On Protected Realizations of Quantum Information

There are two complementary approaches to realizing quantum information so that it is protected from a given set of error operators. Both involve encoding information by means of subsystems. One is initialization-based error protection, which involves a quantum operation that is applied before error events occur. The other is operator quantum error correction, which uses a recovery operation applied after the errors. Together, the two approaches make it clear how quantum information can be stored at all stages of a process involving alternating error and quantum operations. In particular, there is always a subsystem that faithfully represents the desired quantum information. We give a definition of faithful realization of quantum information and show that it always involves subsystems. This justifies the "subsystems principle" for realizing quantum information. In the presence of errors, one can make use of noiseless, (initialization) protectable, or error-correcting subsystems. We give an explicit algorithm for finding optimal noiseless subsystems. Finding optimal protectable or error-correcting subsystems is in general difficult. Verifying that a subsystem is error-correcting involves only linear algebra. We discuss the verification problem for protectable subsystems and reduce it to a simpler version of the problem of finding error-detecting codes.Comment: 17 page

The Role of Water in a Dairy Cow\u27s Ration

In connection with the investigations by this department on \u27\u27The Effect of Alkali Water on Dairy Cows and Dairy Products\u27\u27 it became evident that the information on the functions of water in the ration of a dairy cow was meager. Furthermore, during this work some clews were obtained which the investigators desired to carry to a conclusion. . . . It is the object of the investigation reported in this bulletin to study the effects of watering the cow at different intervals and in varying amounts upon the amount of food consumed, digestibility of nutrients, amount and composition of feces and urine, amount and composition of milk, composition and quality of butterfat, body temperature and physical condition of cows. Incidentally, the bulletin furnishes some data on the mineral metabolism of the cow

Institutionalization of a Software Process Innovation in Large Financial Services Organization: A Case of Re-Invention of a Requirements Inspection Process

Failed software development projects are expensive for society and individual companies. Studies indicate defects in requirements specification are the cause of many of these failures. A large financial services company recently implemented a software requirements inspection process based on the Fagan model with the assistance of the authors. Subsequently, the process was re-invented by users to be less formal, and the organization changed the official process to be consistent with the new process to encourage institutionalization. This change formed a natural experiment. The authors examined inspection documentation under both versions of the process to determine if there were any significant differences in the effectiveness of the versions or their implementation. They found that unplanned implementation effects of the new approach made it impossible to determine whether it was more effective than the original approach. Policy implications are discussed

THE MECHANICS OF SUBGLACIAL BASALTIC LAVA FLOW EMPLACEMENT: INFERRING PALEO-ICE CONDITIONS

Recent studies of terrestrial glaciovolcanic terrains have elucidated the utility of volcanic deposits as recorders of ice conditions at the time of eruption. Practically all of these investigations, however, have focused upon the associations of volcaniclastic and coherent lava lithofacies at or proximal to the source vent. Very few studies have documented the emplacement of effusion-dominated, basaltic glaciovolcanic eruptions and their distal deposits that more accurately reveal paleo-ice conditions. Both Mauna Kea volcano, Hawaii and the Tennena volcanic center (TVC), on Mount Edziza, British Columbia, Canada, preserve records of interaction between coherent lavas and an ice sheet inferred to be associated with the last glacial maximum (LGM). The identification, mapping and description of subglacial TVC lava flows reveals the spatial distribution and characteristics of primary volcanic lithofacies and associated glaciogenic lithofacies, and reveals the processes of the emplacement of the distal lava flows under thick ice. Exposure dating with cosmogenic nuclides proves the most effective technique to temporally constrain the emplacement of these subglacial lavas. This work shows; 1) classification schemes that utilize remotely sensed imagery are locally robust but are not readily viable as identifiers of subglacial lavas in other volcanic terrains, 2) the distribution of primary hydrovolcanic clastic deposits at the TVC are confined to the cone, but coherent pillow lavas including distinctive vertically-oriented and distended pillows are widespread, 3) multiple lobes of massive sheet lavas record high initial magma discharge rates, 4) associated glaciogenic facies that underlie or onlap the TVC lavas indicate active subglacial meltwater drainage at the time of the eruption. Analyses of H2O/CO2 in pillow rim samples give broad constraints for emplacement pressures equivalent to 500-1400 m of overlying ice. No subaerial lava morphologies are found on the cone or in the proximal to distal lithofacies, and the sequence is interpreted as documenting an eruption of basaltic lava flows beneath either the LGM Cordilleran ice sheet or a Younger Dryas expansion of the still-extant Edziza ice cap. To further constrain the age of the eruption exposure dating with cosmogenic chlorine-36 is the most viable method as demonstrated on Mauna Loa explosive deposits

Categorification of persistent homology

We redevelop persistent homology (topological persistence) from a categorical point of view. The main objects of study are diagrams, indexed by the poset of real numbers, in some target category. The set of such diagrams has an interleaving distance, which we show generalizes the previously-studied bottleneck distance. To illustrate the utility of this approach, we greatly generalize previous stability results for persistence, extended persistence, and kernel, image and cokernel persistence. We give a natural construction of a category of interleavings of these diagrams, and show that if the target category is abelian, so is this category of interleavings.Comment: 27 pages, v3: minor changes, to appear in Discrete & Computational Geometr

Early impact of rotavirus vaccination in a large paediatric hospital in the UK.

The impact of routine rotavirus vaccination on community-acquired (CA) and healthcare-associated (HA) rotavirus gastroenteritis (RVGE) at a large paediatric hospital, UK, was investigated over a 13-year period. A total of 1644 hospitalized children aged 0-15 years tested positive for rotavirus between July 2002 and June 2015. Interrupted time-series analysis demonstrated that, post vaccine introduction (July 2013 to June 2015), CA- and HA-RVGE hospitalizations were 83% [95% confidence interval (CI): 72-90%) and 83% (95% CI: 66-92%] lower than expected, respectively. Rotavirus vaccination has rapidly reduced the hospital rotavirus disease burden among both CA- and HA-RVGE cases

The effect of 12C + 12C rate uncertainties on s-process yields

The slow neutron capture process in massive stars (the weak s-process) produces most of the s-only isotopes in the mass region 60 < A < 90. The nuclear reaction rates used in simulations of this process have a profound effect on the final s-process yields. We generated 1D stellar models of a 25 solar mass star varying the 12C + 12C rate by a factor of 10 and calculated full nucleosynthesis using the post-processing code PPN. Increasing or decreasing the rate by a factor of 10 affects the convective history and nucleosynthesis, and consequently the final yields.Comment: Conference proceedings for the Nuclear Physics in Astrophysics IV conference, 8-12 June 2009. 4 pages, 3 figures. Accepted for publication to the Journal of Physics: Conference Serie