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1.
Eur Spine J ; 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39014076

RESUMO

PURPOSE: The study aims to establish the diagnostic accuracy of community spine x-rays for brace candidates. METHODS: A review of adolescent idiopathic scoliosis patients seen for initial visit at a tertiary care pediatric hospital was conducted (n = 170). The index test was the pre-referral community spine x-ray interpreted by a community radiologist. Measures of diagnostic accuracy for the index test were determined against the reference standard if images were obtained within 90 days (n = 111). The reference standard was the 3-foot standing EOS spine x-ray evaluated by spine specialists. Diagnostic criterion for a brace candidate was dichotomized by Cobb angle range (25-40°) according to Scoliosis Research Society criteria. Risser stage was not included given significant missing data in index reports. To mitigate the uncertainty around true progression, sensitivity analyses were conducted on a sub-sample of data when index test was within 60 days of the reference standard (n = 67). RESULTS: Accuracy of the community spine x-ray to detect a brace candidate was 65.8% (95% CI 56.2-74.5). Sensitivity of the index test was 65.4% with a false negative rate of 34.6%. Specificity was 66.1% with a false positive rate of 33.9%. Positive and negative predictive values were 63.0% and 68.4%, respectively. Of the total number of brace candidates (n = 52), 32.7% were missed because of underestimation in Cobb angle (95% CI 21.5-46.2). The proportion of missed brace candidates because of underestimation was unchanged with 60-day data (p = 0.37). CONCLUSIONS: Inaccuracies in community spine radiology may lead to missed opportunities for non-operative treatment.

2.
J Am Acad Orthop Surg ; 32(14): e683-e694, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38967987

RESUMO

Surgical fixation of pediatric pelvic ring injuries is gaining popularity to avoid the poor long-term outcomes of pelvic asymmetry. The surgical techniques and fixation choices depend on the individual injuries affecting the anterior and posterior pelvic ring areas. The immature bony pelvis of young children has anatomic differences including soft bones, elastic ligaments, and the presence of growth centers. Understanding the unique pediatric lesions with unstable pelvic fractures is essential for treatment decisions. Anterior lesions include pubic symphysis disruption through the pubic apophysis, single ramus fractures, pubic rami fractures through the triradiate cartilage, and/or the ischiopubic synchondrosis; ischiopubic ramus infolding injury; or the unstable superior and inferior quadrant lesions. Posterior pelvic lesions include iliac wing infolding and sacroiliac joint dislocation or transiliac (crescent) fracture/dislocations through the iliac apophysis growth plate. Pubic symphysis and sacroiliac disruptions are physeal injuries in children, and they have excellent healing potential. External fixation is an ideal choice for anterior ring fixation including bony and pubic symphysis injuries. Posterior lesions are mostly sacroiliac joint disruptions with iliac apophysis separation that can serve as a landmark for vertical displacement correction. Posterior lesions can be treated by percutaneous iliosacral screw fixation or open reduction techniques.


Assuntos
Fraturas Ósseas , Ossos Pélvicos , Humanos , Fraturas Ósseas/cirurgia , Fraturas Ósseas/diagnóstico por imagem , Ossos Pélvicos/lesões , Ossos Pélvicos/cirurgia , Criança , Articulação Sacroilíaca/lesões , Articulação Sacroilíaca/cirurgia , Fixação de Fratura/métodos , Fixação Interna de Fraturas/métodos , Sínfise Pubiana/lesões
3.
J Safety Res ; 89: 152-159, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38858038

RESUMO

BACKGROUND: The COVID-19 pandemic altered traffic patterns worldwide, potentially impacting pedestrian and bicyclists safety in urban areas. In Toronto, Canada, work from home policies, bicycle network expansion, and quiet streets were implemented to support walking and cycling. We examined pedestrian and bicyclist injury trends from 2012 to 2022, utilizing police-reported killed or severely injured (KSI), emergency department (ED) visits and hospitalization data. METHODS: We used an interrupted time series design, with injury counts aggregated quarterly. We fit a negative binomial regression using a Bayesian modeling approach to data prior to the pandemic that included a secular time trend, quarterly seasonal indicator variables, and autoregressive terms. The differences between observed and expected injury counts based on pre-pandemic trends with 95% credible intervals (CIs) were computed. RESULTS: There were 38% fewer pedestrian KSI (95%CI: 19%, 52%), 35% fewer ED visits (95%CI: 28%, 42%), and 19% fewer hospitalizations (95%CI: 2%, 32%) since the beginning of the COVID-19 pandemic. A reduction of 35% (95%CI: 7%, 54%) in KSI bicyclist injuries was observed, but However, ED visits and hospitalizations from bicycle-motor vehicle collisions were compatible with pre-pandemic trends. In contrast, for bicycle injuries not involving motor vehicles, large increases were observed for both ED visits, 73% (95% CI: 49%, 103%) and for hospitalization 108% (95% CI: 38%, 208%). CONCLUSION: New road safety interventions during the pandemic may have improved road safety for vulnerable road users with respect to collisions with motor vehicles; however, further investigation into the risk factors for bicycle injuries not involving motor vehicles is required.


Assuntos
Acidentes de Trânsito , Ciclismo , COVID-19 , Serviço Hospitalar de Emergência , Análise de Séries Temporais Interrompida , Ferimentos e Lesões , Humanos , COVID-19/epidemiologia , Acidentes de Trânsito/estatística & dados numéricos , Ciclismo/lesões , Ciclismo/estatística & dados numéricos , Ferimentos e Lesões/epidemiologia , Adulto , Masculino , Feminino , Ontário/epidemiologia , Pessoa de Meia-Idade , Serviço Hospitalar de Emergência/estatística & dados numéricos , SARS-CoV-2 , Pedestres/estatística & dados numéricos , Adolescente , Idoso , Pandemias , Adulto Jovem , Criança , Caminhada/lesões , Caminhada/estatística & dados numéricos , Hospitalização/estatística & dados numéricos , Pré-Escolar , Teorema de Bayes , Lactente
4.
J Phys Chem A ; 128(22): 4548-4560, 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38713032

RESUMO

We present results from a covariance ion imaging study, which employs extensive filtering, on the relationship between fragment momenta to gain deeper insight into photofragmentation dynamics. A new data analysis approach is introduced that considers the momentum partitioning between the fragments of the breakup of a molecular polycation to disentangle concurrent fragmentation channels, which yield the same ion species. We exploit this approach to examine the momentum exchange relationship between the products, which provides direct insight into the dynamics of molecular fragmentation. We apply these techniques to extensively characterize the dissociation of 1-iodopropane and 2-iodopropane dications prepared by site-selective ionization of the iodine atom using extreme ultraviolet intense femtosecond laser pulses with a photon energy of 95 eV. Our assignments are supported by classical simulations, using parameters largely obtained directly from the experimental data.

5.
Child Abuse Negl ; 153: 106828, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38749147

RESUMO

BACKGROUND: There is limited understanding of the hypothesized association between the Ehlers-Danlos Syndromes (EDS), hypermobility and fractures in children. Despite this, EDS and hypermobility continue to be raised in the legal setting as possible causes of unexplained fractures in infants where there is a concern for physical abuse. Further understanding is needed regarding fractures in children with EDS and hypermobility. OBJECTIVE: This study assessed fracture prevalence and characteristics in children diagnosed with EDS and Generalized Joint Hypermobility (GJH). The secondary outcome was fracture prevalence in infants <1 year of age. PARTICIPANTS AND SETTING: Children aged <18 years with EDS or GJH seen in a single-center EDS clinic from April 2017 to December 2021 were included. Diagnoses were based on the 2017 international classification. Exclusion criteria were concurrent medical conditions associated with bone fragility. METHODS: This retrospective descriptive study examined variables including fracture history, fracture location, fracture type, age of sustaining fracture, and injury mechanism. Descriptive statistics were used for analysis. RESULTS: Fracture prevalence was 34.6 % (9/26, 95 % CI [16.3, 52.9]) in the EDS population and 25.4 % (15/59, 95 % CI [14.3, 36.5]) in the GJH population. No fractures occurred in infancy. Most fractures occurred in the limbs. There were no rib or skull fractures. Most fractures were the result of an identifiable injury event. CONCLUSION: In a cohort of children with formally diagnosed EDS or GJH, fractures occurred commonly in ambulatory children and generally in the limbs from identifiable events. This study does not support EDS or GJH as a cause of fractures in infancy.


Assuntos
Síndrome de Ehlers-Danlos , Fraturas Ósseas , Instabilidade Articular , Humanos , Síndrome de Ehlers-Danlos/epidemiologia , Síndrome de Ehlers-Danlos/complicações , Instabilidade Articular/epidemiologia , Masculino , Feminino , Prevalência , Estudos Retrospectivos , Pré-Escolar , Criança , Lactente , Fraturas Ósseas/epidemiologia , Fraturas Ósseas/etiologia , Adolescente
6.
BMJ Open ; 14(4): e085850, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38631827

RESUMO

INTRODUCTION: Improving sustainable transportation options will help cities tackle growing challenges related to population health, congestion, climate change and inequity. Interventions supporting active transportation face many practical and political hurdles. Implementation science aims to understand how interventions or policies arise, how they can be translated to new contexts or scales and who benefits. Sustainable transportation interventions are complex, and existing implementation science frameworks may not be suitable. To apply and adapt implementation science for healthy cities, we have launched our mixed-methods research programme, CapaCITY/É. We aim to understand how, why and for whom sustainable transportation interventions are successful and when they are not. METHODS AND ANALYSIS: Across nine Canadian municipalities and the State of Victoria (Australia), our research will focus on two types of sustainable transportation interventions: all ages and abilities bicycle networks and motor vehicle speed management interventions. We will (1) document the implementation process and outcomes of both types of sustainable transportation interventions; (2) examine equity, health and mobility impacts of these interventions; (3) advance implementation science by developing a novel sustainable transportation implementation science framework and (4) develop tools for scaling up and scaling out sustainable transportation interventions. Training activities will develop interdisciplinary scholars and practitioners able to work at the nexus of academia and sustainable cities. ETHICS AND DISSEMINATION: This study received approval from the Simon Fraser University Office of Ethics Research (H22-03469). A Knowledge Mobilization Hub will coordinate dissemination of findings via a website; presentations to academic, community organisations and practitioner audiences; and through peer-reviewed articles.


Assuntos
Fortalecimento Institucional , Ciência da Implementação , Humanos , Cidades , Canadá , Vitória
7.
Plant Physiol Biochem ; 210: 108653, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38670029

RESUMO

Edible plant seeds provide a relatively inexpensive source of protein and make up a large part of nutrients for humans. Plant seeds accumulate storage proteins during seed development. Seed storage proteins act as a reserve of nutrition for seed germination and seedling growth. However, seed storage proteins may be allergenic, and the prevalence of food allergy has increased rapidly in recent years. The 11S globulins account for a significant number of known major food allergens. They are of interest to the public and the agricultural industry because of food safety concerns and the need for crop enhancement. We sought to determine the crystal structure of Cor a 9, the 11 S storage protein of hazelnut and a food allergen. The structure was refined to 1.92 Å, and the R and Rfree for the refined structure are 17.6% and 22.5%, respectively. The structure of Cor a 9 showed a hetero hexamer of an 11S seed storage protein for the first time. The hexamer was two trimers associated back-to-back. Two long alpha helixes at the C-terminal end of the acidic domain of one of the Cor a 9 isoforms lay at the trimer-trimer interface's groove. These data provided much-needed information about the allergenicity of the 11S seed proteins. The information may also facilitate a better understanding of the folding and transportation of 11S seed storage proteins.


Assuntos
Corylus , Proteínas de Armazenamento de Sementes , Corylus/química , Corylus/metabolismo , Proteínas de Armazenamento de Sementes/química , Proteínas de Armazenamento de Sementes/metabolismo , Cristalografia por Raios X , Sementes/metabolismo , Sementes/química , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Globulinas/química , Globulinas/metabolismo , Sequência de Aminoácidos , Multimerização Proteica , Modelos Moleculares
8.
Kidney Med ; 6(3): 100775, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38435066

RESUMO

Vaccinating patients receiving dialysis may prevent morbidity and mortality in this vulnerable population. The National Forum of End-Stage Renal Disease Networks (the Forum) published a revised vaccination toolkit in 2021 to update evidence and recommendations on vaccination for patients receiving dialysis. Significant changes in the last 10 years include more data supporting the use of a high-dose influenza vaccine, the introduction of the Heplisav-B vaccine for hepatitis B, and changes in pneumococcal vaccines, including the approval of the PCV15 and PCV20 to replace the PCV13 and PPSV23 vaccines. Additional key items include the introduction of vaccines against severe acute respiratory syndrome coronavirus 2, the virus that causes coronavirus disease 2019 (COVID-19), and a new vaccine to prevent respiratory syncytial virus disease. Historically, influenza and pneumococcal vaccinations were routinely administered by dialysis facilities, and because of possible risks of hematogenous spread of hepatitis B, dialysis providers often have detailed hepatitis B vaccine protocols. In March 2021, COVID-19 vaccines were made available for dialysis facilities to administer, although with the end of the public health emergency, vaccine policies by dialysis facilities against COVID-19 remains uncertain. The respiratory syncytial virus vaccine was authorized in 2023, and how dialysis facilities will approach this vaccine also remains uncertain. This review summarizes the Forum's vaccination toolkit and discusses the role of the dialysis facility in vaccinating patients to reduce the risk of severe infections.

9.
Inj Prev ; 30(2): 161-166, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38195658

RESUMO

INTRODUCTION: Pedestrian and cyclist injuries represent a preventable burden to Canadians. Police-reported collision data include information on where such collisions occur but under-report the number of collisions. The primary objective of this study was to compare the number of police-reported collisions with emergency department (ED) visits and hospitalisations in Toronto, Canada. METHODS: Police-reported collisions were provided by Toronto Police Services (TPS). Data included the location of the collision, approximate victim age and whether the pedestrian or cyclist was killed or seriously injured. Health services data included ED visits in the National Ambulatory Care Reporting System and hospitalisations from the Discharge Abstract Database using ICD-10 codes for pedestrian and cycling injuries. Data were compared from 2016 to 2021. RESULTS: Injuries reported in the health service data were higher than those reported in the TPS for cyclists and pedestrians. The discrepancy was the largest for cyclists treated in the ED, with TPS capturing 7.9% of all cycling injuries. Cyclist injuries not involving a motor vehicle have increased since the start of the pandemic (from 3629 in 2019 to 5459 in 2020 for ED visits and from 251 in 2019 to 430 for hospital admissions). IMPLICATIONS: While police-reported data are important, it under-reports the burden. There have been increases in cyclist collisions not involving motor vehicles and decreases in pedestrian injuries since the start of the pandemic. The results suggest that using police data alone when planning for road safety is inadequate, and that linkage with other health service data is essential.


Assuntos
População Norte-Americana , Pedestres , Ferimentos e Lesões , Humanos , Acidentes de Trânsito/prevenção & controle , Canadá/epidemiologia , Polícia , Ciclismo/lesões , Ferimentos e Lesões/epidemiologia
10.
Int J Radiat Oncol Biol Phys ; 117(5): 1298, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37980146
11.
Phys Rev Lett ; 131(14): 143001, 2023 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-37862660

RESUMO

Directly imaging structural dynamics involving hydrogen atoms by ultrafast diffraction methods is complicated by their low scattering cross sections. Here we demonstrate that megaelectronvolt ultrafast electron diffraction is sufficiently sensitive to follow hydrogen dynamics in isolated molecules. In a study of the photodissociation of gas phase ammonia, we simultaneously observe signatures of the nuclear and corresponding electronic structure changes resulting from the dissociation dynamics in the time-dependent diffraction. Both assignments are confirmed by ab initio simulations of the photochemical dynamics and the resulting diffraction observable. While the temporal resolution of the experiment is insufficient to resolve the dissociation in time, our results represent an important step towards the observation of proton dynamics in real space and time.

12.
J Phys Chem Lett ; 14(31): 7126-7133, 2023 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-37534743

RESUMO

Recent developments in X-ray free-electron lasers have enabled a novel site-selective probe of coupled nuclear and electronic dynamics in photoexcited molecules, time-resolved X-ray photoelectron spectroscopy (TRXPS). We present results from a joint experimental and theoretical TRXPS study of the well-characterized ultraviolet photodissociation of CS2, a prototypical system for understanding non-adiabatic dynamics. These results demonstrate that the sulfur 2p binding energy is sensitive to changes in the nuclear structure following photoexcitation, which ultimately leads to dissociation into CS and S photoproducts. We are able to assign the main X-ray spectroscopic features to the CS and S products via comparison to a first-principles determination of the TRXPS based on ab initio multiple-spawning simulations. Our results demonstrate the use of TRXPS as a local probe of complex ultrafast photodissociation dynamics involving multimodal vibrational coupling, nonradiative transitions between electronic states, and multiple final product channels.

13.
Nature ; 618(7967): 917-920, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37380688

RESUMO

When main-sequence stars expand into red giants, they are expected to engulf close-in planets1-5. Until now, the absence of planets with short orbital periods around post-expansion, core-helium-burning red giants6-8 has been interpreted as evidence that short-period planets around Sun-like stars do not survive the giant expansion phase of their host stars9. Here we present the discovery that the giant planet 8 Ursae Minoris b10 orbits a core-helium-burning red giant. At a distance of only 0.5 AU from its host star, the planet would have been engulfed by its host star, which is predicted by standard single-star evolution to have previously expanded to a radius of 0.7 AU. Given the brief lifetime of helium-burning giants, the nearly circular orbit of the planet is challenging to reconcile with scenarios in which the planet survives by having a distant orbit initially. Instead, the planet may have avoided engulfment through a stellar merger that either altered the evolution of the host star or produced 8 Ursae Minoris b as a second-generation planet11. This system shows that core-helium-burning red giants can harbour close planets and provides evidence for the role of non-canonical stellar evolution in the extended survival of late-stage exoplanetary systems.

14.
Inj Prev ; 29(4): 363-366, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37336630

RESUMO

Walk Score is a common index used to estimate how suitable the built environment is for walking. Although Walk Score has been extensively validated as a measure of walkability and walking, there are limited studies examining whether commonly used constructs of walkability are associated with traffic safety in children. This study examined the association between Walk Score and child pedestrian injury controlling for observed walking exposure in school zones in Calgary, Toronto and Montreal, Canada. Results indicate that a higher Walk Score was associated with more child pedestrian injuries in all three cities, even after controlling for walking exposure. School travel planning should consider established individual pedestrian collision risk and individual factors rather than assuming a highly walkable environment is also a safe pedestrian environment.


Assuntos
Acidentes de Trânsito , Pedestres , Humanos , Criança , Acidentes de Trânsito/prevenção & controle , Instituições Acadêmicas , Canadá , Caminhada/lesões , Características de Residência , Planejamento Ambiental
15.
Am J Epidemiol ; 2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37288501

RESUMO

Traffic-calming measures (TCMs) are physical modifications to the road network aimed at making the roads safer. Although studies have reported reductions in road crashes and injuries tied to the presence of TCMs, they have been criticized for their pre-post designs. This study aims to complement our knowledge of TCMs effectiveness by assessing their impact using a longitudinal design. The implementation of eight TCMs, including curb extensions and speed humps, was evaluated at the intersections and census tract levels in Montreal, Canada from 2012 to 2019. The primary outcome was fatal or serious collisions among all road users. Inference was performed using a Bayesian implementation of Conditional Poisson regression in which random effects were used to account for the spatiotemporal variation in collisions. TCMs were generally implemented on local roads, although most collisions occurred on arterial roads. Overall, there was weak evidence that TCMs were associated with study outcomes. However, subgroup analyses of intersections on local roads suggested a reduction in collision rates due to TCMs (median IRR: 0.31; 95% Credible Interval: 0.12 - 0.86). To improve road safety, effective counterparts of TCMs on arterial roads must be identified and implemented.

16.
Inj Prev ; 29(5): 407-411, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37295929

RESUMO

BACKGROUND: Injuries resulting from collisions between a bicyclist and driver are preventable and have high economic, personal and societal costs. Studying the language choices used by police officers to describe factors responsible for child bicyclist-motor vehicle collisions may help shift prevention efforts away from vulnerable road users to motorists and the environment. The overall aim was to investigate how police officers attribute blame in child (≤18 years) bicycle-motor vehicle collision scenarios. METHODS: A document analysis approach was used to analyse Alberta Transportation police collision reports from Calgary and Edmonton (2016-2017). Collision reports were categorised by the research team according to perceived blame (child, driver, both, neither, unsure). Content analysis was then used to examine police officer language choices. A narrative thematic analysis of the individual, behavioural, structural and environmental factors leading to collision blame was then conducted. RESULTS: Of 171 police collision reports included, child bicyclists were perceived to be at fault in 78 reports (45.6%) and adult drivers were perceived at fault in 85 reports (49.7%). Child bicyclists were portrayed through language choices as being irresponsible and irrational, leading to interactions with drivers and collisions. Risk perception issues were also mentioned frequently in relation to poor decisions made by child bicyclists. Most police officer reports discussed road user behaviours, and children were frequently blamed for collisions. CONCLUSIONS: This work provides an opportunity to re-examine perceptions of factors related to motor vehicle and child bicyclist collisions with a view to prevention.


Assuntos
Ciclismo , Polícia , Adulto , Humanos , Criança , Ciclismo/lesões , Acidentes de Trânsito/prevenção & controle , Veículos Automotores , Alberta
17.
J Psychoactive Drugs ; : 1-15, 2023 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-37385217

RESUMO

Evidence suggests that psilocybin has therapeutic benefit for treating depression. However, there is little consensus regarding the mechanism by which psilocybin elicits antidepressant effects. This systematic review summarizes existing evidence. Ovid MEDLINE, EMBASE, psychINFO, and Web of Science were searched, for both human and animal studies, using a combination of MeSH Terms and free-text keywords in September 2021. No other mood disorders or psychiatric diagnoses were included. Original papers in English were included. The PRISMA framework was followed for the screening of papers. Two researchers screened the retrieved articles from the literature search, and a third researcher resolved any conflicts. Of 2,193 papers identified, 49 were selected for full-text review. 14 articles were included in the qualitative synthesis. Six supported psilocybin's mechanism of antidepressant action via changes to serotonin or glutamate receptor activity and three papers found an increase in synaptogenesis. Thirteen papers investigated changes in non-receptor or pathway-specific brain activity. Five papers found changes in functional connectivity or neurotransmission, most commonly in the hippocampus or prefrontal cortex. Several neuroreceptors, neurotransmitters, and brain areas are thought to be involved in psilocybin's ability to mitigate depressive symptoms. Psilocybin appears to alter cerebral blood flow to the amygdala and prefrontal cortex, but the evidence on changes in functional connectivity and specific receptor activity remains sparse. The lack of consensus between studies suggests that psilocybin's mechanism of action may involve a variety of pathways, demonstrating the need for more studies on psilocybin's mechanism of action as an antidepressant.

18.
Nature ; 617(7962): 701-705, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37198481

RESUMO

Temperate Earth-sized exoplanets around late-M dwarfs offer a rare opportunity to explore under which conditions planets can develop hospitable climate conditions. The small stellar radius amplifies the atmospheric transit signature, making even compact secondary atmospheres dominated by N2 or CO2 amenable to characterization with existing instrumentation1. Yet, despite large planet search efforts2, detection of low-temperature Earth-sized planets around late-M dwarfs has remained rare and the TRAPPIST-1 system, a resonance chain of rocky planets with seemingly identical compositions, has not yet shown any evidence of volatiles in the system3. Here we report the discovery of a temperate Earth-sized planet orbiting the cool M6 dwarf LP 791-18. The newly discovered planet, LP 791-18d, has a radius of 1.03 ± 0.04 R⊕ and an equilibrium temperature of 300-400 K, with the permanent night side plausibly allowing for water condensation. LP 791-18d is part of a coplanar system4 and provides a so-far unique opportunity to investigate a temperate exo-Earth in a system with a sub-Neptune that retained its gas or volatile envelope. On the basis of observations of transit timing variations, we find a mass of 7.1 ± 0.7 M⊕ for the sub-Neptune LP 791-18c and a mass of [Formula: see text] for the exo-Earth LP 791-18d. The gravitational interaction with the sub-Neptune prevents the complete circularization of LP 791-18d's orbit, resulting in continued tidal heating of LP 791-18d's interior and probably strong volcanic activity at the surface5,6.

20.
Commun Chem ; 6(1): 81, 2023 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-37106058

RESUMO

Filming atomic motion within molecules is an active pursuit of molecular physics and quantum chemistry. A promising method is laser-induced Coulomb Explosion Imaging (CEI) where a laser pulse rapidly ionizes many electrons from a molecule, causing the remaining ions to undergo Coulomb repulsion. The ion momenta are used to reconstruct the molecular geometry which is tracked over time (i.e., filmed) by ionizing at an adjustable delay with respect to the start of interatomic motion. Results are distorted, however, by ultrafast motion during the ionizing pulse. We studied this effect in water and filmed the rapid "slingshot" motion that enhances ionization and distorts CEI results. Our investigation uncovered both the geometry and mechanism of the enhancement which may inform CEI experiments in many other polyatomic molecules.

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