5,289 research outputs found
The two-star model: exact solution in the sparse regime and condensation transition
The -star model is the simplest exponential random graph model that
displays complex behavior, such as degeneracy and phase transition. Despite its
importance, this model has been solved only in the regime of dense
connectivity. In this work we solve the model in the finite connectivity
regime, far more prevalent in real world networks. We show that the model
undergoes a condensation transition from a liquid to a condensate phase along
the critical line corresponding, in the ensemble parameters space, to the
Erd\"os-R\'enyi graphs. In the fluid phase the model can produce graphs with a
narrow degree statistics, ranging from regular to Erd\"os-R\'enyi graphs, while
in the condensed phase, the "excess" degree heterogeneity condenses on a single
site with degree . This shows the unsuitability of the two-star
model, in its standard definition, to produce arbitrary finitely connected
graphs with degree heterogeneity higher than Erd\"os-R\'enyi graphs and
suggests that non-pathological variants of this model may be attained by
softening the global constraint on the two-stars, while keeping the number of
links hardly constrained.Comment: 20 pages, 3 figure
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Neuromodulatory control of localized dendritic spiking in critical period cortex.
Sensory experience in early postnatal life, during so-called critical periods, restructures neural circuitry to enhance information processing1. Why the cortex is susceptible to sensory instruction in early life and why this susceptibility wanes with age are unclear. Here we define a developmentally restricted engagement of inhibitory circuitry that shapes localized dendritic activity and is needed for vision to drive the emergence of binocular visual responses in the mouse primary visual cortex. We find that at the peak of the critical period for binocular plasticity, acetylcholine released from the basal forebrain during periods of heightened arousal directly excites somatostatin (SST)-expressing interneurons. Their inhibition of pyramidal cell dendrites and of fast-spiking, parvalbumin-expressing interneurons enhances branch-specific dendritic responses and somatic spike rates within pyramidal cells. By adulthood, this cholinergic sensitivity is lost, and compartmentalized dendritic responses are absent but can be re-instated by optogenetic activation of SST cells. Conversely, suppressing SST cell activity during the critical period prevents the normal development of binocular receptive fields by impairing the maturation of ipsilateral eye inputs. This transient cholinergic modulation of SST cells, therefore, seems to orchestrate two features of neural plasticity-somatic disinhibition and compartmentalized dendritic spiking. Loss of this modulation may contribute to critical period closure
Phonological Priming In Young Children Who Stutter: Holistic Versus Incremental Processing
Purpose: To investigate the holistic versus incremental phonological encoding processes of young children who stutter (CWS; N = 26) and age- and gender-matched children who do not stutter (CWNS; N = 26) via a picture-naming auditory priming paradigm. Method: Children named pictures during 3 auditory priming conditions: neutral, holistic, and incremental. Speech reaction time (SRT) was measured from the onset of picture presentation to the onset of participant response. Results: CWNS shifted from being significantly faster in the holistic priming condition to being significantly faster in the incremental priming condition from 3 to 5 years of age. In contrast, the majority of 3- and 5-year-old CWS continued to exhibit faster SRT in the holistic than the incremental condition. Conclusion: CWS are delayed in making the developmental shift in phonological encoding from holistic to incremental processing, a delay that may contribute to their difficulties establishing fluent speech.Communication Sciences and Disorder
Rational combinations of Betti diagrams of complete intersections
We investigate decompositions of Betti diagrams over a polynomial ring within
the framework of Boij-S\"oderberg theory. That is, given a Betti diagram, we
determine if it is possible to decompose it into the Betti diagrams of complete
intersections. To do so, we determine the extremal rays of the cone generated
by the diagrams of complete intersections and provide a rudimentary algorithm
for decomposition.Comment: This research was conducted at the Willamette Mathematics Consortium
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Modeling Substance Use and Mental Disorder Comorbidity Using Latent Variable and Network Approaches
Introduction. Substance use disorder (SUD) is a common condition that affects millions of Americans. Addressing SUD has been complicated by comorbid mental disorders and co-occurring substance use. Consequently, detailing and addressing SUD and comorbid SUD represent an important goal to improve the health of Americans.
Objective. The research goal of this dissertation was to characterize the comorbidity between substance use, including tobacco use, and mental disorder symptoms measured as negative affect and externalizing symptoms in a population-based sample using latent variable and network approaches.
Methods. Waves 1 – 3 from the Population Assessment of Tobacco and Health Study were used. Various statistical analyses were used to complete each project including multinomial and ordinal regression, latent class analysis, cumulative ROC curve analysis, and network analysis.
Results. The associations between psychopathology (negative affect vs. externalizing severity) varied by different substance use combinations. Both latent class analysis and network analysis results identified relationships between (1) exclusive cigarette, dual cigarette and e-cigarette, marijuana, and PDNP with negative affect symptoms, and (2) alcohol with externalizing symptoms. The comorbidity structure remained stable with transition to lower severity groups but identification of stronger connections across three data points.
Conclusions. This dissertation identified specific combinations of substance use behaviors and mental disorder symptoms, determined which sociodemographic factors play a role in specific comorbidity profiles, and assessed the patterns of comorbidity among three waves of data. The results can inform robust and targeted prevention strategies to effectively mitigate the substantial burden and societal costs of comorbidity in the U.S. population
The ubiquity of ignorance: a practical theological challenge of our time
Accepted manuscrip
Using LENA to Examine Associations between Parental Speech and Child Language Skills
Children are exposed to language in a variety of ways and by a multitude of people - parents, teachers, friends, etc. Language input that a child receives has been a significant area of study for researchers to determine the cognitive, linguistic, and social developmental levels of speech clients. Traditionally, maternal speech input has been viewed as more influential than paternal speech input. The purpose of this study is to use the Bridge Hypothesis of paternal speech to compare the speech between child and mother vs. child and father through the use of LENA technology. Gathering a speech sample can be a tedious task; however, with the technology of LENA devices, data from a speech sample is sorted and analyzed. Specific information can then be extrapolated from the data to analyze further. This pilot study uses LENA technology to examine the associations between parental input of mothers and fathers and the language skills of preschoolers. The results of this study will aid in determining the value of paternal input on a typically developing child
Knowledge, Perception, and Clinical Management Strategies of US Pediatric Dentists on Molar Incisor Hypomineralization
Purpose: The purpose of this cross-sectional, survey-based study is to determine current US pediatric dentists’ knowledge, perceptions, and clinical management strategies for patients with molar incisor hypomineralization (MIH).
Methods: Following appropriate protocol and authorizations, all active pediatric dentists, general dentists, and post-doctoral student members identified by the 2020 American Academy of Pediatric Dentistry’s membership list were invited to partake in an anonymous email survey. Data regarding participants sociodemographic, education, and clinical backgrounds were collected in addition to information obtained from MIH-focused questions. Descriptive statistics and chi-square tests were used to compare and analyze data. A significance level was set at 0.05.
Results: A total of 594 out of 6623 responses were received (9%). Almost all participants have encountered MIH (98%). Majority (66%) reported a prevalence rate of
Conclusion: MIH is a well-recognized dental condition by U.S. pediatric dentists. Discrepancies and challenges identified in treatment interventions and management strategies, paired with low confidence levels regarding treatment necessitate the need for continued research and subsequent training of dental practitioners involving MIH
A Note on the Reproductive Season of the Carolina Marsh Clam Polymesoda caroliniana (Bosc) in an Irregularly Flooded Mississippi Marsh
The gonadal development of Polymesoda caroliniana in an irregularly flooded, brackish marsh was followed for 13 months. Ripe individuals (condition prior to spawning) were found in May, July, August, and October, suggesting either an extended period of spawning or three discrete spawning periods. This pattern is different from another study of P. caroliniana in a more flooded habitat.
The observed gonadal condition correlates with the presence of newly recruited clams in the marsh during most of the year, but failed to explain a pulse of juveniles found in February. The different reproductive pattern observed in this brackish marsh may be either a genetic or physiological adaptation to life in an unpredictably flooded marsh
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