Von Neumann Entropy from Unitarity.

The von Neumann entropy is a key quantity in quantum information theory and, roughly speaking, quantifies the amount of quantum information contained in a state when many identical and independent (i.i.d.) copies of the state are available, in a regime that is often referred to as being asymptotic. In this Letter, we provide a new operational characterization of the von Neumann entropy which neither requires an i.i.d. limit nor any explicit randomness. We do so by showing that the von Neumann entropy fully characterizes single-shot state transitions in unitary quantum mechanics, as long as one has access to a catalyst-an ancillary system that can be reused after the transition-and an environment which has the effect of dephasing in a preferred basis. Building upon these insights, we formulate and provide evidence for the catalytic entropy conjecture, which states that the above result holds true even in the absence of decoherence. If true, this would prove an intimate connection between single-shot state transitions in unitary quantum mechanics and the von Neumann entropy. Our results add significant support to recent insights that, contrary to common wisdom, the standard von Neumann entropy also characterizes single-shot situations and opens up the possibility for operational single-shot interpretations of other standard entropic quantities. We discuss implications of these insights to readings of the third law of quantum thermodynamics and hint at potentially profound implications to holography.

Bacterial pathogens and antimicrobial resistance in acute otitis media.

INTRODUCTION: Recent studies show an increase in the prevalence of Haemophilus influenzae and a decrease in Streptococcus pneumoniae among the bacteria that cause acute otitis media (AOM). The objective of our study was to analyse the distribution of pathogens identified in children aged less than 14 years presenting to the emergency department with AOM and their patterns of antimicrobial resistance. PATIENTS AND METHODS: Single centre retrospective, analytical study in patients aged less than 14 years with a diagnosis of AOM in whom an ear drainage sample was collected for culture in the paediatric emergency department of a tertiary care hospital between 2013 and 2021. RESULTS: During the study period, there were 14 684 documented care episodes corresponding to children with a diagnosis of AOM. An ear drainage culture was performed in 768 of those episodes. The median age of the patients was 2 years, 57% were male and 70% had a previous history of AOM. The most frequently isolated pathogens were: Haemophilus influenzae (n = 188 [24.5%]; 15.5% of them resistant to ampicillin), Streptococcus pyogenes (n = 86 [11.2%]), Staphylococcus aureus (n = 82 [10.7%]), Streptococcus pneumoniae (n = 54 [6.9%]; 9.4% with intermediate resistance to penicillin), Pseudomonas aeruginosa (n = 42 [5.5%]) and Moraxella catarrhalis (n = 11 [1.4%]). No pathogen was isolated in 34.9% of cases. CONCLUSIONS: Haemophilus influenzae is the leading cause of AOM in children aged less than 14 years. This, combined with the low frequency of isolation and penicillin resistance of Streptococcus pneumoniae, calls into question the appropriateness of high-dose amoxicillin for empiric treatment of AOM.

Operational framework for nonlocality.

Because of the importance of entanglement for quantum information purposes, a framework has been developed for its characterization and quantification as a resource based on the following operational principle: entanglement among N parties cannot be created by local operations and classical communication, even when N-1 parties collaborate. More recently, nonlocality has been identified as another resource, alternative to entanglement and necessary for device-independent quantum information protocols. We introduce an operational framework for nonlocality based on a similar principle: nonlocality among N parties cannot be created by local operations and allowed classical communication even when N-1 parties collaborate. We then show that the standard definition of multipartite nonlocality, due to Svetlichny, is inconsistent with this operational approach: according to it, genuine tripartite nonlocality could be created by two collaborating parties. We finally discuss alternative definitions for which consistency is recovered.

Fully nonlocal, monogamous, and random genuinely multipartite quantum correlations.

Local measurements on bipartite maximally entangled states can yield correlations that are maximally nonlocal, monogamous, and with fully random outcomes. This makes these states ideal for bipartite cryptographic tasks. Genuine-multipartite nonlocality constitutes a stronger notion of nonlocality in the multipartite case. Maximal genuine-multipartite nonlocality, monogamy, and random outcomes are thus highly desired properties for genuine-multipartite cryptographic scenarios. We prove that local measurements on any Greenberger-Horne-Zeilinger state can produce correlations that are fully genuine-multipartite nonlocal, monogamous, and with fully random outcomes. A key ingredient in our proof is a multipartite chained Bell inequality detecting genuine-multipartite nonlocality, which we introduce. Finally, we discuss applications to device-independent secret sharing.

Quantum correlations require multipartite information principles.

Identifying which correlations among distant observers are possible within our current description of nature, based on quantum mechanics, is a fundamental problem in physics. Recently, information concepts have been proposed as the key ingredient to characterize the set of quantum correlations. Novel information principles, such as information causality or nontrivial communication complexity, have been introduced in this context and successfully applied to some concrete scenarios. We show in this work a fundamental limitation of this approach: no principle based on bipartite information concepts is able to singleout the set of quantum correlations for an arbitrary number of parties. Our results reflect the intricate structure of quantum correlations and imply that new and intrinsically multipartite information concepts are needed for their full understanding.

Treatment of wastewater effluents from Bogotá - Colombia by the photo-electro-Fenton process: Elimination of bacteria and pharmaceutical.

In this work, the occurrences of bacteria families and relevant pharmaceuticals in municipal wastewater effluents from Bogotá (Colombia), and their treatment by the photo-electro-Fenton process were studied. Twenty-five representative pharmaceuticals (azithromycin, carbamazepine, ciprofloxacin, clarithromycin, diclofenac, enalapril, gabapentin, iopromide, metoprolol, sulfamethoxazole, trimethoprim, valsartan, clindamycin, erythromycin, levamisole, lincomycin, norfloxacin, oxolinic acid, phenazone, primidone, salbutamol, sulfadiazine, tetracycline, tramadol, and venlafaxine) were quantified in the effluent by LC-MS/MS analysis. Four of these target compounds (azithromycin, diclofenac, trimethoprim, norfloxacin) were found at concentrations that represent an environmental risk. In addition, several bacteria families related to water and foodborne diseases were identified in such effluents (e.g., Pseudomonadaceae, Campylobacteraceae, Aeromonadaceae, Enterobacteriaceae, and Bacteroidaceae), via shotgun-metagenomic technique. Then, a bench-scale photo-electro-Fenton (PEF) system equipped with a DSA anode (Ti/IrO2-SnO2) and a GDE cathode was applied to treat such effluents. After 60 min, this treatment led to a decrease in the ratio of the bacterial content in the original samples, ~150 thousand times, and a pondered removal of 66.12% for the pharmaceuticals. The study of the process pathways indicated that the bacteria and pharmaceuticals elimination mainly occurred through attacks of hydroxyl and chlorine radicals. Interestingly, in the case of pharmaceuticals, their environmental risk quotients were diminished after the PEF application. Furthermore, the prolonged action of this electrochemical process induced ~15% of mineralization and a significant reduction of the total DNA (removal >85%). Hence, the photo-electro-Fenton process showed to be a promising alternative to deal with municipal effluents for limiting the waterborne diseases, pollution by pharmaceuticals, and mobility/availability of genetic material coming from microorganisms.

Device-independent tests of classical and quantum dimensions.

We address the problem of testing the dimensionality of classical and quantum systems in a "black-box" scenario. We develop a general formalism for tackling this problem. This allows us to derive lower bounds on the classical dimension necessary to reproduce given measurement data. Furthermore, we generalize the concept of quantum dimension witnesses to arbitrary quantum systems, allowing one to place a lower bound on the Hilbert space dimension necessary to reproduce certain data. Illustrating these ideas, we provide simple examples of classical and quantum dimension witnesses.

Patógenos bacterianos y resistencia a los antibióticos en otitis media aguda / Bacterial pathogens and antimicrobial resistance in acute otitis media

Introducción: Estudios recientes señalan un aumento de la prevalencia de Haemophilus influenzae y una disminución de Streptococcus pneumoniae entre las bacterias causantes de otitis media aguda (OMA). El objetivo del estudio es conocer la distribución de microorganismos patógenos identificados en Urgencias en los menores de 14 años con OMA y su patrón de resistencias. Pacientes y métodos: Estudio retrospectivo, analítico y unicéntrico incluyendo pacientes menores de 14 años diagnosticados de OMA en los que se recogió un cultivo de secreción ótica en el servicio de urgencias pediátricas de un hospital terciario entre 2013 y 2021. Resultados: Durante el periodo de estudio se registraron 14.684 episodios con diagnóstico de OMA, recogiéndose en 768 cultivo de secreción ótica. La mediana de edad fue de 2 años, el 57% varones y el 70% habían presentado al menos una OMA previa. Los patógenos más frecuentemente aislados fueron: Haemophilus influenzae, 188 (24,5%; de ellos, 15,5% resistentes a ampicilina); Streptococcus pyogenes, 86 (11,2%); Staphylococcus aureus, 82 (10,7%); Streptococcus pneumoniae, 54 (6,9%; de ellos, 9,4% con resistencia intermedia a penicilina); Pseudomonas aeruginosa, 42 (5,5%) y Moraxella catarrhalis, 11 (1,4%). En el 34,9% no se aislaron patógenos. Conclusiones: Haemophilus influenzae es la primera causa de OMA en menores de 14 años. Este hecho, junto a la baja tasa de aislamientos y resistencia a penicilina de Streptococcus pneumoniae, cuestiona la idoneidad de la amoxicilina a dosis elevadas como tratamiento antibiótico empírico de la OMA.(AU)

Introduction: Recent studies show an increase in the prevalence of Haemophilus influenzae and a decrease in Streptococcus pneumoniae among the bacteria that cause acute otitis media (AOM). The objective of our study was to analyse the distribution of pathogens identified in children aged less than 14 years presenting to the emergency department with AOM and their patterns of antimicrobial resistance. Patients and methods: Single centre retrospective, analytical study in patients aged less than 14 years with a diagnosis of AOM in whom an ear drainage sample was collected for culture in the paediatric emergency department of a tertiary care hospital between 2013 and 2021. Results: During the study period, there were 14,684 documented care episodes corresponding to children with a diagnosis of AOM. An ear drainage culture was performed in 768 of those episodes. The median age of the patients was 2 years, 57% were male and 70% had a previous history of AOM. The most frequently isolated pathogens were: Haemophilus influenzae (n=188 [24.5%]; 15.5% of them resistant to ampicillin), Streptococcus pyogenes (n=86 [11.2%]), Staphylococcus aureus (n=82 [10.7%]), Streptococcus pneumoniae (n=54 [6.9%]; 9.4% with intermediate resistance to penicillin), Pseudomonas aeruginosa (n=42 [5.5%]) and Moraxella catarrhalis (n=11 [1.4%]). No pathogen was isolated in 34.9% of cases. Conclusions: Haemophilus influenzae is the leading cause of AOM in children aged less than 14 years. This, combined with the low frequency of isolation and penicillin resistance of Streptococcus pneumoniae, calls into question the appropriateness of high-dose amoxicillin for empiric treatment of AOM.(AU)

Statistical ensembles without typicality.

Maximum-entropy ensembles are key primitives in statistical mechanics. Several approaches have been developed in order to justify the use of these ensembles in statistical descriptions. However, there is still no full consensus on the precise reasoning justifying the use of such ensembles. In this work, we provide an approach to derive maximum-entropy ensembles, taking a strictly operational perspective. We investigate the set of possible transitions that a system can undergo together with an environment, when one only has partial information about the system and its environment. The set of these transitions encodes thermodynamic laws and limitations on thermodynamic tasks as particular cases. Our main result is that the possible transitions are exactly those that are possible if both system and environment are assigned the maximum-entropy state compatible with the partial information. This justifies the overwhelming success of such ensembles and provides a derivation independent of typicality or information-theoretic measures.

Full randomness from arbitrarily deterministic events.

Do completely unpredictable events exist? Classical physics excludes fundamental randomness. Although quantum theory makes probabilistic predictions, this does not imply that nature is random, as randomness should be certified without relying on the complete structure of the theory being used. Bell tests approach the question from this perspective. However, they require prior perfect randomness, falling into a circular reasoning. A Bell test that generates perfect random bits from bits possessing high-but less than perfect-randomness has recently been obtained. Yet, the main question remained open: does any initial randomness suffice to certify perfect randomness? Here we show that this is indeed the case. We provide a Bell test that uses arbitrarily imperfect random bits to produce bits that are, under the non-signalling principle assumption, perfectly random. This provides the first protocol attaining full randomness amplification. Our results have strong implications onto the debate of whether there exist events that are fully random.