390 research outputs found
IUE observations of Seyfert galaxies
The L alpha/H beta ratio and line profiles for several galaxies are presented. The continuous energy distribution of NGC 4151 and MKN 509 are presented from the X-ray region to the infrared
Practice variation in late-preterm deliveries: a physician survey
Objective: Late preterm (LPT) neonates account for over 70% of all preterm births in the US. Approximately 60% of LPT births are the result of non-spontaneous deliveries.The optimal timing of delivery for many obstetric conditions at LPT gestations is unclear, likely resulting in obstetric practice variation. The purpose of this study is to identify variation in the obstetrical management of LPT pregnancies. Study design: We surveyed obstetrical providers in NC identified from NC Medical Board and NC Obstetrical and Gynecological Society membership lists. Participants answered demographic questions and 6 multiple-choice vignettes on management of LPT pregnancies. Result: We obtained 215/859 (29%) completed surveys; 167 (78%) from Obstetrics/Gynecology, 27 (13%) from Maternal-Fetal Medicine, and 21 (10%) from Family Medicine physicians. Overall, we found more agreement on respondents’ management of chorioamnionitis (97% would proceed with delivery), mild preeclampsia (84% would delay delivery/expectantly manage), and fetal growth restriction (80% would delay delivery/expectantly manage). We found less agreement on the management of severe preeclampsia (71% would proceed with delivery), premature preterm rupture of membranes (69% would proceed with delivery), and placenta previa (67% would delay delivery/expectantly manage). Management of LPT pregnancies complicated by PPROM, FGR, and placenta previa vary by specialty. Conclusion: Obstetrical providers report practice variation in the management of LPT pregnancies. Variation might be influenced by provider specialty. The absence of widespread agreement on best practice might be a source of modifiable LPT birth
Infrared receivers for low background astronomy: Incoherent detectors and coherent devices from one micrometer to one millimeter
The status of incoherent detectors and coherent receivers over the infrared wavelength range from one micrometer to one millimeter is described. General principles of infrared receivers are included, and photon detectors, bolometers, coherent receivers, and important supporting technologies are discussed, with emphasis on their suitability for low background astronomical applications. Broad recommendations are presented and specific opportunities are identified for development of improved devices
Materials Solutions for Hydrogen Delivery in Pipelines
The main objective of the study is as follows: Identify steel compositions/microstructures suitable for construction of new pipeline infrastructure and evaluate the potential use of the existing steel pipeline infrastructure in high pressure gaseous hydrogen applications. The microstructures of four pipeline steels were characterized and tensile testing was conducted in gaseous hydrogen and helium at pressures of 5.5 MPa (800 psi), 11 MPa (1600 psi) and 20.7 MPa (3000 psi). Based on reduction of area, two of the four steels that performed the best across the pressure range were selected for evaluation of fracture and fatigue performance in gaseous hydrogen at 5.5 MPa (800 psi) and 20.7 MPa (3000 psi). The basic format for this phase of the study is as follows: Microstructural characterization of volume fraction of phases in each alloy; Tensile testing of all four alloys in He and H{sub 2} at 5.5 MPa (800 psi), 11 MPa (1600 psi), and 20.7 MPa (3000 psi). RA performance was used to choose the two best performers for further mechanical property evaluation; Fracture testing (ASTM E1820) of two best tensile test performers in H{sub 2} at 5.5 MPa (800 psi) and 20.7 MPa (3000 psi); Fatigue testing (ASTM E647) of two best tensile test performers in H2 at 5.5 MPa (800 psi) and 20.7 MPa (3000 psi) with frequency =1.0 Hz and R-ratio=0.5 and 0.1
Extremal discs and the holomorphic extension from convex hypersurfaces
Let D be a convex domain with smooth boundary in complex space and let f be a
continuous function on the boundary of D. Suppose that f holomorphically
extends to the extremal discs tangent to a convex subdomain of D. We prove that
f holomorphically extends to D. The result partially answers a conjecture by
Globevnik and Stout of 1991
Infrared, optical, and ultraviolet observations of hydrogen line emission from Seyfert galaxies
Nearly simultaneous observations are reported of Pɑ, Hɑ, and Hβ emission from 18 Seyfert galaxies and of Lyɑ from eight of these galaxies. In many cases, Pɑ is stronger relative to the Balmer lines than is predicted by recombination calculations; reddening appears to be required. Dispersion in the Pɑ/Hɑ/Hβ ratios orthogonal to the reddening track indicates that high densities or optical depths also affect the line flux ratios. Several galaxies, notably NGC 1275, have very low Pɑ/Hɑ ratios. High densities, large optical depths, and reddening probably all contribute to the low observed Lɑ/Hβ ratios
Does the Robotic Platform Reduce Morbidity Associated With Combined Radical Surgery and Adjuvant Radiation for Early Cervical Cancers?
Open radical hysterectomy followed by adjuvant radiation for cervical cancer has been associated with significant rates of morbidity. Radical hysterectomy is now often performed robotically. We sought to examine if the robotic platform decreased the morbidity associated with radical hysterectomy followed by adjuvant radiation
Factors Associated with Previable Delivery following Second Trimester Rupture of Membranes
Objective To identify factors associated with previable delivery in second trimester preterm rupture of membranes (PROM). Study Design We conducted a single-center retrospective cohort study of women with pregnancies complicated by second trimester PROM (14.0-21.9 weeks' gestation) from 2000 to 2015 who elected expectant pregnancy management and achieved at least 24 hours latency. Maternal characteristics and clinical factors were compared among pregnancies that reached viability (≥ 23.0 weeks) and pregnancies delivered before viability ( 1cm, Group B streptococcus carrier status, bacterial vaginosis, and chlamydial infection during pregnancy were similar between groups. Median time to delivery was significantly shorter in women who delivered < 23 weeks compared with those who reached ≥ 23 weeks (6 vs. 46 days, p < 0.01). Conclusion Previable delivery occurred in the majority of women with second trimester PROM. No maternal or clinical factors were associated with delivery prior to viability. Counseling women with second trimester PROM should include the inability to determine which pregnancies will reach viability
Spin relaxation in (110) and (001) InAs/GaSb superlattices
We report an enhancement of the electron spin relaxation time (T1) in a (110)
InAs/GaSb superlattice by more than an order of magnitude (25 times) relative
to the corresponding (001) structure. The spin dynamics were measured using
polarization sensitive pump probe techniques and a mid-infrared, subpicosecond
PPLN OPO. Longer T1 times in (110) superlattices are attributed to the
suppression of the native interface asymmetry and bulk inversion asymmetry
contributions to the precessional D'yakonov Perel spin relaxation process.
Calculations using a nonperturbative 14-band nanostructure model give good
agreement with experiment and indicate that possible structural inversion
asymmetry contributions to T1 associated with compositional mixing at the
superlattice interfaces may limit the observed spin lifetime in (110)
superlattices. Our findings have implications for potential spintronics
applications using InAs/GaSb heterostructures.Comment: 4 pages, 2 figure
Ondansetron use in early pregnancy and the risk of late pregnancy outcomes
Background: The effects of ondansetron, used off-label to treat nausea and vomiting during pregnancy, on common pregnancy complications are understudied. Modest effects of a commonly used drug could result in adverse events for large numbers of pregnant women. Therefore, our objective was to compare the risk of stillbirth, preterm birth, gestational hypertensive disorders, small for gestational age, and differences in birth weight between women prescribed ondansetron and women prescribed alternative antiemetics in early pregnancy. Methods: A cohort of pregnant women receiving a prescription for ondansetron or comparator antiemetics (metoclopramide or promethazine) during the first 20 weeks of pregnancy was identified using electronic health record data from a health care system in North Carolina, USA. Confounding by multiple covariates was controlled using stabilized inverse probability of treatment weights. Weighted hazard ratios (HR) and 95% confidence intervals (CI) accounted for competing events. Results: We identified 2677 eligible pregnancies with antiemetic orders, 66% for ondansetron. The small number of stillbirths (n = 15) resulted in an imprecise estimate of the association with ondansetron (HR = 1.60; 95%CI 0.51, 4.97). No association was observed for preterm birth (HR = 0.90; 95%CI 0.67, 1.20) or gestational hypertensive disorders (HR = 0.87; 95%CI 0.68, 1.12). We observed an association with small for gestational age (HR = 1.37; 95%CI 0.98, 1.90), however mean birth weight among term births was similar between groups. Conclusions: Our results do not suggest that ondansetron increases the risk of preterm birth or gestational hypertensive disorders. The weak association observed between ondansetron use and small for gestational age warrants further investigation
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