Evaluation of soil salinity indexes based on bulk electrical conductivity

[SPA] Los sensores del suelo que miden conductividad eléctrica (CE) y humedad desempeñan un papel esencial en el control de la salinidad del suelo. Sin embargo, la interpretación precisa de la salinidad del suelo depende del desarrollo de Índices de Salinidad (IS) adecuados. Este trabajo se enfoca en el estudio del potencial de varios IS basados en la CE del medio (ECb), utilizando análisis de regresión para conocer cómo estos IS representan la salinidad del suelo. Los resultados indican que el ECb es un IS eficiente siempre que se mida a humedad constante. Además, la precisión de esta medida aumenta con la humedad del sustrato. La pendiente del ajuste de regresión lineal humedad-ECb se propone como un IS nuevo y fiable. [ENG] Soil sensors that measure electrical conductivity (EC) and moisture play an essential role in monitoring soil salinity. However, the accurate understanding of salinity depends on the development of suitable sensor-based Salinity Indices (SI). This work studied the potential of several SIs based on bulk EC (ECb), which is the only EC directly measured by sensors. Regression studies were performed to know how these SIs describe soil salinity. The results indicate that ECb is an efficient SI as long as humidity is constant. Moreover, its accuracy increases with substrate moisture. The slope of the linear regression fit moisture-ECb is proposed as a novel and reliable SIEsta investigación ha sido financiada por el Ministerio de Ciencia, Innovación y Universidades de España, el Fondo Europeo de Desarrollo Regional, subvención número RTI2018-093997-B-I00, y por la AEI española (subvención número PCI 2019-103608) bajo el programa PRIMA en el marco del proyecto PRECIMED

Targeting Alzheimer’s disease with multimodal polypeptide-based nanoconjugates

Alzheimer’s disease (AD), the most prevalent form of dementia, remains incurable mainly due to our failings in the search for effective pharmacological strategies. Here, we describe the development of targeted multimodal polypeptide-based nanoconjugates as potential AD treatments. Treatment with polypeptide nanoconjugates bearing propargylamine moieties and bisdemethoxycurcumin or genistein afforded neuroprotection and displayed neurotrophic effects, as evidenced by an increase in dendritic density of pyramidal neurons in organotypic hippocampal culture. The additional conjugation of the Angiopep-2 targeting moiety enhanced nanoconjugate passage through the blood-brain barrier and modulated brain distribution with nanoconjugate accumulation in neurogenic areas, including the olfactory bulb. Nanoconjugate treatment effectively reduced neurotoxic amyloid aggregate levels and rescued impairments to olfactory memory and object recognition in APP/PS1 transgenic AD model mice. Overall, this study provides a description of a targeted multimodal polyglutamate-based nanoconjugate with neuroprotective and neurotrophic potential for AD treatment. Copyrigh

Small-scale solar magnetic fields

As we resolve ever smaller structures in the solar atmosphere, it has become clear that magnetism is an important component of those small structures. Small-scale magnetism holds the key to many poorly understood facets of solar magnetism on all scales, such as the existence of a local dynamo, chromospheric heating, and flux emergence, to name a few. Here, we review our knowledge of small-scale photospheric fields, with particular emphasis on quiet-sun field, and discuss the implications of several results obtained recently using new instruments, as well as future prospects in this field of research.Comment: 43 pages, 18 figure

Ordovician (Floian-lower Darriwilian) conodont biofacies of the San Juan Formation in the Cerro Viejo of Huaco, Argentine Precordillera

The conodont biofacies from the San Juan Formation at the Cerro Viejo of Huaco, Central Precordillera of Argentina, are analyzed for the identification of faunal dynamics and sea-level changes. The Prioniodus elegans and Oepikodus evae zones, Floian in age (Lower Ordovician), are identified in the lower San Juan Formation at the inner part of the Huaco anticline. In the western flank of the anticline the succession of the carbonate stratigraphic unit extends from the Floian/Dapingian boundary (Lower-Middle Ordovician) up to the lower Darriwilian (Middle Ordovician) Lenodus variabilis Zone. For the interpretation of conodont biofacies through the Los Gatos creek section, 5044 conodonts from rock samples of the Floian to the lower Darriwilian are studied. Conodont abundance and generic diversity graphs, and cluster analysis, reveal the following biofacies. The Juanognathus-Bergstroemognathus, Protopanderodus-Reutterodus-Drepanodus, Protopanderodus-Oepikodus, Juanognathus-Semiacontiodus and Rossodus-Periodon-Protopanderodus biofacies are determined, which indicate various deposits stacking from inner to middle and outer carbonate ramp environments of the San Juan Formation. The associated analysis of biofacies and lithology allow for the recognition of two transgressive events in the San Juan Formation at the Los Gatos creek section, which could be related to transgressive systems tracts (TST) that occurred during the Lower and Middle Ordovician. The recovered conodonts have a CAI that varies from 2 to 2.5, indicating a burial paleotemperature between 60 and 155 °C. Furthermore, the variation of CAI in conodonts of the same sample, the presence of conodonts with corroded surface lamella, recrystallization and crystal overgrowths, and the presence of stylolites in limestone beds of the San Juan Formation indicate the circulation of hydrothermal fluids.Fil: Mango, Matías Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Albanesi, Guillermo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentin

The exposure of the hybrid detector of the Pierre Auger Observatory

The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays. It consists of a surface array to measure secondary particles at ground level and a fluorescence detector to measure the development of air showers in the atmosphere above the array. The "hybrid" detection mode combines the information from the two subsystems. We describe the determination of the hybrid exposure for events observed by the fluorescence telescopes in coincidence with at least one water-Cherenkov detector of the surface array. A detailed knowledge of the time dependence of the detection operations is crucial for an accurate evaluation of the exposure. We discuss the relevance of monitoring data collected during operations, such as the status of the fluorescence detector, background light and atmospheric conditions, that are used in both simulation and reconstruction.Comment: Paper accepted by Astroparticle Physic

Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at $\lg(E/{\rm eV})=18.5-19.0$ differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass $A > 4$. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe

Deep-sequencing reveals broad subtype-specific HCV resistance mutations associated with treatment failure

A percentage of hepatitis C virus (HCV)-infected patients fail direct acting antiviral (DAA)-based treatment regimens, often because of drug resistance-associated substitutions (RAS). The aim of this study was to characterize the resistance profile of a large cohort of patients failing DAA-based treatments, and investigate the relationship between HCV subtype and failure, as an aid to optimizing management of these patients. A new, standardized HCV-RAS testing protocol based on deep sequencing was designed and applied to 220 previously subtyped samples from patients failing DAA treatment, collected in 39 Spanish hospitals. The majority had received DAA-based interferon (IFN) a-free regimens; 79% had failed sofosbuvir-containing therapy. Genomic regions encoding the nonstructural protein (NS) 3, NS5A, and NS5B (DAA target regions) were analyzed using subtype-specific primers. Viral subtype distribution was as follows: genotype (G) 1, 62.7%; G3a, 21.4%; G4d, 12.3%; G2, 1.8%; and mixed infections 1.8%. Overall, 88.6% of patients carried at least 1 RAS, and 19% carried RAS at frequencies below 20% in the mutant spectrum. There were no differences in RAS selection between treatments with and without ribavirin. Regardless of the treatment received, each HCV subtype showed specific types of RAS. Of note, no RAS were detected in the target proteins of 18.6% of patients failing treatment, and 30.4% of patients had RAS in proteins that were not targets of the inhibitors they received. HCV patients failing DAA therapy showed a high diversity of RAS. Ribavirin use did not influence the type or number of RAS at failure. The subtype-specific pattern of RAS emergence underscores the importance of accurate HCV subtyping. The frequency of “extra-target” RAS suggests the need for RAS screening in all three DAA target regions

Trends and outcome of neoadjuvant treatment for rectal cancer: A retrospective analysis and critical assessment of a 10-year prospective national registry on behalf of the Spanish Rectal Cancer Project

Introduction: Preoperative treatment and adequate surgery increase local control in rectal cancer. However, modalities and indications for neoadjuvant treatment may be controversial. Aim of this study was to assess the trends of preoperative treatment and outcomes in patients with rectal cancer included in the Rectal Cancer Registry of the Spanish Associations of Surgeons. Method: This is a STROBE-compliant retrospective analysis of a prospective database. All patients operated on with curative intention included in the Rectal Cancer Registry were included. Analyses were performed to compare the use of neoadjuvant/adjuvant treatment in three timeframes: I)2006–2009; II)2010–2013; III)2014–2017. Survival analyses were run for 3-year survival in timeframes I-II. Results: Out of 14, 391 patients, 8871 (61.6%) received neoadjuvant treatment. Long-course chemo/radiotherapy was the most used approach (79.9%), followed by short-course radiotherapy ± chemotherapy (7.6%). The use of neoadjuvant treatment for cancer of the upper third (15-11 cm) increased over time (31.5%vs 34.5%vs 38.6%, p = 0.0018). The complete regression rate slightly increased over time (15.6% vs 16% vs 18.5%; p = 0.0093); the proportion of patients with involved circumferential resection margins (CRM) went down from 8.2% to 7.3%and 5.5% (p = 0.0004). Neoadjuvant treatment significantly decreased positive CRM in lower third tumors (OR 0.71, 0.59–0.87, Cochrane-Mantel-Haenszel P = 0.0008). Most ypN0 patients also received adjuvant therapy. In MR-defined stage III patients, preoperative treatment was associated with significantly longer local-recurrence-free survival (p < 0.0001), and cancer-specific survival (p < 0.0001). The survival benefit was smaller in upper third cancers. Conclusion: There was an increasing trend and a potential overuse of neoadjuvant treatment in cancer of the upper rectum. Most ypN0 patients received postoperative treatment. Involvement of CRM in lower third tumors was reduced after neoadjuvant treatment. Stage III and MRcN + benefited the most