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1.
Science ; 367(6475): 266-272, 2020 01 17.
Article in English | MEDLINE | ID: mdl-31949074

ABSTRACT

The cause of the end-Cretaceous mass extinction is vigorously debated, owing to the occurrence of a very large bolide impact and flood basalt volcanism near the boundary. Disentangling their relative importance is complicated by uncertainty regarding kill mechanisms and the relative timing of volcanogenic outgassing, impact, and extinction. We used carbon cycle modeling and paleotemperature records to constrain the timing of volcanogenic outgassing. We found support for major outgassing beginning and ending distinctly before the impact, with only the impact coinciding with mass extinction and biologically amplified carbon cycle change. Our models show that these extinction-related carbon cycle changes would have allowed the ocean to absorb massive amounts of carbon dioxide, thus limiting the global warming otherwise expected from postextinction volcanism.


Subject(s)
Carbon Cycle , Extinction, Biological , Volcanic Eruptions , Carbon Dioxide/analysis , Global Warming , Mexico , Models, Theoretical
2.
Mon Not R Astron Soc ; 474(3): 4264-4277, 2018 Mar 01.
Article in English | MEDLINE | ID: mdl-30344345

ABSTRACT

We present near infrared high-precision photometry for eight transiting hot Jupiters observed during their predicted secondary eclipses. Our observations were carried out using the staring mode of the WIRCam instrument on the Canada-France-Hawaii Telescope (CFHT). We present the observing strategies and data reduction methods which delivered time series photometry with statistical photometric precision as low as 0.11%. We performed a Bayesian analysis to model the eclipse parameters and systematics simultaneously. The measured planet-to-star flux ratios allowed us to constrain the thermal emission from the day side of these hot Jupiters, as we derived the planet brightness temperatures. Our results combined with previously observed eclipses reveal an excess in the brightness temperatures relative to the blackbody prediction for the equilibrium temperatures of the planets for a wide range of heat redistribution factors. We find a trend that this excess appears to be larger for planets with lower equilibrium temperatures. This may imply some additional sources of radiation, such as reflected light from the host star and/or thermal emission from residual internal heat from the formation of the planet.

3.
JBRA Assist Reprod ; 22(4): 301-306, 2018 Nov 01.
Article in English | MEDLINE | ID: mdl-30106541

ABSTRACT

OBJECTIVE: Coasting is a well-known strategy to decrease severity of Ovarian Hyperstimulation Syndrome (OHSS). The purpose of this study is to assess the effect of Coasting on blastocyst development and subsequent clinical outcome following exclusive blastocyst transfer. METHODS: We conducted an observational cohort study of patients having blastocyst transfer following IVF/ICSI treatment. Patients undergoing IVF/ICSI cycles were included in the study. Patients at risk of OHSS were coasted. Outcome following exclusive blastocyst transfer was compared between coasted and non-coasted groups. The main outcome measures were the rate of blastocyst development and live birth rates in coasted and non-coasted cycles. Within coasted cycles, outcome was further analysed based on coasting duration and serum estradiol (E2) drop (difference between peak E2 and E2 on day of HCG). RESULTS: A total of 166 coasted cycles and 656 non-coasted cycles had blastocyst transfer. Blastocyst development (45.97% vs. 48.6%) and live birth rates (45.18% vs. 43.44%) were not significantly different between coasted and non-coasted cycles. The overall clinical pregnancy (54.21% vs. 49.08%) and implantation rates (43.95% vs. 39.54%) following blastocyst transfer in coasted cycles were not significantly different from those of non-coasted cycles. CONCLUSION: Coasting duration up to 6 days and drop in serum E2 levels did not compromise blastocyst development, implantation, clinical pregnancy or live birth rates. We conclude that coasting with subsequent blastocyst transfer can be used as an effective strategy in patients at risk of OHSS with no detrimental effects on blastocyst development or live birth outcome.


Subject(s)
Embryonic Development , Ovarian Hyperstimulation Syndrome/prevention & control , Ovulation Induction/methods , Adult , Cohort Studies , Female , Fertilization in Vitro , Humans , Pregnancy , Pregnancy Outcome , Sperm Injections, Intracytoplasmic
4.
Biomed Res Int ; 2015: 179156, 2015.
Article in English | MEDLINE | ID: mdl-26495287

ABSTRACT

OBJECTIVES: In public health and clinical settings insufficient dissemination of evidence-based practices limits the reach of new discoveries to broad populations. This study aimed to describe characteristics of the dissemination process by researchers across three countries (Brazil, United Kingdom, and United States), explore how designing for dissemination practices has been used, and analyze factors associated with dissemination. METHODS: A similar online survey was used to query researchers across the three countries; data were pooled to draw cross-country conclusions. FINDINGS: This study identified similarities and differences between countries. Importance of dissemination to nonresearcher audiences was widely recognized as important; however, traditional academic venues were the main dissemination method. Several factors were associated with self-rated dissemination effort in the pooled sample, but these predictive factors (e.g., support and resources for dissemination) had low prevalence. Less than one-third of researchers rated their level of effort for dissemination as excellent. Respondents reported limited support and resources to make it easier for researchers who might want to disseminate their findings. CONCLUSION: Though intentions show the importance of dissemination, researchers across countries lack supports to increase dissemination efforts. Additional resources and training in designing for dissemination along with improved partnerships could help bridge the research-practice gap.


Subject(s)
Access to Information , Health Services Research/statistics & numerical data , Information Dissemination/methods , Internationality , Resource Allocation/statistics & numerical data , Science/statistics & numerical data , Brazil , Public Health/statistics & numerical data , United Kingdom , United States
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