669 research outputs found
Network structure within the cerebellar input layer enables lossless sparse encoding.
No full textThe synaptic connectivity within neuronal networks is thought to determine the information processing they perform, yet network structure-function relationships remain poorly understood. By combining quantitative anatomy of the cerebellar input layer and information theoretic analysis of network models, we investigated how synaptic connectivity affects information transmission and processing. Simplified binary models revealed that the synaptic connectivity within feedforward networks determines the trade-off between information transmission and sparse encoding. Networks with few synaptic connections per neuron and network-activity-dependent threshold were optimal for lossless sparse encoding over the widest range of input activities. Biologically detailed spiking network models with experimentally constrained synaptic conductances and inhibition confirmed our analytical predictions. Our results establish that the synaptic connectivity within the cerebellar input layer enables efficient lossless sparse encoding. Moreover, they provide a functional explanation for why granule cells have approximately four dendrites, a feature that has been evolutionarily conserved since the appearance of fish
Avoiding a meltdown: managing the value of small change
No full textTo prevent a shortage of small change, the U.S. Department of the Treasury recently prohibited the melting and exportation of pennies and other coins. The problem arises because pennies and nickels are made of inappropriately expensive material, and there is or soon will be a profit to be made from transferring their content to alternative uses. The author provides a historical context for the problem of small change and discusses possible remediesCoinage
The Curse of Moctezuma: American Silver and the Dutch Disease, 1501-1650
No full textThis study formalizes and empirically tests the conjecture that the discovery of large silver reserves in its American colonies triggered in Spain a phenomenon known as the Dutch disease,diverting factors of production to non-traded goods industries and undermining the Spanishcomparative advantages in the Early Modern Age. I develop an open-economy model to mimic the economic conditions in Spain in the wake of the silver discoveries, which predicts anincrease in the relative price of non-traded goods following a positive wealth shock. I thenconstruct price indexes for traded and non-traded goods using Earl Hamilton's price series and new consumption baskets. Using a Markov- switching regression model, I identify a strong andpersistent increase in the relative price of non-traded goods coinciding with the silverdiscoveries, lasting for almost three decades and reversing itself only after the 1575 and 1579 crown bankruptcies. These findings largely support the Dutch Disease hypothesis.Early Modern Spain, Dutch Disease, Prices, Consumption Baskets, Switching Regression
The forgotten first: John MacCormick's 'Dùn-Àluinn'
No full textThe first Gaelic novel, John MacCormick's Dùn-Àluinn, no an t-Oighre 'na Dhìobarach, was serialised in the People's Journal in 1910 before being published in its entirety in 1912. Within a year of the publication of Dùn-Àluinn as a novel the second Gaelic novel, Angus Robertson's An t-Ogha Mòr, appeared in print, underlining the renaissance which Gaelic literature was experiencing. Both novels, while remarked upon by contemporaries and by general studies of Gaelic literature, have been all but ignored to date, with no criticism or analysis of either having been published. The main aim of this article is to offer some general comments about MacCormick's Dùn-Àluinn and thus to open up both the novel and indeed other early twentieth-century Gaelic writers and their work to further scrutiny. Consideration will be given to the author himself, the contemporary Gaelic literary scene and finally some of the more interesting aspects of the novel itself
An accountability model for Pakeha practitioners
No full textThis paper outlines a model of accountability for Pakeha practitioners developed over many years
as a practising community psychologist involved in research and development projects in Aotearoa
in the 1980s and 1990s, during an era of contract-funded health projects, and increasing
prominence of the Treaty of Waitangi2. The model could be termed 'transformative' in that it
reverses the usual flow of power by making the Pakeha practitioner accountable to relevant Maori
authority, and maximises the potential for new outcomes and new learning for all parties. A brief
case study is outlined where the model placed a local iwi governance structure and a national
psychiatric survivor organisation in positions of authority alongside the funder of a mental health
project. Helpful conditions, positive outcomes and barriers to transformative accountability
processes are briefly discussed
The Open Source Brain Initiative: enabling collaborative modelling in computational neuroscience
No full textOral presentation at CNS 201
Calcium signaling genes in association with altitude-induced pulmonary hypertension in Angus cattle
No full text2019 Fall.Includes bibliographical references.This research used multi-omics technology (i.e., RNA-seq, qPCR for gene expression, SNP discovery and validation) to understand the influence of a particular subset genes on altitude-induced pulmonary hypertension susceptibility in Angus cattle. Three research aims were established to test the hypothesis that calcium-related genes may be associated with pulmonary hypertension in beef cattle. Data and samples utilized for the research came from the Colorado State University Beef Improvement Center Angus herd managed at 2,150 m of altitude. Transcriptome data from 6 tissues and 14 hypertensive and normotensive Angus steers were utilized for differential expression and pathway analyses. The objectives of the first aim were to: 1) to estimate and identify differentially expressed genes from RNA-Seq and pathway analyses, and 2) select putative candidate genes to analyze with qPCR (gene expression level). The largest number of DE genes was revealed in aorta (n = 631) and right ventricle (n = 2,183) samples. Top canonical pathways related to calcium signaling or utilization included: synaptic long-term depression, signaling by Rho family GTPases, and oxidative phosphorylation. Genes regulating calcium availability and utilization were expressed differently (log2 fold change > 0.589, < -0.589; P < 0.05) in Angus cattle with and without pulmonary hypertension. Isolated RNA from cardiac muscle (n = 9) and control muscle (n = 2) tissues from hypertensive and normotensive Angus steers were utilized to estimate gene expression using quantitative reverse transcription PCR in the candidate genes from Chapter 3. The objectives of this chapter were: 1) to establish the most appropriate reference genes in cardiac muscle tissues, and 2) to estimate and validated relative gene expression of calcium-related genes in cardiac muscle tissues using qPCR methods. Differences (P < 0.0055) among hypertensive and normotensive steers were estimated for right papillary muscle and right cardiac ventricle tissues (top, middle, and bottom) in candidate genes: ASIC2, EDN1, NOX4, PLA2G4A, RCAN1, and THBS4. Results of the current study validate the expression differences previously established of genes that regulate the availability and utilization of calcium with PH status in Angus steers at high altitude. Variant detection and association analyses were completed with 2 sets of available -omics data to identify opportunities for development of selection tools for reduced susceptibility to PH. The objectives of the third aim were to: 1) detect single nucleotide polymorphisms (SNP) in the transcriptome of 6 tissues, and 2) identify functional consequences of those variants associated with validated candidate genes from qPCR analyses. Pooled Angus sample analysis revealed 68 SNP in the 6 candidate genes: ASIC2, EDN1, NOX4, PLA2G4A, RCAN1, and THBS4. Thirty-eight SNP were revealed in the hypertensive group and 8 SNP in the normotensive steer group. Ten of the 68 identified SNP are utilized on large density commercially available bovine SNP chips (Illumina BovineHD BeadChip; GeneSeek Genomic Profiler HD; GeneSeek Genomic Profiler HDv2; Affymetrix Axiom Bovine). Analysis of transcriptome data identified SNP within genes regulating calcium availability and utilization, enhancing our understanding of sequence polymorphisms that may be involved in regulating pulmonary hypertension in Angus cattle raised at high altitude. These SNP are available for additional validation and potential use in genetic improvement programs
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