Source Density Research Articles

The key determinant for forming pollen density and using crop barriers to mitigate wind-blown pollen dispersal in alfalfa (Medicago sativa L.)

The potential for commercial cultivation of genetically engineered (GE) alfalfa has raised ecological concerns due to the possibility of introgression of GE alleles into conventional populations. The main objectives of this study were to determine the key affecting factors (i.e. size of pollen source, number of pollinating bees) on forming alfalfa pollen cloud density and test the mitigating effect using maize barrier rows on alfalfa pollen dispersal. The results showed that the mean pollen densities of alfalfa pollen source (Ø = 10 or 20 m) were statistically similar when treated with the same number of worker bumblebees and increased accordingly with increasing the worker bees (887 and 853 pollens m−3 h−1 for Ø = 10 and 20 m with 100–150 worker bees, respectively; 1040 and 1070 pollens m−3 h−1 for the two plots with 200–300 worker bees, respectively), demonstrating that the number of worker bees but not the size of the pollen source was the key determinant for forming alfalfa pollen density. A maize barrier row established at 0.5 m from the alfalfa edge consistently decreased downwind pollen densities (percent pollen density of pollen source) to 0.2–4.4 % at 1–9 m compared to 3.4–25.4 % and 7.5–37.8 % at the same distance range for the upwind and downwind sites without maize barrier rows, respectively. Based on the pods formed on the emasculated alfalfa flowers (due to pollen dispersal) located at various distances from the pollen source and subsequent prediction model, the pollen density threshold value for fertilizing alfalfa recipient under the wind-blown condition was determined of 65.8 pollens m−3 h−1 at 14.7 m from the pollen source edge. The results would help in understanding the pollination biology (minimum pollen density for fertilizing alfalfa recipient ovule) and the process of pollen-mediated gene flow and helpful in developing management strategies to reduce the pollen density and thus mitigate the gene flow in alfalfa.

Simultaneous waveform inversion of seismic-while-drilling data for P-wave velocity, density, and source parameters

Full-waveform inversion (FWI), as an optimization-based approach to estimating subsurface models, is limited by incomplete acquisition and illumination of the subsurface. The incorporation of additional data from new and independent raypaths should be expected to result in significant increase in the accuracy of FWI models. In principle, seismic-while-drilling (SWD) technology can supply these additional raypaths; however, it introduces a new suite of unknowns, namely precise source locations (i.e., drilling path), source signature, and radiation characteristics. A new FWI algorithm is formulated in which the source radiation patterns and positions join the velocity and density values of the grid cells as unknowns to be determined. Several numerical inversion experiments are then conducted with different source settings using a synthetic model. The SWD sources are supplemented by explosive sources and multicomponent receivers at the surface, simulating a conventional surface acquisition geometry. The subsurface model and SWD source properties are recovered and analyzed. The analysis is suggestive that SWD involvement can enhance the accuracy of FWI models, with varying degrees of enhancement depending on factors such as trajectory inclination, source density, and drill path extension. The impact of SWD-FWI over standard FWI is reduced when low-frequency data are missing, but improvements over the models constructed with no subsurface sources remain. This formulation permits general source information, such as position and moment tensor components, to be independently obtained. This inversion scheme may lead to a range of potential applications for which medium properties and source information are required.

Cortical origin of theta error signals.

A multi-scale approach elucidated the origin of the error-related-negativity (ERN), with its associated theta-rhythm, and the post-error-positivity (Pe) in macaque supplementary eye field (SEF). Using biophysical modeling, synaptic inputs to a subpopulation of layer-3 (L3) and layer-5 (L5) pyramidal cells (PCs) were optimized to reproduce error-related spiking modulation and inter-spike intervals. The intrinsic dynamics of dendrites in L5 but not L3 error PCs generate theta rhythmicity with random phases. Saccades synchronized the phases of the theta-rhythm, which was magnified on errors. Contributions from error PCs to the laminar current source density (CSD) observed in SEF were negligible and could not explain the observed association between error-related spiking modulation in L3 PCs and scalp-EEG. CSD from recorded laminar field potentials in SEF was comprised of multipolar components, with monopoles indicating strong electro-diffusion, dendritic/axonal electrotonic current leakage outside SEF, or violations of the model assumptions. Our results also demonstrate the involvement of secondary cortical regions, in addition to SEF, particularly for the later Pe component. The dipolar component from the observed CSD paralleled the ERN dynamics, while the quadrupolar component paralleled the Pe. These results provide the most advanced explanation to date of the cellular mechanisms generating the ERN.

Direction-of-arrival and power spectral density estimation using a single directional microphone and group-sparse optimization

In this paper, two approaches are proposed for estimating the direction of arrival (DOA) and power spectral density (PSD) of stationary point sources by using a single, rotating, directional microphone. These approaches are based on a method previously presented by the authors, in which point source DOAs were estimated by using a broadband signal model and solving a group-sparse optimization problem, where the number of observations made by the rotating directional microphone can be lower than the number of candidate DOAs in an angular grid. The DOA estimation is followed by the estimation of the sources’ PSDs through the solution of an overdetermined least squares problem. The first approach proposed in this paper includes the use of an additional nonnegativity constraint on the residual noise term when solving the group-sparse optimization problem and is referred to as the Group Lasso Least Squares (GL-LS) approach. The second proposed approach, in addition to the new nonnegativity constraint, employs a narrowband signal model when building the linear system of equations used for formulating the group-sparse optimization problem, where the DOAs and PSDs can be jointly estimated by iterative, group-wise reweighting. This is referred to as the Group-Lasso with l_1-reweighting (GL-L1) approach. Both proposed approaches are implemented using the alternating direction method of multipliers (ADMM), and their performance is evaluated through simulations in which different setup conditions are considered, ranging from different types of model mismatch to variations in the acoustic scene and microphone directivity pattern. The results obtained show that in a scenario involving a microphone response mismatch between observed data and the signal model used, having the additional nonnegativity constraint on the residual noise can improve the DOA estimation for the case of GL-LS and the PSD estimation for the case of GL-L1. Moreover, the GL-L1 approach can present an advantage over GL-LS in terms of DOA estimation performance in scenarios with low SNR or where multiple sources are closely located to each other. Finally, it is shown that having the least squares PSD re-estimation step is beneficial in most scenarios, such that GL-LS outperformed GL-L1 in terms of PSD estimation errors.

Probing the faint-end luminosity function of Lyman-alpha emitters at 3 <z< 7 behind 17 MUSE lensing clusters

Context.This paper presents a study of the galaxy Lyman-alpha luminosity function (LF) using a large sample of 17 lensing clusters observed by the Multi Unit Spectroscopic Explorer (MUSE) at the ESO Very Large Telescope (VLT). The magnification resulting from strong gravitational lensing by clusters of galaxies and MUSE spectroscopic capabilities allows for blind detections of LAEs without any photometric pre-selection, reaching the faint luminosity regime.Aims.The present work aims to constrain the abundance of Lyman-alpha emitters (LAEs) and quantify their contribution to the total cosmic reionization budget.Methods.We selected 600 lensed LAEs behind these clusters in the redshift range of 2.9 <z< 6.7, covering four orders of magnitude in magnification-corrected Ly-αluminosity (39.0 < log(L)[erg s−1] < 43.0). These data were collected behind lensing clusters, indicating an increased complexity in the computation of the LF to properly account for magnification and dilution effects. We applied a non-parametricVmaxmethod to compute the LF to carefully determine the survey volume where an individual source could have been detected. The method used in this work follows the recipes originally developed in previous works, with some improvements to better account for the effects of lensing when computing the effective volume.Results.The total co-moving volume at 2.9 < z < 6.7 in the present survey is ∼50 103Mpc3. Our LF points in the bright end (log(L) [erg s−1] > 42) are consistent with those obtained from blank field observations. In the faint luminosity regime, the density of sources is well described by a steep slope,α ∼ −2 for the global redshift range. Up to log(L) [erg s−1] ∼ 41, the steepening of the faint end slope with redshift, suggested in earlier works, is observed, but the uncertainties are still large. A significant flattening is observed towards the faintest end, for the highest redshift bins, namely, log(L)[erg s−1] < 41.Conclusions.When taken at face value, the steep slope at the faint-end causes the star formation rate density (SFRD) to dramatically increase with redshift, implying that LAEs could play a major role in the process of cosmic reionization. The flattening observed towards the faint end for the highest redshift bins still requires further investigation. This turnover is similar to the one observed for the UV LF atz ≥ 6 in lensing clusters, with the same conclusions regarding the reliability of current results. Improving the statistical significance of the sample in this low-luminosity high-redshift regime is a difficult endeavour that may lead to potentially valuable leads in understanding the process of reionization.

A Near-infrared-faint, Far-infrared-luminous Dusty Galaxy at z ∼ 5 in COSMOS-Web

A growing number of far-infrared (FIR) bright sources completely invisible in deep extragalactic optical surveys hint at an elusive population of z > 4 dusty, star-forming galaxies. Cycle 1 JWST surveys are now detecting their rest-frame optical light, which provides key insight into their stellar properties and statistical constraints on the population as a whole. This work presents the JWST Near Infrared Camera (NIRCam) counterpart from the COSMOS-Web survey to an FIR SCUBA-2 and Atacama Large Millimeter/submillimeter Array (ALMA) source, AzTECC71, which was previously undetected at wavelengths shorter than 850 μm. AzTECC71, among the reddest galaxies in COSMOS-Web with F277W − F444W ∼ 0.9, is undetected in NIRCam/F150W and F115W and fainter in F444W than other submillimeter galaxies identified in COSMOS-Web by 2–4 magnitudes. This is consistent with the system having both a lower stellar mass and higher redshift than the median dusty, star-forming galaxy. With deep ground- and space-based upper limits combined with detections in F277W, F444W, and the FIR including ALMA Band 6, we find a high probability (99%) that AzTECC71 is at z > 4 with . This galaxy is massive () and infrared-luminous (), comparable to other optically undetected but FIR-bright dusty, star-forming galaxies at z > 4. This population of luminous, infrared galaxies at z > 4 is largely unconstrained but comprises an important bridge between the most extreme dust-obscured galaxies and more typical high-redshift star-forming galaxies. If further FIR-selected galaxies that drop out of the F150W filter in COSMOS-Web have redshifts z > 4 like AzTECC71, then the volume density of such sources may be ∼3–10 × greater than previously estimated.

Research status of insect infestation of Chinese medicinal materials during storage

During the storage process, Chinese medicinal materials are susceptible to insect infestation due to their own nature and external storage factors. Infestation by insects can have varying impacts on the materials. In mild cases, it affects the appearance and reduces consumer purchasing power, while in severe cases, it affects the quality, reduces medicinal value, and introduces impurities such as insect bodies, excrement, and secretions, resulting in significant contamination of the medicinal materials. This study reviewed the rele-vant factors influencing insect infestation in Chinese medicinal materials and the compositional changes that occur after infestation and summarized maintenance measures for preventing insect infestation. Additionally, it provided an overview of detection techniques applicable to identifying insect infestation during the storage of Chinese medicinal materials. During the storage process, insect infestation is the result of the combined effects of biological factors(source, species, and population density of insects), intrinsic factors(moisture, chemical composition, and metabolism), and environmental factors(temperature, relative humidity, and oxygen content). After infestation, there are significant changes in the content of constituents in the medicinal materials. By implementing strict pre-storage inspections, regular maintenance after storage, and appropriate storage and maintenance methods, the occurrence of insect infestation can be reduced, and the preservation rate of Chinese medicinal materials can be improved. The storage and maintenance of Chinese medicinal materials are critical for ensuring their quality. Through scientifically standardized storage and strict adherence to operational management standards, the risk of insect infestation can be minimized, thus guaranteeing the quality of Chinese medicinal materials.

Resolving Moving Heliospheric Structures Using Interplanetary Scintillation Observations With the Murchison Widefield Array

AbstractWe have conducted a blind search in 49 consecutive days of interplanetary scintillation observations made by the Murchison Widefield Array from mid‐2019, with overlapping daily observations approximately East and South‐East of the Sun at an elongation of ∼30° and a field of view of 30°. These observations detect an unprecedented density of sources. In spite of these observations being taken at sunspot minimum, this search has revealed several interesting transitory features characterized by elevated scintillation levels. One solar wind enhancement is captured in two observations several hours apart, allowing its radial movement away from the Sun to be measured. We present here a methodology for measuring the plane‐of‐sky velocity for the moving heliospheric structure. The plane‐of‐sky velocity was inferred as 0.66 ± 0.147 hr−1, or 480 ± 106 kms−1 assuming a distance of 1AU. After cross‐referencing our observed structure with multiple catalogs of heliospheric events, we propose that the likely source of our observed structure is a stream‐interaction region originating from a low‐latitude coronal hole. This work demonstrates the power of widefield interplanetary scintillation observations to capture detailed features in the heliosphere which are otherwise unresolvable and go undetected.

Plausible association of distant late M dwarfs with low-frequency radio emission

We present the serendipitous discovery of eight distant (> 50 pc) late M dwarfs with plausible associated radio emission at 144 MHz. The M-dwarf nature of our sources has been confirmed with optical spectroscopy performed using HET/LRS2 and Subaru/FOCAS, and their radio flux densities are within the range of 0.5−1.0 mJy at 144 MHz. Considering the radio-optical source separation and source densities of the parent catalogues, we suggest that it is statistically probable that the M dwarfs are associated with the radio emission. However, it remains plausible that for some of the sources the radio emission originates from an optically faint and red galaxy hiding behind the M dwarf. The isotropic radio luminosities (∼1017 − 18 erg s−1 Hz−1) of the M dwarfs suggest that if the association is real, the radio emission is likely driven by a coherent emission process produced via plasma or electron-cyclotron maser instability processes, which is potentially caused by binary interaction. Long-term monitoring in the radio and high-resolution radio follow-up observations are necessary to search for any variability and pinpoint the radio emission to determine whether our tentative conclusion that these ultracool dwarfs are radio emitting is correct. If the low-frequency radio emission is conclusively associated with the M dwarfs, this would reveal a new population of optically faint and distant (> 50 pc) radio-emitting M dwarfs.

The Association of Nocturnal Seizures and Interictal Cardiac/Central Autonomic Function in Frontal Lobe Epilepsy: Heart Rate Variability and Central Autonomic Network Analysis.

Patients with epilepsy frequently experience autonomic dysfunction, closely related to sudden unexplained death in epilepsy (SUDEP). SUDEP occurs most often at night or during sleep, and frequent nocturnal seizures are an established risk factor. This study investigated the influence of nocturnal seizures on autonomic dysfunction in epilepsy. This retrospective study enrolled frontal lobe epilepsy (FLE) patients who performed 24-hour EEG monitoring. All participants were divided into nocturnal FLE (NFLE, > 90% of seizures occurring during sleep) or diurnal FLE (DFLE) groups. EEG and ECG signals were simultaneously obtained during waking and sleep stages. EEG current density source and connectivity analysis of the autonomic network were performed. ECG was analyzed across time and frequency domains heart rate variability (HRV) analysis method was used. The obtained parameters were compared between the NFLE and DFLE groups. Fifteen NFLE and 16 DFLE patients were enrolled with no significant difference in age, sex, disease duration, seizure frequency, or the number of anti-seizure medications between the two groups. During sleep, a decrease in HRV parameters and an increase of the beta-1 (13-22 Hz) current source density power in the bilateral paracentral lobule (BA4,5,6), precuneus (BA7), and cingulate (BA31) were observed in the NFLE group compared to DFLE group. The NFLE group also showed hyperconnectivity in the central autonomic (12 edges distributed over 10 nodes), sympathetic (2 edges distributed over 3 nodes), and parasympathetic (4 edges distributed over 6 nodes) beta-1 frequency band networks during sleep. During wakefulness, central and cardiac autonomic variables were not significantly different between the NFLE and DFLE groups. Interictal cardiac and central autonomic dysfunction occurred simultaneously and can be attributed to the brain-heart autonomic axis. Our findings suggest that nocturnal seizures may contribute to interictal autonomic dysfunction during sleep in people with epilepsy.

Assessment of the integration of a switched nuclear isomer material with a kinematic Stirling engine

Presently, power systems are limited by the source and energy density of the chemical fuels that are currently in use. In response to this challenge, nuclear energy sources are being developed. Metastable nuclear states, or isomers, have an intrinsic energy density that is many orders of magnitude larger than chemical fuels. Through isomer depletion (or switching), these materials can be transformed from a long-lived half-life energy-storage state to a shorter-lived half-life energy-releasing state. The abundance of energy released by switched nuclear isomer (SNI) materials introduces unique engineering challenges for the power conversion system. Once an SNI material has been switched, its heat output decays with time. In contrast to hydrocarbon-based fuels, which can be throttled, generating constant power from an SNI system requires sufficient material based on duration of use and system efficiency. Despite these challenges, SNI materials could be used to replace chemical fuels for relatively high-power applications providing months of power from a compact energy source.The purpose of this work is to explore the coupling of an SNI heat source to a kinematic Stirling engine in order to assess the potential of such a system. First, the characteristics of a reference SNI material are discussed in the context of the conversion efficiency and power density of the power conversion system that it is coupled to. Second, the integration of an SNI with a kinematic Stirling engine is explored at two power levels, 6 kWe and 60 kWe, in order to explore the feasibility and efficiency of such a power system. In order to carry out this study, a second-order Stirling engine model (the Stirling Engine Trade-space Tool, or SETT) has been developed. The potential of the SETT tool to predict performance trends has been shown through comparison of the predicted to the measured performance for two baseline, well-documented Stirling engines: the GPU-3 (nominally 6 kW) and Mod II (nominally 60 kW) engines. The SETT model is then used to optimize the design of the integration heat exchanger that is used to thermally couple a Stirling engine to the SNI and evaluate the performance characteristics of this energy conversion system. The resulting model is also used to show that the kinematic Stirling engine has advantages related to its inherent ability to modulate its output through speed or inventory control, allowing it to effectively deal with the time varying rate of heat transfer that is inevitably provided by the SNI. This work shows that the kinematic Stirling engine is an attractive power conversion system to use with SNI material as it can achieve high conversion efficiency, high power density, and provides inherent modulation capability.

Feedback negativity and feedback-related P3 in individuals at risk for depression: Comparing surface potentials and current source densities.

Blunted responses to reward feedback have been linked to major depressive disorder (MDD) and depression risk. Using a monetary incentive delay task (win, loss, break-even), we investigated the impact of family risk for depression and lifetime history of MDD and anxiety disorder with 72-channel electroencephalograms (EEG) recorded from 29 high-risk and 32 low-risk individuals (15-58 years, 30 male). Linked-mastoid surface potentials (ERPs) and their corresponding reference-free current source densities (CSDs) were quantified by temporal principal components analysis (PCA). Each PCA solution revealed a midfrontal feedback negativity (FN; peak around 310 ms) and a posterior feedback-P3 (fb-P3; 380 ms) as two distinct reward processing stages. Unbiased permutation tests and multilevel modeling of component scores revealed greater FN to loss than win and neutral for all stratification groups, confirming FN sensitivity to valence. Likewise, all groups had greater fb-P3 to win and loss than neutral, confirming that fb-P3 indexes motivational salience and allocation of attention. By contrast, group effects were subtle, dependent on data transformation (ERP, CSD), and did not confirm reduced FN or fb-P3 for at-risk individuals. Instead, CSD-based fb-P3 was overall reduced in individuals with than without MDD history, whereas ERP-based fb-P3 was greater for high-risk individuals than for low-risk individuals for monetary, but not neutral outcomes. While the present findings do not support blunted reward processing in depression and depression risk, our side-by-side comparison underscores how the EEG reference choice affects the characterization of subtle group differences, strongly advocating the use of reference-free techniques.

Detection of Transmission State of Multiple Wireless Sources: A Statistical Mechanics Approach

Consider a random network of static primary wireless sources and a co-located network of secondary wireless devices. The channel coefficients between the two networks are assumed to be known to the secondary users (SUs), e.g., using radio environment maps (REM). However, the operational state of the sources is unknown due to intermittency. In this paper, we study the performance of primary source detection by SUs using a message-passing algorithm. Additionally, we employ methods from statistical mechanics, in particular, the Replica approach, to obtain analytic results for the performance of such networks in the large system-size limit. We test the results through a large-scale simulation analysis, obtaining good agreement. The proposed method provides a simple way to evaluate the performance of the system and assess how it depends on the macroscopic parameters that characterize it, such as the average density of SUs and sources and the signal-to-noise ratio. The main contribution of this paper is the application of an algorithm that quantitatively predicts the parameter value region for which accurate and reliable detection of the operational state of the primary sources can be achieved in a fast and decentralized manner.

Interictal spikes in Alzheimer's disease: Preclinical evidence for dominance of the dentate gyrus and cholinergic control by the medial septum

Interictal spikes (IIS) are a common type of abnormal electrical activity in Alzheimer's disease (AD) and preclinical models. The brain regions where IIS are largest are not known but are important because such data would suggest sites that contribute to IIS generation. Because hippocampus and cortex exhibit altered excitability in AD models, we asked which areas dominate the activity during IIS along the cortical-CA1-dentate gyrus (DG) dorso-ventral axis. Because medial septal (MS) cholinergic neurons are overactive when IIS typically occur, we also tested the novel hypothesis that silencing the MS cholinergic neurons selectively would reduce IIS.We used mice that simulate aspects of AD: Tg2576 mice, presenilin 2 (PS2) knockout mice and Ts65Dn mice. To selectively silence MS cholinergic neurons, Tg2576 mice were bred with choline-acetyltransferase (ChAT)-Cre mice and offspring were injected in the MS with AAV encoding inhibitory designer receptors exclusively activated by designer drugs (DREADDs). We recorded local field potentials along the cortical-CA1-DG axis using silicon probes during wakefulness, slow-wave sleep (SWS) and rapid eye movement (REM) sleep.We detected IIS in all transgenic or knockout mice but not age-matched controls. IIS were detectable throughout the cortical-CA1-DG axis and occurred primarily during REM sleep. In all 3 mouse lines, IIS amplitudes were significantly greater in the DG granule cell layer vs. CA1 pyramidal layer or overlying cortex. Current source density analysis showed robust and early current sources in the DG, and additional sources in CA1 and the cortex also. Selective chemogenetic silencing of MS cholinergic neurons significantly reduced IIS rate during REM sleep without affecting the overall duration, number of REM bouts, latency to REM sleep, or theta power during REM. Notably, two control interventions showed no effects.Consistent maximal amplitude and strong current sources of IIS in the DG suggest that the DG is remarkably active during IIS. In addition, selectively reducing MS cholinergic tone, at times when MS is hyperactive, could be a new strategy to reduce IIS in AD.

Alteration of Neural Network and Hippocampal Slice Activation through Exosomes Derived from 5XFAD Nasal Lavage Fluid.

Exosomes, key mediators of intercellular transmission of pathogenic proteins, such as amyloid-beta and tau, significantly influence the progression and exacerbation of Alzheimer's disease (AD) pathology. Present in a variety of biological fluids, including cerebrospinal fluid, blood, saliva, and nasal lavage fluid (NLF), exosomes underscore their potential as integral mediators of AD pathology. By serving as vehicles for disease-specific molecules, exosomes could unveil valuable insights into disease identification and progression. This study emphasizes the imperative to investigate the impacts of exosomes on neural networks to enhance our comprehension of intracerebral neuronal communication and its implications for neurological disorders like AD. After harvesting exosomes derived from NLF of 5XFAD mice, we utilized a high-density multielectrode array (HD-MEA) system, the novel technology enabling concurrent recordings from thousands of neurons in primary cortical neuron cultures and organotypic hippocampal slices. The ensuing results revealed a surge in neuronal firing rates and disoriented neural connectivity, reflecting the effects provoked by pathological amyloid-beta oligomer treatment. The local field potentials in the exosome-treated hippocampal brain slices also exhibited aberrant rhythmicity, along with an elevated level of current source density. While this research is an initial exploration, it highlights the potential of exosomes in modulating neural networks under AD conditions and endorses the HD-MEA as an efficacious tool for exosome studies.

Diffusive shock acceleration at EeV and associated multimessenger flux from ultra-fast outflows driven by active galactic nuclei

ABSTRACT Active galactic nuclei (AGN) can launch and sustain powerful winds featuring mildly relativistic velocity and wide opening angle. Such winds, known as ultra-fast outflows (UFOs), can develop a bubble structure characterized by a forward shock expanding in the host galaxy and a wind termination shock separating the fast, cool wind from the hot shocked wind. In this work, we explore whether diffusive shock acceleration can take place efficiently at the wind termination shock of UFOs. We calculate the spectrum of accelerated particles and find that protons can be energized up to the EeV range promoting UFOs to promising candidates for accelerating ultra-high energy cosmic rays (UHECRs). We also compute the associated gamma-ray and neutrino fluxes and compare them with available data in the literature. We observe that high-energy (HE) neutrinos are efficiently produced up to hundreds of PeV while the associated gamma rays could be efficiently absorbed beyond a few tens of GeV by the optical-ultraviolet AGN photon field. By assuming a typical source density of non-jetted AGN, we expect that UFOs could play a dominant role as diffuse sources of UHECRs and HE neutrinos. We finally apply our model to the recently observed NGC1068 and we find out that under specific parametric conditions an obscured UFO could provide a sizeable contribution to the observed gamma-ray flux while only contributing up to ∼10 per cent to the associated neutrino flux.

Identification of Contamination Sources and Assessment of Risk Factors Associated with the Occurrence of Escherichia coli O157:H7 on Small-scale Cow-calf Operations in Oklahoma and Louisiana

Escherichia coli O157:H7 is a human pathogen that exists as part of the commensal microflora of cattle and is shed in animal feces. Little is known about the effect of management practices on its occurrence and transmission on small-scale cow-calf operations. Identification of risk factors associated with farm practices could help implement effective measures to control E. coli O157:H7. This study quantified the risk of E. coli O157:H7 occurrence associated with cow-calf farm practices using risk modeling. Management practices of small-scale cow-calf operations in OK and LA were assessed through survey-based research. Fecal, water, sediments and water-trough-swab samples were collected to determine the incidence of E. coli O157:H7, and potential on-farm contamination sources and risk factors identified. Association between the occurrence of pathogen and farm practices was determined using two risk assessment models (I and II). Model I determined the association of E. coli O157:H7 occurrence with water source, water container, feed, cattle breed, and herd density, while Model II determined its association with farm cleanliness. For both models, logistic regression was followed using a two-step approach, univariable and multivariable analysis. In OK and LA, E. coli O157:H7 was present in 5.8% and 8.8% fecal, 4.4% and 9.4% water, 10.3% and 9.6% sediments, and 1.5% and 10.6% water-trough-swab samples, respectively. In Model I, univariable analysis identified water container and feed, whereas multivariable analysis identified feed as a significant risk factor. In Model II, the univariable analysis found cleanliness of cattle-contact areas, such as, alleyways, water-trough, chute and equipment, to be a significant risk factor. In multivariable analysis, only the cleanliness of water-trough was identified to be a significant risk factor. Results from the study could aid in the development of on-farm best management practices for the reduction of E. coli O157:H7.

Impact of the oxidation temperature on the density of single-photon sources formed at SiO2/SiC interface

The impact of oxidation temperature on the formation of single photon-emitting defects located at the silicon dioxide (SiO2)/silicon carbide (SiC) interface was investigated. Thermal oxidation was performed in the temperature range between 900 and 1300 °C. After oxidation, two different cooling processes—cooling down in N2 or O2 ambient—were adopted. Single photon emission was confirmed with second-order correlation function measurements. For the samples cooled in an N2 ambient, the density of interface single photon sources (SPSs) increased with decreasing oxidation temperature with a density that could be controlled over the 105 to 108 cm−2 range. For the O2 cooled samples, on the other hand, many interface SPSs were formed irrespective of the oxidation temperature. This is attributed to the low-temperature oxidation during the cooling process after oxidation.

A bibliometric evaluation of the top 100 cited articles on ocrelizumab.

To analyze the 100 most cited articles (T100) on ocrelizumab using bibliometric methods to determine the current situation and identify research hotspots. Articles with "ocrelizumab" in their title were searched for in the Web of Science (WoS) database, identifying 900 articles. After the exclusion criteria were applied, 183 original articles and reviews were obtained. The T100 were selected from among these articles. Data on these articles (author, source, institution, country, scientific category, citation number, and citation density) were analyzed. The number of articles showed a fluctuating upward trend from 2006 to 2022. The total number of citations for the T100 ranged from two to 923. The average number of citations per article was 45.11. The most articles were published in 2021 (n=31). The "Ocrelizumab versus Placebo in Primary Progressive Multiple Sclerosis" study (T1) was the most cited article among the T100 and had the highest annual average number of citations. T1, T2, and T3 were clinical trials on treating multiple sclerosis. The USA was the most productive and influential research country, with 44 articles. Multiple Sclerosis and Related Disorders was the most productive journal (n=22). Clinical neurology ranked first among the WoS categories (n=70). Hauser Stephen and Kappos Ludwig were the most influential authors, with 10 articles each. Biotechnology company Roche was at the top of the publication list, with 36 articles. This study's results can give researchers an idea about current developments and research collaborations on ocrelizumab. These data can help researchers easily obtain publications that have become classics. We conclude that the clinical and academic communities have shown a growing interest in ocrelizumab for treating primary progressive multiple sclerosis in recent years.

A high HDO/H2O ratio in the Class I protostar L1551 IRS5

Context. Water is a very abundant molecule in star-forming regions. Its deuterium fractionation provides an important tool for understanding its formation and evolution during the star and planet formation processes. While the HDO/H2O abundance ratio has been determined toward several young Class 0 protostars and comets, the number of studies toward Class I protostars is limited. Aims. Our aim is to study the water deuteration toward the Class I protostellar binary L1551 IRS5 and to investigate the effect of evolutionary stage and environment on variations in the water D/H ratio. Methods. Observations were carried out toward L1551 IRS5 using the NOrthern Extended Millimeter Array (NOEMA) interferometer. The HDO 31, 2–22, 1 transition at 225.9 GHz and the H218O 31, 3–22, 0 transition at 203.4 GHz were covered with a spatial resolution of 0.5″× 0.8″, while the HDO 42, 2–42, 3 transition at 143.7 GHz was observed with a resolution of 2.0″ × 2.5″. We constrained the water D/H ratio using both local thermodynamic equilibrium (LTE) and non-LTE models. Results. The three transitions are detected. The line profiles display two peaks, one at ∼6 km s−1 and one at ∼9 km s−1. We derive an HDO/H2O ratio of (2.1 ± 0.8) × 10−3 for the redshifted component and a lower limit of > 0.3 × 10−3 for the blueshifted component. This lower limit is due to the blending of the blueshifted H218O component with redshifted CH3OCH3 emission. Conclusions. The HDO/H2O ratio in L1551 IRS5 is similar to the values in Class 0 isolated sources and in the disk of the Class I protostar V883 Ori, while it is significantly higher than in the previously studied clustered Class 0 sources and the comets. This result suggests that the chemistry of protostars that belong to molecular clouds with relatively low source densities, such as L1551, share more similarities with the isolated sources than the protostars of very dense clusters. If the HDO/H2O ratios in Class 0 protostars with few sources around are comparable to those found to date in isolated Class 0 objects, it would mean that there is little water reprocessing from the Class 0 to Class I protostellar stage.