Longitudinal development of initial, chronic and mucoid Pseudomonas aeruginosa infection in young children with cystic fibrosis

BACKGROUND: While the emergence of chronic and mucoid Pseudomonas aeruginosa (Pa) infection are both associated with poorer outcomes among CF patients, their relationship is poorly understood. We examined the longitudinal relationship of incident, chronic and mucoid Pa in a contemporary, young CF cohort in the current era of Pa eradication therapy. METHODS: This retrospective cohort was comprised of patients in the U.S. CF Foundation Patient Registry born 2006-2015, diagnosed before age 2, and with at least 3 respiratory cultures annually. Incidence and age-specific prevalence of Pa infection stages (initial and chronic [≥ 3Pa+cultures in prior year]) and of mucoid Pa were summarized. Transition times and the interaction between Pa stage and acquisition of mucoid Pa were examined via Cox models. RESULTS: Among the 5592 CF patients in the cohort followed to a mean age of 5.5years, 64% (n=3580) acquired Pa. Of those, 13% (n=455) developed chronic Pa and 17% (n=594) cultured mucoid Pa. Among those with mucoid Pa, 36% (211/594) had it on their first recorded Pa+culture, while mucoid Pa emerged at or after entering the chronic stage in 12% (73/594). Mucoidy was associated with significantly increased risk of transition to chronic Pa infection (HR=2.59, 95% CI 2.11, 3.19). CONCLUSIONS: Two-thirds of early-diagnosed young children with CF acquired Pa during a median 5.6years of follow up, among whom 13% developed chronic Pa and 17% acquired mucoid Pa. Contrary to our hypothesis, 87% of young children who developed mucoid Pa did so before becoming chronically infected

Absence of lattice strain anomalies at the electronic topological transition in zinc at high pressure

High pressure structural distortions of the hexagonal close packed (hcp) element zinc have been a subject of controversy. Earlier experimental results and theory showed a large anomaly in lattice strain with compression in zinc at about 10 GPa which was explained theoretically by a change in Fermi surface topology. Later hydrostatic experiments showed no such anomaly, resulting in a discrepancy between theory and experiment. We have computed the compression and lattice strain of hcp zinc over a wide range of compressions using the linearized augmented plane wave (LAPW) method paying special attention to k-point convergence. We find that the behavior of the lattice strain is strongly dependent on k-point sampling, and with large k-point sets the previously computed anomaly in lattice parameters under compression disappears, in agreement with recent experiments.Comment: 9 pages, 6 figures, Phys. Rev. B (in press

A supergene determines highly divergent male reproductive morphs in the ruff

Three strikingly different alternative male mating morphs (aggressive 'independents', semicooperative 'satellites' and female-mimic 'faeders') coexist as a balanced polymorphism in the ruff, Philomachus pugnax, a lek-breeding wading bird1, 2, 3. Major differences in body size, ornamentation, and aggressive and mating behaviors are inherited as an autosomal polymorphism4, 5. We show that development into satellites and faeders is determined by a supergene6, 7, 8 consisting of divergent alternative, dominant and non-recombining haplotypes of an inversion on chromosome 11, which contains 125 predicted genes. Independents are homozygous for the ancestral sequence. One breakpoint of the inversion disrupts the essential CENP-N gene (encoding centromere protein N), and pedigree analysis confirms the lethality of homozygosity for the inversion. We describe new differences in behavior, testis size and steroid metabolism among morphs and identify polymorphic genes within the inversion that are likely to contribute to the differences among morphs in reproductive traits

Discovery of the Millisecond X-Ray Pulsar HETE J1900.1-2455

We report the discovery of millisecond pulsations from the low-mass X-ray binary HETE J1900.1-2455 which was discovered by the detection of a type I X-ray burst by the High Energy Transient Explorer 2 (HETE-2). The neutron star emits coherent pulsations at 377.3 Hz and is in an 83.3 minute circular orbit with a companion with a mass greater than 0.016 solar masses and likely less than 0.07 solar masses. The companion star's Roche lobe could be filled by a brown dwarf with no need for heating or non-standard evolution. During one interval with an unusually high X-ray flux, the source produced quasiperiodic oscillations with a single peak at 883 Hz and on subsequent days, the pulsations were suppressed. We consider the distribution of spin versus orbital period in neutron star low-mass X-ray binaries.Comment: 8 pages, to appear in Ap

Survey of the impact of COVID-19 on oncologists’ decision making in cancer

PURPOSE To understand readiness measures taken by oncologists to protect patients and health care workers from the novel coronavirus (COVID-19) and how their clinical decision making was influenced by the pandemic. METHODS An online survey was conducted between March 24 and April 29, 2020. RESULTS A total of 343 oncologists from 28 countries participated. The median age was 43 years (range, 29-68 years), and the majority were male (62%). At the time of the survey, nearly all participants self-reported an outbreak in their country (99.7%). Personal protective equipment was available to all participants, of which surgical mask was the most common (n = 308; 90%). Telemedicine, in the form of phone or video encounters, was common and implemented by 80% (n = 273). Testing patients with cancer for COVID-19 via reverse transcriptase polymerase chain reaction before systemic treatment was not routinely implemented: 58% reported no routine testing, 39% performed testing in selected patients, and 3% performed systematic testing in all patients. The most significant factors influencing an oncologist’s decision making regarding choice of systemic therapy included patient age and comorbidities (81% and 92%, respectively). Although hormonal treatments and tyrosine kinase inhibitors were considered to be relatively safe, cytotoxic chemotherapy and immune therapies were perceived as being less safe or unsafe by participants. The vast majority of participants stated that during the pandemic they would use less chemotherapy, immune checkpoint inhibitors, and steroids. Although treatment in neoadjuvant, adjuvant, and first-line metastatic disease was less affected, most of the participants stated that they would be more hesitant to recommend second- or third-line therapies in metastatic disease. CONCLUSION Decision making by oncologists has been significantly influenced by the ongoing COVID-19 pandemic

Origins of the Ambient Solar Wind: Implications for Space Weather

The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress -- in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue connected with a 2016 ISSI workshop on "The Scientific Foundations of Space Weather." 44 pages, 9 figure

The effect of asymmetries on stock index return value-at-risk estimates

It is widely accepted that equity return volatility increases more following negative shocks rather than positive shocks. However, much of value-at-risk (VaR) analysis relies on the assumption that returns are normally distributed (a symmetric distribution). This article considers the effect of asymmetries on the evaluation and accuracy of VaR by comparing estimates based on various models