328 research outputs found
Physical-depth architectural requirements for generating universal photonic cluster states
Most leading proposals for linear-optical quantum computing (LOQC) use
cluster states, which act as a universal resource for measurement-based
(one-way) quantum computation (MBQC). In ballistic approaches to LOQC, cluster
states are generated passively from small entangled resource states using
so-called fusion operations. Results from percolation theory have previously
been used to argue that universal cluster states can be generated in the
ballistic approach using schemes which exceed the critical threshold for
percolation, but these results consider cluster states with unbounded size.
Here we consider how successful percolation can be maintained using a physical
architecture with fixed physical depth, assuming that the cluster state is
continuously generated and measured, and therefore that only a finite portion
of it is visible at any one point in time. We show that universal LOQC can be
implemented using a constant-size device with modest physical depth, and that
percolation can be exploited using simple pathfinding strategies without the
need for high-complexity algorithms.Comment: 18 pages, 10 figure
High levels of congenital transmission of toxoplasma gondii in longitudinal and cross-sectional studies on sheep farms provides evidence of vertical transmission in ovine hosts
Recent research suggests that vertical transmission may play an important role in sustaining Toxoplasma gondii infection in some species. We report here that congenital transmission occurs at consistently high levels in pedigree Charollais and outbred sheep flocks sampled over a 3-year period. Overall rates of transmission per pregnancy determined by PCR based diagnosis, were consistent over time in a commercial sheep flock (69%) and in sympatric (60%) and allopatric (41%) populations of Charollais sheep. The result of this was that 53·7% of lambs were acquiring an infection prior to birth: 46·4% of live lambs and 90·0% of dead lambs (in agreement with the association made between T. gondii and abortion). No significant differences were observed between lamb sexes. Although we cannot distinguish between congenital transmission occurring due to primary infection at pregnancy or reactivation of chronic infection during pregnancy, our observations of consistently high levels of congenital transmission over successive lambings favour the latter
Significant familial differences in the frequency of abortion and Toxoplasma gondii infection within a flock of Charollais sheep
A study was carried out to investigate the frequencies of abortion and congenital Toxoplasma gondii infection within 27
families (765 individuals) of a pedigree Charollais sheep flock maintained on a working farm in Worcestershire, UK, since
1992. Pedigree lambing records were analysed to establish the frequency of abortion for each family. The frequency of
congenital infection was determined for each family by PCR analysis of tissue samples taken from newborn lambs. Atotal of
155 lambs were tested for congenital T. gondii infection, which were all born during the study period 2000â2003. Significant
differences in the frequency of abortion between sheep families within this flock were observed with frequencies ranging
between 0% and 48% (P<0.01). Significantly different infection frequencies with T. gondii were also observed for different
families and ranged between 0% and 100% (P<0.01). Although the actual cause of each abortion was not verified, a highly
significant positive correlation was found to exist between the frequency of abortion and the frequency of T. gondii infection
in the same families (P<0.01). The data presented here raise further questions regarding the significance of congenital
transmission of T. gondii within sheep populations, the possible successive vertical transmission of T. gondii within families
of sheep, and the potential role of inherited genetic susceptibility to abortion with respect to T. gondii infection. This work
invites further study into the epidemiology of ovine toxoplasmosis and may have implications for sheep husbandry methods
in the future.
Key words: Toxoplasma gondii, ovine, toxoplasmosis, congenital, transmission, pedigree, sheep
The prevalence of Neospora caninum and co-infection with Toxoplasma gondii by PCR analysis in naturally occurring mammal populations
Neospora caninum and Toxoplasma gondii are closely related intracellular protozoan parasites associated with bovine and ovine abortion respectively. Little is known about the extent of Neospora/Toxoplasma co-infection in naturally infected populations of animals. Using nested PCR techniques, based on primers from the Nc5 region of N. caninum and SAG1 for T. gondii, the prevalence of N. caninum and its co-infection with T. gondii were investigated in populations of Mus domesticus, Rattus norvegicus and aborted lambs (Ovis aries). A low frequency of infection with N. caninum was detected in the Mus domesticus (3%) and Rattus norvegicus (4·4%) populations. A relatively high frequency of infection with N. caninum was detected in the brains of aborted lambs (18·9%). There was no significant relationship between N. caninum and T. gondii co-infection. Investigation of the tissue distribution of Neospora, in aborted lambs, showed that Neospora could not be detected in tissues other than brain and this was in contrast to Toxoplasma where the parasite could be frequently detected in a range of tissues
Whole-Genome Sequencing and Concordance Between Antimicrobial Susceptibility Genotypes and Phenotypes of Bacterial Isolates Associated with Bovine Respiratory Disease.
Extended laboratory culture and antimicrobial susceptibility testing timelines hinder rapid species identification and susceptibility profiling of bacterial pathogens associated with bovine respiratory disease, the most prevalent cause of cattle mortality in the United States. Whole-genome sequencing offers a culture-independent alternative to current bacterial identification methods, but requires a library of bacterial reference genomes for comparison. To contribute new bacterial genome assemblies and evaluate genetic diversity and variation in antimicrobial resistance genotypes, whole-genome sequencing was performed on bovine respiratory disease-associated bacterial isolates (Histophilus somni, Mycoplasma bovis, Mannheimia haemolytica, and Pasteurella multocida) from dairy and beef cattle. One hundred genomically distinct assemblies were added to the NCBI database, doubling the available genomic sequences for these four species. Computer-based methods identified 11 predicted antimicrobial resistance genes in three species, with none being detected in M. bovis While computer-based analysis can identify antibiotic resistance genes within whole-genome sequences (genotype), it may not predict the actual antimicrobial resistance observed in a living organism (phenotype). Antimicrobial susceptibility testing on 64 H. somni, M. haemolytica, and P. multocida isolates had an overall concordance rate between genotype and phenotypic resistance to the associated class of antimicrobials of 72.7% (P < 0.001), showing substantial discordance. Concordance rates varied greatly among different antimicrobial, antibiotic resistance gene, and bacterial species combinations. This suggests that antimicrobial susceptibility phenotypes are needed to complement genomically predicted antibiotic resistance gene genotypes to better understand how the presence of antibiotic resistance genes within a given bacterial species could potentially impact optimal bovine respiratory disease treatment and morbidity/mortality outcomes
Loss-tolerant teleportation on large stabilizer states
We present a general method for finding loss-tolerant teleportation on large,
entangled stabilizer states using only single-qubit measurements, known as
\emph{stabilizer pathfinding} (SPF). For heralded loss, SPF is shown to
generate optimally loss-tolerant measurement patterns on any given stabilizer
state. Furthermore, SPF also provides highly loss-tolerant teleportation
strategies when qubit loss is unheralded. We provide a fast algorithm for SPF
that updates continuously as a state is generated and measured, which is
therefore suitable for real-time implementation on a quantum-computing device.
When compared to simulations of previous heuristics for loss-tolerant
teleportation on graph states, SPF provides considerable gains in tolerance to
both heralded and unheralded loss, achieving a near-perfect teleportation rate
() in the regime of low qubit loss () on various graph state
lattices. Using these results we also present evidence that points towards the
existence of loss-tolerant thresholds on such states, which in turn indicates
that the loss-tolerant behaviour we have found also applies as the number of
qubits tends to infinity. Our results represent a significant advance towards
the realistic implementation of teleportation in both large-scale and
near-future quantum architectures that are susceptible to qubit loss, such as
linear optical quantum computation and quantum communication networks.Comment: 29 pages, 12 figures. Quantum Science and Technology (2018
Pleasure and meaningful discourse: an overview of research issues
The concept of pleasure has emerged as a multi-faceted social and cultural phenomenon in studies of media audiences since the 1980s. In these studies different forms of pleasure have been identified as explaining audience activity and commitment. In the diverse studies pleasure has emerged as a multi-faceted social and cultural concept that needs to be contextualized carefully. Genre and genre variations, class, gender, (sub-)cultural identity and generation all seem to be instrumental in determining the kind and variety of pleasures experienced in the act of viewing. This body of research has undoubtedly contributed to a better understanding of the complexity of audience activities, but it is exactly the diversity of the concept that is puzzling and poses a challenge to its further use. If pleasure is maintained as a key concept in audience analysis that holds much explanatory power, it needs a stronger theoretical foundation. The article maps the ways in which the concept of pleasure has been used by cultural theorists, who have paved the way for its application in reception analysis, and it goes on to explore the ways in which the concept has been used in empirical studies. Central to our discussion is the division between the âpublic knowledgeâ and the âpopular cultureâ projects in reception analysis which, we argue, have major implications for the way in which pleasure has come to be understood as divorced from politics, power and ideology. Finally, we suggest ways of bridging the gap between these two projects in an effort to link pleasure to the concepts of hegemony and ideology
Subtle variation in sepsis-III definitions markedly influences predictive performance within and across methods
Early detection of sepsis is key to ensure timely clinical intervention. Since very few end-toend pipelines are publicly available, fair comparisons between methodologies are difficult if
not impossible. Progress is further limited by discrepancies in the reconstruction of sepsis
onset time.
This retrospective cohort study highlights the variation in performance of predictive
models under three subtly different interpretations of sepsis onset from the sepsis-III
definition and compares this against inter-model differences. The models are chosen to
cover tree-based, deep learning, and survival analysis methods.
Using the MIMIC-III database, between 867 and 2178 intensive care unit admissions with
sepsis were identified, depending on the onset definition. We show that model performance
can be more sensitive to differences in the definition of sepsis onset than to the model itself.
Given a fixed sepsis definition, the best performing method had a gain of 1â5% in the area
under the receiver operating characteristic (AUROC). However, the choice of onset time can
cause a greater effect, with variation of 0â6% in AUROC.
We illustrate that misleading conclusions can be drawn if models are compared without
consideration of the sepsis definition used which emphasizes the need for a standardized
definition for sepsis onset
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