Multi-species and multi-interest management: An ecosystem approach to market squid (Loligo opalescens) harvest in California

Market squid (Loligo opalescens) plays a vital role in the California ecosystem and serves as a major link in the food chain as both a predator and prey species. For over a century, market squid has also been harvested off the California coast from Monterey to San Pedro. Expanding global markets, coupled with a decline in squid product from other parts of the world, in recent years has fueled rapid expansion of the virtually unregulated California fishery. Lack of regulatory management, in combination with dramatic increases in fishing effort and landings, has raised numerous concerns from the scientific, fishing, and regulatory communities. In an effort to address these concerns, the National Oceanic and Atmospheric Administration’s (NOAA) Channel Islands National Marine Sanctuary (CINMS) hosted a panel discussion at the October 1997 California Cooperative Oceanic and Fisheries Investigations (CalCOFI) Conference; it focused on ecosystem management implications for the burgeoning market squid fishery. Both panel and audience members addressed issues such as: the direct and indirect effects of commercial harvesting upon squid biomass; the effects of harvest and the role of squid in the broader marine community; the effects of environmental variation on squid population dynamics; the sustainability of the fishery from the point of view of both scientists and the fishers themselves; and the conservation management options for what is currently an open access and unregulated fishery. Herein are the key points of the ecosystem management panel discussion in the form of a preface, an executive summary, and transcript. (PDF contains 33 pages.

A Coding Theoretic Study on MLL proof nets

Coding theory is very useful for real world applications. A notable example is digital television. Basically, coding theory is to study a way of detecting and/or correcting data that may be true or false. Moreover coding theory is an area of mathematics, in which there is an interplay between many branches of mathematics, e.g., abstract algebra, combinatorics, discrete geometry, information theory, etc. In this paper we propose a novel approach for analyzing proof nets of Multiplicative Linear Logic (MLL) by coding theory. We define families of proof structures and introduce a metric space for each family. In each family, 1. an MLL proof net is a true code element; 2. a proof structure that is not an MLL proof net is a false (or corrupted) code element. The definition of our metrics reflects the duality of the multiplicative connectives elegantly. In this paper we show that in the framework one error-detecting is possible but one error-correcting not. Our proof of the impossibility of one error-correcting is interesting in the sense that a proof theoretical property is proved using a graph theoretical argument. In addition, we show that affine logic and MLL + MIX are not appropriate for this framework. That explains why MLL is better than such similar logics.Comment: minor modification

Nerve commitment in Hydra. II. Localization of commitment in S phase

The kinetics of nerve differentiation were investigated during head regeneration in Hydra. In particular the cell cycle parameters of stem cells undergoing nerve commitment were determined. Head regeneration induces extensive nerve commitment localized at the regenerating tip (G. Venugopal and C. David, 1981, Develop. Biol.83, 353–360). The appearance of committed nerve precursors is followed 12 hr later by the appearance of newly differentiated nerves. Under these conditions the time from the end of S phase to nerve differentiation is about 9 hr and the time from the beginning of S phase to nerve differentiation is about 18 hr. Thus nerve commitment occurs in mid- to late S phase of the stem cell precursor

Breaking the PPSZ Barrier for Unique 3-SAT

The PPSZ algorithm by Paturi, Pudl\'ak, Saks, and Zane (FOCS 1998) is the fastest known algorithm for (Promise) Unique k-SAT. We give an improved algorithm with exponentially faster bounds for Unique 3-SAT. For uniquely satisfiable 3-CNF formulas, we do the following case distinction: We call a clause critical if exactly one literal is satisfied by the unique satisfying assignment. If a formula has many critical clauses, we observe that PPSZ by itself is already faster. If there are only few clauses allover, we use an algorithm by Wahlstr\"om (ESA 2005) that is faster than PPSZ in this case. Otherwise we have a formula with few critical and many non-critical clauses. Non-critical clauses have at least two literals satisfied; we show how to exploit this to improve PPSZ.Comment: 13 pages; major revision with simplified algorithm but slightly worse constant

Developing Ordinary Differential Equations to Describe the Motion of a Paper Helicopter

Since George Box\u27s article was published in 1991, paper helicopters have been used to teach students experimental design [2]. It is simple and inexpensive to produce and can easily provide physically measurable data for use in experiments. This paper attempts to create a model that describes the motion of a paper helicopter using engineering, physical and statistical knowledge. A search for the optimum/maximum flight time of a helicopter was conducted in order to provide a design allowing for the largest amount of data collection possible. This data collected was then used to build and test a model that can be described by two separate equations: one describing the helicopter\u27s linear velocity and the other describing its angular velocity. These equations may be able to be solved exactly, but the path that was chosen to best fit our time constraint was to use a numerical analysis approach to create these estimations of the equations. It is important to keep in mind that although Box\u27s paper is often quoted it still remains true: All models are wrong, however some are useful [2]. Future work on this approach to the problem may contain exact solutions to our equations, but the model designed for use here is sufficient enough for one to accurately predict the flight velocities within small discrepancies compared to the physically collected data

On optimal quantum codes

We present families of quantum error-correcting codes which are optimal in the sense that the minimum distance is maximal. These maximum distance separable (MDS) codes are defined over q-dimensional quantum systems, where q is an arbitrary prime power. It is shown that codes with parameters [[n,n-2d+2,d]]_q exist for all 3 <= n <= q and 1 <= d <= n/2+1. We also present quantum MDS codes with parameters [[q^2,q^2-2d+2,d]]_q for 1 <= d <= q which additionally give rise to shortened codes [[q^2-s,q^2-2d+2-s,d]]_q for some s.Comment: Accepted for publication in the International Journal of Quantum Informatio

Universal Quantum Computation with ideal Clifford gates and noisy ancillas

We consider a model of quantum computation in which the set of elementary operations is limited to Clifford unitaries, the creation of the state $|0>$, and qubit measurement in the computational basis. In addition, we allow the creation of a one-qubit ancilla in a mixed state $\rho$, which should be regarded as a parameter of the model. Our goal is to determine for which $\rho$ universal quantum computation (UQC) can be efficiently simulated. To answer this question, we construct purification protocols that consume several copies of $\rho$ and produce a single output qubit with higher polarization. The protocols allow one to increase the polarization only along certain ``magic'' directions. If the polarization of $\rho$ along a magic direction exceeds a threshold value (about 65%), the purification asymptotically yields a pure state, which we call a magic state. We show that the Clifford group operations combined with magic states preparation are sufficient for UQC. The connection of our results with the Gottesman-Knill theorem is discussed.Comment: 15 pages, 4 figures, revtex

Donald Trump’s victories show that authoritarian voters are now in control of the Republican nomination process

Up to now, many political scientists and commentators have argued that support for Donald Trump is ‘capped’, given that he and Senator Ted Cruz (TX) are competing for the same pool of antiestablishment voters. Using new survey data from South Carolina Republican voters, Matthew C. MacWilliams finds that, along with concerns about terrorism, authoritarianism is a major predictor of people’s support for Donald Trump, and not a predictor of support for Ted Cruz. With these findings in mind, he argues that so long as people are concerned about outside threats – concerns which Trump is stoking – his support will continue to grow

Nerve commitment in Hydra. I. Role of morphogenetic signals

The kinetics of nerve commitment during head regeneration in Hydra were investigated using a newly developed assay for committed cells. Committed nerve precursors were assayed by their ability to continue nerve differentiation following explanation of small pieces of tissue. Committed nerve precursors appear at the site of regeneration within 6 hr after cutting and increase rapidly. The increase is localized to the site of regeneration and does not occur at proximal sites in the body column of the regenerate. The increase is delayed about 8–12 hr when regeneration occurs at sites lower in the body column. The results show, furthermore, that redistribution of committed precursors does not play a major role in the pattern of nerve differentiation during regeneration. Since the increase in committed nerves coincides with the increase in morphogenetic potential of the regenerating tissue, the results strengthen the idea that morphogenetic signals are involved directly in the control of nerve commitment in Hydra