Very-high-energy particle acceleration powered by the jets of the microquasar SS 433.

SS 433 is a binary system containing a supergiant star that is overflowing its Roche lobe with matter accreting onto a compact object (either a black hole or neutron star)1-3. Two jets of ionized matter with a bulk velocity of approximately 0.26c (where c is the speed of light in vacuum) extend from the binary, perpendicular to the line of sight, and terminate inside W50, a supernova remnant that is being distorted by the jets2,4-8. SS 433 differs from other microquasars (small-scale versions of quasars that are present within our own Galaxy) in that the accretion is believed to be super-Eddington9-11, and the luminosity of the system is about 1040 ergs per second2,9,12,13. The lobes of W50 in which the jets terminate, about 40 parsecs from the central source, are expected to accelerate charged particles, and indeed radio and X-ray emission consistent with electron synchrotron emission in a magnetic field have been observed14-16. At higher energies (greater than 100 gigaelectronvolts), the particle fluxes of γ-rays from X-ray hotspots around SS 433 have been reported as flux upper limits6,17-20. In this energy regime, it has been unclear whether the emission is dominated by electrons that are interacting with photons from the cosmic microwave background through inverse-Compton scattering or by protons that are interacting with the ambient gas. Here we report teraelectronvolt γ-ray observations of the SS 433/W50 system that spatially resolve the lobes. The teraelectronvolt emission is localized to structures in the lobes, far from the centre of the system where the jets are formed. We have measured photon energies of at least 25 teraelectronvolts, and these are certainly not Doppler-boosted, because of the viewing geometry. We conclude that the emission-from radio to teraelectronvolt energies-is consistent with a single population of electrons with energies extending to at least hundreds of teraelectronvolts in a magnetic field of about 16 microgauss.

Publisher Correction: Very-high-energy particle acceleration powered by the jets of the microquasar SS 433.

In this Letter, owing to a production error, the penultimate version of the PDF was published. The HTML version was always correct. The PDF has been corrected online.

Temporal reflection and refraction in the presence of a zero-nonlinearity wavelength.

We put forth a theoretical model allowing for the analysis of short-pulse interactions at time boundaries in waveguides with arbitrary frequency-dependent nonlinear profiles, in particular those exhibiting a zero-nonlinearity wavelength. Moreover, this is performed within a photon-conserving framework, thus circumventing use of the nonlinear Schrödinger equation in such scenarios, as it may lead to unphysical outcomes. Results indicate that the waveguide zero-nonlinearity wavelength has a great influence on said interactions, specifically by defining spectral bands where either signal total reflection or signal transmission can occur. We believe these findings to be of relevance in the area of all-optical switching schemes based on the interaction of short pulses in nonlinear media.

Discovery of Gamma Rays from the Quiescent Sun with HAWC.

We report the first detection of a TeV γ-ray flux from the solar disk (6.3σ), based on 6.1 years of data from the High Altitude Water Cherenkov (HAWC) observatory. The 0.5-2.6 TeV spectrum is well fit by a power law, dN/dE=A(E/1 TeV)^{-γ}, with A=(1.6±0.3)×10^{-12} TeV^{-1} cm^{-2} s^{-1} and γ=3.62±0.14. The flux shows a strong indication of anticorrelation with solar activity. These results extend the bright, hard GeV emission from the disk observed with Fermi-LAT, seemingly due to hadronic Galactic cosmic rays showering on nuclei in the solar atmosphere. However, current theoretical models are unable to explain the details of how solar magnetic fields shape these interactions. HAWC's TeV detection thus deepens the mysteries of the solar-disk emission.

Evaluation of stress response in black-tailed prairie dogs (Cynomys ludovicianus) in arid regions from colonies in Chihuahua Mexico.

Among all the regulatory homeostatic networks in vertebrates, the activation of the hypothalamic-pituitaryadrenal axis during the stress response, has gained considerable attention, and the measurement of fecal glucocorticoids (FGC) has become an invaluable tool to assess adrenocortical activity related to stressful events in wild and captive animals. However, the use of FGC requires the validation of measurement techniques and the proper selection of the specific hormone according to the study species. The main objective of this study was to identify the dominant glucocorticoid (GC) hormone in the stress response of black-tailed prairie dogs (Cynomys ludovicianus) in an arid grassland of Chihuahua, Mexico. A capture stress challenge in the field was developed to determine if the levels of glucocorticoids (cortisol and corticosterone) both in serum and fecal samples could be attributed to stress in Cynomys ludovicianus. The samples were analysed with the technique of liquid phase radioimmunoassay , and this study showed that both cortisol and corticosterone are present at measurable levels in serum and fecal samples of black-tailed prairie dogs. We found that both GCs were present in similar concentrations in serum, however, corticosterone concentration in fecal samples was higher than cortisol. Likewise, biochemical validations performed in this study to test the assay reached acceptable levels of reliability. Therefore, we confirm that fecal analysis can be implemented as a method to measure stress responses in wild prairie dogs.

Microsurgical clipping as a retreatment strategy for previously ruptured aneurysms treated with the Woven EndoBridge (WEB) device: a mono-institutional case series.

BACKGROUND: Since its approval by the US Food and Drug Administration (FDA) in 2018, the flow disruptor Woven EndoBridge (WEB) device has become increasingly popular for the endovascular treatment of unruptured and ruptured cerebral aneurysms. However, the occlusion rates seem rather low and the retreatment rates rather high compared to other treatment methods. For initially ruptured aneurysms, a retreatment rate of 13 % has been reported. A variety of retreatment strategies has been proposed; however, there is a paucity of data concerning microsurgical clipping of WEB-pretreated aneurysms, especially previously ruptured ones. Thus, we present a single-center series of five ruptured aneurysms treated with the WEB device and retreated with microsurgical clipping. METHODS: A retrospective study including all patients presenting with a ruptured aneurysm undergoing WEB treatment at our institution between 2019 and 2021 was performed. Subsequently, all patients with an aneurysm remnant or recurrence of the target aneurysm retreated with microsurgical clipping were identified. RESULTS: Overall, five patients with a ruptured aneurysm treated with WEB and retreated with microsurgical clipping were included. Besides one basilar apex aneurysm, all aneurysms were located at the anterior communicating artery (AComA) complex. All aneurysms were wide-necked with a mean dome-to-neck ratio of 1.5. Clipping was feasible and safe in all aneurysms, and complete occlusion was achieved in 4 of 5 aneurysms. CONCLUSIONS: Microsurgical clipping for initially ruptured WEB-treated aneurysms is a feasible, safe, and effective treatment method in well-selected patients.

Risky business in Georgia's wild birds: contact rates between wild birds and backyard chickens is influenced by supplemental feed.

Backyard chickens are increasingly popular, and their husbandry varies widely. How backyard chickens are housed may influence the accessibility of chicken feed and water to wild birds, and thus, the contact rates between both groups. Increased contacts have implications for pathogen transmission; for instance, Newcastle disease virus or avian influenza virus may be transmitted to and from backyard chickens from contaminated water or feed. Given this potentially increased pathogen risk to wild birds and backyard chickens, we examined which wild bird species are likely to encounter backyard chickens and their resources. We performed a supplemental feeding experiment followed by observations at three sites associated with backyard chickens in North Georgia, USA. At each site, we identified the species of wild birds that: (a) shared habitat with the chickens, (b) had a higher frequency of detection relative to other species and (c) encountered the coops. We identified 14 wild bird species that entered the coops to consume supplemental feed and were considered high-risk for pathogen transmission. Our results provide evidence that contact between wild birds and backyard chickens is frequent and more common than previously believed, which has crucial epidemiological implications for wildlife managers and backyard chicken owners.

The Debye length and anionic transport properties of composite membranes based on supported ionic liquid-like phases (SILLPS).

An analysis of the ionic transport properties of BMIM [NTf2] in supported ionic-liquid-like phase (SILLP)-based membranes has been carried out based on experimental impedance spectroscopy measurements. The direct current (dc)-conductivity was analyzed to determine the temperature and frequency dependence. The fit of the loss tangent curve data with the Cole-Cole approximation of the electrode polarization model provides the conductivity, diffusivity, and density of charge carriers. Among these quantities, a significant increase in conductivity is observed when an ionic liquid is added to the polymeric matrix containing imidazolium fragments. The use of a recent generalization of Eyring's absolute rate theory allowed the elucidation of how the local entropy restrictions, due to the porosity of the polymeric matrix, control the conductive process. The fit of the conductivity data as a function of temperature manifests the behavior of the excess entropy with respect to the temperature. The activation entropy and enthalpy were also determined. Our results correlate the Debye length (LD) with the experimental values of conductivity, electrode polarization relaxation time, and sample relaxation time involved. Our work provides novel insights into the description of ionic transport in membranes as the diffusivity, mobility, and free charge density depend on the LD. Moreover, we discuss the behavior of the polarization relaxation time, the sample relaxation time, and the static permittivity as a function of the temperature.

Effect of clay and guishe-ash as substrate on Lycopersicon esculentum germination and production.

The effect of biomass ash and clay on tomato plants (Lycopersicon esculentum) in greenhouse conditions from germination to production was studied. Biomass ash is a waste obtained from thermal treatment of guishe (a by-product of natural fiber), and clay is collected from local soils. Several trials were performed to assess the influence of the addition of clay and guishe-ash on seeds germination, seedling growth, and production yield. The decrease in the values of these variables was considered an indicator of toxicity. The obtained results showed that based clay/ash materials positively affect germination (average ∼90% and six materials allow obtaining 90%) and seedlings growth (an increase of ∼20% in height and more than 50% in fresh air corpuscular weight). However, applying these materials on the production stage induces minor positive effects on fruit diameter, locule number, pericarp thickness, and the number of seeds per fruit. Also, adverse effects (first harvest yield, number of fruits, fresh mass of ripe fruits, lycopene content) were observed. To valorize biomass ash, its combination with other materials such as clay could be an alternative to improve tomato production.

The concern to attend the growing demand for food has promoted the use of different kinds of materials as enhancers of plant growth and crop productivity. Among the materials that have been applied in crops are the wastes of biomass thermochemical processes, such as biochar and ashes. This work highlights the importance of evaluating the effect of applying a residue (guishe-ash) to a crop before promoting its use.

Comparison of 2 Anesthetic Techniques in Onychocryptosis Surgery of the Great Toe: A Randomized Clinical Trial. / Comparación de 2 técnicas de bloqueo anestésico en el tratamiento quirúrgico de onicocriptosis del primer dedo del pie.

BACKGROUND AND OBJECTIVE: Surgery for an ingrown toenail of the great toe is a common procedure that requires an anesthetic neuromuscular blockade of the entire digit. Various digital block techniques have been described, but no evidence-based recommendations on the best choice have emerged. We aimed to compare the V block to the H block in this type of surgery. MATERIAL AND METHODS: Multicenter randomized clinical trial in patients undergoing onychocryptosis surgery between February 2018 and February 2020. We recorded sex, age, foot intervened, type of blockade used (H block or V block), efficacy 10 and 20minutes after injection of the anesthetic, and number of attempts. RESULTS: A total of 140 surgeries to treat ingrown toenails were assigned to 2 groups (H block or V block) of 70 patients each. The same anesthetic, dose, and volume were used in all cases. The V technique produced a better neuromuscular block in 7.2% more cases at 10minutes and in 12.8% more at 20minutes. CONCLUSIONS: Both block techniques are safe and effective. The V block is a good alternative to the H block in patients undergoing surgery to treat an ingrown toenail.

Master equation approach to propagation in nonlinear fibers.

In this Letter, we revisit the quantum theory of propagation in nonlinear fibers. Unlike previous works, we present an effective propagation equation for the reduced density matrix of the complex envelope of the electric field. This original proposal is shown to be in agreement with the theory of quantum noise in fibers and puts forth a powerful tool for the study of fiber-based quantum devices. To underscore its applicability, we analyze the performance of a heralded single-photon scheme in terms of probabilities, an approach that conveniently lends itself to the optimization of such sources.

Quantum Noise in Fibers with Arbitrary Nonlinear Profiles.

In this Letter we introduce a novel equation addressing the effect of quantum noise in optical fibers with arbitrary frequency-dependent nonlinear profiles. To the best of our knowledge, such an endeavor has not been undertaken before despite the growing relevance of fiber optics in the design of new quantum devices. We show that the stochastic generalized nonlinear Schrödinger equation, derived from a quantum theory of optical fibers, leads to unphysical results such as a negative photon number and the appearance of a dominant anti-Stokes sideband when applied to this kind of waveguides. Starting from a recently introduced master-equation approach to propagation in fibers, we derive a novel stochastic photon-conserving nonlinear Schrödinger equation suitable for modeling arbitrary nonlinear profiles, thus greatly enhancing the study of fiber-based quantum devices.

Added prognostic value of longitudinal changes of angiogenic factors in early-onset severe pre-eclampsia: a prospective cohort study.

OBJECTIVE: To assess in women with early-onset severe pre-eclampsia whether longitudinal changes in angiogenic factors improve the prediction of adverse outcome. DESIGN: Prospective cohort study. SETTING: Maternity units in two Spanish hospitals. POPULATION: Women with diagnosis of early-onset severe pre-eclampsia. METHODS: Levels of placental growth factor (PlGF), soluble fms-like tyrosine kinase (sFlt-) and sFlt-1/PlGF ratio were measured at admission and before delivery, and average daily change calculated. The association of longitudinal changes of angiogenic factors with the time interval to delivery and with complications was evaluated by logistic and Cox regression. MAIN OUTCOME MEASURES: Interval to delivery and composite of adverse outcomes. RESULTS: We included 63 women, of which 26 (41.3%) had a complication. Longitudinal changes of sFlt-1 were more pronounced in complicated pregnancies (median: 1047 versus 342 pg/ml/day; P = 0.04). On the multivariate analysis, the clinical risk score and sFlt-1 at admission explained 6.2% of the uncertainty for complication; the addition of sFlt-1 longitudinal changes improved this to 25.3% (P = 0.002). The median time from admission to delivery was 4 days (95% CI 1.6-6.04) in those in the highest quartile of sFlt-1 longitudinal changes versus 16 days (95% CI 12.4-19.6) in the remaining women (Log-rank test P < 0.001). CONCLUSIONS: Longitudinal changes in sFlt-1 maternal levels from admission for confirmed early-onset severe pre-eclampsia add to baseline characteristics in the prediction of adverse outcome and interval to delivery. TWEETABLE ABSTRACT: In early-onset severe pre-eclampsia, longitudinal changes in sFlt-1 levels improve the prediction of complications and interval to delivery.

Correction: Temperature dependence of anomalous protonic and superprotonic transport properties in mixed salts based on CsH2PO4.

Correction for 'Temperature dependence of anomalous protonic and superprotonic transport properties in mixed salts based on CsH2PO4' by Andreu Andrio et al., Phys. Chem. Chem. Phys., 2019, 21, 12948-12960, DOI: 10.1039/C8CP07472K.

Reported Clinical and Financial Performance of Hospitals With Physician CEOs Compared to Those With Nonphysician CEOs.

EXECUTIVE SUMMARY: Little work has been done comparing the performance of hospitals with physician CEOs versus nonphysician CEOs, despite the ease of identifying this characteristic and extant leadership theories suggesting a relationship between technical expertise and success in leading highly technical organizations. We performed a detailed analysis of several widely accepted measures of clinical and financial performance across a randomly selected group of U.S. acute care hospitals with more than 40 beds and found no statistically significant differences between the two groups. The 30-day acute myocardial infarction mortality rate showed a positive statistically significant difference in the bivariate analysis (p < .001), but the effect was nullified in the multivariable regression analysis.

Measuring self-steepening with the photon-conserving nonlinear Schrödinger equation.

We propose an original, simple, and direct method to measure self-steepening (SS) in nonlinear waveguides. Our proposal is based on results derived from the recently introduced photon-conserving nonlinear Schrödinger equation (NLSE) and relies on the time shift experienced by soliton-like pulses due to SS upon propagation. In particular, a direct measurement of this time shift allows for a precise estimation of the SS parameter. Furthermore, we show that such an approach cannot be tackled by resorting to the NLSE. The proposed method is validated through numerical simulations, in excellent agreement with the analytical model, and results are presented for relevant spectral regions in the near infrared, the telecommunication band, and the mid infrared, and for realistic parameters of available laser sources and waveguides. Finally, we demonstrate the robustness of the proposed scheme against deviations expected in real-life experimental conditions, such as pulse shape, pulse peak power, pulsewidth, and/or higher-order linear and nonlinear dispersion.

Modulation instability in waveguides with an arbitrary frequency-dependent nonlinear coefficient.

In this Letter, we present, for the first time, to the best of our knowledge, the modulation instability (MI) gain spectrum of waveguides with an arbitrary frequency-dependent nonlinear coefficient ensuring strict energy and photon-number conservation of the parametric process. This is achieved by starting from a linear stability analysis of the recently introduced photon-conserving nonlinear Schrödinger equation. The derived MI gain is shown to predict some unique features, such as a nonzero gain extending beyond a zero-nonlinearity wavelength and a complex structure of the MI gain spectrum. Analytical results are shown to be in excellent agreement with numerical simulations.

Constraints on Lorentz Invariance Violation from HAWC Observations of Gamma Rays above 100 TeV.

Because of the high energies and long distances to the sources, astrophysical observations provide a unique opportunity to test possible signatures of Lorentz invariance violation (LIV). Superluminal LIV enables the decay of photons at high energy. The high altitude water Cherenkov (HAWC) observatory is among the most sensitive gamma-ray instruments currently operating above 10 TeV. HAWC finds evidence of 100 TeV photon emission from at least four astrophysical sources. These observations exclude, for the strongest of the limits set, the LIV energy scale to 2.2×10^{31} eV, over 1800 times the Planck energy and an improvement of 1 to 2 orders of magnitude over previous limits.

Multiple Galactic Sources with Emission Above 56 TeV Detected by HAWC.

We present the first catalog of gamma-ray sources emitting above 56 and 100 TeV with data from the High Altitude Water Cherenkov Observatory, a wide field-of-view observatory capable of detecting gamma rays up to a few hundred TeV. Nine sources are observed above 56 TeV, all of which are likely galactic in origin. Three sources continue emitting past 100 TeV, making this the highest-energy gamma-ray source catalog to date. We report the integral flux of each of these objects. We also report spectra for three highest-energy sources and discuss the possibility that they are PeVatrons.

Toward RGB LEDs based on rare earth-doped ZnO.

By using ZnO thin films doped with Ce, Tb or Eu, deposited via radiofrequency magnetron sputtering, we have developed monochromatic (blue, green and red, respectively) light emitting devices (LEDs). The rare earth ions introduced with doping rates lower than 2% exhibit narrow and intense emission peaks due to electronic transitions in relaxation processes induced after electrical excitation. This study proves zinc oxide to be a good host for these elements, its high conductivity and optical transparency in the visible range being as well exploited as top transparent electrode. After structural characterization of the different doped layers, a device structure with intense electroluminescence is presented, modeled, and electrically and optically characterized. The different emission spectra obtained are compared in a chromatic diagram, providing a reference for future works with similar devices. The results hereby presented demonstrate three operating monochromatic LEDs, as well as a combination of the three species into another one, with a simply-designed structure compatible with current Si technology and demonstrating an integrated red-green-blue emission.