1,721,212 research outputs found
Linear Recurrent Subsequences of Generalized Meta-Fibonacci Sequences
No full textIn a recent paper, Frank Ruskey asked whether every linear recurrent sequence can occur in some solution of a meta-Fibonacci sequence. In this paper, we consider the natural generalization of meta-Fibonacci recurrences to more than two terms. In this context, we show, using an explicit construction, that any sequence satisfying a linear recurrence with positive coefficients occurs as an evenly-spaced subsequence in some generalized meta-Fibonacci sequence.Peer reviewe
Minnesota's Water and Mine Tailings Program
No full textFox, Nathan. (1998). Minnesota's Water and Mine Tailings Program. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/58960
Social media, geodiversity and the provision of cultural ecosystem services
No full textTo provide a more holistic approach to the conservation of ecosystem services (ES) there is a need to further develop our understanding of how features of biotic and abiotic nature, as well as people and society, interact to provide them. However, the role of geodiversity – the diversity of geology, geomorphology, sediments and soils and hydrology – is overlooked in ES literature and frameworks. Furthermore, geosystem services (GS) – the services that geodiversity provides in isolation of interactions with biotic nature – are also currently underrepresented in ES science. This thesis will focus on the role of geodiversity in providing cultural ecosystem services (CES), in particular how we interact with geodiversity when undertaking recreational actives. Here, social media datasets from the website Flickr and, for the first time in the field of CES, Reddit are used to assess human-nature interactions through a range of analytical methods including image content analysis, textual sentiment analysis and distribution modelling. The results of these methods contribute to our understanding of both the complex relationship between geodiversity and CES and to the applications of social media data to CES studies. First, the empirical methods highlight that geodiversity is important at driving both the distribution of CES as well as the positive experience of the activity undertaken. It is demonstrated that geomorphological features, such as topography, and hydrological features, such as coastal waters and lakes, play an important role in determining the distribution and experience of the recreational activity of hiking. The results also highlight the complex relationships between geodiversity and biodiversity features, such as trees and plants, as well as between geodiversity and human-made features, such as trails and roads, in providing CES. The results of these studies can help inform future geoconservation management with the aim of promoting the sustainable use of geodiversity to ensure the future of the ES it provides. Second, this work advances current uses of social media data by providing novel methods of obtaining data through an accessible R package, photosearcher, as well as informing on the best practice for enriching social media datasets. Furthermore, we investigate Reddit as a novel source of data for CES and demonstrate its usefulness in assessing a range of CES. It is suggested that future work continues to investigate the role of geodiversity on ES, using both social media data and other analytical methods, to better inform the holistic conservation of ES for now and for future generations
Maternal Anxiety, Temperament & Brain Morphometry in Infancy
Full text linkMaternal factors (e.g., maternal anxiety) and infant temperament (e.g., distress to novelty) shape children’s social-emotional development. However, we know relatively little about the impact these factors have on infant brain development. This study investigates associations between maternal anxiety, distress to novelty (i.e., negative reactivity) and brain morphometry at 4-months.
At 4-months, infants’ temperament was assessed by identifying distress in response to novel stimuli. Mothers completed the Beck Anxiety Inventory (BAI) to measure maternal anxiety. Within 2-weeks, high-resolution structural MRI data were acquired during infants’ natural sleep. MRI data were processed using the iBEAT (Dai et al, 2013) pipeline to obtain subcortical and cortical volume estimates.
Regression analyses were conducted to investigate whether infant temperament moderated the relation between maternal anxiety and brain volume at a priori selected regions of interest, controlling for total intracranial volume. Results indicate that there was no significant interaction or main effect of temperament. However, there was a main effect of maternal anxiety in all ROIs tested. Greater maternal anxiety predicted larger hippocampus (β=.417,p<.036), amygdala (β=.429,p<.031), superior frontal gyrus (β=.410,p<.041), middle frontal gyrus (β=.411,p<.039), inferior frontal gyrus (β=.404,p<.039), dorsal anterior cingulate cortex (β=.416,p<.039) and posterior cingulate cortex (β=.407,p<.042). This study provides novel evidence that increased maternal anxiety is linked to differences in child-brain morphometry.NARSAD: Brain & Behavior Research Foundation #28024
UMD Maryland Neuroimaging Center Seed Grant
Maryland Summer Scholars Progra
MRI Processing Pipeline Variability and Infant Brain Morphometry Associations to 4-Month Infant Temperament
Full text linkNegative reactive temperament, an infant temperament characterized by fear of novelty, is associated with adolescent amygdala volume (Filippi et al, 2020) and adult prefrontal cortex (PFC) thickness (Schwartz et al, 2010). However, it remains unknown whether these differences in brain morphometry emerge in infancy. Further, evaluating this possibility is a challenge because few pipelines are optimized for processing infant magnetic resonance imaging (MRI) data. Thus, evaluation of available infant MRI processing pipelines is necessary prior to examining associations between negative reactivity and brain morphometry. This study examines (1) which MRI pipeline performs best for 4-month-old infant MRI data and (2) associations between temperament and brain morphometry. Behavioral reactivity was assessed by presenting novel stimuli to infants. High-resolution structural MRI data was acquired a few weeks later. MRI data were processed using the iBEAT (Dai et al, 2013), dHCP (Makropoulos et al, 2018), and CIVET (Ad-Dab’bagh et al., 2006) pipelines to obtain estimates of amygdala and PFC volume. The quality of segmentations of the three pipelines was then assessed. The processing pipelines showed differences in terms of quality of gray/white segmentation and percentage of processing failures. Overall, iBEAT performed the best with the highest percent of useable data. Using the iBEAT output, we examined the associations between infant brain morphometry and reactivity. Results indicated no significant association between amygdala or PFC volume and reactivity
Exploring Music Visualization Using MIDI and Java
No full textFaculty adviser: Dr. John CarlisSheet music has been used to represent a musical piece. One problem with sheet music is its difficulty in displaying a wide range of pitches on a single staff. Also, to some, it is unclear what the relationship is between two notes at a glance. Most importantly, sheet music has difficulty illustrating volume changes, and it does not allow for a continuum of pitches.
This research explored displaying notes on a spiral instead of a staff. The spiral uses spokes to represent common tones, and the notes in the music are represented as collections of cylinders along a time axis perpendicular to the spiral [Belifuss et al., 2003].
A three-dimensional musical display would be difficult to use effectively when read from a page. Computers, though, can represent such a structure usefully. Hence, we tried to develop a working piece of software based on the spiral display.This research was supported by the Undergraduate Research Opportunities Program (UROP).Fox, Nathan; Carlis, John. (2011). Exploring Music Visualization Using MIDI and Java. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/104910
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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