Polynomial-time T-depth Optimization of Clifford+T circuits via Matroid Partitioning

Most work in quantum circuit optimization has been performed in isolation from the results of quantum fault-tolerance. Here we present a polynomial-time algorithm for optimizing quantum circuits that takes the actual implementation of fault-tolerant logical gates into consideration. Our algorithm re-synthesizes quantum circuits composed of Clifford group and T gates, the latter being typically the most costly gate in fault-tolerant models, e.g., those based on the Steane or surface codes, with the purpose of minimizing both T-count and T-depth. A major feature of the algorithm is the ability to re-synthesize circuits with additional ancillae to reduce T-depth at effectively no cost. The tested benchmarks show up to 65.7% reduction in T-count and up to 87.6% reduction in T-depth without ancillae, or 99.7% reduction in T-depth using ancillae.Comment: Version 2 contains substantial improvements and extensions to the previous version. We describe a new, more robust algorithm and achieve significantly improved experimental result

Marine Sponges as Bioindicators of Nitrogen within Estuaries on the Oregon Coast

As filter feeders, sponges are highly integrated with their environment. Many sponges also host diverse communities of bacteria, including many that are hypothesized to carry out a variety of nitrogen transformations. The presence of these bacteria makes sponges an integral part of the nitrogen cycle in their habitats and suggests that sponges are an excellent bioindicator of environmental conditions. To test these hypotheses, we collected sponge tissue from two Oregon estuaries and extracted microbial DNA from these samples. To assess bacterial diversity, we performed Denaturing Gradient Gel Electrophoresis (DGGE) on a fragment of the 16S gene. We also examined nitrogen cycling in sponges by examining the sponge samples for the presence of the amoA and nirS genes, which encode for enzymes in the nitrification and denitrification pathways, respectively. DGGE results showed diverse bacterial communities, with clear differences between the sites. The results also showed little variation within sites, but were suggestive of seasonal variation. Both functional genes were present in all five species of sponge that we collected. These results suggest that sponges and their associated bacterial communities play a critical role in nitrogen transformations within these bays and that these sponge-associated bacterial communities are bioindicators of environmental variation

Tidal Variation in Nitrogen Cycling in Oregon Sponges

As filter feeders, marine sponges are closely integrated with their environment. Sponges also host many diverse species of bacteria that carry out a gamut of metabolic processes, including several nitrogen transformations. The variable nature of tidal exchanges can influence the biogeochemicals available for the sponge and its associated microbes to obtain from the environment. As ambient nutrient concentrations change, it is suggested that the pumping rates of the sponge will change, thus altering the activity of the symbionts. To explore these hypotheses, ambient and exhalent water samples were collected at both high tide and low tide in Netarts Bay, Oregon. To assess pumping rates, transect images between tides were analyzed for changes in oscula diameter within species. Nitrate, ammonia, and total nitrogen concentrations were analyzed via spectroscopy. Transect results demonstrated decreased oscula diameter and therefore decreased pumping rates during high tide and inverse results at low tide. Significant variation was found between inhalant and exhalent nitrate, ammonia, and total nitrogen values between species and between tides. This suggests that ambient nitrogen concentrations influence internal nitrogen cycling, but varies between species. These results suggest that sponges and their associated microbial communities adjust their metabolism based on tidal influences

Creation of a New Domain and Evaluation of Comparison Generation in a Natural Language Generation System

We describe the creation of a new domain for the Methodius Natural Language Generation System, and an evaluation of Methodius ’ parameterized comparison generation algorithm. The new domain was based around music and performers, and texts about the domain were generated using Methodius. Our evaluation showed that test subjects learned more from texts that contained comparisons than from those that did not. We also established that the comparison generation algorithm could generalize to the music domain.

Approaches to Estimating the Health State Dependence of the Utility Function

If the marginal utility of consumption depends on health status, this will affect the economic analysis of a number of central problems in public finance, including the optimal structure of health insurance and optimal life cycle savings. In this paper, we describe the promises and challenges of various approaches to estimating the effect of health on the marginal utility of consumption. Our basic conclusion is that while none of these approaches is a panacea, many offer the potential to shed important insights on the nature of health state dependence.insurance, health, state dependence, marginal utility

The Return of the Plague: Inequitable Conduct After Regeneron V. Merus

The Return of the Plague: Inequitable Conduct After Regeneron V. Meru