scholarly journals Dusty phenomena in the vicinity of giant exoplanets

2019 ◽  
Vol 631 ◽  
pp. A152 ◽  
Author(s):  
O. V. Arkhypov ◽  
M. L. Khodachenko ◽  
A. Hanslmeier
Keyword(s):  
Physical Modeling ◽  
Light Curves ◽  
Circumstellar Dust ◽  
Systematic Effect ◽  
Related Phenomenon ◽  
Time Intervals ◽  
Magnetic Traps ◽  
Hot Jupiters ◽  
Before And After ◽  
Distant Region

Context. Hitherto, searches for exoplanetary dust have focused on the tails of decaying rocky or approaching icy bodies only at short circumstellar distances. At the same time, dust has been detected in the upper atmospheric layers of hot jupiters, which are subject to intensive mass loss. The erosion and/or tidal decay of hypothetic moonlets might be another possible source of dust around giant gaseous exoplanets. Moreover, volcanic activity and exozodiacal dust background may additionally contribute to exoplanetary dusty environments. Aims. In the present study, we look for photometric manifestations of dust around different kinds of exoplanets (mainly giants). Methods. We used linear approximation of pre- and post-transit parts of the long-cadence transit light curves (TLCs) of 118 Kepler objects of interest after their preliminary whitening and phase-folding. We then determined the corresponding flux gradients G1 and G2, respectively. These gradients were defined before and after the transit border for two different time intervals: (a) from 0.03 to 0.16 days and (b) from 0.01 to 0.05 days, which correspond to the distant and adjoining regions near the transiting object, respectively. Statistical analysis of gradients G1 and G2 was used for detection of possible dust manifestation. Results. It was found that gradients G1 and G2 in the distant region are clustered around zero, demonstrating the absence of artifacts generated during the light curve processing. However, in the adjoining region, 17 cases of hot jupiters show significantly negative gradients, G1, whereas the corresponding values of G2 remain around zero. The analysis of individual TLCs reveals the localized pre-transit decrease of flux, which systematically decreases G1. This effect was reproduced with the models using a stochastic obscuring precursor ahead of the planet. Conclusions. Since only a few TLCs show the presence of such pre-transit anomalies with no analogous systematic effect in the post-transit phase, we conclude that the detected pre-transit obscuration is a real planet-related phenomenon. Such phenomena may be caused by dusty atmospheric outflows or background circumstellar dust compressed in front of the mass-losing exoplanet, the study of which requires dedicated physical modeling and numeric simulations. Of certain importance may be the retarding of exozodiacal dust relative to the planet by the Poynting-Robertson effect leading to dust accumulation in electrostatic or magnetic traps in front of the planet.

scholarly journals Properties of Circumstellar Dust in Symbiotic Miras

2006 ◽  
Vol 2 (S240) ◽  
pp. 596-604
Author(s):  
D. Kotnik-Karuza ◽  
T. Jurkic ◽  
M. Friedjung
Keyword(s):  
Temperature Distribution ◽  
Systematic Study ◽  
Light Curves ◽  
Circumstellar Dust ◽  
Symbiotic Stars ◽  
Time Intervals ◽  
Dust Temperature ◽  
Long Time ◽  
Long Term Variations

AbstractWe present a study of the properties of circumstellar dust in symbiotic Miras during sufficiently long time intervals of minimal obscuration. The publishedJHKLmagnitudes of o Ceti, RX Pup, KM Vel, V366 Car, V835 Cen, RR Tel and R Aqr have been collected. In order to investigate their long-term variations, we removed the Mira pulsations to correct their light curves. Assuming spherical temperature distribution of the dust in the close neighbourhood of the Mira, the DUSTY code was used to solve the radiative transfer in order to determine the dust temperature and its properties in each particular case.The preliminary results of this systematic study of dust envelopes in symbiotic stars with Miras as cool components provide information on nature of dust in these objects.

scholarly journals Progression of cerebral infarction before and after thrombectomy is modified by prehospital pathways

2021 ◽  
pp. neurintsurg-2020-017155
Author(s):  
Alexander M Kollikowski ◽  
Franziska Cattus ◽  
Julia Haag ◽  
Jörn Feick ◽  
Alexander G März ◽  
...  
Keyword(s):  
Patient Characteristics ◽  
Large Vessel ◽  
Stroke Severity ◽  
Large Vessel Occlusion ◽  
Time Intervals ◽  
Vessel Occlusion ◽  
Before And After ◽  
Transferred Patients ◽  
Stroke Center

BackgroundEvidence of the consequences of different prehospital pathways before mechanical thrombectomy (MT) in large vessel occlusion stroke is inconclusive. The aim of this study was to investigate the infarct extent and progression before and after MT in directly admitted (mothership) versus transferred (drip and ship) patients using the Alberta Stroke Program Early CT Score (ASPECTS).MethodsASPECTS of 535 consecutive large vessel occlusion stroke patients eligible for MT between 2015 to 2019 were retrospectively analyzed for differences in the extent of baseline, post-referral, and post-recanalization infarction between the mothership and drip and ship pathways. Time intervals and transport distances of both pathways were analyzed. Multiple linear regression was used to examine the association between infarct progression (baseline to post-recanalization ASPECTS decline), patient characteristics, and logistic key figures.ResultsASPECTS declined during transfer (9 (8–10) vs 7 (6-9), p<0.0001), resulting in lower ASPECTS at stroke center presentation (mothership 9 (7–10) vs drip and ship 7 (6–9), p<0.0001) and on follow-up imaging (mothership 7 (4–8) vs drip and ship 6 (3–7), p=0.001) compared with mothership patients. Infarct progression was significantly higher in transferred patients (points lost, mothership 2 (0–3) vs drip and ship 3 (2–6), p<0.0001). After multivariable adjustment, only interfacility transfer, preinterventional clinical stroke severity, the degree of angiographic recanalization, and the duration of the thrombectomy procedure remained predictors of infarct progression (R2=0.209, p<0.0001).ConclusionsInfarct progression and postinterventional infarct extent, as assessed by ASPECTS, varied between the drip and ship and mothership pathway, leading to more pronounced infarction in transferred patients. ASPECTS may serve as a radiological measure to monitor the benefit or harm of different prehospital pathways for MT.

scholarly journals Usefulness of Imaging Response Assessment after Irreversible Electroporation of Localized Pancreatic Cancer—Results from a Prospective Cohort

Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2862
Author(s):  
Rasmus V. Flak ◽  
Rune V. Fisker ◽  
Niels H. Bruun ◽  
Mogens T. Stender ◽  
Ole Thorlacius-Ussing ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Irreversible Electroporation ◽  
Response Assessment ◽  
Time Intervals ◽  
Patient Level ◽  
Positron Emission ◽  
Included Patient ◽  
Before And After ◽  
Lesion Level ◽  
Level Analysis

(1) Background: Irreversible electroporation (IRE) is a nonthermal ablation technique that is being studied in nonmetastatic pancreatic cancer (PC). Most published studies use imaging outcomes as an efficacy endpoint, but imaging interpretation can be difficult and has yet to be correlated with survival. The aim of this study was to examine the correlation of imaging endpoints with survival in a cohort of IRE-treated PC patients. (2) Methods: Several imaging endpoints were examined before and after IRE on 18F-fluorodeoxyglucose positron emission tomography (PET) with computed tomography. Separate analyses were performed at the patient and lesion levels. Mortality rate (MR) ratios for imaging endpoints after IRE were estimated. (3) Results: Forty-one patients were included. Patient-level analysis revealed that progressive disease (PD), as defined by RECIST 1.1, is correlated with a higher MR at all time intervals, but PD, as defined by EORTC PET response criteria, is only correlated with the MR in the longest interval. No correlation was found between PD, as defined by RECIST, and the MR in the lesion-level analysis. (4) Conclusions: Patient-level PD, as defined by RECIST, was correlated with poorer survival after IRE ablation, whereas no correlations were observed in the lesion-level analyses. Several promising lesion-level outcomes were identified.

scholarly journals HPV and Cytology Testing in Women Undergoing 9-Valent HPV Opportunistic Vaccination: A Single-Cohort Follow Up Study

Vaccines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 643
Author(s):  
Rosa De Vincenzo ◽  
Nicola Caporale ◽  
Valentina Bertoldo ◽  
Caterina Ricci ◽  
Maria Teresa Evangelista ◽  
...  
Keyword(s):  
Pap Smear ◽  
Cox Regression ◽  
Vaccine Dose ◽  
Pap Smears ◽  
Adult Women ◽  
Sexually Active ◽  
Time Intervals ◽  
Dose Administration ◽  
Before And After ◽  
Single Cohort

Background: This study evaluates the possible effect of 9-valent (9vHPV) vaccination on the results of HPV and cytological tests in a cohort of adult women. Methods: This study is a retrospective, single-cohort, monocentric study. Sexually active women aged 14–70 years, who underwent 9vHPV vaccination, were enrolled. Dose administration dates, side effects and data on Pap smears and HPV tests performed before and after the first vaccine dose were collected. Subjects were considered “unexposed” to the vaccine for all time intervals before the first dose administration, and “exposed” to the first, second and third vaccine doses in all time intervals following each specific dose. Results: A total of 512 women underwent the first 9vHPV dose administration and were enrolled in the study. Median age at vaccination was 30.5 (14–70). Log-rank tests and Cox regression analyses showed a highly statistically significant (p < 0.0001) difference in the time to negativization after the exposure to the third vaccine dose in the 207 women starting with a Pap+ smear (HR (95% C.I.), 2.66 (1.83–3.86)) and in the 198 women starting with an HPV HR+ test (HR (95% C.I.), 7.80 (4.83–12.60)). Conclusions: 9vHPV vaccination may play a role in shortening the clearance time of HPV HR+ or Pap positivity in sexually active adult women.

scholarly journals The Outcome of the Single Step Questionnaire in Pectus Excavatum Patients is Phase Dependent

2019 ◽  
Vol 30 (02) ◽  
pp. 205-209
Author(s):  
Wietse P. Zuidema ◽  
Alida F. W. van der Steeg ◽  
Stefan van der Heide ◽  
Gerda W. Zijp ◽  
Robertine van Baren ◽  
...  
Keyword(s):  
Social Life ◽  
Pectus Excavatum ◽  
Single Step ◽  
Chest Wall Deformity ◽  
Single Measurement ◽  
Time Intervals ◽  
Time Of Application ◽  
Before And After ◽  
Postoperative Time ◽  
Measurement Moment

Abstract Introduction Pectus excavatum (PE) is the most common chest wall deformity. Patients with PE may have cosmetic complaints, restricted physical capabilities, or both and may seek surgical correction. One method to assess satisfaction after surgery is the single step questionnaire (SSQ). Although the developers state that the SSQ produces a stabile score and only needs to be used once, we hypothesized that the score may depend on point in time after surgery. Materials and Methods One hundred and eight patients from a longitudinal cohort of patients undergoing a Nuss bar placement for PE were selected. Mean age was 16.0 years (range: 12–29). SSQ was completed at 6 weeks, 6 months, 1 year, and 2 years postoperatively. Mean and median scores per question and total scores were calculated on each measurement moment. Overall scores were tested using the Friedman test. Results There were significant differences in overall SSQ scores (p < 0.009) throughout the postoperative period, especially between 6 weeks and 6 months (p = 0.006). Scores on general health, exercise capacity, impact on social life, pain during hospital stay, and after discharge changed also significant in the first 2 years after Nuss bar placement. Conclusion There were significant differences in total SSQ score depending on the time of application postoperatively. However, the most clinical relevant difference was between 6 weeks and 6 months. Assessment of the overall satisfaction postoperative with the SSQ questionnaire should not be done with a single measurement but rather at different postoperative time intervals before and after 6 months postoperatively.

scholarly journals Interpreting the Evolving Clumpy Shell Structure of IRC +10216 in Terms of Time Dependent Dust Shell Models

2003 ◽  
Vol 209 ◽  
pp. 127-128
Author(s):  
J. M. Winters ◽  
T. Blöcker ◽  
K.-H. Hofmann ◽  
G. Weigelt
Keyword(s):  
Time Scale ◽  
High Spatial Resolution ◽  
Light Curves ◽  
Infrared Light ◽  
Pulsation Period ◽  
Line Profiles ◽  
Dust Shell ◽  
Time Intervals ◽  
Stellar Pulsation ◽  
Shell Models

The prototypical dust-enshrouded carbon Mira IRC +10216 is known to exhibit intrinsic changes on a time scale of the order of only a few years as revealed, e.g., by CO infrared line profiles (Winters et al. 2000a), its infrared light curves, and by high spatial resolution monitoring in the infrared (Osterbart et al. 2000; Tuthill et al. 2000). In particular, the infrared light curves indicate a possible periodicity on a ≈ 20 yr time scale, i.e. that a recurrent phenomenon might lead to the observed variations. Such multi-periodicity time scales of several (≈ 10) stellar pulsation periods are predicted by consistent hydrodynamical models which include a proper treatment of dust formation (e.g. Winters et al. 2000b). In these models discrete dust layers form in time intervals which are several times longer than the typical pulsation period of an AGB star (Fleischer, Gauger, & Sedlmayr 1995; Höfner, Feuchtinger, & Dorfi 1995).

EFFECTS OF INSULIN ON RATES OF GLUCOSE TRANSFER IN THE DEPANCREATIZED DOG

1955 ◽  
Vol 33 (6) ◽  
pp. 926-939 ◽  
Author(s):  
Margaret J. Henderson ◽  
Gerald A. Wrenshall ◽  
Paul Odense
Keyword(s):  
Plasma Glucose ◽  
Dynamic Equilibrium ◽  
Specific Activity ◽  
The State ◽  
Time Intervals ◽  
Lower Blood Glucose ◽  
In Vivo Experiments ◽  
Lower Blood ◽  
Before And After

An attempt to answer the question as to whether insulin acts to lower blood glucose by increasing utilization, or by decreasing production, or by both, has been made using a new experimental approach. A trace dose of radioactive glucose was injected into each of six postabsorptive depancreatized dogs which had been deprived of exogenous insulin for 66 hr. Blood samples were collected before and after the intravenous injection of insulin, and plasma glucose concentration and specific activity were measured. From these data the simultaneous rates of appearance and disappearance of plasma glucose were calculated for a sequence of time intervals, both before and after insulin, by a method which did not assume dynamic equilibrium. Previous in vivo experiments using radioactive tracers to measure rates of production and utilization of glucose have been made in animals which were in steady states, either with or without insulin, and the effects of insulin were ascertained by comparison of the state with insulin and the state without insulin. The method described in this paper has made it possible to follow the effects of insulin while it is acting in one and the same animal. Insulin was found to cause an abrupt and marked increase in the rate of disappearance of glucose, and this increased rate became less with time, reaching the preinsulin level in about 90 min. Insulin caused a slower and much smaller decrease in the rate of appearance, but the decrease became greater with time during the three hour period of observation. Thus, it appeared that insulin acted in vivo both to increase the utilization of glucose and to decrease its production, but the effects differed in magnitude and in speed of response.

Comparison of cortisol concentrations in plasma and saliva in dairy cattle following ACTH stimulation

2019 ◽  
Vol 86 (4) ◽  
pp. 406-409 ◽  
Author(s):  
Alexander Riek ◽  
Lars Schrader ◽  
Frank Zerbe ◽  
Stefanie Petow
Keyword(s):  
Dairy Cattle ◽  
Salivary Cortisol ◽  
Plasma Cortisol ◽  
Acth Stimulation ◽  
Time Intervals ◽  
Acth Challenge ◽  
Baseline Cortisol ◽  
Strong Positive Relationship ◽  
Before And After ◽  
Baseline Values

AbstractThe experiments described in this research communication compared cortisol concentrations in plasma and saliva samples collected from dairy cattle before and after an adrenocorticotropic hormone (ACTH) application. For that purpose, blood and saliva samples were collected from five dairy cows at determined time intervals before (490 min and down to 0 min) and after (10 min and up to 500 min) an ACTH application. Mean baseline cortisol concentrations were greater in plasma compared to saliva. The relative increases and decreases in plasma and salivary cortisol concentrations following ACTH were similar. After ACTH, we observed an increase in cortisol concentrations in plasma after 10 min and in saliva after 20 min. The time of peak concentrations after ACTH were reached at 70 and 80 min for plasma and saliva, respectively. After peak concentrations, values steadily declined and returned to baseline values at 169 ± 15 min in plasma and 170 ± 14 min in saliva. Ratios between salivary and plasma cortisol concentrations were on average 0.09 and did not change substantially during the ACTH challenge. There was a strong positive relationship between salivary and plasma cortisol concentrations. These results indicate that salivary cortisol concentrations can be a good indicator of ACTH-induced plasma cortisol concentrations in dairy cattle.

scholarly journals Antiarrhythmic Effect of Sacubitril-Valsartan: Cause or Consequence of Clinical Improvement?

2019 ◽  
Vol 8 (6) ◽  
pp. 869 ◽  
Author(s):  
António Valentim Gonçalves ◽  
Tiago Pereira-da-Silva ◽  
Ana Galrinho ◽  
Pedro Rio ◽  
Luísa Moura Branco ◽  
...  
Keyword(s):  
Global Longitudinal Strain ◽  
Left Ventricular ◽  
Antiarrhythmic Effect ◽  
Qtc Interval ◽  
Dispersion Index ◽  
Time Intervals ◽  
Mechanical Dispersion ◽  
Before And After ◽  
Qrs Duration

Sacubitril/Valsartan (LCZ696) reduced sudden cardiac death in the PARADIGM-HF trial. However, the mechanism by which LCZ696 reduces ventricular arrhythmias remains unclear. The aim of this study was to compare electrocardiographic (ECG) parameters and mechanical dispersion index, assessed by left ventricular (LV) global longitudinal strain (GLS), before and after LCZ696 therapy. We prospectively evaluated chronic Heart Failure (HF) patients with LV ejection fraction ≤40%, despite optimal medical and device therapy, in which LCZ696 therapy was started, while no additional HF treatment was expected to change. ECG and transthoracic echocardiographic data were gathered in the week before starting LCZ696 and at six months of therapy. A semiautomated analysis of LV GLS was performed and mechanical dispersion index was defined as the standard deviation from 16 time intervals corresponding to each LV segment. Of the 42 patients, 35 completed the six month follow-up, since two patients died and five discontinued treatment for adverse events. QTc interval (451.9 vs. 426.0 ms, p < 0.001), QRS duration (125.1 vs. 120.8 ms, p = 0.033) and mechanical dispersion index (88.4 vs. 78.1 ms, p = 0.036) were significantly reduced at six months. LCZ696 therapy is associated with a reduction in QTc interval, QRS duration and mechanical dispersion index as assessed by LV GLS.

scholarly journals Physical Interpretation of Light Curves of R Coronae Borealis-Type Stars

1975 ◽  
Vol 67 ◽  
pp. 149-157 ◽  
Author(s):  
Jacek Krełowski
Keyword(s):  
Laboratory Experiment ◽  
Radiation Field ◽  
Physical Interpretation ◽  
Light Curves ◽  
Circumstellar Dust ◽  
Dust Envelope ◽  
Preliminary Results ◽  
Theoretical Investigations ◽  
Grain Formation

The paper contains preliminary results of theoretical investigations of the light curves of RCB variables. A circumstellar dust envelope is assumed to be the source of the great visual opacity as well as the infrared and violet excesses. The processes of grain formation and the interaction with the radiation field are discussed briefly. The results of a laboratory experiment concerning the problem of the violet continuum are also described.

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