The Puzzle of Environmental Politics

In this report we study estimation of time-delays in linear dynamical systems with additive noise. Estimating time-delays is a common engineering problem, e.g. in automatic control, system identification and signal processing. The purpose with this work is to test and evaluate a certain class of methods for time-delay estimation, especially with automatic control applications in mind. Particularly interesting it is to determine the best method. Is one method best in all situations or should different methods be used for different situations? The tested class of methods consists essentially of thresholding the cross correlation between the output and input signals. This is a very common method for time-delay estimation. The methods are tested and evaluated experimentally with the aid of simulations and plots of RMS error, bias and confidence intervals. The results are: The methods often miss to detect because the threshold is too high. The threshold has nevertheless been selected to give the best result. All methods over-estimate the time-delay. Nearly the whole RMS error is due to the bias. None of the tested methods is always best. Which method is best depends on the system and what is done when missing detections. Some form of averaging of the cross correlation, e.g. integration to step response or CUSUM, is advantageous. Fast systems are easiest. White noise input signal is easiest and steps is hardest. The RMS-errors are high in average (approximately greater than 6 sampling intervals). The error is lower for fast system or for high SNR

Hysteresis and unemployment : a preliminary investigation

This paper points out what hysteresis is using a simple model of market entry and exit. A procedure for calculating hysteresis indices for economic time series is outlined. Some preliminary results are presented to assess the explanatory power of hysteresis variables with regard to the equilibrium rate of unemployment in the UK. We find that both natural and "unnatural" variables enter a cointegrating vector for UK unemployment 1959-1996. The natural variable is the replacement ratio. The 'unnatural' variables are the hysteresis index of the exchange rate; and hysteresis indices for the real oil price and the real interest rate

The Mr. Big Sting in Canada

For approximately the last fifteen years, the Royal Canadian Mounted Police have been mounting highly sophisticated undercover sting operations in Canada known colloquially as Mr. Big stings. These undercover operations involve multiple officers posing as members of a ruthless, powerful and wealthy criminal organization in order to trick suspects into making confessions to serious crimes, nearly always homicides. The undercover officers essentially orchestrate a chance meeting with the suspect, known operationally as the “target”, and exert their considerable influence and resources to convince him that he is being inducted into a criminal gang. The target is typically a person suspected of having committed a murder in the past, but who has never been charged due to lack of evidence. Over a period of months or weeks the undercover officers attempt to build a relationship with the target based on fear, greed, companionship, or a combination of those or other emotions. The target is given tasks to perform which appear criminal in nature, but which are actually staged crimes in which every participant is an undercover officer. The target is eventually told he must meet with the boss of the gang, the “Mr. Big” after whom the sting is named, in order for a final decision to be made on whether or not the target can join the gang. The target is told that he must confess to the previous murder of which he is suspected in order to join the gang. Sometimes the target confesses readily, other times he protests his innocence, but Mr. Big will not accept exculpatory statements. Often further inducements are offered by Mr. Big, most notably a promise to derail the investigation by using his influence over corrupt justice system participants. If the suspect admits culpability he will be charged with the crime and nearly always convicted at trial. Canadian courts have exercised virtually no control over police tactics in these cases. Defence counsel have argued against the use of the evidence on the basis of a breach of the Charter of Rights and Freedoms with regard to the right to silence and also with regard to abuse of process. These arguments have been unsuccessful. Defence counsel have also argued unsuccessfully that the statements should be inadmissible under Canadian hearsay law. It has also been argued, equally unsuccessfully, that the undercover operators should be treated as persons-in-authority, and hence that the statements elicited from the targets should have to be proven voluntary beyond a reasonable doubt. Canadian judges have also been unwilling to allow the defence to lead expert evidence in these cases to tell the trier of fact about the possibility of false confessions. The ultimate result is that there is no control over police tactics in these stings. There has been one proven wrongful conviction as a result of these stings, that of Kyle Wayne Unger. Other wrongful convictions may come to light. Short of its outright abolition, probably the best way to control the sting and prevent wrongful convictions is to subject the statements to a formal voluntariness inquiry

Inefficiency of classically simulating linear optical quantum computing with Fock-state inputs

Aaronson and Arkhipov recently used computational complexity theory to argue that classical computers very likely cannot efficiently simulate linear, multimode, quantum-optical interferometers with arbitrary Fock-state inputs [Aaronson and Arkhipov, Theory Comput. 9, 143 (2013)]. Here we present an elementary argument that utilizes only techniques from quantum optics. We explicitly construct the Hilbert space for such an interferometer and show that its dimension scales exponentially with all the physical resources. We also show in a simple example just how the Schr\"odinger and Heisenberg pictures of quantum theory, while mathematically equivalent, are not in general computationally equivalent. Finally, we conclude our argument by comparing the symmetry requirements of multiparticle bosonic to fermionic interferometers and, using simple physical reasoning, connect the nonsimulatability of the bosonic device to the complexity of computing the permanent of a large matrix.Comment: 7 pages, 1 figure Published in PRA Phys. Rev. A 89, 022328 (2014

Regulated degradation of the APC coactivator Cdc20

<p>Abstract</p> <p>Background</p> <p>Cdc20 is a highly conserved activator of the anaphase-promoting complex (APC), promoting cell-cycle-regulated ubiquitination and proteolysis of a number of critical cell-cycle-regulatory targets including securin and mitotic cyclins. APC-Cdc20 activity is tightly regulated, and this regulation is likely important for accurate cell cycle control. One significant component of Cdc20 regulation is thought to be Cdc20 proteolysis. However, published literature suggests different mechanisms and requirements for Cdc20 proteolysis. The degree to which Cdc20 proteolysis is cell-cycle regulated, the dependence of Cdc20 proteolysis on Cdc20 destruction boxes (recognition sequences for APC-mediated ubiqutination, either by Cdc20 or by the related Cdh1 APC activator), and the need for APC itself for Cdc20 proteolysis all have been disputed to varying extents. In animals, Cdc20 proteolysis is thought to be mediated by Cdh1, contributing an intrinsic order of APC activation by Cdc20 and then by Cdh1. One report suggests a Cdh1 requirement for Cdc20 proteolysis in budding yeast; this idea has not been tested further.</p> <p>Results</p> <p>We characterized Cdc20 proteolysis using Cdc20 expressed from its endogenous locus; previous studies generally employed strongly overexpressed Cdc20, which can cause significant artifacts. We analyzed Cdc20 proteolysis with or without mutations in previously identified destruction box sequences, using varying methods of cell cycle synchronization, and in the presence or absence of Cdh1. Cdc20 instability is only partially dependent on destruction boxes. A much stronger dependence on Cdh1 for Cdc20 proteolysis was observed, but Cdh1-independent proteolysis was also clearly observed. Cdc20 proteolysis independent of both destruction boxes and Cdh1 was especially detectable around the G1/S transition; Cdh1-dependent proteolysis was most notable in late mitosis and G1.</p> <p>Conclusions</p> <p>Cdc20 proteolysis is under complex control, with different systems operating at different points in the cell cycle. This complexity is likely to explain apparent conflicts in previously published literature on this subject. A major mode of control of Cdc20 proteolysis occurs in late mitosis/early G1 and is Cdh1-dependent, as in animal cells; this mode may contribute to the known sequential activation of the APC by Cdc20 followed by Cdh1. An independent mode of Cdc20 proteolysis, independent of destruction boxes and Cdh1, occurs at G1/S; we do not know the mechanism or function of this mode of proteolysis, but speculate that it may contribute to sharpening and restricting activation of APC-Cdc20 to early mitosis.</p

Bargaining Market Equity Adjustments by Rank and Discipline

Faculty contract negotiations generally include wages, hours, and other conditions of employment as well as mutually agreed non-mandatory subjects of bargaining. Negotiators typically address wages in terms of across-the-board increases, promotion in rank, merit increases, and one-time signing bonuses. Less typically, faculty salary negotiations include various forms of equity adjustments and salary increases linked to the underlying market and social forces and to salary compression that may, or may not, be related to these forces. The authors describe how they negotiated differential discipline-specific target salaries based in part on College and University Personnel Association faculty salary data