Experimental and Computational Studies of Cortical Neural Network Properties Through Signal Processing

Previous studies, both theoretical and experimental, of network level dynamics in the cerebral cortex show evidence for a statistical phenomenon called criticality; a phenomenon originally studied in the context of phase transitions in physical systems and that is associated with favorable information processing in the context of the brain. The focus of this thesis is to expand upon past results with new experimentation and modeling to show a relationship between criticality and the ability to detect and discriminate sensory input. A line of theoretical work predicts maximal sensory discrimination as a functional benefit of criticality, which can then be characterized using mutual information between sensory input, visual stimulus, and neural response,. The primary finding of our experiments in the visual cortex in turtles and neuronal network modeling confirms this theoretical prediction. We show that sensory discrimination is maximized when visual cortex operates near criticality. In addition to presenting this primary finding in detail, this thesis will also address our preliminary results on change-point-detection in experimentally measured cortical dynamics

Getting Ready for a Nuclear-Ready Iran

As Iran edges closer to acquiring a nuclear bomb and its missiles extend an ever darker diplomatic shadow over the Middle East and Europe, Iran is likely to pose three threats. First, Iran could dramatically up the price of oil by interfering with the free passage of vessels in and through the Persian Gulf as it did during the l980s or by threatening to use terrorist proxies to target other states\u27 oil facilities. Second, it could diminish American influence in the Gulf and Middle East by increasing the pace and scope of terrorist activities against Iraq, Saudi Arabia, other Gulf states, Israel, and other perceived supporters of the United States. Finally, it could become a nuclear proliferation model for the world and its neighbors (including many states that otherwise would be more dependent on the United States for their security) by continuing to insist that it has a right to make nuclear fuel under the Nuclear Nonproliferation Treaty and then withdrawing once it decides to get a bomb. To contain and deter Iran from posing such threats, the United States and its friends could take a number of steps: increasing military cooperation (particularly in the naval sphere) to deter Iranian naval interference; reducing the vulnerability of oil facilities in the Gulf outside of Iran to terrorist attacks, building and completing pipelines in the lower Gulf region that would allow most of the non-Iranian oil and gas in the Gulf to be exported without having to transit the Straits of Hormuz; diplomatically isolating Iran by calling for the demilitarization of the Straits and adjacent islands, creating country-neutral rules against Nuclear Nonproliferation Treaty state members who are suspected of violating the treaty from getting nuclear assistance from other state members and making withdrawal from the treaty more difficult; encouraging Israel to set the pace of nuclear restraint in the region by freezing its large reactor at Dimona and calling on all other states that have large nuclear reactors to follow suit; and getting the Europeans to back targeted economic sanctions against Iran if it fails to shut down its most sensitive nuclear activities.https://press.armywarcollege.edu/monographs/1726/thumbnail.jp

Liberal market economies, business, and political finance: Britain under New Labour

The extent and nature of business financing of parties is an important feature of political finance. Britain’s transparent and permissive regulatory system provides an excellent opportunity to study business financing of parties. Business donations have been very important to the Conservative party over the last decade, and of only marginal importance to Labour. Unlike other Conservative contributors, business donors are more likely to contribute when the party is popular. In contrast to the previous period of Conservative government, the biggest British businesses tended to abstain from political finance under New Labour. However, their bias towards the Conservatives is affected by the party’s popularity and the closeness of an election. Britain shares the political importance of business financing of parties and its mixture of ideological and pragmatic motivations with other liberal market economies. However, in Britain the bias towards the right is much stronger and the role of big business more marginal

A high-resolution map of human evolutionary constraint using 29 mammals.

The comparison of related genomes has emerged as a powerful lens for genome interpretation. Here we report the sequencing and comparative analysis of 29 eutherian genomes. We confirm that at least 5.5% of the human genome has undergone purifying selection, and locate constrained elements covering ∼4.2% of the genome. We use evolutionary signatures and comparisons with experimental data sets to suggest candidate functions for ∼60% of constrained bases. These elements reveal a small number of new coding exons, candidate stop codon readthrough events and over 10,000 regions of overlapping synonymous constraint within protein-coding exons. We find 220 candidate RNA structural families, and nearly a million elements overlapping potential promoter, enhancer and insulator regions. We report specific amino acid residues that have undergone positive selection, 280,000 non-coding elements exapted from mobile elements and more than 1,000 primate- and human-accelerated elements. Overlap with disease-associated variants indicates that our findings will be relevant for studies of human biology, health and disease

Ideological Labels in America

This paper extends Ellis and Stimson’s (Ideology in America. New York: Cambridge UniversityPress, 2012) study of the operational-symbolic paradox using issue-level measures of ideological incongruence based on respondent positions and symbolic labels for these positions across 14 issues. Like Ellis and Stimson, we find that substantial numbers—over 30 %—of Americans experience conflicted conservatism. Our issue-level data reveal, furthermore, that conflicted conservatism is most common on the issues of education and welfare spending. In addition, we also find that 20 % of Americans exhibit conflicted liberalism. We then replicate Ellis and Stimson’s finding that conflicted conservatism is associated with low sophistication and religiosity, but also find that it is associated with being socialized in a post-1960s generation and using Fox News as a main news source. Finally, we show the important role played by identities, with both conflicted conservatism and conflicted liberalism linked with partisan and ideological identities, and conflicted liberalism additionally associated with ethnic identities

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead