Causal contribution and dynamical encoding in the striatum during evidence accumulation.

A broad range of decision-making processes involve gradual accumulation of evidence over time, but the neural circuits responsible for this computation are not yet established. Recent data indicate that cortical regions that are prominently associated with accumulating evidence, such as the posterior parietal cortex and the frontal orienting fields, may not be directly involved in this computation. Which, then, are the regions involved? Regions that are directly involved in evidence accumulation should directly influence the accumulation-based decision-making behavior, have a graded neural encoding of accumulated evidence and contribute throughout the accumulation process. Here, we investigated the role of the anterior dorsal striatum (ADS) in a rodent auditory evidence accumulation task using a combination of behavioral, pharmacological, optogenetic, electrophysiological and computational approaches. We find that the ADS is the first brain region known to satisfy the three criteria. Thus, the ADS may be the first identified node in the network responsible for evidence accumulation

Coherent Control of Causal Order of Entanglement Distillation

We present an application of indefinite causal order in quantum communication: a compound entanglement distillation protocol which features two steps of a basic distillation protocol applied in a coherent superposition of two causal orders. This is achieved by using one faulty entangled pair to control-swap two others before a fourth pair is combined with the two swapped ones consecutively. As a result, the protocol distills the four faulty entangled states into one of a higher fidelity. Our protocol has a higher fidelity of distillation and probability of success for some input faulty pairs than conventional concatenations of the basic protocol that follow a definite distillation order. Our proposal shows advantage of indefinite causal order in an application setting consistent with the requirements of quantum communication

Noise-tailored Constructions for Spin Wigner Function Kernels

The effective use of noisy intermediate-scale quantum devices requires error mitigation to improve the accuracy of sampled measurement distributions. The more accurately the effects of noise on these distributions can be modeled, the more closely error mitigation will be able to approach theoretical bounds. The characterisation of noisy quantum channels and the inference of their effects on general observables are challenging problems, but in many cases a change in representation can greatly simplify the analysis. Here, we investigate spin Wigner functions for multi-qudit systems. We generalise previous kernel constructions, capturing the effects of several probabilistic unitary noise models in few parameters

Non-Pauli errors can be efficiently sampled in qudit surface codes

Surface codes are the most promising candidates for fault-tolerant quantum computation. Single qudit errors are typically modelled as Pauli operators, to which general errors are converted via randomizing methods. In this Letter, we quantify remaining correlations after syndrome measurement for a qudit 2D surface code subject to non-Pauli errors. Using belief propagation and percolation theory, we relate correlations to loops on the lattice. Below the error correction threshold, remaining correlations are sparse and locally constrained. Syndromes for qudit surface codes are therefore efficiently samplable for non-Pauli errors, independent of the exact forms of the error and decoder.Comment: Main text 6 pages, 4 figures, Supplemental Material 6 pages, 7 figure

Recognizing and Extracting Cybersecurtity-relevant Entities from Text

Cyber Threat Intelligence (CTI) is information describing threat vectors, vulnerabilities, and attacks and is often used as training data for AI-based cyber defense systems such as Cybersecurity Knowledge Graphs (CKG). There is a strong need to develop community-accessible datasets to train existing AI-based cybersecurity pipelines to efficiently and accurately extract meaningful insights from CTI. We have created an initial unstructured CTI corpus from a variety of open sources that we are using to train and test cybersecurity entity models using the spaCy framework and exploring self-learning methods to automatically recognize cybersecurity entities. We also describe methods to apply cybersecurity domain entity linking with existing world knowledge from Wikidata. Our future work will survey and test spaCy NLP tools and create methods for continuous integration of new information extracted from text

ABC transporter FtsABCD of Streptococcus pyogenes mediates uptake of ferric ferrichrome

BACKGROUND: The Streptococcus pyogenes or Group A Streptococcus (GAS) genome encodes three ABC transporters, namely, FtsABCD, MtsABC, and HtsABC, which share homology with iron transporters. MtsABC and HtsABC are believed to take up ferric (Fe(3+)) and manganese ions and heme, respectively, while the specificity of FtsABCD is unknown. RESULTS: Recombinant FtsB, the lipoprotein component of FtsABCD, was found to bind Fe(3+ )ferrichrome in a 1:1 stoichiometry. To investigate whether FtsABCD transports Fe(3+ )ferrichrome, GAS isogenic strains defective in lipoprotein gene ftsB and permease gene ftsC were generated, and the effects of the mutations on uptake of Fe(3+ )ferrichrome were examined using radioactive (55)Fe(3+ )ferrichrome. FtsB was produced in the wild-type strain but not in the ftsB mutant, confirming the ftsB inactivation. While wild-type GAS took up 3.6 × 10(4 )Fe(3+ )ferrichrome molecules per bacterium per min at room temperature, the ftsB and ftsC mutants did not have a detectable rate of Fe(3+ )ferrichrome uptake. The inactivation of ftsB or ftsC also decreased (55)Fe(3+ )ferrichrome uptake by >90% under growth conditions in the case of limited uptake time. Complementation of the ftsB mutant with a plasmid carrying the ftsB gene restored FtsB production and (55)Fe(3+ )ferrichrome association at higher levels compared with the parent strain. The inactivation of mtsA and htsA and Fe-restricted conditions enhanced the production of FtsB and Fe(3+ )ferrichrome uptake. CONCLUSION: The FtsB protein bound Fe(3+ )ferrichrome, and inactivation of ftsB or ftsC, but not htsA or mtsA, diminished Fe(3+ )ferrichrome uptake, indicating that FtsABCD, but not HtsABC and MtsABC, is the transporter that takes up Fe(3+ )ferrichrome in GAS. Fe acquisition systems are virulence factors in many bacterial pathogens and are attractive vaccine candidates. The elucidation of the FtsABCD specificity advances the understanding of Fe acquisition processes in GAS and may help evaluating the GAS Fe acquisition systems as vaccine candidates