scholarly journals Correcting the effect of stellar spots on ARIEL transmission spectra

2020 ◽  
Vol 501 (2) ◽  
pp. 1733-1747
Author(s):  
G Cracchiolo ◽  
G Micela ◽  
G Peres
Keyword(s):  
Temporal Evolution ◽  
Transmission Spectra ◽  
Stellar Spectrum ◽  
Stellar Spectra ◽  
Chi Squared ◽  
Minimization Procedure ◽  
Systematic Biases ◽  
Planetary Transmission ◽  
The Impact ◽  
Average Uncertainty

ABSTRACT The goal of this study is to assess the impact of the stellar spots on the extraction of the planetary transmission spectra observed by ARIEL. We develop a method to model the stellar spectrum of a star in the presence of spots by using the out-of-transit observations. It is based on a chi squared minimization procedure of the out-of-transit spectrum on a grid of stellar spectra with different sizes and temperatures of the spots. The approach allows us also to study the temporal evolution of the spots when comparing stellar spectra observed at different epochs. We also present a method to correct the transit depth variations due to non-occulted stellar spots and estimate the error we introduce if we apply the same correction to crossings over the stellar spots. The method is tested on three types of stellar targets that ARIEL will observe in its 4-yr mission lifetime. In all the explored cases, the approach allows us to reliably recover the spot parameters (size and temperature) from out-of-transit observations and, for non-occulted spots, to confidently recover the planetary atmosphere transmission spectrum within the noise level (with average uncertainty of at most $3.3{{\ \rm per\ cent}}$ of the planetary signal). Conversely, we find systematic biases in the inferred planetary spectra due to the occulted spots, with measurable effects for the brightest targets especially for more contrasted spots.

The impact of time-dependent stellar activity on the atmospheric chemistry and observability of exoplanets

2021 ◽  
Author(s):  
Amy Louca ◽  
Yamila Miguel ◽  
Shang-Min Tsai
Keyword(s):  
Atmospheric Chemistry ◽  
Emission Spectra ◽  
Time Dependent ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Stellar Spectrum ◽  
Stellar Spectra ◽  
Chemical Tracers ◽  
Atmospheric Escape ◽  
The Impact

<p class="p1">Observations of exoplanets used to characterize the chemistry and dynamics of atmospheres have developed considerably throughout the years. Nonetheless, it remains a difficult task to give a full and detailed description using solely observations. With future space missions such as JWST and ARIEL, both expected to be launched within this decade, it becomes even more crucial to be able to fully explain and predict the underlying chemistry and physics involved. In this research, we focus on modeling star-planet interactions by using synthetic flare spectra to predict chemical tracers for future missions. We make use of a chemical kinetics code that includes synthetic time-dependent stellar spectra and thermal atmospheric escape to simulate the atmospheres of known exoplanets. Using a radiative transfer model we then retrieve emission spectra. This ongoing study is focused on various known planetary systems of which the stellar spectrum has been obtained by the (mega-)MUSCLES collaboration. Preliminary results on these systems show that stellar flares and thermal escape can have a significant effect on the chemistry in atmospheres. </p>

scholarly journals Correcting the effect of stellar spots on ARIEL transmission spectra II. The limb darkening effect

2021 ◽  
Author(s):  
G Cracchiolo ◽  
G Micela ◽  
G Morello ◽  
G Peres
Keyword(s):  
Impact Parameter ◽  
Transmission Spectrum ◽  
Stellar Disk ◽  
Transmission Spectra ◽  
Potential Bias ◽  
Temperature Contrast ◽  
Planetary Transmission ◽  
Limb Darkening ◽  
The Impact

Abstract This paper is part of an effort to correct the transmission spectra of a transiting planet orbiting an active star. In Paper I (Cracchiolo et al. 2020) we have demonstrated a methodology to minimize the potential bias induced by unocculted star spots on the transmission spectrum, assuming a spot model parameterized by filling factor and temperature. In this work we introduce the limb darkening effect, therefore the position of the spot in the stellar disk and the impact parameter of the transiting planet now play a key role. The method is tested on simulations of planetary transits of three representative kinds of planetary systems, at ARIEL resolution. We find that a realistic treatment of the limb darkening is required to reliably estimate both the spots parameters and the transmission spectrum of the transiting planet. Furthermore, we show that the influence of the spots on the retrieval of the planetary transmission spectrum is significant for spots close to the center of the star, covering a fraction greater than 0.05 and with a temperature contrast greater than 500 K, and that for these cases our method can confidently extract the transmission spectrum and the impact parameter of the transiting planet for both cases of occulted and not occulted spots, provided that we have an accurate characterization of the stellar parameters and a reliable simulator of the instrument performances.

scholarly journals Characteristics of visits and predictors of admission from a paediatric emergency room in Saudi Arabia

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mohammad H. Al-Qahtani ◽  
Abdullah A. Yousef ◽  
Bassam H. Awary ◽  
Waleed H. Albuali ◽  
Mohammed A. Al Ghamdi ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Hospital Admission ◽  
Hospital Admissions ◽  
Binary Logistic Regression ◽  
Total Sample ◽  
Age Group ◽  
Chi Squared ◽  
Improper Use ◽  
Level Shifts ◽  
The Impact

Abstract Background The Emergency Repartment (ER) is one of the most used areas in healthcare institutions. Problems with over utilisation and overcrowding have been reported worldwide. This study aims at examining the characteristics of paediatric ER visits, the rate of hospital admissions and its associated predictors at King Fahd Hospital of the University in the Eastern Province of Saudi Arabia. Methods This is a retrospective, medical record-based study. Variables included gender, age group, nationality, complaints, Triage level, shifts and seasons. Descriptive statistics were reported as frequencies/percentages. P-values were obtained through a Chi-Squared test while unadjusted and adjusted odds ratios were estimated by binary logistic regression, where admission was considered as the outcome. Results The total number of paediatric patients included was 46,374, and only 2.5% were admitted. Males comprised 55.4% while females comprised 44.6%. The most common age group were toddlers, and 92.4% of the total sample were Saudis. The most common complaint was fever (26.9%) followed by respiratory symptoms (24.9%). Only 7 patients (0.02%) were classified as triage I (Resuscitation), and most were triage IV (Less urgent) (71.0%). Most visits occurred during the winter months. Adjusted ORs showed that neonates had higher odds of admission (OR = 3.85, 95%CI = 2.57–5.76). Moreover, those presenting with haematological conditions showed an OR of 65.49 (95%CI = 47.85–89.64), followed by endocrine conditions showing an OR of 34.89 (95%CI = 23.65–51.47). Triage I had a very high odds of admission (OR = 19.02, 95%CI = 2.70–133.76), whereas triage V was associated with a very low odds of admission (OR = 0.30, 95%CI = 0.23–0.38). Conclusions A low rate of hospital admission was found in comparison with other rates worldwide. This was mostly attributed to an alarmingly high number of non-urgent ER visits. This further emphasises the problem with improper use of ER services, as these cases should be more appropriately directed towards primary healthcare centres. Further studies to examine the impact of prioritising patients in the ER based on the identified predictors of hospital admission, in addition to the standard triage system, are suggested.

scholarly journals An Investigation of Soundscape Factors Influencing Perceptions of Square Dancing in Urban Streets: A Case Study in a County Level City in China

2019 ◽  
Vol 16 (5) ◽  
pp. 840 ◽  
Author(s):  
Jieling Xiao ◽  
Andrew Hilton
Keyword(s):  
Daily Basis ◽  
County Level ◽  
Urban Streets ◽  
Site Survey ◽  
Chi Squared ◽  
Related Group ◽  
Physical Features ◽  
The Impact ◽  
The City

Square dancing is a popular music-related group physical exercise for health benefits in China mainly participated by mid-aged women and elderly people. This paper investigates the soundscape and enjoyment of the square dancing in urban streets through a case study in Lichuan, a county level city in southwest China, in December 2017. It examines the impact of gender, age, participation and places on perceptions of square dancing soundscape. Two sites along two main urban streets in the city were selected to conduct onsite investigations where residents spontaneously perform square dancing on a daily basis. Ethnographical observations were conducted to identify the social-physical features and sounds of both sites during the dance and without dance. Sound pressure measurements (LAeq and LAmax) were also conducted under the two conditions. An off-site survey was distributed through the local social media groups to understand residents’ everyday experiences and perceptions of square dancing in the city; 106 responses were received for the off-site survey. T-tests and Chi-squared tests were used for statistical analysis of the survey data. The results show gender does appear to be a factor influencing the regularity of participation in square dancing, with a bias towards more female participants. Participation frequency of square dance has an impact on the enjoyment of square dancing. There is no correlation between the dislike of watching square dancing, or dislike of the music and a desire to restrict locations for square dancing.

scholarly journals Model sensitivity studies of the decrease in atmospheric carbon tetrachloride

2016 ◽  
Vol 16 (24) ◽  
pp. 15741-15754 ◽  
Author(s):  
Martyn P. Chipperfield ◽  
Qing Liang ◽  
Matthew Rigby ◽  
Ryan Hossaini ◽  
Stephen A. Montzka ◽  
...  
Keyword(s):  
Carbon Tetrachloride ◽  
Transport Model ◽  
Three Dimensional ◽  
Montreal Protocol ◽  
Chemical Transport Model ◽  
Uncertainty Range ◽  
The Past ◽  
Systematic Biases ◽  
Lifetime Uncertainty ◽  
The Impact

Abstract. Carbon tetrachloride (CCl4) is an ozone-depleting substance, which is controlled by the Montreal Protocol and for which the atmospheric abundance is decreasing. However, the current observed rate of this decrease is known to be slower than expected based on reported CCl4 emissions and its estimated overall atmospheric lifetime. Here we use a three-dimensional (3-D) chemical transport model to investigate the impact on its predicted decay of uncertainties in the rates at which CCl4 is removed from the atmosphere by photolysis, by ocean uptake and by degradation in soils. The largest sink is atmospheric photolysis (74 % of total), but a reported 10 % uncertainty in its combined photolysis cross section and quantum yield has only a modest impact on the modelled rate of CCl4 decay. This is partly due to the limiting effect of the rate of transport of CCl4 from the main tropospheric reservoir to the stratosphere, where photolytic loss occurs. The model suggests large interannual variability in the magnitude of this stratospheric photolysis sink caused by variations in transport. The impact of uncertainty in the minor soil sink (9 % of total) is also relatively small. In contrast, the model shows that uncertainty in ocean loss (17 % of total) has the largest impact on modelled CCl4 decay due to its sizeable contribution to CCl4 loss and large lifetime uncertainty range (147 to 241 years). With an assumed CCl4 emission rate of 39 Gg year−1, the reference simulation with the best estimate of loss processes still underestimates the observed CCl4 (overestimates the decay) over the past 2 decades but to a smaller extent than previous studies. Changes to the rate of CCl4 loss processes, in line with known uncertainties, could bring the model into agreement with in situ surface and remote-sensing measurements, as could an increase in emissions to around 47 Gg year−1. Further progress in constraining the CCl4 budget is partly limited by systematic biases between observational datasets. For example, surface observations from the National Oceanic and Atmospheric Administration (NOAA) network are larger than from the Advanced Global Atmospheric Gases Experiment (AGAGE) network but have shown a steeper decreasing trend over the past 2 decades. These differences imply a difference in emissions which is significant relative to uncertainties in the magnitudes of the CCl4 sinks.

scholarly journals P078 Oral Appliance Fabrication Settings Impact Treatment Efficacy

2021 ◽  
Vol 2 (Supplement_1) ◽  
pp. A46-A46
Author(s):  
D Levendowski ◽  
E Sall ◽  
W Odom ◽  
B Beine ◽  
D Cruz Arista ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Sleep Apnea ◽  
Treatment Outcomes ◽  
Body Mass ◽  
Treatment Efficacy ◽  
Oral Appliance ◽  
Chi Squared ◽  
Pre Treatment ◽  
The Impact

Abstract Purpose Assess the impact of custom oral appliance (CA) fabrication settings on treatment outcomes. Methods CPAP-intolerant patients completed a two-night home-sleep-apnea study (HSAT); Night1=baseline, Night2=Apnea Guard® trial appliance (AG). The AG vertical-dimension-of-occlusion (VDO) selection was based on tongue-scallop (women=5.5/6.5 mm, men= 6.5/8.0 mm), with a target protrusion of 70% from neutral-maximum while in situ. Study1 CA VDO was dependent on sex (women=2.5 mm, men=5 mm), with protrusion set using a George-Gauge measured 70% from maximum retrusion-protrusion with dentist-directed titration. Study2 CA was fabricated to the AG VDO and target protrusion bite-registration. Efficacy HSATs were conducted after completion of Study1 CA titration with vertical-elastics optional, and at the AG target protrusion with vertical-elastics mandatory in Study2. Statistics included Mann-Whitney, Chi-squared, and Bland-Altman analyses. Results The Study1 (n=84) and Study2 (n=46) distributions were equivalent for tongue-scallop (64/63%) and sex (women=45/41%), however, noted differences in age (53.8±11.9 vs. 58.4±12.2; P=0.052), body-mass-index (29.4±5.7 vs. 27.8±4.0; P=0.128) and pre-treatment AHI severities (24.6±14.4 vs. 29.2±17.4 events/h; P=0.155) were observed. The Bland-Altman biases were significant different (Study1=4.2±7.8 vs. Study2=1.3±7.0 events/h, P=0.035). The significant Study1 differences between the CA vs. AG AHIs (12.3±9.2 vs. 8.2±5.9 events/h, P<0.0002) were not apparent in Study2 (11.7±8.0 vs. 10.4±6.7 events/h, P=0.362), however, the Study2 AG AHI values were higher (P=0.055). Discussion Despite the trend toward greater Study2 pre-treatment and AG AHI severities, CA treatment efficacy was equivalent to the AG once VMO was controlled and fabricated using the AG VDO and protrusion bite-registration. These findings confirmed CA fabrication settings impact treatment outcomes.

scholarly journals Understanding the impact of the COVID-19 pandemic on a socially deprived UK coastal town: a preliminary exploratory analysis of health and socioeconomic data

2021 ◽  
Author(s):  
Maddy French ◽  
Mark Spencer ◽  
Mike Walker ◽  
Afzal Patel ◽  
Neil Clarke ◽  
...  
Keyword(s):  
Primary Care ◽  
Hospital Admissions ◽  
Exploratory Analysis ◽  
Social Outcomes ◽  
Socioeconomic Outcomes ◽  
Chi Squared ◽  
Service Activity ◽  
Indirect Impacts ◽  
The Uk ◽  
The Impact

Introduction In addition to the direct impact of COVID-19 infections on health and mortality, a growing body of literature indicates there are wide-ranging indirect impacts of the COVID-19 pandemic and associated public health measures on population health and wellbeing. Exploring these indirect impacts in the context of a socially deprived UK coastal town will help identify priority areas to focus COVID-19 recovery efforts on. Methods Data on primary care diagnosis, hospital admissions, and several socioeconomic outcomes between 2016 and Spring 2021 in the UK town of Fleetwood were collected and analysed in an exploratory analysis looking at pre- and post- COVID-19 patterns in health and social outcomes. Weekly and monthly trends were plotted by time and differences between periods examined using Chi-squared and t-tests. Results Initial falls in hospital admissions and diagnoses of conditions in primary care in March 2020 were followed by sustained changes to health service activity for specific diagnostic and demographic groups, including for chronic kidney disease and young people. Increases in the number of people receiving Universal Credit and children eligible for free school meals appear to be greater for those in the least deprived areas of the town. Discussion These exploratory findings provide initial evidence of the sustained impact of the pandemic across several health and social outcomes. Examining these trends in multivariate analyses will further test these associations and establish the strength of the medium term impact of the pandemic on the population of this coastal town. Advanced modelling of this data is ongoing and will be published shortly.

scholarly journals Tuberculosis in Saudi Arabia: Prevalence between Saudis and Non-Saudis from 2013 to 2018 with a special concern about regions of the KSA

2019 ◽  
Vol 4 (6) ◽  
Keyword(s):  
Saudi Arabia ◽  
Migrant Workers ◽  
Action Plan ◽  
Age Groups ◽  
Incidence Rates ◽  
Arab Countries ◽  
Surveillance Data ◽  
Significance Level ◽  
Chi Squared ◽  
The Impact

The Kingdom of Saudi Arabia is one of the largest Arab countries with a moderate annual problem of tuberculosis that is either pulmonary or extra-pulmonary. TB is still one of the most significant health troubles in the KSA, affecting different nationalities (Saudis, non-Saudis), ages, provinces, and genders. The control of TB still faces some challenges in different provinces of the KSA. Data were collected, arranged, analyzed and presented in tables and figures. In this retrospective study, we appraised TB surveillance data for the period between 2013 (1434H) and 2018 (1439H). Data were handled using Microsoft Excel and SPSS version 23. Data were checked for normality using Shapiro-Wilk normality test at 0.05 levels to determine whether they are parametric or nonparametric. Chi-squared, Kruskal Wallis, and analysis of variance tests were used to evaluate trends at a significance level of p< 0.05. Statistical analyses were performed using IBM-SPSS version 23 for Mac OS. We appraised TB surveillance data for the period between 2013 (1434H) and 2018 (1439H). The data included the region of the country (province), age, sex, and nationality (Saudis, non-Saudis). The study evaluated the impact of TB on various nationalities (Saudis and non-Saudis), age groups (0-14, 15-34, 35-55, more than 55 years old), and genders (males and females). Non-Saudis had a higher incidence rate than Saudis in 2013-2018. The number of cases and incidence rates of TB recorded in males between 2013 to 2018 were about two to three times greater than estimates for females. The Makkah, Riyadh, and Jeddah regions attract enormous numbers of non-Saudi migrant workers, who account for ~60% of all TB cases in the KSA. Assessing the main TB risk factors contributing to high TB rates in non-Saudi workers is essential. Furthermore, periodical accurate studies, including evidence-based studies for optimum surveillance, avoidance, spread risk, inspection, control procedures and treatment of TB, should be conducted. These assessments would lead to evaluating the strengths and weaknesses of KSA-NTP’s TB action plan.

scholarly journals Monitoring of the evolution of H2O vapor in the stratosphere of Jupiter over an 18-yr period with the Odin space telescope

2020 ◽  
Vol 641 ◽  
pp. A140
Author(s):  
◽  
B. Benmahi ◽  
T. Cavalié ◽  
M. Dobrijevic ◽  
N. Biver ◽  
...  
Keyword(s):  
Pressure Range ◽  
Temporal Evolution ◽  
Line Emission ◽  
Eddy Diffusion ◽  
Space Telescope ◽  
1D Modeling ◽  
The Impact ◽  
Vertical Eddy ◽  
Vertical Eddy Diffusion

Context. The comet Shoemaker-Levy 9 impacted Jupiter in July 1994, leaving its stratosphere with several new species, with water vapor (H2O) among them. Aims. With the aid of a photochemical model, H2O can be used as a dynamical tracer in the Jovian stratosphere. In this paper, we aim to constrain the vertical eddy diffusion (Kzz) at levels where H2O is present. Methods. We monitored the H2O disk-averaged emission at 556.936 GHz with the space telescope between 2002 and 2019, covering nearly two decades. We analyzed the data with a combination of 1D photochemical and radiative transfer models to constrain the vertical eddy diffusion in the stratosphere of Jupiter. Results. Odin observations show us that the emission of H2O has an almost linear decrease of about 40% between 2002 and 2019. We can only reproduce our time series if we increase the magnitude of Kzz in the pressure range where H2O diffuses downward from 2002 to 2019, that is, from ~0.2 mbar to ~5 mbar. However, this modified Kzz is incompatible with hydrocarbon observations. We find that even if an allowance is made for the initially large abundances of H2O and CO at the impact latitudes, the photochemical conversion of H2O to CO2 is not sufficient to explain the progressive decline of the H2O line emission, which is suggestive of additional loss mechanisms. Conclusions. The Kzz we derived from the Odin observations of H2O can only be viewed as an upper limit in the ~0.2 mbar to ~5 mbar pressure range. The incompatibility between the interpretations made from H2O and hydrocarbon observations probably results from 1D modeling limitations. Meridional variability of H2O, most probably at auroral latitudes, would need to be assessed and compared with that of hydrocarbons to quantify the role of auroral chemistry in the temporal evolution of the H2O abundance since the SL9 impacts. Modeling the temporal evolution of SL9 species with a 2D model would naturally be the next step in this area of study.

Abstract TMP86: Telestroke Improves Guideline-Based Comprehensive Stroke Care: The TELECAST Trial

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Christopher D Streib ◽  
Oladi Bentho ◽  
Kathryn Bard ◽  
Eric Jaton ◽  
Sarah Engkjer ◽  
...  
Keyword(s):  
Acute Stroke ◽  
Stroke Care ◽  
Composite Score ◽  
Stroke Recurrence ◽  
Acute Stroke Care ◽  
Specialist Service ◽  
Stroke Treatment ◽  
Chi Squared ◽  
Secondary Outcomes ◽  
The Impact

Introduction: Limited access to stroke specialist expertise produces disparities in inpatient stroke treatment. The impact of telestroke on the remote delivery of guideline-based inpatient stroke care is yet to be comprehensively studied. The TELECAST trial (NCT03672890) prospectively examined the impact of a 24-7 telestroke specialist service dedicated to inpatient acute stroke care spanning admission to discharge. Methods: AHA stroke guidelines were used to derive outcome metrics in the following acute stroke inpatient care categories: diagnostic stroke evaluation (DSE), secondary stroke prevention (SSP), health screening and evaluation (HSE), and stroke education (SE). Adherence to AHA guidelines for stroke inpatients pre-telestroke (July 1, 2016-June 30, 2018) and post-telestroke intervention (July 1, 2018-June 30, 2019) were studied. The primary outcome was a composite score of all guideline-based stroke care. Secondary outcomes consisted of subcategory composite scores in DSE, SSP, HSE, and SE. Chi-squared tests were utilized to assess primary and secondary outcomes. Statistical analysis was performed using STATA 15.0. Results: Following institution of a comprehensive inpatient telestroke service, overall adherence to guideline-based metrics improved (composite score: 85% vs 94%, p<0.01) as did adherence to DSE guidelines (subgroup score: 90 vs 95%, p<0.01). SSP, HSE, and SE subgroup scores were not significantly different. See Table 1. Conclusion: The implementation of a 24-7 inpatient telestroke service improved adherence to AHA guidelines for inpatient acute stroke care. Dedicated inpatient telestroke specialist coverage may improve inpatient stroke care and reduce stroke recurrence in hospitals without access to stroke specialists.

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