Overcoming the Challenges Associated with Image-based Mapping of Small Bodies in Preparation for the OSIRIS-REx Mission to (101955) Bennu

The OSIRIS-REx Asteroid Sample Return Mission is the third mission in NASA's New Frontiers Program and is the first U.S. mission to return samples from an asteroid to Earth. The most important decision ahead of the OSIRIS-REx team is the selection of a prime sample-site on the surface of asteroid (101955) Bennu. Mission success hinges on identifying a site that is safe and has regolith that can readily be ingested by the spacecraft's sampling mechanism. To inform this mission-critical decision, the surface of Bennu is mapped using the OSIRIS-REx Camera Suite and the images are used to develop several foundational data products. Acquiring the necessary inputs to these data products requires observational strategies that are defined specifically to overcome the challenges associated with mapping a small irregular body. We present these strategies in the context of assessing candidate sample-sites at Bennu according to a framework of decisions regarding the relative safety, sampleability, and scientific value across the asteroid's surface. To create data products that aid these assessments, we describe the best practices developed by the OSIRIS-REx team for image-based mapping of irregular small bodies. We emphasize the importance of using 3D shape models and the ability to work in body-fixed rectangular coordinates when dealing with planetary surfaces that cannot be uniquely addressed by body-fixed latitude and longitude.Comment: 31 pages, 10 figures, 2 table

Comparison of demographic and clinical characteristics between pulmonary and extra-pulmonary tuberculosis patients in Kiambu County, 2012-2015

Background: Tuberculosis (TB) continues to be a public health challenge globally. The most common organ to be involved is the lung although it can affect any organ in the body. The diagnosis of extra-pulmonary TB (EPTB) has faced many challenges mainly due to inadequate expertise to diagnose or lack of equipment for diagnosis.Objective: To compare the demographic and clinical characteristics between pulmonary and extrapulmonary tuberculosis in Kiambu CountyDesign: Retrospective cross-sectional studySetting: Kiambu County, KenyaSubjects: Tuberculosis patients notified in TIBU surveillance systemResults: Of the 15, 833 patients analyzed, 2,704 (17%) had extra-pulmonary tuberculosis. Male to female ratio was 1:1.7 in PTB and 1:1.3 in EPTB patients. There was declining trend of TB cases notified over the years for both PTB and EPTB. Pleural TB accounted for 38% with TB lymphadenitis accounting for 14% of the EPTB subtypes. TB-HIV co-infection was higher among EPTB (36%) compared to PTB (30%). The treatment success rate was 85% and 86% among PTB and EPTB cases respectively. The mortality was 10% among EPTB and 5% in PTB cases. The 5-14 age category were more likely to developing EPTB compared to PTB (AOR 4.67 95% CI (1.5-13.99). Kabete zone was most affected with EPTB (AOR 2.11(1.19-2.74) while a protective factor was observed among the HIV positive clients (AOR 0.58 (0.43 - 0.78)Conclusion: There was a general decline in cases for both EPTB and PTB. However, the age category most affected was 5-14 years. The co-infectivity rate was higher among the EPTB patients compared to the PTB patients. High index of suspicion and appropriate diagnostic tools are needed in evaluation particularly in EPTB which will assist in early management of the patients. ART uptake could play a big role in protecting HIV positive clients from getting EPTB

The ultraluminous GRB 110918A

GRB 110918A is the brightest long GRB detected by Konus-WIND during its 19 years of continuous observations and the most luminous GRB ever observed since the beginning of the cosmological era in 1997. We report on the final IPN localization of this event and its detailed multiwavelength study with a number of space-based instruments. The prompt emission is characterized by a typical duration, a moderare $E_{peak}$ of the time-integrated spectrum, and strong hard-to-soft evolution. The high observed energy fluence yields, at z=0.984, a huge isotropic-equivalent energy release $E_{iso}=(2.1\pm0.1)\times10^{54}$ erg. The record-breaking energy flux observed at the peak of the short, bright, hard initial pulse results in an unprecedented isotropic-equivalent luminosity $L_{iso}=(4.7\pm0.2)\times10^{54}$erg s$^{-1}$. A tail of the soft gamma-ray emission was detected with temporal and spectral behavior typical of that predicted by the synchrotron forward-shock model. Swift/XRT and Swift/UVOT observed the bright afterglow from 1.2 to 48 days after the burst and revealed no evidence of a jet break. The post-break scenario for the afterglow is preferred from our analysis, with a hard underlying electron spectrum and ISM-like circumburst environment implied. We conclude that, among multiple reasons investigated, the tight collimation of the jet must have been a key ingredient to produce this unusually bright burst. The inferred jet opening angle of 1.7-3.4 deg results in reasonable values of the collimation-corrected radiated energy and the peak luminosity, which, however, are still at the top of their distributions for such tightly collimated events. We estimate a detection horizon for a similar ultraluminous GRB of $z\sim7.5$ for Konus-WIND, and $z\sim12$ for Swift/BAT, which stresses the importance of GRBs as probes of the early Universe.Comment: 22 pages, 20 figures, accepted for publication in Ap

Verticalization of bacterial biofilms

Biofilms are communities of bacteria adhered to surfaces. Recently, biofilms of rod-shaped bacteria were observed at single-cell resolution and shown to develop from a disordered, two-dimensional layer of founder cells into a three-dimensional structure with a vertically-aligned core. Here, we elucidate the physical mechanism underpinning this transition using a combination of agent-based and continuum modeling. We find that verticalization proceeds through a series of localized mechanical instabilities on the cellular scale. For short cells, these instabilities are primarily triggered by cell division, whereas long cells are more likely to be peeled off the surface by nearby vertical cells, creating an "inverse domino effect". The interplay between cell growth and cell verticalization gives rise to an exotic mechanical state in which the effective surface pressure becomes constant throughout the growing core of the biofilm surface layer. This dynamical isobaricity determines the expansion speed of a biofilm cluster and thereby governs how cells access the third dimension. In particular, theory predicts that a longer average cell length yields more rapidly expanding, flatter biofilms. We experimentally show that such changes in biofilm development occur by exploiting chemicals that modulate cell length.Comment: Main text 10 pages, 4 figures; Supplementary Information 35 pages, 15 figure

Route of feeding as a proxy for dysphagia after stroke and the effect of transdermal glyceryl trinitrate: data from the efficacy of nitric oxide in stroke randomised controlled trial

Post-stroke dysphagia is common, associated with poor outcome and often requires non-oral feeding/fluids. The relationship between route of feeding and outcome, as well as treatment with glyceryl trinitrate (GTN), was studied prospectively. The Efficacy of Nitric Oxide in Stroke (ENOS) trial assessed transdermal GTN (5 mg versus none for 7 days) in 4011 patients with acute stroke and high blood pressure. Feeding route (oral = normal or soft diet; nonoral = nasogastric tube, percutaneous endoscopic gastrostomy tube, parenteral fluids, no fluids) was assessed at baseline and day 7. The primary outcome was the modified Rankin Scale (mRS) measured at day 90. At baseline, 1331 (33.2%) patients had non-oral feeding, were older, had more severe stroke and more were female, than 2680 (66.8%) patients with oral feeding. By day 7, 756 patients had improved from non-oral to oral feeding, and 119 had deteriorated. Non-oral feeding at baseline was associated with more impairment at day 7 (Scandinavian Stroke Scale 29.0 versus 43.7; 2p < 0.001), and worse mRS (4.0 versus 2.7; 2p < 0.001) and death (23.6 versus 6.8%; 2p = 0.014) at day 90. Although GTN did not modify route of feeding overall, randomisation ≤6 hours of stroke was associated with a move to more oral feeding at day 7 (odds ratio = 0.61, 95% confidence intervals 0.38, 0.98; 2p = 0.040). As a proxy for dysphagia, non-oral feeding is present in 33% of patients with acute stroke and associated with more impairment, dependency and death. GTN moved feeding route towards oral intake if given very early after stroke

Genetic diversity from proviral DNA as a proxy for time since HIV-1 infection.

HIV-1 RNA genetic diversity predicts time since infection which is important for clinical care and research. It's unclear, however, whether proviral DNA genetic diversity sampled under suppressive antiretroviral therapy can be used for this purpose. We tested whether proviral genetic diversity from NGS sequences predicts time since infection and recency in 221 people with HIV-1 with known infection time. Proviral diversity was significantly associated with time since infection (p<5*10-07, R2 up to 25%) and predictive of treatment initiation during recent infection (AUC-ROC up to 0.85). This shows the utility of proviral genetic diversity as a proxy for time since infection

Costs and acceptability of simplified monitoring in HIV-suppressed patients switching to dual therapy: the SIMPL’HIV open-label, factorial randomised controlled trial

BACKGROUND: Clinical and laboratory monitoring of patients on antiretroviral therapy is an integral part of HIV care and determines whether treatment needs enhanced adherence or modification of the drug regimen. However, different monitoring and treatment strategies carry different costs and health consequences. MATERIALS AND METHODS: The SIMPL’HIV study was a randomised trial that assessed the non-inferiority of dual maintenance therapy. The co-primary outcome was a comparison of costs over 48 weeks of dual therapy with standard antiretroviral therapy and the costs associated with a simplified HIV care approach (patient-centred monitoring [PCM]) versus standard, tri-monthly routine monitoring. Costs included outpatient medical consultations (HIV/non-HIV consultations), non-medical consultations, antiretroviral therapy, laboratory tests and hospitalisation costs. PCM participants had restricted immunological and blood safety monitoring at weeks 0 and 48, and they were offered the choice to complete their remaining study visits via a telephone call, have medications delivered to a specified address, and to have blood tests performed at a location of their choice. We analysed the costs of both strategies using invoices for medical consultations issued by the hospital where the patient was followed, as well as those obtained from health insurance companies. Secondary outcomes included differences between monitoring arms for renal function, lipids and glucose values, and weight over 48 weeks. Patient satisfaction with treatment and monitoring was also assessed using visual analogue scales. RESULTS: Of 93 participants randomised to dolutegravir plus emtricitabine and 94 individuals to combination antiretroviral therapy (median nadir CD4 count, 246 cells/mm3; median age, 48 years; female, 17%),patient-centred monitoring generated no substantial reductions or increases in total costs (US$–421 per year [95$ –2620.4 [95% CI –2864.3 to –2331.4]) compared to standard triple-drug antiretroviral therapy costs. Approximately 50% of participants selected one monitoring option, one-third chose two, and a few opted for three. The preferred option was telephone calls, followed by drug delivery. The number of additional visits outside the study schedule did not differ by type of monitoring. Patient satisfaction related to treatment and monitoring was high at baseline, with no significant increase at week 48. CONCLUSIONS: Patient-centred monitoring did not reduce costs compared to standard monitoring in individuals switching to dual therapy or those continuing combined antiretroviral therapy. In this representative sample of patients with suppressed HIV, antiretroviral therapy was the primary factor driving costs, which may be reduced by using generic drugs to mitigate the high cost of lifelong HIV treatment. Trial registration: ClinicalTrials.gov NCT03160105

An Approach to Quantifying the Interaction between Behavioral and Transmission Clusters

We hypothesize that patterns of sexual behavior play a role in the conformation of transmission networks, i.e., the way you behave might influence whom you have sex with. If that was the case, behavioral grouping might in turn correlate with, and potentially predict transmission networking, e.g., proximity in a viral phylogeny. We rigorously present an intuitive approach to address this hypothesis by quantifying mapped interactions between groups defined by similarities in sexual behavior along a virus phylogeny while discussing power and sample size considerations. Data from the Swiss HIV Cohort Study on condom use and hepatitis C virus (HCV) sequences served as proof-of-concept. In this case, a strict inclusion criteria contrasting with low HCV prevalence hindered our possibilities to identify significant relationships. This manuscript serves as guide for studies aimed at characterizing interactions between behavioral patterns and transmission networks. Large transmission networks such as those of HIV or COVID-19 are prime candidates for applying this methodological approach

An Approach to Quantifying the Interaction between Behavioral and Transmission Clusters.

We hypothesize that patterns of sexual behavior play a role in the conformation of transmission networks, i.e., the way you behave might influence whom you have sex with. If that was the case, behavioral grouping might in turn correlate with, and potentially predict transmission networking, e.g., proximity in a viral phylogeny. We rigorously present an intuitive approach to address this hypothesis by quantifying mapped interactions between groups defined by similarities in sexual behavior along a virus phylogeny while discussing power and sample size considerations. Data from the Swiss HIV Cohort Study on condom use and hepatitis C virus (HCV) sequences served as proof-of-concept. In this case, a strict inclusion criteria contrasting with low HCV prevalence hindered our possibilities to identify significant relationships. This manuscript serves as guide for studies aimed at characterizing interactions between behavioral patterns and transmission networks. Large transmission networks such as those of HIV or COVID-19 are prime candidates for applying this methodological approach

Competition and Complementarity in Diffusion: The Case of Octane

The standard ontogenic (life-cycle) model of technological evolution can be characterized briefly as follows (Ayres, 1987): (1) a radical invention (birth) creates a new technology; (2) it is commercialized on the basis of performance and rapidly developed by a series of improvements and modifications (infancy); (3) it is successful enough in the marketplace to attract many variants and imitators who hope to exploit a growing market (adolescence); (4) the pace of technological change finally slows down enough to permit standardization and exploitation of economies of scale, and competition on the basis of price rather than performance (maturity); and finally a new and better technology supplants it (senescence)