The potential impact of the global financial crisis on world trade

This paper models the global financial crisis as a combination of shocks to global housing markets and sharp increases in risk premia of firms, households and international investors in a global economic model. The model has six sectors of production and trade in 15 major economies and regions. The paper shows that the shocks observed in financial markets can be used to generate the severe economic contraction in global trade and production experienced in 2009. In particular the distinction between the production and trade of durable and non durable goods plays a key role in explaining the much larger contraction in trade than GDP experienced by most economies. The paper explores the implications of the large increase in fiscal deficits and the implications of a global trade war in response to the financial crisis.Economic Theory&Research,Debt Markets,Emerging Markets,Banks&Banking Reform,Labor Policies

Speech production and short-term memory

SIGLELD:D50543/84 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Global fiscal consolidation

The buildup in government debt in response to the great recession

Detuned Mechanical Parametric Amplification as a Quantum Non-Demolition Measurement

Recently it has been demonstrated that the combination of weak-continuous position detection with detuned parametric driving can lead to significant steady-state mechanical squeezing, far beyond the 3 dB limit normally associated with parametric driving. In this work, we show the close connection between this detuned scheme and quantum non-demolition (QND) measurement of a single mechanical quadrature. In particular, we show that applying an experimentally realistic detuned parametric drive to a cavity optomechanical system allows one to effectively realize a QND measurement despite being in the bad-cavity limit. In the limit of strong squeezing, we show that this scheme offers significant advantages over standard backaction evasion, not only by allowing operation in the weak measurement and low efficiency regimes, but also in terms of the purity of the mechanical state.Comment: 17 pages, 2 figure

Mechanical Entanglement via Detuned Parametric Amplification

We propose two schemes to generate entanglement between a pair of mechanical oscillators using parametric amplification. In contrast to existing parametric drive-based protocols, both schemes operate in the steady-state. Using a detuned parametric drive to maintain equilibrium and to couple orthogonal quadratures, our approach can be viewed as a two-mode extension of previous proposals for parametric squeezing. We find that robust steady-state entanglement is possible for matched oscillators with well-controlled coupling. In addition, one of the proposed schemes is robust to differences in the damping rates of the two oscillators.Comment: 13 pages, 2 figure

Anomalously large marine potholes on a submerged relict shore platform: The Eastern Cape shelf of SE Africa

Marine potholes are common features along rocky shore platforms from around the world. Their occurrence can be used as a palaeo-sea level indicator, however, little attention has been given to submerged marine potholes found on relict shore platforms below the depth limits of SCUBA (≤50 m). This paper examines (n = 238) anomalously large potholes found on a submerged aeolianite shore platform on the outer shelf of the Eastern Cape, South Africa. Using a combined ultra-high resolution seismic reflection, side scan sonar and multibeam bathymetry approach, together with remote observation vehicle dives, the pothole occurrences are mapped.Potholes are either individual or occasionally conjoined, form on sediment-free aeolianite platform and cluster mostly between water depths of 85–95 m. Their sizes are an order of magnitude larger than previously documented, and larger than their fluvial equivalents. Pothole strings are common, associated with the high points between NNW-SSE striking bedding planes of the aeolianite that crop out at the seabed. Potholes are often elongated and aligned with these bedding planes, or in a coast parallel fashion, associated with joints and micro-cliffs in the aeolianite.The potholes possibly formed during several slowstands or stillstands surrounding the Last Glacial Maximum (LGM, 25,000 to 20,000 yr BP) and the Bølling-Allerød interstadial (B-A, 14,500 yr BP). Given their sizes, we ascribe part of their development to chemical weathering of the platform, especially during the periods where sea spray could pond to form dissolution pans in the supratidal part of the aeolianite platform. A wet and warm B-A climate exacerbated chemical weathering, with karst processes initially dominant, followed by mechanical weathering with shoreline migration. Once submerged, only horizontal enlargement ensued. Geological contingencies (joints, bedding planes and platform lowpoints), modified by early weathering-dominant and later wave-dominant processes, were responsible for the evolution of the shore platform morphology

Global Progress Toward Implementing the United Nations Fish Stocks Agreement

This brief examines the progress made in implementing the Fish Stocks Agreement, based on a review of the status of certain highly migratory stocks and the effectiveness of regional fishery management organization (RFMO) measures in meeting specific mandates. It also looks at whether recommendations made in prior reviews have been implemented

Fixed points of arbitrarily deep 1-dimensional neural networks

In this paper, we establish a sharp upper bound on the the number of fixed points a certain class of neural networks can have. The networks under study (autoencoders) can be viewed as discrete dynamical systems whose nonlinearities are given by the choice of activation functions. To this end, we introduce a new class $\mathcal{F}$ of $C^1$ activation functions that is closed under composition, and contains e.g. the logistic sigmoid function. We use this class to show that any 1-dimensional neural network of arbitrary depth with activation functions in $\mathcal{F}$ has at most three fixed points. Due to the simple nature of such networks, we are able to completely understand their fixed points, providing a foundation to the much needed connection between application and theory of deep neural networks.Comment: 9 pages, 3 figure

Minimum requirements for feedback enhanced force sensing

The problem of estimating an unknown force driving a linear oscillator is revisited. When using linear measurement, feedback is often cited as a mechanism to enhance bandwidth or sensitivity. We show that as long as the oscillator dynamics are known, there exists a real-time estimation strategy that reproduces the same measurement record as any arbitrary feedback protocol. Consequently some form of nonlinearity is required to gain any advantage beyond estimation alone. This result holds true in both quantum and classical systems, with non-stationary forces and feedback, and in the general case of non-Gaussian and correlated noise. Recently, feedback enhanced incoherent force sensing has been demonstrated [Nat. Nano. \textbf{7}, 509 (2012)], with the enhancement attributed to a feedback induced modification of the mechanical susceptibility. As a proof-of-principle we experimentally reproduce this result through straightforward filtering.Comment: 5 pages + 2 pages of Supplementary Informatio