Quantum broadcast channels

We consider quantum channels with one sender and two receivers, used in several different ways for the simultaneous transmission of independent messages. We begin by extending the technique of superposition coding to quantum channels with a classical input to give a general achievable region. We also give outer bounds to the capacity regions for various special cases from the classical literature and prove that superposition coding is optimal for a class of channels. We then consider extensions of superposition coding for channels with a quantum input, where some of the messages transmitted are quantum instead of classical, in the sense that the parties establish bipartite or tripartite GHZ entanglement. We conclude by using state merging to give achievable rates for establishing bipartite entanglement between different pairs of parties with the assistance of free classical communication.Comment: 15 pages; IEEE Trans. Inform. Theory, vol. 57, no. 10, October 201

Capacity Theorems for Quantum Multiple Access Channels: Classical-Quantum and Quantum-Quantum Capacity Regions

We consider quantum channels with two senders and one receiver. For an arbitrary such channel, we give multi-letter characterizations of two different two-dimensional capacity regions. The first region is comprised of the rates at which it is possible for one sender to send classical information, while the other sends quantum information. The second region consists of the rates at which each sender can send quantum information. For each region, we give an example of a channel for which the corresponding region has a single-letter description. One of our examples relies on a new result proved here, perhaps of independent interest, stating that the coherent information over any degradable channel is concave in the input density operator. We conclude with connections to other work and a discussion on generalizations where each user simultaneously sends classical and quantum information.Comment: 38 pages, 1 figure. Fixed typos, added new example. Submitted to IEEE Tranactions on Information Theor

Capacity Theorems for Quantum Multiple Access Channels

We consider quantum channels with two senders and one receiver. For an arbitrary such channel, we give multi-letter characterizations of two different two-dimensional capacity regions. The first region characterizes the rates at which it is possible for one sender to send classical information while the other sends quantum information. The second region gives the rates at which each sender can send quantum information. We give an example of a channel for which each region has a single-letter description, concluding with a characterization of the rates at which each user can simultaneously send classical and quantum information.Comment: 5 pages. Conference version of quant-ph/0501045, to appear in the proceedings of the IEEE International Symposium on Information Theory, Adelaide, Australia, 200

A new class of codes for Boolean masking of cryptographic computations

We introduce a new class of rate one-half binary codes: {\bf complementary information set codes.} A binary linear code of length $2n$ and dimension $n$ is called a complementary information set code (CIS code for short) if it has two disjoint information sets. This class of codes contains self-dual codes as a subclass. It is connected to graph correlation immune Boolean functions of use in the security of hardware implementations of cryptographic primitives. Such codes permit to improve the cost of masking cryptographic algorithms against side channel attacks. In this paper we investigate this new class of codes: we give optimal or best known CIS codes of length $<132.$ We derive general constructions based on cyclic codes and on double circulant codes. We derive a Varshamov-Gilbert bound for long CIS codes, and show that they can all be classified in small lengths $\le 12$ by the building up construction. Some nonlinear permutations are constructed by using $\Z_4$-codes, based on the notion of dual distance of an unrestricted code.Comment: 19 pages. IEEE Trans. on Information Theory, to appea

Pyrolysis of Dried Wastewater Biosolids Can Be Energy Positive

Pyrolysis is a thermal process that converts biosolids into biochar (a soil amendment), py-oil and py-gas, which can be energy sources. The objectives of this research were to determine the product yield of dried biosolids during pyrolysis and the energy requirements of pyrolysis. Bench-scale experiments revealed that temperature increases up to 500 °C substantially decreased the fraction of biochar and increased the fraction of py-oil. Py-gas yield increased above 500 °C. The energy required for pyrolysis was approximately 5-fold less than the energy required to dry biosolids (depending on biosolids moisture content), indicating that, if a utility already uses energy to dry biosolids, then pyrolysis does not require a substantial amount of energy. However, if a utility produces wet biosolids, then implementing pyrolysis may be costly because of the energy required to dry the biosolids. The energy content of py-gas and py-oil was always greater than the energy required for pyrolysis

Red Eyes on Wolf-Rayet Stars: 60 New Discoveries via Infrared Color Selection

We have spectroscopically identified 60 Galactic Wolf-Rayet (WR) stars, including 38 nitrogen types (WN) and 22 carbon types (WC). Using photometry from the Spitzer/GLIMPSE and 2MASS databases, the WRs were selected via a method we have established that exploits their unique infrared colors, which is mainly the result of excess radiation from free-free scattering within their dense ionized winds. The selection criteria has been refined since our last report, and now yields WRs at a rate of ~20% in spectroscopic follow-up of candidates that comprise a broad color space defined by the color distribution of all known WRs having B>14 mag. However, there are subregions within the broad color space which yield WRs at a rate of >50%. Cross-correlation of WR candidates with archival X-ray point-source catalogs increases the WR detection rate of the broad color space to ~40%; ten new WR X-ray sources have been found, in addition to a previously unrecognized X-ray counterpart to a known WR. The extinction values, distances, and galactocentric radii of all new WRs are calculated using the method of spectroscopic parallax. Although the majority of the new WRs have no obvious association with stellar clusters, two WC8 stars reside in a previously unknown massive-star cluster that lies near the intersection of the Scutum-Centaurus Arm and the Galaxy's bar, in which five OB supergiants were also identified. In addition, two WC and four WN stars were identified in association with the stellar clusters Danks 1 and 2. A WN9 star has also been associated with the cluster [DBS2003] 179. This work brings the total number of known Galactic WRs to 476, or ~7-8% of the total empirically estimated population. An examination of their Galactic distribution reveals a tracing of spiral arms and an enhanced WR surface density toward several massive-star formation sites (abridged).Comment: Accepted to the Astronomical Journal on May 20, 2011. Document is 39 pages, including 20 figures and 8 table

A decoupling approach to the quantum capacity

We give a short proof that the coherent information is an achievable rate for the transmission of quantum information through a noisy quantum channel. Our method is to produce random codes by performing a unitarily covariant projective measurement on a typical subspace of a tensor power state. We show that, provided the rank of each measurement operator is sufficiently small, the transmitted data will with high probability be decoupled from the channel's environment. We also show that our construction leads to random codes whose average input is close to a product state and outline a modification yielding unitarily invariant ensembles of maximally entangled codes.Comment: 13 pages, published versio

Improving Feed Efficiency Through Forage Strategies for Increasing Dairy Profitability and Sustainability

Three studies were conducted to determine production parameters and study specific hypothesis in regard to improving feed efficiency through various forage utilization strategies with or without the inclusion of various supplemented products. The first study evaluated the supplementation of a cobalt-lactate product and its effects on fiber digestibility and milk production parameters when fed to cows consuming a 70% forage diet. Treatments included: 1) CONTROL diet containing 12.5 mg/cow/d of cobalt (carbonate carbonate) and 2) TEST diet being the same basal diet but including an additional 50 mg/cow/d of cobalt via a 1% Co-lactate product (Co-Max®). In a feeding trial with 24 late lactation cows, feeding the cobalt-lactate product had no effect on production parameters. However, cobalt-lactate supplementation decreased rumen ammonia concentrations, increased ruminal molar concentrations of acetate and numerically increased fiber digestion. The second study evaluated Saccharomyces cerevisiae fermentation products (SCFP); (Diamond V original XPC and two prototypes) on lactational performance and ruminal fermentation. Eight ruminally cannulated Holstein dairy cows were used in a replicated 4 x 4 Latin square. Treatments were: 1) Control (C): corn silage and haylage based ration; 2) XPC: C ration with 14 g/hd/d Original XPC; 3) Prototype 1 (P1): C ration with 5 g/hd/d P1; and 4) Prototype 2 (P2): C ration with 19 g/hd/d P2. Ruminal pH (6.06, 6.07, 6.02 and 6.13 for C, XPC, P1, and P2 respectively) was greater (P \u3c 0.05) for cows fed P2 compared to cows fed other treatments. Rumen concentration and percentage of propionate and iso-butyrate were increased (P \u3c 0.05) for cows fed P2 when compared to C with cows fed other treatments being intermediate and similar. The feeding of a dairy ration with P2 SCFP can improve ruminal pH while increasing propionate and iso-butyrate concentrations and percentages. The third study evaluated two forage production programs with subsequent feeding to evaluate the lactational performance of Holstein dairy cows. Thirty peak-lactation (58 DIM ± 2.9) Holstein dairy cows were used in a randomized complete block design. Treatments were: 1) CONTROL: normal forages (65% of diet) ration formulated using alfalfa haylage and corn silage produced with a standard university soil and agronomy program; 2) TEST: high forage level (65% of diet) ration formulated using alfalfa haylage and corn silage produced on an enhanced soil and agronomy program. Milk production was increased for cows fed TEST compared to cows fed control forage while DMI were similar. Energy corrected milk was increased for the TEST fed cows. There was an increasing trend in starch digestibility for cows fed TEST forage. Digestibility of NDF and ADF were increased for the TEST fed cows compared to cows fed CONTROL forages. Feeding higher quality forages obtained from enhanced agronomy procedures increased milk production, milk composition, and fiber digestibility when lactating dairy cows were fed a high forage ration. Based on these results, lactating dairy can greatly benefit from increases in forage quality and forage digestibility. Supplemental products such as SCFP can be utilized to aide in increases in propionate production which typically lead to increases in milk yield

Mitigating Distortion of Light-Polymerized Composite Trial Bases

Triad Visible Light Cure (VLC) Denture Base Material, a light-polymerizing resin material, is commonly used by clinicians to make trial bases during the fabrication of dentures and in planning the prosthetic and surgical rehabilitation of edentulous patients. A well-known drawback to this material, however, is its tendency to distort during the light-polymerization process. This distortion tends to occur most often towards the posterior aspect of the palate, and can negatively impact the bases ability to be retained through suction to the edentulous arch. The purpose of this study was to evaluate whether an experimental polymerization protocol can mitigate distortion during the polymerization process to allow for a trial base with improved fit and retention. Forty maxillary record bases were created, with one base fabricated on each cast. Twenty casts were used to fabricate trial bases per manufacturer recommendations, another 20 trial bases were fabricated according to the experimental protocol. These subgroups divided into 2 groups of 10, in which one-half of the trial bases made by a given protocol were evaluated for distortion at 1 hour, and the other half was evaluated at 7 days. Statistical analysis was completed for the data collected. From this study, the following conclusions were made: 1. The experimental protocol for fabricating a trial base from Triad VLC material does not experience distortion up to 7 days after being polymerized that is statistically significant when compared to the distortion at 1 hour, but the manufacturer\u27s protocol does experience distortion that is statistically significant. 2. The experimental protocol for fabricating a trial base from Trial VLC material experienced far less distortion than the manufacturer protocol. 3. The experimental protocol might allow for a trial base that fits and retains better than one made using the manufacturer’s protocol