Predicting Network Dynamics Based on Neural Connectivity

Many networks in the brain exhibit internally-generated dynamics—patterned activity that does not reflect changes in external stimuli, but rather is generated intrinsically by the network itself. The source of this internally-generated activity is not well understood, but explanations range from single-cell properties, such as intrinsically oscillatory neurons, to network-level properties, such as complex network connectivity. Past efforts to model and explain the full range of behaviors have involved a variety of complex ingredients, making the models mathematically intractable. In this presentation, we focus on a new minimal model with simple threshold-linear neurons and two-valued synapses whose dynamics are controlled solely by an underlying directed connectivity graph. This model is simple enough to be mathematically tractable, and yet still captures the full variety of internally-generated behaviors. Through this model, we can isolate the role that connectivity plays alone to address the question of how neural connectivity shapes network dynamics. To answer, we simulate trials of various network connectivity structures to determine patterns of behavior that occur within a family of related connected networks, called necklaces. Within this family, we investigate the roles of various parameters in determining network behavior, such as the number of neurons in each component of the necklace. In particular, we give conditions for the presence/absence of limit cycles. This project is relevant to experimentalists who are investigating the connectome, which is a mapping of the neural connectivity in the brains of different organisms. Our work may help determine why certain network structures developed based on their functionality and may help experimentalists predict the type of connectivity within a given region based on experimental records of neural activity

LGBT Adoptions in the US & South Africa

With the increased commonality of gay relationships, marriages, and unions, there is a growing conversation about the LGBT and their adoption of children. The purpose of this case study analysis is not to sway your opinion of LGBT adoptions, but instead to examine the recent policy implications for LGBT adoption in the U.S. in comparison to current South African adoption policies

LGBT Adoptions in the US & South Africa

With the increased commonality of gay relationships, marriages, and unions, there is a growing conversation about the LGBT and their adoption of children. The purpose of this case study analysis is not to sway your opinion of LGBT adoptions, but instead to examine the recent policy implications for LGBT adoption in the U.S. in comparison to current South African adoption policies

Investigations of laser-induced neuronal guidance

One of the long-standing goals of neuroscience has been to look for ways in which to control neuronal growth. It has been discovered recently that placing a focused near-infrared laser spot at the leading edge of a neuronal growth cone elicits a turn in the direction of the laser spot [Ehrlicher et al., PNAS 99: 16024 (2002)]. Optical guidance has the advantage over conventional neuronal guidance methods that neither steric strain nor chemical gradients are necessary to its functionality. Although the success of optical guidance suggests potential therapeutic applications, our first priority is to decipher the mechanism underlying the phenomenon in order better to understand it. Several hypotheses are presented as well as preliminary evidence supporting biased diffusion as an appropriate model for the system.Physic

Out of sight: using animation to document perceptual brain states

It is acknowledged that the genre of animated documentary is particularly suited to depicting the subjective point of view (Wells, 1997, Honess Roe, 2013). It has also been suggested that animated documentary may have a tendency toward collaborative working methods (Ward, 2005: 94). This PhD work explores and expands these suggestions and presents the development of a methodology adapted from what has been termed collaborative ethnography (Lassiter, 2005) when using animation to document perceptual brain states. The claim to originality in this thesis lies in the methodological approach taken through the documenting of idiopathic perceptual brain states, previously unrepresented in animation. It involves a shifting of the roles of subject and director to collaborative consultant and facilitator respectively, and differentiates between the recording of an animated document and the creation of an animated documentary . It rejects the sound reliant template of the 'animated interview' (Strøm, 2005: 15) as the dominant model of creating animated documents, which assumes both that the indexical is crucial to documenting, and that this can only be achieved in animation through the use of indexical sound. It agrees with Tom Gunning s argument that Charles Sanders Pierce's original idea of the index as part of an interconnected triad of signs (index, symbol and icon) has been abstracted from its richer signifying context and extracted a simplified version of what Pierce intended it to mean (a trace or impression left by an object) to become a 'diminished concept' (2007:30-1), essentially a short hand coda in this instance for document . The practice in this work challenges this by presenting an alternative; using a collaborative cycle methodology

Longitudinal and Temporal Comparison of Beach Sand on the Rio Grande Delta System

The Rio Grande is the 5th longest river in North America and defines a significant extent of the United States-Mexico border. It extends for 2830 km from its headwaters in the Rocky Mountains of Colorado to the Gulf of Mexico. The Rio Grande is fed by streams from the Sangre de Cristo Mountains, the Rio Conchos, the Pecos River, runoff from the Sacramento Mountains area, Devils River, the Rio Salado, and the Rio San Juan. This study addresses how the composition of sand forming the Rio Grande river delta into the Gulf of Mexico at Boca Chica Beach is changed by input of additional sand transported northward by longshore current along the Mexican coastline. To determine the effect, we collected sand samples from the Rio Grande river, from the Mexican coast to the south, and along Boca Chica Beach. Second, we also investigated how the sand composition was modified going across the jetty from Boca Chica Beach to South Padre Island. There were several potential sources including from Boca Chica, the Brownsville Ship Channel or possible erosion from the jetty itself contributing to the composition on South Padre Island. We tested by collecting sand samples from Boca Chica Beach, east of the jetties, and farther north along South Padre Island. We also verified the temporal relationship between the sands at Boca Chica Beach and South Padre Island. This was tested by taking two core samples at approximately 5 m depth. Detrital zircon geochronology was used to characterize the provenance of the sands. In general, most of the nine samples studied yielded U-Pb age distributions that indicated a mixed Rocky Mountain and Mexican volcanic provenance signature. Six of eight sands were indistinguishable at 95% confidence from the Rio Grande River reference sample. We did find that sands from the Mexican coastline sampled south of the mouth of the Rio Grande River were moderately enriched in Miocene and Grenville age zircon relative to those sampled north of the River mouth. One of the two core samples was also enriched in Miocene and Grenville zircon and could be distinguished from its corresponding surface sample at 95% confidence. This latter may be explained by anthropogenic impacts upon the beach sand

A New New Woman: the Portrayal of Women in the Late Nineteenth-Early Twentieth Century Novel

The thesis examines how women are portrayed in Bram Stoker\u27s Dracula, E.M. Forster\u27s Howards End, and Elizabeth Robins\u27s The Convert and Votes for Women. I specifically focus on how the ideal of Victorian womanhood is juxtaposed to the attributed horrors of the New Woman in Dracula and Howards End. In The Convert and Votes for Women I explore how the ideas of and about the New Woman transition into the Suffragette. Finally, I argue that the women I examine establish a new New Woman that is worthy of praise

A National Portrait of Domestic Violence Courts

A growing number of criminal courts nationwide handle domestic violence cases on separate calendars, termed domestic violence courts. There are now 208 confirmed domestic violence courts across the U.S. (Center for Court Innovation 2009). More than 150 similar projects have been established internationally. Some domestic violence courts emerged in the context of the broader "problem-solving court" movement and share characteristics with other specialized courts, such as separate dockets and specially trained judges. However, the origins of domestic violence courts are also distinct, growing out of the increased attention afforded domestic violence matters by the justice system over the past 30 years. With funding from the National Institute of Justice, this study explores how criminal domestic violence courts have evolved, their rationale, and how their operations vary across the U.S. This study does not test whether domestic violence courts reduce recidivism, protect victims, or achieve other specific effects -- although we provide a thorough literature review on these points. Rather, our aim is to present a comprehensive national portrait of the field as it exists today, laying the groundwork for future information exchange and research

Bigraded Betti numbers and Generalized Persistence Diagrams

Commutative diagrams of vector spaces and linear maps over $\mathbb{Z}^2$ are objects of interest in topological data analysis (TDA) where this type of diagrams are called 2-parameter persistence modules. Given that quiver representation theory tells us that such diagrams are of wild type, studying informative invariants of a 2-parameter persistence module $M$ is of central importance in TDA. One of such invariants is the generalized rank invariant, recently introduced by Kim and M\'emoli. Via the M\"obius inversion of the generalized rank invariant of $M$, we obtain a collection of connected subsets $I\subset\mathbb{Z}^2$ with signed multiplicities. This collection generalizes the well known notion of persistence barcode of a persistence module over $\mathbb{R}$ from TDA. In this paper we show that the bigraded Betti numbers of $M$, a classical algebraic invariant of $M$, are obtained by counting the corner points of these subsets $I$s. Along the way, we verify that an invariant of 2-parameter persistence modules called the interval decomposable approximation (introduced by Asashiba et al.) also encodes the bigraded Betti numbers in a similar fashion.Comment: 26 pages, 7 figures; v3:improvements to expositio