Tunneling processes between Yu-Shiba-Rusinov bound states

Very recent experiments have reported the tunneling between Yu-Shiba-Rusinov (YSR) bound states at the atomic scale. These experiments have been realized with the help of a scanning tunneling microscope where a superconducting tip is functionalized with a magnetic impurity and is used to probe another magnetic impurity deposited on a superconducting substrate. In this way it has become possible to study for the first time the spin-dependent transport between individual superconducting bound states. Motivated by these experiments, we present here a comprehensive theoretical study of the tunneling processes between YSR bound states in a system in which two magnetic impurities are coupled to superconducting leads. Our theory is based on a combination of an Anderson model with broken spin degeneracy to describe the impurities and nonequilibrium Green's function techniques to compute the current-voltage characteristics. This combination allows us to describe the spin-dependent transport for an arbitrary strength of the tunnel coupling between the impurities. We first focus on the tunnel regime and show that our theory naturally explains the experimental observations of the appearance of current peaks in the subgap region due to both the direct and thermal tunneling between the YSR states in both impurities. Then, we study in detail the case of junctions with increasing transparency, which has not been experimentally explored yet, and predict the occurrence of a large variety of (multiple) Andreev reflections mediated by YSR states that give rise to a very rich structure in the subgap current. In particular, we predict the occurrence of multiple Andreev reflections that involve YSR states in different impurities. These processes have no analogue in single-impurity junctions and they are manifested as current peaks with negative differential conductance for subgap voltages.Comment: 16 pages, 9 figures. arXiv admin note: text overlap with arXiv:2005.0649

Validation of the INCREMENT-SOT-CPE score in a large cohort of liver transplant recipients with carbapenem-resistant Enterobacterales infection

Background: Management of infections due to carbapenemase-resistant Enterobacterales (CRE) in solid organ transplant (SOT) recipients remains a difficult challenge. The INCREMENT-SOT-CPE score has been specifically developed from SOT recipients to stratify mortality risk, but an external validation is lacking.Methods: Multicenter retrospective cohort study of liver transplant (LT) recipients colonized with CRE infection who developed infection after transplant over 7-year period. Primary endpoint was all-cause 30-day mortality from infection onset. A comparison between INCREMENT-SOT-CPE and other selected scores was performed. A two-level mixed effects logistic regression model with random effects for the center was fitted. Performance characteristics at optimal cut-point were calculated. Multivariable Cox regression analysis of risk factors for all-cause 30-day mortality was carried out.Results: Overall, 250 CRE carriers developed infection after LT and were analyzed. The median age was 55 years (interquartile range [IQR]: 46-62) and 157 were males (62.8%). All-cause 30-day mortality was 35.6%. A sequential organ failure assessment (SOFA) score >= 11 showed a sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of 69.7%, 76.4%, 62.0%, 82.0%, and 74.0%, respectively. An INCREMENT-SOT-CPE >= 11 reported a sensitivity, specificity, PPV, NPV, and accuracy of 73.0%, 62.1%, 51.6%, 80.6% and 66.0%, respectively. At multivariable analysis acute renal failure, prolonged mechanical ventilation, INCREMENT-SOT-CPE score >= 11 and SOFA score >= 11 were independently associated with all-cause 30-day mortality, while a tigecycline-based targeted regimen was found to be protective.Conclusions: Both INCREMENT-SOT-CPE >= 11 and SOFA >= 11 were identified as strong predictors of all-cause 30-day mortality in a large cohort of CRE carriers developing infection after LT

The population of merging compact binaries inferred using gravitational waves through GWTC-3

We report on the population properties of 76 compact binary mergers detected with gravitational waves below a false alarm rate of 1 per year through GWTC-3. The catalog contains three classes of binary mergers: BBH, BNS, and NSBH mergers. We infer the BNS merger rate to be between 10 $\rm{Gpc^{-3} yr^{-1}}$ and 1700 $\rm{Gpc^{-3} yr^{-1}}$ and the NSBH merger rate to be between 7.8 $\rm{Gpc^{-3}\, yr^{-1}}$ and 140 $\rm{Gpc^{-3} yr^{-1}}$ , assuming a constant rate density versus comoving volume and taking the union of 90% credible intervals for methods used in this work. Accounting for the BBH merger rate to evolve with redshift, we find the BBH merger rate to be between 17.9 $\rm{Gpc^{-3}\, yr^{-1}}$ and 44 $\rm{Gpc^{-3}\, yr^{-1}}$ at a fiducial redshift (z=0.2). We obtain a broad neutron star mass distribution extending from $1.2^{+0.1}_{-0.2} M_\odot$ to $2.0^{+0.3}_{-0.3} M_\odot$. We can confidently identify a rapid decrease in merger rate versus component mass between neutron star-like masses and black-hole-like masses, but there is no evidence that the merger rate increases again before 10 $M_\odot$. We also find the BBH mass distribution has localized over- and under-densities relative to a power law distribution. While we continue to find the mass distribution of a binary's more massive component strongly decreases as a function of primary mass, we observe no evidence of a strongly suppressed merger rate above $\sim 60 M_\odot$. The rate of BBH mergers is observed to increase with redshift at a rate proportional to $(1+z)^{\kappa}$ with $\kappa = 2.9^{+1.7}_{-1.8}$ for $z\lesssim 1$. Observed black hole spins are small, with half of spin magnitudes below $\chi_i \simeq 0.25$. We observe evidence of negative aligned spins in the population, and an increase in spin magnitude for systems with more unequal mass ratio

GWTC-3: Compact Binary Coalescences Observed by LIGO and Virgo During the Second Part of the Third Observing Run

The third Gravitational-wave Transient Catalog (GWTC-3) describes signals detected with Advanced LIGO and Advanced Virgo up to the end of their third observing run. Updating the previous GWTC-2.1, we present candidate gravitational waves from compact binary coalescences during the second half of the third observing run (O3b) between 1 November 2019, 15:00 UTC and 27 March 2020, 17:00 UTC. There are 35 compact binary coalescence candidates identified by at least one of our search algorithms with a probability of astrophysical origin $p_\mathrm{astro} > 0.5$. Of these, 18 were previously reported as low-latency public alerts, and 17 are reported here for the first time. Based upon estimates for the component masses, our O3b candidates with $p_\mathrm{astro} > 0.5$ are consistent with gravitational-wave signals from binary black holes or neutron star-black hole binaries, and we identify none from binary neutron stars. However, from the gravitational-wave data alone, we are not able to measure matter effects that distinguish whether the binary components are neutron stars or black holes. The range of inferred component masses is similar to that found with previous catalogs, but the O3b candidates include the first confident observations of neutron star-black hole binaries. Including the 35 candidates from O3b in addition to those from GWTC-2.1, GWTC-3 contains 90 candidates found by our analysis with $p_\mathrm{astro} > 0.5$ across the first three observing runs. These observations of compact binary coalescences present an unprecedented view of the properties of black holes and neutron stars

Superconducting Quantum Interference at the Atomic Scale

A single spin in a Josephson junction can reverse the flow of the supercurrent. At mesoscopic length scales, such $\pi$-junctions are employed in various instances from finding the pairing symmetry to quantum computing. In Yu-Shiba-Rusinov (YSR) states, the atomic scale counterpart of a single spin in a superconducting tunnel junction, the supercurrent reversal so far has remained elusive. Using scanning tunneling microscopy (STM), we demonstrate such a 0 to $\pi$ transition of a Josephson junction through a YSR state as we continuously change the impurity-superconductor coupling. We detect the sign change in the critical current by exploiting a second transport channel as reference in analogy to a superconducting quantum interference device (SQUID), which provides the STM with the required phase sensitivity. The measured change in the Josephson current is a signature of the quantum phase transition and allows its characterization with unprecedented resolution.Comment: 10 pages, 6 figures, including supplementary informatio

Soils of the Pampean Region

Pampean landscapes are characterized by the presence ofextensive plains originally covered by grasslands. At present,rainfed production of cereal and oil crops is the maineconomic farming activity of the region and constitutes ahigh proportion of Argentina exports. The most fertile soilsof Argentina are located in this region. They are Mollisols(mainly Argiudolls and Hapludolls), the most important andwidespread soil order in the region. Argiudolls are usuallyvery deep and show a complex profile, with highlydifferentiated horizons. Hapludolls have simpler profileswith surface layers occupied by coarser deposits. LocalMollisols were developed from loessic materials of predominantlysilty granulometry, with some involvement of sand,leading to very favourable natural soil physical conditionsfor crop growth. Other conspicuous soil orders are Entisolsand Alfisols. In this chapter, soil genesis and major soil typesare described and four subregions were considered: Northern,Western, Southern and Flooding Pampa.Fil: Rubio, Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; ArgentinaFil: Pereira, Fernando X.. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; ArgentinaFil: Taboada, Miguel Angel. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Suelos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Condemning violence without rejecting sexism? : Exploring how young men understand intimate partner violence in Ecuador

Background: This study aims to explore young men's understanding of intimate partner violence (IPV) in Ecuador, examining similarities and differences between how ordinary and activist young men conceptualize IPV against women. Methods: We conducted individual interviews and focus group discussions (FGDs) with 35 young men - five FGDs and five interviews with ordinary young men, and 11 interviews with activists - and analysed the data generated using qualitative content analysis. Results: Among the ordinary young men the theme 'too much gender equality leads to IPV' emerged, while among the activists the theme 'gender inequality is the root of IPV'. Although both groups in our study rejected IPV, their positions differed, and we claim that this is relevant. While activists considered IPV as rooted in gender inequality, ordinary young men understood it as a response to the conflicts generated by increasing gender equality and women's attempts to gain autonomy

Changes in soil organic matter under different land management in misiones province (Argentina) Mudanças na matéria orgânica edafica sob diferentes manejos de solo na província de misiones (Argentina)

Highly weathered tropical soils rapidly loose soil organic matter (SOM) and may be affected by water erosion and soil compaction after deforestation and intensive cultivation. With the main objective to estimate the SOM balances in a subtropical soil we determined the dynamics of SOM in a degraded yerba mate (Ilex paraguaiensis Saint Hil.) plantation introduced after deforestation and with elephant grass (Pennisetum purpureum L.) as a cover crop. The study site was in Misiones, Argentina, and we use the natural 13C abundance methodology and a descriptive model. The study was conducted on three contiguous 50 x 100 m plots of a typic Kandihumult soil with: (i) native forest, (ii) 50 years of continuous yerba mate monoculture with intensive tillage, and (iii) yerba mate associated with elephant grass as a cover crop and no tillage. We determined bulk density, carbon (C), nitrogen (N) and 13C content of the soil (0 - 0.05, 0.05 - 0.15 m layers) and the grass biomass. Yerba mate monoculture reduced soil C and N content as well as porosity at 0 - 0.15 m depth by 43 and 23%, respectively, as compared to the native forest. After ten years of yerba mate - elephant grass association soil C and N contents at the same depth increased by 19 and 12%, respectively, compared to the yerba mate monoculture, while soil porosity remained similar. Total C input,13C, and soil organic C were incorporated into a three compartment model to evaluate elephant grass C dynamics. Through the natural 13C abundance methodology we tracked the elephant grass C incorporation and the "old" soil C loss, and determined the model parameters - humification (k1) and mineralization (k) coefficients and stable C (Cs)- unambiguously. The high k1 and k predicted by the model are probably explained by elephant grass root system incorporation under no tillage and humid subtropical climate, respectively. In soil under yerba mate monoculture, Cs was counted as 91% of the total soil organic C.<br>Os solos altamente intemperizados dos trópicos perdem rapidamente matéria orgânica do solo (SOM)&#160;e podem ser afetados pela erosão hídrica&#160;e compactação depois de seu deflorestamento e agricultura contínua.&#160;O objetivo foi determinar a dinâmica da matéria orgânica do solo com capim-elefante (Pennisetum purpureum L.) em um Kandihumult da província de Misiones (Argentina) após desmatamento e cultivo contínuo de erva-mate (Ilex paraguaiensis Saint Hil.), utilizando a metodologia da abundância natural em carbono 13 (13C) e um modelo descritivo. O estudo foi conduzido em três parcelas contíguas de 50 x 100 m. As situações comparadas foram: (a) floresta nativa, e (b) local com 50 anos de monocultivo intensivo de erva- mate, e (c) erva-mate associada com capim-elefante como cultivo de cobertura sob plantio direto. Determinaram-se os conteúdos de carbono (C), de nitrogênio (N) e de 13C e a densidade aparente do solo (camadas 0 - 0,05 e 0.05 - 0,15 m) e a biomassa da gramínea. Depois de 50 anos de monocultivo de erva-mate, os conteúdos de C e N e a porosidade da camada 0 - 0,15 m da floresta nativa diminuíram em 42, 47 e 23%, respectivamente. Depois de 10 anos de associação erva-mate - capim-elefante, os conteúdos de C e N do solo e na mesma profundidade aumentaram em relação ao monocultivo de erva-mate em 19 e 12%, respectivamente, mas a porosidade não foi modificada. O aporte de C, o 13C e o C orgânico total do solo foram incorporados em um modelo de três compartimentos para avaliar a dinâmica do C proveniente do capim-elefante. A metodologia da abundância natural em 13C permitiu traçar a incorporação do C proveniente do capim-elefante e a perda do C "velho" no solo, e determinar sem ambigüidade os parâmetros do modelo: coeficiente de humificação (k1), coeficiente de mineralização da fração ativa de C (k) e o C estável (Cs). Os altos valores de k1 e k preditos pelo modelo foram atribuídos à alta contribuição do sistema radicular do capim-elefante sob plantio direto e ao clima subtropical úmido, respectivamente. No solo sob monocultivo de erva-mate, Cs representou 91% do C orgânico total do solo