Potential Consequences of Intra-Regional Trade in Short-Term Food Security Crises in Southeastern Africa

A report prepared by Michigan State University for the World Bank under contract No. 7144132, Strengthening Food Security in Sub-Saharan Africa through Trade Liberalization and Regional IntegrationAfrica, trade, emergency, Food Security and Poverty, International Relations/Trade, Q13,

Facing up to the challenge of behavioural observation in infant hearing assessment

The ability to assess detection and discrimination of speech by infants has proved elusive. Dr Iain Jackson and colleagues discuss how new technologies and fresh approaches might offer valuable insight into young infants’ behavioural responses to sound

On thermalization in the SYK and supersymmetric SYK models

The eigenstate thermalization hypothesis is a compelling conjecture which strives to explain the apparent thermal behavior of generic observables in closed quantum systems. Although we are far from a complete analytic understanding, quantum chaos is often seen as a strong indication that the ansatz holds true. In this paper, we address the thermalization of energy eigenstates in the Sachdev-Ye-Kitaev model, a maximally chaotic model of strongly-interacting Majorana fermions. We numerically investigate eigenstate thermalization for specific few-body operators in the original SYK model as well as its $\mathcal{N}=1$ supersymmetric extension and find evidence that these models satisfy ETH. We discuss the implications of ETH for a gravitational dual and the quantum information-theoretic properties of SYK it suggests.Comment: Published versio

A critique of avian CHD-based molecular sexing protocols illustrated by a Z-chromosome polymorphism detected in auklets

The sexes of non-ratite birds can be determined routinely by PCR amplification of the CHD-Z and CHD-W genes. CHD -based molecular sexing of four species of auklets revealed the presence of a polymorphism in the Z chromosome. No deviation from a 1:1 sex ratio was observed among the chicks, though the analyses were of limited power. Polymorphism in the CHD-Z gene has not been reported previously in any bird, but if undetected it could lead to the incorrect assignment of sex. We discuss the potential difficulties caused by a polymorphism such as that identified in auklets and the merits of alternative CHD -based sexing protocols and primers

Sanctions for E-Discovery Violations: By the Numbers

This Article reviews our comprehensive survey of written opinions from cases in federal courts prior to January 1, 2010, involving motions for sanctions relating to the discovery of electronically stored information (ESI) We analyzed each case for various factors, including date, court, type of case, sanctioning authority, sanctioned party, sanctioned misconduct, sanction type, sanctions to counsel, if any, and the protections provided from sanctions by Federal Rule of Civil Procedure 37(e) The survey identified 401 sanction cases and 230 sanction awards and showed that sanction motions and awards have increased over time, particularly in the last five years Sanctions against counsel are rare but are also increasing Sanction motions have been filed in all types of cases and in courts across the country Failure to produce ESI is the most common basis for sanctions Courts have used a variety of different rules, statutes, and powers to sanction parties for e-disco very violations, including Rule 37 and the inherent power of the court, and courts impose many different sanction types on e-discovery violators, including the severe sanctions of dismissal, default Judgment, adverse jury instructions, and sizeable monetary awards Rule 37(e) has not provided broad protection from such sanction

Chaos, Complexity, and Random Matrices

Chaos and complexity entail an entropic and computational obstruction to describing a system, and thus are intrinsically difficult to characterize. In this paper, we consider time evolution by Gaussian Unitary Ensemble (GUE) Hamiltonians and analytically compute out-of-time-ordered correlation functions (OTOCs) and frame potentials to quantify scrambling, Haar-randomness, and circuit complexity. While our random matrix analysis gives a qualitatively correct prediction of the late-time behavior of chaotic systems, we find unphysical behavior at early times including an $\mathcal{O}(1)$ scrambling time and the apparent breakdown of spatial and temporal locality. The salient feature of GUE Hamiltonians which gives us computational traction is the Haar-invariance of the ensemble, meaning that the ensemble-averaged dynamics look the same in any basis. Motivated by this property of the GUE, we introduce $k$-invariance as a precise definition of what it means for the dynamics of a quantum system to be described by random matrix theory. We envision that the dynamical onset of approximate $k$-invariance will be a useful tool for capturing the transition from early-time chaos, as seen by OTOCs, to late-time chaos, as seen by random matrix theory.Comment: 61 pages, 14 figures; v2: references added, typos fixe

Sanctions for E-Discovery Violations: By the Numbers

This Article reviews our comprehensive survey of written opinions from cases in federal courts prior to January 1, 2010, involving motions for sanctions relating to the discovery of electronically stored information (ESI) We analyzed each case for various factors, including date, court, type of case, sanctioning authority, sanctioned party, sanctioned misconduct, sanction type, sanctions to counsel, if any, and the protections provided from sanctions by Federal Rule of Civil Procedure 37(e) The survey identified 401 sanction cases and 230 sanction awards and showed that sanction motions and awards have increased over time, particularly in the last five years Sanctions against counsel are rare but are also increasing Sanction motions have been filed in all types of cases and in courts across the country Failure to produce ESI is the most common basis for sanctions Courts have used a variety of different rules, statutes, and powers to sanction parties for e-disco very violations, including Rule 37 and the inherent power of the court, and courts impose many different sanction types on e-discovery violators, including the severe sanctions of dismissal, default Judgment, adverse jury instructions, and sizeable monetary awards Rule 37(e) has not provided broad protection from such sanction

Consistency Conditions for an AdS/MERA Correspondence

The Multi-scale Entanglement Renormalization Ansatz (MERA) is a tensor network that provides an efficient way of variationally estimating the ground state of a critical quantum system. The network geometry resembles a discretization of spatial slices of an AdS spacetime and "geodesics" in the MERA reproduce the Ryu-Takayanagi formula for the entanglement entropy of a boundary region in terms of bulk properties. It has therefore been suggested that there could be an AdS/MERA correspondence, relating states in the Hilbert space of the boundary quantum system to ones defined on the bulk lattice. Here we investigate this proposal and derive necessary conditions for it to apply, using geometric features and entropy inequalities that we expect to hold in the bulk. We show that, perhaps unsurprisingly, the MERA lattice can only describe physics on length scales larger than the AdS radius. Further, using the covariant entropy bound in the bulk, we show that there are no conventional MERA parameters that completely reproduce bulk physics even on super-AdS scales. We suggest modifications or generalizations of this kind of tensor network that may be able to provide a more robust correspondence.Comment: 38 pages, 9 figure