665 research outputs found
All you need is spin: SU(2) equivariant variational quantum circuits based on spin networks
Variational algorithms require architectures that naturally constrain the
optimisation space to run efficiently. In geometric quantum machine learning,
one achieves this by encoding group structure into parameterised quantum
circuits to include the symmetries of a problem as an inductive bias. However,
constructing such circuits is challenging as a concrete guiding principle has
yet to emerge. In this paper, we propose the use of spin networks, a form of
directed tensor network invariant under a group transformation, to devise SU(2)
equivariant quantum circuit ans\"atze -- circuits possessing spin rotation
symmetry. By changing to the basis that block diagonalises SU(2) group action,
these networks provide a natural building block for constructing parameterised
equivariant quantum circuits. We prove that our construction is mathematically
equivalent to other known constructions, such as those based on twirling and
generalised permutations, but more direct to implement on quantum hardware. The
efficacy of our constructed circuits is tested by solving the ground state
problem of SU(2) symmetric Heisenberg models on the one-dimensional triangular
lattice and on the Kagome lattice. Our results highlight that our equivariant
circuits boost the performance of quantum variational algorithms, indicating
broader applicability to other real-world problems.Comment: 36+14 page
Characterization of a Functional NTPDase in the Endoplasmic Reticulum of Rat Submandibular Salivary Gland
Nucleotidase activity and Ca-uptake were characterized in endoplasmic reticulum (ER) enriched rat submandibular gland (SMG) microsomal preparations. (i) Ca-uptake had characteristics of an ER Ca-ATPase. (ii) Nucleotidase activity was equally stimulated by calcium, magnesium and manganese, but with different Km values. (iii) Specific inhibitors of P-type Ca-ATPases were ineffective on nucleotidase activity, demonstrating that this activity was not related to calcium uptake and did not correspond to classical Ca2+ pumps. (iv) ATP and UTP were more efficient substrates, whereas ADP and UDP were hydrolyzed at significantly slower rate. (v) Nucleotidase activity was sensitive to mild detergent solubilization and insensitive to ionophore addition. (vi) Nucleotidase activity was strongly inhibited by suramin, a nucleoside triphosphate diphosphohydrolase (NTPDase) inhibitor. (vii) Nucleotidase activity exponentially diminished as function of time. All these observations are consistent with a NTPDase identity. The presence of a NTPDase was demonstrated by immunohistochemistry in rat SMG. Immunoreactivity was stronger in ductal cells than in mucous and serous acini. Although this enzyme was observed in the plasma membrane, colocalization with the ER marker calnexin revealed a specific subcellular localization in this organelle of all three types of cell. The putative function of this NTPDase activity in salivary glands is discussed.Fil: Ostuni, M. A.. Inserm; Francia. UniversitĂ© Paris; Francia. Universidad de Buenos Aires. Facultad de OdontologĂa; ArgentinaFil: Egido, P.. Universidad de Buenos Aires. Facultad de OdontologĂa; ArgentinaFil: Peranzi, G.. Inserm; Francia. UniversitĂ© Paris; FranciaFil: Alonso, Guillermo Luis. Universidad de Buenos Aires. Facultad de OdontologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Lacapere, J. J.. Inserm; Francia. UniversitĂ© Paris; FranciaFil: Gonzalez, D. A.. Inserm; Francia. UniversitĂ© Paris; Franci
Automatic Generators for a Family of Matrix Multiplication Routines with Apache TVM
We explore the utilization of the Apache TVM open source framework to
automatically generate a family of algorithms that follow the approach taken by
popular linear algebra libraries, such as GotoBLAS2, BLIS and OpenBLAS, in
order to obtain high-performance blocked formulations of the general matrix
multiplication (GEMM). % In addition, we fully automatize the generation
process, by also leveraging the Apache TVM framework to derive a complete
variety of the processor-specific micro-kernels for GEMM. This is in contrast
with the convention in high performance libraries, which hand-encode a single
micro-kernel per architecture using Assembly code. % In global, the combination
of our TVM-generated blocked algorithms and micro-kernels for GEMM 1)~improves
portability, maintainability and, globally, streamlines the software life
cycle; 2)~provides high flexibility to easily tailor and optimize the solution
to different data types, processor architectures, and matrix operand shapes,
yielding performance on a par (or even superior for specific matrix shapes)
with that of hand-tuned libraries; and 3)~features a small memory footprint.Comment: 35 pages, 22 figures. Submitted to ACM TOM
Compatison of S-SI, A-SI and CDTE technologies wording at the same conditions, after the first year of electricity production
Grid connected solar plants are a good opportunity for their use for research as a secondary objective. In countries were feed-in tariffs are still active, it is possible to include in the design of the solar plant elements for its use for research. In the case of the solar plant presented here both objectives are covered. The solar plant of this work is formed by PV modules of three different technologies: Multicrystalline, amorphous and CdTe. In one part of the solar plant, the three technologies are working at the same conditions, not only ambient conditions but also similar voltage and current input to the inverters. Both the commercial and the experimental parts of the solar plant have their own independent inverters with their meters but are finally connected to the same meter to inject. In this work we analyse the results for the first year of operation of the experimental solar plant. Productions of three different technologies in exactly the same conditions are compared and presented. According to the results, all the three technologies have conversion efficiencies dropping when the temperature increases. Amorphous module experiences the lesser reduction, whereas the multicrystalline module suffers the most
Selective pressure against horizontally acquired prokaryotic genes as a driving force of plastid evolution
Altres ajuts: del Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas- Argentina (CONICET) i del Programa Iberoamericano de Ciencia y TecnologĂa para el Desarrollo (IBERCAROT).The plastid organelle comprises a high proportion of nucleus-encoded proteins that were acquired from different prokaryotic donors via independent horizontal gene transfers following its primary endosymbiotic origin. What forces drove the targeting of these alien proteins to the plastid remains an unresolved evolutionary question. To better understand this process we screened for suitable candidate proteins to recapitulate their prokaryote-to-eukaryote transition. Here we identify the ancient horizontal transfer of a bacterial polyphenol oxidase (PPO) gene to the nuclear genome of an early land plant ancestor and infer the possible mechanism behind the plastidial localization of the encoded enzyme. Arabidopsis plants expressing PPO versions either lacking or harbouring a plastid-targeting signal allowed examining fitness consequences associated with its subcellular localization. Markedly, a deleterious effect on plant growth was highly correlated with PPO activity only when producing the non-targeted enzyme, suggesting that selection favoured the fixation of plastid-targeted protein versions. Our results reveal a possible evolutionary mechanism of how selection against heterologous genes encoding cytosolic proteins contributed in incrementing plastid proteome complexity from non-endosymbiotic gene sources, a process that may also impact mitochondrial evolution
Toward a clinical practice guide in pharmacogenomics testing for functional polymorphisms of drug-metabolizing enzymes. Gene/drug pairs and barriers perceived in Spain
The development of clinica lpractice recommendations or
guidelines for the clinical use of biomarkers is an issue of great importance withr regard to adverse drug reactions.The poten-tial of pharmacogenomicbiomarkers has been extensively investigated in recent years.However,several barriers to implementing the use of pharmacogenomics testing exist.We conducted a survey among members of the Spanish Societies of Pharmacology and Clinical Pharmacology to obtain information about the perception of such barriers and to compare the perceptions of participants about the relative importance of majorgene/drug pairs.Of 11 potential barriers,the highest importance was attributed to lack of institutional support for pharmacogenomic stesting,and to the issues related to the lack of guidelines.Of the proposed gene/drug pairs the highest importance was assigned to HLA-B/abacavir, UGT1A1/irinotecan, and CYP2D6/tamoxifen.In this perspective article,we compare the relative importance of 29 gene/drugpairs in the Spanish study with that of the same pairs in the American Society for Clinical Pharmacology and Therapeutic sstudy,and we provide suggestions and areas of focus to develop a guide for clinical practice in pharmacogenomics testingThe work in the authorâs laboratory is financed by Grants
PS09/00943, PS09/00469, RETICS RIRAAF RD07/0064/0016,
and CIBERehd from Instituto de Salud CarlosIII,Madrid,
Spain, and by Grants GR10068 from Junta de Extremadura,
Spain. Financed in part with FEDER funds from the European
Unio
The Spectroscopic Orbit of the Planetary Companion Transiting HD209458
We report a spectroscopic orbit with period P = 3.52433 +/- 0.00027 days for
the planetary companion that transits the solar-type star HD209458. For the
metallicity, mass, and radius of the star we derive [Fe/H] = 0.00 +/- 0.02, M =
1.1 +/- 0.1 solar masses, and R = 1.3 +/- 0.1 solar radii. This is based on a
new analysis of the iron lines in our HIRES template spectrum, and also on the
absolute magnitude and color of the star, and uses isochrones from four
different sets of stellar evolution models. Using these values for the stellar
parameters we reanalyze the transit data and derive an orbital inclination of i
= 85.2 +/- 1.4 degrees. For the planet we derive a mass of Mp = 0.69 +/- 0.05
Jupiter masses, a radius of Rp = 1.54 +/- 0.18 Jupiter radii, and a density of
0.23 +/- 0.08 grams per cubic cm.Comment: 11 pages, 1 figure, 2 tables, LaTex, aastex, accepted for publication
by ApJ Letter
Phase separation and enhanced charge-spin coupling near magnetic transitions
The generic changes of the electronic compressibility in systems which show
magnetic instabilities is studied. It is shown that, when going into the
ordered phase, the compressibility is reduced by an amount comparable to the
its original value, making charge instabilities also possible. We discuss,
within this framework, the tendency towards phase separation of the double
exchange systems, the pyrochlores, and other magnetic materials
Nanoinformatics: developing new computing applications for nanomedicine
Nanoinformatics has recently emerged to address the need of computing applications at the nano level. In this regard, the authors have participated in various initiatives to identify its concepts, foundations and challenges. While nanomaterials open up the possibility for developing new devices in many industrial and scientific areas, they also offer breakthrough perspectives for the prevention, diagnosis and treatment of diseases. In this paper, we analyze the different aspects of nanoinformatics and suggest five research topics to help catalyze new research and development in the area, particularly focused on nanomedicine. We also encompass the use of informatics to further the biological and clinical applications of basic research in nanoscience and nanotechnology, and the related concept of an extended ?nanotype? to coalesce information related to nanoparticles. We suggest how nanoinformatics could accelerate developments in nanomedicine, similarly to what happened with the Human Genome and other -omics projects, on issues like exchanging modeling and simulation methods and tools, linking toxicity information to clinical and personal databases or developing new approaches for scientific ontologies, among many others
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