Thermal inertia and surface roughness are proxies for the physical characteristics of planetary surfaces. Global maps of these two propertiesdistinguish the boulder population on near-Earth asteroid ...(NEA) (101955)Bennuinto two typesthat differ in strength,andboth havelower thermal inertiathan expectedfor boulders and meteorites. Neither has strongly temperature-dependent thermal properties. The weakerbouldertypeprobably would not survive atmospheric entry and thus may not berepresented in the meteorite collection. The maps also show ahigh-thermal-inertia band at Bennu’s equator, which might be explained by processes such as compaction or strength sorting during mass movement, but these explanations are not wholly consistent with other data. Our findings imply that other C-complex NEAs likely have boulderssimilar to those on Bennu,rather than finer-particulate regoliths.A tentative correlation between albedo and thermal inertia of C-complex NEAs may be due to relative abundances of boulder types.
The Event Horizon Telescope (EHT) has led to the first images of a supermassive black hole, revealing the central compact objects in the elliptical galaxy M87 and the Milky Way. Proposed upgrades to ...this array through the next-generation EHT (ngEHT) program would sharply improve the angular resolution, dynamic range, and temporal coverage of the existing EHT observations. These improvements will uniquely enable a wealth of transformative new discoveries related to black hole science, extending from event-horizon-scale studies of strong gravity to studies of explosive transients to the cosmological growth and influence of supermassive black holes. Here, we present the key science goals for the ngEHT and their associated instrument requirements, both of which have been formulated through a multi-year international effort involving hundreds of scientists worldwide.
The LIFE study is a two-phase randomized clinical trial comparing two approaches to maintaining weight loss following guided weight loss. Phase I provided a nonrandomized intensive 6-month behavioral ...weight loss intervention to 472 obese (body mass index 30-50) adult participants. Phase II is the randomized weight loss maintenance portion of the study. This paper focuses on Phase I measures of sleep, screen time, depression and stress.
The Phase I intervention consisted of 22 group sessions led over 26 weeks by behavioral counselors. Recommendations included reducing dietary intake by 500 calories per day, adopting the Dietary Approaches to Stop Hypertension (DASH) dietary pattern and increasing physical exercise to at least 180 min per week. Measures reported here are sleep time, insomnia, screen time, depression and stress at entry and post-weight loss intervention follow-up.
The mean weight loss for all participants over the intensive Phase I weight loss intervention was 6.3 kg (s.d. 7.1). Sixty percent (N=285) of participants lost at least 4.5 kg (10 lbs) and were randomized into Phase II. Participants (N=472) attended a mean of 73.1% (s.d. 26.7) of sessions, completed 5.1 (s.d. 1.9) daily food records/week, and reported 195.1 min (s.d. 123.1) of exercise per week. Using logistic regression, sleep time (quadratic trend, P=0.030) and lower stress (P=0.024) at entry predicted success in the weight loss program, and lower stress predicted greater weight loss during Phase I (P=0.021). In addition, weight loss was significantly correlated with declines in stress (P=0.048) and depression (P=0.035).
Results suggest that clinicians and investigators might consider targeting sleep, depression and stress as part of a behavioral weight loss intervention.
Asteroid crater retention ages have unknown accuracy because projectile-crater scaling laws are difficult to verify. At the same time, our knowledge of asteroid and crater size-frequency ...distributions has increased substantially over the past few decades. These advances make it possible to empirically derive asteroid crater scaling laws by fitting model asteroid size distributions to crater size distributions from asteroids observed by spacecraft. For D > 10 km diameter asteroids like Ceres, Vesta, Lutetia, Mathilde, Ida, Eros, and Gaspra, the best matches occur when the ratio of crater to projectile sizes is f ∼ 10. The same scaling law applied to 0.3 < D < 2.5 km near-Earth asteroids such as Bennu, Ryugu, Itokawa, and Toutatis yield intriguing yet perplexing results. When applied to the largest craters on these asteroids, we obtain crater retention ages of ∼1 billion years for Bennu, Ryugu, and Itokawa and ∼2.5 billion years for Toutatis. These ages agree with the estimated formation ages of their source families and could suggest that the near-Earth asteroid population is dominated by bodies that avoided disruption during their traverse across the main asteroid belt. An alternative interpretation is that f > 10, which would make their crater retention ages much younger. If true, crater scaling laws need to change in a substantial way between D > 10 km asteroids, where f ∼ 10, and 0.3 < D < 2.5 km asteroids, where f > 10.
Geological investigations planned for the Europa Clipper mission will examine the formation, evolution, and expression of geomorphic structures found on the surface. Understanding geologic features, ...their formation, and any recent activity are key inputs in constraining Europa’s potential for habitability. In addition to providing information about the moon’s habitability, the geologic study of Europa is compelling in and of itself. Here we provide a high-level, cross-instrument, and cross-discipline overview of the geologic investigations planned within the Europa Clipper mission. Europa’s fascinating collection of ice-focused geology provides an unparalleled opportunity to investigate the dynamics of icy shells, ice-ocean exchange processes, and global-scale tectonic and tidal stresses. We present an overview of what is currently known about the geology of Europa, from global to local scales, highlighting outstanding issues and open questions, and detailing how the Europa Clipper mission will address them. We describe the mission’s strategy for searching for and characterizing current activity in the form of possible active plumes, thermal anomalies, evidence for surface changes, and extremely fresh surface exposures. The complementary and synergistic nature of the data sets from the various instruments and their integration will be key to significantly advancing our understanding of Europa’s geology.
Habitable ocean environments on Europa require an influx of reactants to maintain chemical disequilibrium. One possible source of reactants is seafloor volcanism. Modeling has shown that dissipation ...of tidal energy in Europa's asthenosphere can generate melt, but melt formation cannot be equated with volcanism. Melt must also be transported through Europa's cold lithosphere to erupt at the seafloor. Here, we use two models of dike propagation to show that dikes can only traverse the lithosphere if either the fracture toughness of the lithosphere or the flux into the dike is large (>500 MPa m1/2 or ∼1 m2 s−1, respectively). We conclude that cyclic volcanic episodes might provide reactants to Europa's ocean if magma accumulates at the base of the lithosphere for several thousand years. However, if dikes form too frequently, or are too numerous, the magma flux into each will be insufficient, and volcanism cannot support a habitable ocean environment.
Plain Language Summary
Beneath the icy crust of Jupiter's moon Europa lies a deep, liquid‐water ocean that might provide an environment suitable for life. In the absence of sunlight, organisms must extract energy from chemical reactions within the ocean. Over time, organisms would use up all the chemical ingredients needed for these reactions, leading to extinction unless new ingredients were added to the environment. Because the ocean is closed‐off from Europa's surface by the thick ice crust, seafloor volcanism has been proposed as a source of chemical ingredients. Europa's deep rock interior can get hot enough to form small amounts of magma that will rise upward; however, the magma must also travel across the outer cold portion of the rock interior, which requires the formation and growth of magmatic dikes. Here we determine that dikes long enough to supply magma to Europa's seafloor only form if the rock is either very strong, or the amount of magma entering the dike is very large. In those cases, volcanism could occur on Europa's seafloor every few thousand years, supplying the necessary life‐sustaining chemical ingredients. NASA's upcoming Europa Clipper mission will provide new data that helps clarify whether the conditions needed for seafloor volcanism are met.
Key Points
For volcanism to provide life‐sustaining reactants to Europa's ocean, asthenospheric‐formed melt must traverse the cold thick lithosphere
Dikes can propagate across the entire lithosphere if either the fracture toughness or the flux into the dike is large
Volcanism plausibly provides reactants to Europa's ocean every several thousand years, but seafloor volcanism is far from assured
We manually mapped particles ranging in longest axis from 0.3 cm to 95 m on (101955) Bennu for the Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer ...(OSIRIS-REx) asteroid sample return mission. This enabled the mission to identify candidate sample collection sites and shed light on the processes that have shaped the surface of this rubble-pile asteroid. Building on a global survey of particles, we used higher-resolution data from regional observations to calculate particle size-frequency distributions (PSFDs) and assess the viability of four candidate sites for sample collection (presence of unobstructed particles ≤ 2 cm). The four candidate sites have common characteristics: each is situated within a crater with a relative abundance of sampleable material. Their PSFDs, however, indicate that each site has experienced different geologic processing. The PSFD power-law slopes range from −3.0 ± 0.2 to −2.3 ± 0.1 across the four sites, based on images with a 0.01-m pixel scale. These values are consistent with, or shallower than, the global survey measurements. At one site, Osprey, the particle packing density appears to reach geometric saturation. We evaluate the uncertainty in these measurements and discuss their implications for other remotely sensed and mapped particles, and their importance to OSIRIS-REx sampling operations.
Aims
Bovine respiratory disease (BRD) has serious impacts on dairy production and animal welfare. It is most commonly diagnosed based on clinical respiratory signs (CRS), but in recent years, ...thoracic ultrasonography (TUS) has emerged as a diagnostic tool with improved sensitivity and specificity. This study aimed to assess the alignment of BRD diagnoses based on a Clinical Respiratory Scoring Chart (CRSC) and weekly TUS findings throughout the progression of BRD of variable severity in preweaned Holstein dairy heifers.
Methods
A total of 60 calves on two farms were followed from the 2nd week of life through the 11th week of life and assessed on a weekly basis for CRS and lung consolidation via TUS. The alignment of BRD diagnoses based on CRSC scores and TUS findings was evaluated across disease progression (pre‐consolidation, onset, chronic, or recovered) and severity (lobular or lobar lung consolidation) using receiver operator curves and area under the curves combined with Cohen's kappa (κ), sensitivity, and specificity.
Results
The diagnosis of BRD using CRSC scores ≥5 aligned best with the onset of lobar lung consolidation (>1 cm in width and full thickness). This equated to an acceptable level of discrimination (AUC = 0.76), fair agreement (κ = 0.37), and a sensitivity of 29% and specificity of 99%. Similarly, there was acceptable discrimination (AUC = 0.70) and fair agreement (κ = 0.33) between CRSC ≥5 and the onset of a less severe threshold of disease based on lobular (1–3 cm2 but not full thickness) or lobar consolidation. Discrimination remained acceptable (AUC = 0.71) with fair agreement (κ = 0.28) between CRSC scores ≥2 for nasal discharge and/or cough (spontaneous or induced) and the onset of lobar consolidation. However, sensitivity was <40% across comparisons and outside of the onset of disease there tended to be poor discrimination, slight agreement, and lowered sensitivity between CRS and TUS diagnoses of lobular or lobar consolidation (pre‐consolidation, chronic, or recovered). Conversely, specificity was relatively high (≥92%) across comparisons suggesting that CRSC diagnoses indicative of BRD and associated lung consolidation tend to result in few false positive diagnoses and accurate identification of healthy animals.
Conclusions and clinical relevance
Although we found the specificity of clinical signs for diagnosing lung consolidation to be ≥92% across all methods of TUS evaluations, the low levels of sensitivity dictate that clinical assessments lead to many false negative diagnoses. Consequently, depending on clinical signs alone to diagnose BRD within populations of dairy calves will likely result in overlooking a substantial proportion of subclinically affected animals that could inform the success of treatment and prevention protocols and guide management decisions.
To clarify the mechanism underlying improvement of parkinsonian signs by high-frequency electrical stimulation (HFS) of the subthalamic nucleus (STN), we investigated the effects of STN HFS on ...neuronal activity of the internal and external segment of the globus pallidus (GPi and GPe, respectively) in two rhesus monkeys rendered parkinsonian by administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. A scaled-down version of the chronic stimulating electrode used in humans, consisting of four metal contacts 0.50 mm in length each separated by 0.50 mm, was implanted through a cephalic chamber targeting the STN. Histological reconstruction revealed that the cathode was located in the STN in both monkeys. Extracellular recordings from a total of 110 pallidal neurons during STN stimulation were performed. Poststimulus time histograms of single neurons triggered by 2 Hz STN stimulation pulses at 2.4-3.0 V revealed short-latency excitations at 2.5-4.5 and 5.5-7.0 msec after stimulation onset and inhibitions at 1.0-2.5, 4.5-5.5, and 7.0-9.0 msec for both GPe and GPi neurons. These short-latency responses were present with 136 Hz stimulation, at voltages effective for alleviation of parkinsonian signs, resulting in a significant increase in mean discharge rate and a stimulus-synchronized regular firing pattern. These results indicate that activation of the STN efferent fibers and resultant changes in the temporal firing pattern of neurons in GPe and GPi underlie the beneficial effect of HFS in the STN in Parkinson's disease and further support the role of temporal firing patterns in the basal ganglia in the development of Parkinson's disease and other movement disorders.
The dissemination of carbapenem-resistant and third generation cephalosporin-resistant pathogens is a critical issue that is no longer restricted to hospital settings. The rapid spread of critical ...priority pathogens in Brazil is notably worrying, considering its continental dimension, the diversity of international trade, livestock production, and human travel. We conducted a nationwide genomic investigation under a One Health perspective that included Escherichia coli strains isolated from humans and nonhuman sources, over 45 years (1974-2019). One hundred sixty-seven genomes were analyzed extracting clinically relevant information (i.e., resistome, virulome, mobilome, sequence types STs, and phylogenomic). The endemic status of extended-spectrum β-lactamase (ESBL)-positive strains carrying a wide diversity of
variants, and the growing number of colistin-resistant isolates carrying
-type genes was associated with the successful expansion of international ST10, ST38, ST115, ST131, ST354, ST410, ST648, ST517, and ST711 clones; phylogenetically related and shared between human and nonhuman hosts, and polluted aquatic environments. Otherwise, carbapenem-resistant ST48, ST90, ST155, ST167, ST224, ST349, ST457, ST648, ST707, ST744, ST774, and ST2509 clones from human host harbored
and
genes. A broad resistome to other clinically relevant antibiotics, hazardous heavy metals, disinfectants, and pesticides was further predicted. Wide virulome associated with invasion/adherence, exotoxin and siderophore production was related to phylogroup B2. The convergence of wide resistome and virulome has contributed to the persistence and rapid spread of international high-risk clones of critical priority E. coli at the human-animal-environmental interface, which must be considered a One Health challenge for a post-pandemic scenario.
A One Health approach for antimicrobial resistance must integrate whole-genome sequencing surveillance data of critical priority pathogens from human, animal and environmental sources to track hot spots and routes of transmission and developing effective prevention and control strategies. As part of the Grand Challenges Explorations: New Approaches to Characterize the Global Burden of Antimicrobial Resistance Program, we present genomic data of WHO critical priority carbapenemase-resistant, ESBL-producing, and/or colistin-resistant Escherichia coli strains isolated from humans and nonhuman sources in Brazil, a country with continental proportions and high levels of antimicrobial resistance. The present study provided evidence of epidemiological and clinical interest, highlighting that the convergence of wide virulome and resistome has contributed to the persistence and rapid spread of international high-risk clones of E. coli at the human-animal-environmental interface, which must be considered a One Health threat that requires coordinated actions to reduce its incidence in humans and nonhuman hosts.
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