787 research outputs found
Generating Einstein gravity, cosmological constant and Higgs mass from restricted Weyl invariance
Recently, it has been pointed out that dimensionless actions in four
dimensional curved spacetime possess a symmetry which goes beyond scale
invariance but is smaller than full Weyl invariance. This symmetry was dubbed
{\it restricted Weyl invariance}. We show that starting with a restricted Weyl
invariant action that includes a Higgs sector with no explicit mass, one can
generate the Einstein-Hilbert action with cosmological constant and a Higgs
mass. The model also contains an extra massless scalar field which couples to
the Higgs field (and gravity). If the coupling of this extra scalar field to
the Higgs field is negligibly small, this fixes the coefficient of the
nonminimal coupling between the Higgs field and gravity. Besides the
Higgs sector, all the other fields of the standard model can be incorporated
into the original restricted Weyl invariant action.Comment: 7 pages, no figure
Artificial Itelligence Teaches Drugs to Target Proteins by Tackling the Induced Folding Problem
We explore the possibility of a deep learning (DL) platform that steers drug design to target proteins by inducing binding-competent conformations. We deal with the fact that target proteins are usually not fixed targets but structurally adapt to the ligand in ways that need to be predicted to enable pharmaceutical discovery. In contrast with protein folding predictors, the proposed DL system integrates signals for structural disorder to predict conformations in floppy regions of the target protein that rely on associations with the purposely designed drug to maintain their structural integrity. This is tantamount to solve the drug-induced folding problem within an AI-empowered drug discovery platform. Preliminary testing of the proposed DL platform reveals that it is possible to infer the induced folding ensemble from which a therapeutically targetable conformation gets selected by DL-instructed drug design.Fil: Fernandez, Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentin
The logistic map and the birth of period-3 cycle
The goal of this paper is to present a proof that for the logistic map the period-3 begins at . The third-iterate map is the key for understanding the birth of the period-3 cycle. Any point in a period-3 cycle repeats every three iterates by definition. Such points satisfy the condition ,and they are therefore fixed points of the third-iterate map. This fact and the so called tangent bifurcation for the logistic map, as well as the fixed points definition, are used for finding the value. The algebraic treatment utilizes some properties of symmetric polynomials in three variables. For the purposes of this paper, the bifurcation diagram for the logistic map is also presented, as well as a program in Mathematica for its construction
Targeted Deletion of PTEN in Kisspeptin Cells Results in Brain Region- and Sex-Specific Effects on Kisspeptin Expression and Gonadotropin Release
Kisspeptin-expressing neurons in the anteroventral periventricular nucleus (AVPV) and
the arcuate nucleus (ARC) of the hypothalamus relay hormonal and metabolic information to
gonadotropin-releasing hormone neurons, which in turn regulate pituitary and gonadal function.
Phosphatase and tensin homolog (PTEN) blocks phosphatidylinositol 3-kinase (PI3K), a signaling
pathway utilized by peripheral factors to transmit their signals. However, whether PTEN signaling
in kisspeptin neurons helps to integrate peripheral hormonal cues to regulate gonadotropin release is
unknown. To address this question, we generated mice with a kisspeptin cell-specific deletion of
Pten (Kiss-PTEN KO), and first assessed kisspeptin protein expression and gonadotropin release in
these animals. Kiss-PTEN KO mice displayed a profound sex and region-specific kisspeptin neuron
hyperthrophy. We detected both kisspeptin neuron hyperthrophy as well as increased kisspeptin fiber
densities in the AVPV and ARC of Kiss-PTEN KO females and in the ARC of Kiss-PTEN KO males.
Moreover, Kiss-PTEN KO mice showed a reduced gonadotropin release in response to gonadectomy.
We also found a hyperactivation of mTOR, a downstream PI3K target and central regulator of cell
metabolism, in the AVPV and ARC of Kiss-PTEN KO females but not males. Fasting, known to inhibit
hypothalamic kisspeptin expression and luteinizing hormone levels, failed to induce these changes in
Kiss-PTEN KO females. We conclude that PTEN signaling regulates kisspeptin protein synthesis in
both sexes and that its role as a metabolic signaling molecule in kisspeptin neurons is sex-specific
Conclave: secure multi-party computation on big data (extended TR)
Secure Multi-Party Computation (MPC) allows mutually distrusting parties to
run joint computations without revealing private data. Current MPC algorithms
scale poorly with data size, which makes MPC on "big data" prohibitively slow
and inhibits its practical use.
Many relational analytics queries can maintain MPC's end-to-end security
guarantee without using cryptographic MPC techniques for all operations.
Conclave is a query compiler that accelerates such queries by transforming them
into a combination of data-parallel, local cleartext processing and small MPC
steps. When parties trust others with specific subsets of the data, Conclave
applies new hybrid MPC-cleartext protocols to run additional steps outside of
MPC and improve scalability further.
Our Conclave prototype generates code for cleartext processing in Python and
Spark, and for secure MPC using the Sharemind and Obliv-C frameworks. Conclave
scales to data sets between three and six orders of magnitude larger than
state-of-the-art MPC frameworks support on their own. Thanks to its hybrid
protocols, Conclave also substantially outperforms SMCQL, the most similar
existing system.Comment: Extended technical report for EuroSys 2019 pape
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