
Population and antenatal-based HIV prevalence estimates in a high contracepting female population in rural South Africa.
No full textBACKGROUND: To present and compare population-based and antenatal-care (ANC) sentinel surveillance HIV prevalence estimates among women in a rural South African population where both provision of ANC services and family planning is prevalent and fertility is declining. With a need, in such settings, to understand how to appropriately adjust ANC sentinel surveillance estimates to represent HIV prevalence in general populations, and with evidence of possible biases inherent to both surveillance systems, we explore differences between the two systems. There is particular emphasis on unrepresentative selection of ANC clinics and unrepresentative testing in the population. METHODS: HIV sero-prevalence amongst blood samples collected from women consenting to test during the 2005 annual longitudinal population-based serological survey was compared to anonymous unlinked HIV sero-prevalence amongst women attending antenatal care (ANC) first visits in six clinics (January to May 2005). Both surveillance systems were conducted as part of the Africa Centre Demographic Information System. RESULTS: Population-based HIV prevalence estimates for all women (25.2%) and pregnant women (23.7%) were significantly lower than that for ANC attendees (37.7%). A large proportion of women attending urban or peri-urban clinics would be predicted to be resident within rural areas. Although overall estimates remained significantly different, presenting and standardising estimates by age and location (clinic for ANC-based estimates and individual-residence for population-based estimates) made some group-specific estimates from the two surveillance systems more predictive of one another. CONCLUSION: It is likely that where ANC coverage and contraceptive use is widespread and fertility is low, population-based surveillance under-estimates HIV prevalence due to unrepresentative testing by age, residence and also probably by HIV status, and that ANC sentinel surveillance over-estimates prevalence due to selection bias in terms of age of sexual debut and contraceptive use. The results presented highlight the importance of accounting for unrepresentative testing, particularly by individual residence and age, through system design and statistical analyses
Continued fractions and solutions of the Feigenbaum-Cvitanović equation
No full textIn this paper, we develop a new approach to the construction of solutions of the
Feigenbaum-Cvitanovic equation whose existence was shown by H.Epstein. Our main
tool is the analytic theory of continued fractions
Replication Data for: Childhood cross-ethnic exposure predicts political behavior seven decades later: Evidence from linked administrative data
No full textReplication data for:
Brown, Jacob R. Brown, Ryan D. Enos, James Feigenbaum, and Soumyajit Mazumder, "Childhood cross-ethnic exposure predicts political behavior seven decades later: Evidence from linked administrative data," Science Advances, 2021
The Role of Language Anxiety in Teacher-fronted and Small-group Interaction in Spanish as a Foreign Language: How is Pronunciation Accuracy Affected?
No full textThe use of group work in the second language classroom has become common with the introduction of Communicative Language Teaching. The focus on group work has led to a body of research analyzing differences in student speech in the group work and teacher-fronted environments. The present study focused on differences in pronunciation accuracy in these two environments, and the influence that language anxiety may have on these differences. The results show that pronunciation accuracy does not differ between the two environments. In addition, there was no significant relationship between pronunciation accuracy and anxiety in the group work environment. However, there was a significant negative correlation (r = -.562, p = .012) between language anxiety and pronunciation accuracy in the teacher-fronted environment. This suggests that language anxiety only has negative effects on pronunciation during teacher-fronted activities
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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