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Title:

Quaternionic Computing

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We introduce a model of computation based on quaternions, which is inspired on the quantum computing model. Pure states are vectors of a suitable linear space over the quaternions. Every other aspect of the theory is the same as in quantum computing: superposition and linearity of the state space, unitarity of the transformations, and projective...

We introduce a model of computation based on quaternions, which is inspired on the quantum computing model. Pure states are vectors of a suitable linear space over the quaternions. Every other aspect of the theory is the same as in quantum computing: superposition and linearity of the state space, unitarity of the transformations, and projective measurements. We then show that this model is no more powerful than quantum computing. More concretely we show, that any quaternionic computation using n quaterbits, can be simulated with n+1 qubits, and this with little or no overhead in circuit size. Furthermore, by using the same technique, we provide a new proof that a similar model based on real amplitudes is not weaker than quantum computing, since any quantum computation using n qubits can be simulated with n+1 rebits, and in this with no circuit size overhead. 1 Minimize

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The Pennsylvania State University CiteSeerX Archives

Year of Publication:

2012-12-05

Source:

http://arxiv.org/pdf/quant-ph/0307017v1.pdf

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text

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en

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Title:

The Primary Pretenders

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Perhaps the most famous theorem in number theory is Fermat’s theorem. Not Fer-mat’s Last Theorem, of course, because that’s now old hat, but Fermat’s Little Theorem: If p is a prime, and b is a positive integer prime to p, then b p−1 ≡ 1 (mod p), which we prefer to write in the simpler form b p ≡ b (mod p). If the converse of the theorem were tr...

Perhaps the most famous theorem in number theory is Fermat’s theorem. Not Fer-mat’s Last Theorem, of course, because that’s now old hat, but Fermat’s Little Theorem: If p is a prime, and b is a positive integer prime to p, then b p−1 ≡ 1 (mod p), which we prefer to write in the simpler form b p ≡ b (mod p). If the converse of the theorem were true, then number theory would be a lot simpler than it is, but fortunately that is not the case. Counterexamples to the converse of the first (and, very occasionally, the second) form of Fermat’s theorem are called pseu-doprimes. A well-known example is 341 = 11 × 31, which is a pseudoprime to base Minimize

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The Pennsylvania State University CiteSeerX Archives

Year of Publication:

2008-07-01

Source:

http://www.research.att.com/~njas/doc/guy.pdf

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text

Language:

en

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Title:

The Primary Pretenders

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Perhaps the most famous theorem in number theory is Fermat’s theorem. Not Fermat’s Last Theorem, of course, because that’s now old hat, but Fermat’s Little Theorem: If p is a prime, and b is a positive integer prime to p, then bp−1 ≡ 1 (mod p), which we prefer to write in the simpler form b p ≡ b (mod p). If the converse of the theorem were true...

Perhaps the most famous theorem in number theory is Fermat’s theorem. Not Fermat’s Last Theorem, of course, because that’s now old hat, but Fermat’s Little Theorem: If p is a prime, and b is a positive integer prime to p, then bp−1 ≡ 1 (mod p), which we prefer to write in the simpler form b p ≡ b (mod p). If the converse of the theorem were true, then number theory would be a lot simpler than it is, but fortunately that is not the case. Counterexamples to the converse of the first (and, very occasionally, the second) form of Fermat’s theorem are called pseudoprimes. A well-known example is 341 = 11 × 31, which is a pseudoprime to base Minimize

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The Pennsylvania State University CiteSeerX Archives

Year of Publication:

2012-11-14

Source:

http://arxiv.org/pdf/math/0207180v1.pdf

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Document Type:

text

Language:

en

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Metadata may be used without restrictions as long as the oai identifier remains attached to it.

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Title:

Prevalence of periprosthetic osteolysis after total hip replacement in patients with rheumatic diseases

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Rodolfo Perez Alamino, Carolina Casellini, Andrea Banos, Emilce Edith Schneeberger, Susana Alicia Gagliardi, José Antonio Maldonado Cocco, Gustavo CiteraSection of Rheumatology, Instituto de Rehabilitación Psicofísica, Buenos Aires, ArgentinaAbstract: Periprosthetic osteolysis (PO) is a frequent complication in patients with joint implants. Ther...

Rodolfo Perez Alamino, Carolina Casellini, Andrea Banos, Emilce Edith Schneeberger, Susana Alicia Gagliardi, José Antonio Maldonado Cocco, Gustavo CiteraSection of Rheumatology, Instituto de Rehabilitación Psicofísica, Buenos Aires, ArgentinaAbstract: Periprosthetic osteolysis (PO) is a frequent complication in patients with joint implants. There are no data regarding the prevalence of PO in patients with rheumatoid arthritis (RA), juvenile chronic arthritis (JCA), ankylosing spondylitis (AS), and osteoarthritis (OA).Objectives: To evaluate the prevalence of PO in patients with RA, JCA, AS, and OA, who have undergone total hip replacement (THR), and to identify factors associated with its development.Methods: The study included patients diagnosed with RA (ACR 1987), AS (modified New York criteria), JCA (European 1977 criteria), and osteoarthritis (OA) (ACR 1990 criteria) with unilateral or bilateral THR. Demographic, clinical, and therapeutic data were collected. Panoramic pelvic plain radiographs were performed, to determine the presence of PO at acetabular and femoral levels. Images were read by two independent observers.Results: One hundred twenty-two hip prostheses were analyzed (74 cemented, 30 cementless, and 18 hybrids). The average time from prosthesis implantation to pelvic radiograph was comparable among groups. PO was observed in 72 hips (59%). In 55% of cases, PO was detected on the femoral component, with a lower prevalence in RA (53%) vs AS (64.7%) and JCA (76.5%). Acetabular PO was more frequent in JCA patients (58.8%), compared with RA (11.6%) and OA (28.5%) patients (P = 0.0001 and P = 0.06, respectively). There was no significant association between the presence of PO and clinical, functional, or therapeutic features.Conclusion: The prevalence of PO was 59%, being more frequent at the femoral level. Larger studies must be carried out to determine the clinical significance of radiologic PO.Keywords: periprosthetic osteolysis, hip prosthesis, rheumatoid arthritis, juvenile chronic arthritis, ankylosing spondylitis Minimize

Publisher:

Dove Press

Contributors:

Perez Alamino R, Casellini C, BaÅˆos A, Schneeberger EE, Gagliardi SA, Maldonado Cocco JA, Citera G

Year of Publication:

2012-06-06

Source:

http://www.dovepress.com/prevalence-of-periprosthetic-osteolysis-after-total-hip-replacement-in-peer-reviewed-article-OARRR

http://www.dovepress.com/prevalence-of-periprosthetic-osteolysis-after-total-hip-replacement-in-peer-reviewed-article-OARRR Minimize

Language:

English

Subjects:

Open Access Rheumatology: Research and Reviews

Open Access Rheumatology: Research and Reviews Minimize

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Title:

The Arabidopsis lyrata genome sequence and the basis of rapid genome size change

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Hu, Tina T.; Pattyn, Pedro; Bakker, Erica G.; Cao, Jun; Cheng, Jan-Fang; Clark, Richard M.; Fahlgren, Noah; Fawcett, Jeffrey A.; Grimwood, Jane; Gundlach, Heidrun; Haberer, Georg; Hollister, Jesse D.; Ossowski, Stephan; Ottilar, Robert P.; Salamov, Asaf A.; Schneeberger, Korbinian; Spannagl, Manuel; Wang, Xi; Yang, Liang; Nasrallah, Mikhail E.; Bergelson, Joy; Carrington, James C.; Gaut, Brandon S.; Schmutz, Jeremy; Mayer, Klaus F. X.; Van de Peer, Yves; Grigoriev, Igor V.; Nordborg, Magnus; Weigel, Detlef; Guo, Ya-Long Minimize authors

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In our manuscript, we present a high-quality genome sequence of the Arabidopsis thaliana relative, Arabidopsis lyrata, produced by dideoxy sequencing. We have performed the usual types of genome analysis (gene annotation, dN/dS studies etc. etc.), but this is relegated to the Supporting Information. Instead, we focus on what was a major motivati...

In our manuscript, we present a high-quality genome sequence of the Arabidopsis thaliana relative, Arabidopsis lyrata, produced by dideoxy sequencing. We have performed the usual types of genome analysis (gene annotation, dN/dS studies etc. etc.), but this is relegated to the Supporting Information. Instead, we focus on what was a major motivation for sequencing this genome, namely to understand how A. thaliana lost half its genome in a few million years and lived to tell the tale. The rather surprising conclusion is that there is not a single genomic feature that accounts for the reduced genome, but that every aspect centromeres, intergenic regions, transposable elements, gene family number is affected through hundreds of thousands of cuts. This strongly suggests that overall genome size in itself is what has been under selection, a suggestion that is strongly supported by our demonstration (using population genetics data from A. thaliana) that new deletions seem to be driven to fixation. Minimize

Year of Publication:

2011-11-03

Subjects:

99; ARABIDOPSIS; CENTROMERES; GENES; GENETICS

99; ARABIDOPSIS; CENTROMERES; GENES; GENETICS Minimize

DDC:

580 Plants (Botany) *(computed)*

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Title:

Quaternionic Computing

Author:

Description:

We introduce a model of computation based on quaternions, which is inspired on the quantum computing model. Pure states are vectors of a suitable linear space over the quaternions. Other aspects of the theory are the same as in quantum computing: superposition and linearity of the state space, unitarity of the transformations, and projective mea...

We introduce a model of computation based on quaternions, which is inspired on the quantum computing model. Pure states are vectors of a suitable linear space over the quaternions. Other aspects of the theory are the same as in quantum computing: superposition and linearity of the state space, unitarity of the transformations, and projective measurements. However, one notable exception is the fact that quaternionic circuits do not have a uniquely defined behaviour, unless a total ordering of evaluation of the gates is defined. Given such an ordering a unique unitary operator can be associated with the quaternionic circuit and a proper semantics of computation can be associated with it. The main result of this paper consists in showing that this model is no more powerful than quantum computing, as long as such an ordering of gates can be defined. More concretely we show, that for all quaternionic computation using n quaterbits, the behaviour of the circuit for each possible gate ordering can be simulated with n+1 qubits, and this with little or no overhead in circuit size. The proof of this result is inspired of a new simplified and improved proof of the equivalence of a similar model based on real amplitudes to quantum computing, which states that any quantum computation using n qubits can be simulated with n+1 rebits, and in this with no circuit size overhead. Beyond this potential computational equivalence, however, we propose this model as a simpler framework in which to discuss the possibility of a quaternionic quantum mechanics or information theory. In particular, it already allows us to illustrate that the introduction of quaternions might violate some of the ``natural'' properties that we have come to expect from physical models. ; Comment: Version 2: 32 pages, 8 PS figures. Ver 2 is a substantially revised version, which addresses a major problem with the previous version: the output of quaternionic circuits is in general ambiguous unless an total order of evaluation of gates is defined. The main complexity result is essentially unaffected. This version addresses this issue and discusses in detail the complexity and physical consequences of this "ambiguity" Minimize

Year of Publication:

2003-07-02

Document Type:

text

Subjects:

Quantum Physics ; Computer Science - Computational Complexity

Quantum Physics ; Computer Science - Computational Complexity Minimize

DDC:

190 Modern western philosophy *(computed)*

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Title:

Specific DNA Alterations Associated with the Environmental Induction of Heritable Changes in Flax

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Several flax varieties have been shown to undergo environmentally induced heritable changes resulting in stable lines termed genotrophs. The most notable of these is the variety Stormont Cirrus, also termed ``plastic'' or Pl. A number of morphological, biochemical and genetic differences are associated with environmental induction of heritable c...

Several flax varieties have been shown to undergo environmentally induced heritable changes resulting in stable lines termed genotrophs. The most notable of these is the variety Stormont Cirrus, also termed ``plastic'' or Pl. A number of morphological, biochemical and genetic differences are associated with environmental induction of heritable changes in flax. We have studied 5S rDNA alterations as a model system for understanding environmental induction of heritable changes in flax. This paper reports the isolation of a flax 5S rRNA gene variant which identifies genotroph specific restriction fragment length polymorphisms (RFLPs) in flax. Restriction fragment patterns for several enzymes were observed in both large and small genotrophs which consistently differed from the progenitor, Stormont Cirrus. Identical RFLP profiles for all restriction endonucleases tested were observed in four small genotrophs produced from separate environmental induction experiments. Comparison between Stormont Cirrus and these small genotrophs showed at least six differing bands in addition to several high molecular weight polymorphisms. Genetic data indicate that the polymorphisms were all produced from a repetitive 5S rRNA gene cluster at a single chromosomal locus. Similar, but not identical, polymorphisms are also detected in other flax varieties and Linum species suggesting that the induced variation is related to that which occurs naturally. The results are evidence that a specific set of DNA alterations occur in association with the induction of heritable changes in flax. This is the first genetic marker which is altered to an identical state in one type of genotroph. The results are discussed with respect to mechanisms for environmentally induced heritable change in plants. Minimize

Year of Publication:

1991-07

Document Type:

Text

Language:

en

Subjects:

Investigations

Investigations Minimize

DDC:

580 Plants (Botany) *(computed)*

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Title:

Increased susceptibility of magnesium-deficient rats to a phosphate-induced nephropathy.

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Year of Publication:

1967-04

Document Type:

Text

Language:

en

Subjects:

Research Article

Research Article Minimize

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Title:

Immune Profile Predicts Survival and Reflects Senescence in a Small, Long-Lived Mammal, the Greater Sac-Winged Bat (Saccopteryx bilineata)

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The immune system imposes costs that may have to be traded against investment of resources in other costly life-history traits. Yet, it is unknown if a trade-off between immunity and longevity occurs in free-ranging mammals. Here, we tested if age and survival, two aspects associated with longevity, are linked to immune parameters in an 8 g bat ...

The immune system imposes costs that may have to be traded against investment of resources in other costly life-history traits. Yet, it is unknown if a trade-off between immunity and longevity occurs in free-ranging mammals. Here, we tested if age and survival, two aspects associated with longevity, are linked to immune parameters in an 8 g bat species. Using a combination of cross-sectional and longitudinal data, we assessed whether total white blood cell (WBC) counts, bacterial killing ability of the plasma (BKA) and immunoglobulin G (IgG) concentration change with age. Furthermore, we asked if these immune parameters impose costs resulting in decreased survival probabilities. We found that WBC counts decreased with age both within and among individuals. IgG concentrations were higher in older individuals, but did not change with age within individuals. Furthermore, individuals with above average WBC counts or IgG concentration had lower probabilities to survive the next six months. High WBC counts and IgG concentrations may reflect infections with parasites and pathogens, however, individuals that were infected with trypanosomes or nematodes showed neither higher WBC counts or IgG concentrations, nor was infection connected with survival rates. BKA was higher in infected compared with uninfected bats, but not related to age or survival. In conclusion, cellular (WBC) and humoral (IgG) parts of the immune system were both connected to age and survival, but not to parasite infections, which supports the hypothesis that energetically costly immunological defences are traded against other costly life-history traits, leading to a reduced lifespan in this free-ranging mammal. Minimize

Publisher:

Freie Universität Berlin Universitätsbibliothek, Garystr. 39, 14195 Berlin

Year of Publication:

2014-12-16

Document Type:

doc-type:article

Language:

eng

Subjects:

630 Landwirtschaft ; Veterinärmedizin ; ddc:630 ; 630 Agriculture ; Veterinary medicine

630 Landwirtschaft ; Veterinärmedizin ; ddc:630 ; 630 Agriculture ; Veterinary medicine Minimize

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enses/by/4.0/"> This work is licensed under a Creative Commons Attribution 4.0

enses/by/4.0/"> This work is licensed under a Creative Commons Attribution 4.0 Minimize

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Title:

Immune Profile Predicts Survival and Reflects Senescence in a Small, Long-Lived Mammal, the Greater Sac-Winged Bat (Saccopteryx bilineata)

Author:

Description:

The immune system imposes costs that may have to be traded against investment of resources in other costly life-history traits. Yet, it is unknown if a trade-off between immunity and longevity occurs in free-ranging mammals. Here, we tested if age and survival, two aspects associated with longevity, are linked to immune parameters in an 8 g bat ...

The immune system imposes costs that may have to be traded against investment of resources in other costly life-history traits. Yet, it is unknown if a trade-off between immunity and longevity occurs in free-ranging mammals. Here, we tested if age and survival, two aspects associated with longevity, are linked to immune parameters in an 8 g bat species. Using a combination of cross-sectional and longitudinal data, we assessed whether total white blood cell (WBC) counts, bacterial killing ability of the plasma (BKA) and immunoglobulin G (IgG) concentration change with age. Furthermore, we asked if these immune parameters impose costs resulting in decreased survival probabilities. We found that WBC counts decreased with age both within and among individuals. IgG concentrations were higher in older individuals, but did not change with age within individuals. Furthermore, individuals with above average WBC counts or IgG concentration had lower probabilities to survive the next six months. High WBC counts and IgG concentrations may reflect infections with parasites and pathogens, however, individuals that were infected with trypanosomes or nematodes showed neither higher WBC counts or IgG concentrations, nor was infection connected with survival rates. BKA was higher in infected compared with uninfected bats, but not related to age or survival. In conclusion, cellular (WBC) and humoral (IgG) parts of the immune system were both connected to age and survival, but not to parasite infections, which supports the hypothesis that energetically costly immunological defences are traded against other costly life-history traits, leading to a reduced lifespan in this free-ranging mammal. Minimize

Publisher:

Public Library of Science

Year of Publication:

2014-09-25

Document Type:

Text

Language:

en

Subjects:

Research Article

Research Article Minimize

Rights:

This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Minimize

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