328 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 Open Source Brain Initiative: enabling collaborative modelling in computational neuroscience
No full textOral presentation at CNS 201
Oro, plata y mercurio, nervios de la monarquía de España
No full textEditada en la Fundación Empresa PúblicaEl carácter distintivo de la monarquía española durante toda la Edad
Moderna fue el dominio de las principales zonas del planeta productoras de
plata y mercurio, lo que le proporcionó una ventaja monetaria comparativa
prácticamente inexpugnable, especialmente durante el período de siglo y medio
que siguió a la introducción del patrón-plata en la China de los Ming, en
que la relación bimetálica plata/oro resultó extremadamente favorable para
la plata. Esto permitió que el poder imperial descansase sobre una combinación
sencilla de políticas extractivas, logísticas y financieras, cuyo indicador privilegiado
es el mercado del azogue, que se reconstruye en este trabajo.The distinctive character of the Spanish monarchy all along the modern
age was the domination on the main producing zones of silver and mercury
in the planet, which provided practically uncontestable a comparative monetary
advantage to her, specially during the period of century and a half following
the introduction of the silver-standard in the Ming's China, during which
the bimetallic relation was extremely favorable for the silver. This allowed
the imperial power to rest on an very simple combination of extractive, logistic
and fínancial policies, whose privileged indicator is the market of the mercury,
that reconstructs in this work.Publicad
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