Studies on the use of sulfites to control shrimp melanosis (Blackspot) (Presented at the 11th Annual Meeting of the Tropical and Subtropical Fisheries Technological Conference of the Americas, January 14, 1986, Tampa, Florida)

Shrimp melanosis, commonly known as 'blackspot' is a harmless but objectionable surface dicoloration caused by polyphenoloxidase enzyme systems which remain active during refrigeration or ice storage. In the early 1950's sulfiting agents, particularily sodium bisulfite was first introduced to prevent or inhibit melanosis, thus yielding a more valuable harvest (1). Such use of sulfites was 'prior sanctioned1 by the U.S. Food and Drug Administration (FDA) in 1956 (2). More recent FDA decisions reaffirmed this practice, (3) but continuing regulatory scrutiny could restrict or eliminate the application of sulfite on shrimp. The regulatory action is prompted by an increasing concern for adverse 'allergic' reactions most common amongst hyper-(sulfite) sensitive asthmatics. Thus work was initiated to find alternatives to replace or reduce the amount of sulfites required to inhibit shrimp melanosis. This work would screen for possible alternatives which would require subsequent verification with field tests and statistical evaluations. (21pp.

Absolute FKBP binding affinities obtained via non-equilibrium unbinding simulations

We compute absolute binding affinities for two ligands bound to the FKBP protein using non-equilibrium unbinding simulations. The methodology is straight-forward, requiring little or no modification to many modern molecular simulation packages. The approach makes use of a physical pathway, eliminating the need for complicated alchemical decoupling schemes. Results of this study are promising. For the ligands studied here the binding affinities are typically estimated within less than 4.0 kJ/mol of the target values; and the target values are within less than 1.0 kJ/mol of experiment. These results suggest that non-equilibrium simulation could provide a simple and robust means to estimate protein-ligand binding affinities.Comment: 9 pages, 3 figures (no necessary color). Changes made to methodology and results between revision

The X-ray nebula of the filled center supernova remnant 3C58 and its interaction with the environment

An \xmm observation of the plerionic supernova remnant 3C58 has allowed us to study the X-ray nebula with unprecedented detail. A spatially resolved spectral analysis with a resolution of 8\arcsec has yielded a precise determination of the relation between the spectral index and the distance from the center. We do not see any evidence for bright thermal emission from the central core. In contrast with previous ASCA and {\em Einstein} results, we derive an upper limit to the black-body 0.5-10 keV luminosity and emitting area of $1.8\times 10^{32}$ \ergsec and $1.3\times 10^{10}$ cm$^2$, respectively, ruling out emission from the hot surface of the putative neutron star and also excluding the "outer-gap" model for hot polar caps. We have performed for the first time a spectral analysis of the outer regions of the X-ray nebula, where most of the emission is still non-thermal, but where the addition of a soft (kT=0.2-0.3 keV) optically thin plasma component is required to fit the spectrum at $E<1$ keV. This component provides 6% of the whole remnant observed flux in the 0.5-10.0 keV band. We show that a Sedov interpretation is incompatible with the SN1181-3C58 association, unless there is a strong deviation from electron-ion energy equipartition, and that an origin of this thermal emission in terms of the expansion of the nebula into the ejecta core nicely fits all the radio and X-ray observations.Comment: 10 pages, 7 figures, accepted for publication in A&

Why We Should Have Seen That Coming: Comments on Microsoft’s Tay “Experiment,” and Wider Implications

In this paper we examine the case of Tay, the Microsoft AI chatbot that was launched in March, 2016. After less than 24 hours, Microsoft shut down the experiment because the chatbot was generating tweets that were judged to be inappropriate since they included racist, sexist, and anti-Semitic language. We contend that the case of Tay illustrates a problem with the very nature of learning software (LS is a term that describes any software that changes its program in response to its interactions) that interacts directly with the public, and the developer’s role and responsibility associated with it. We make the case that when LS interacts directly with people or indirectly via social media, the developer has additional ethical responsibilities beyond those of standard software. There is an additional burden of care

Temperature dependence of the resonance and low energy spin excitations in superconducting FeTe0.6_{0.6}Se0.4_{0.4}

We use inelastic neutron scattering to study the temperature dependence of the low-energy spin excitations in single crystals of superconducting FeTe$_{0.6}$Se$_{0.4}$ ($T_c=14$ K). In the low-temperature superconducting state, the imaginary part of the dynamic susceptibility at the electron and hole Fermi surfaces nesting wave vector $Q=(0.5,0.5)$, $\chi^{\prime\prime}(Q,\omega)$, has a small spin gap, a two-dimensional neutron spin resonance above the spin gap, and increases linearly with increasing $\hbar\omega$ for energies above the resonance. While the intensity of the resonance decreases like an order parameter with increasing temperature and disappears at temperature slightly above $T_c$, the energy of the mode is weakly temperature dependent and vanishes concurrently above $T_c$. This suggests that in spite of its similarities with the resonance in electron-doped superconducting BaFe$_{2-x}$(Co,Ni)$_x$As$_2$, the mode in FeTe$_{0.6}$Se$_{0.4}$ is not directly associated with the superconducting electronic gap.Comment: 7 pages, 6 figure

On the Responsibility for Uses of Downstream Software

In this paper we explore an issue that is different from whether developers are responsible for the direct impact of the software they write. We examine, instead, in what ways, and to what degree, developers are responsible for the way their software is used “downstream.” We review some key scholarship analyzing responsibility in computing ethics, including some recent work by Floridi. We use an adaptation of a mechanism developed by Floridi to argue that there are features of software that can be used as guides to better distinguish situations where a software developer might share in responsibility for the software’s downstream use from those in which the software developer likely does not share in that responsibility. We identify five such features and argue how they are useful in the model of responsibility that we develop. The features are: closeness to the hardware, risk, sensitivity of data, degree of control over or knowledge of the future population of users, and the nature of the software (general vs. special purpose)

On Using Model For Downstream Responsibility

The authors identify features of software and the software development process that may contribute to the differences in the level of responsibility assigned to the software developers when they make their software available for others to use as a tool in building a second piece of software. They call this second use of the software downstream use