Longitudinal Intervals Research Articles

МАГНІТО-АКТИВНІ ДОВГОТИ НА СОНЦІ І ЗОРЯХ

An overview of studies of long-term increased magnetic activity in two discrete longitudinal intervals observed on the Sun and on the surface of stars of certain types is reviewed. Active longitudes on the Sun were first discovered at the end of the 19th century. Today, as a result of statistical analysis of data observed for more than a century, it has been established that there are two active longitudinal sectors on the solar surface, shifted by approximately 180° relative to each other, which can stably maintain the phase coherence of activity for a long time. At each given moment of time, one of the two longitude intervals are more active (dominant). The occasionally observed “flip-flop” phenomenon, the essence of which consists in a sudden rapid switching of the specified dominance between two active longitudes, is highlighted. The detected phenomenon is regularly repeated, which indicates the existence of stellar magnetic flip-flop cycles. At the same time, solar-type cycles are also characteristic of young analogues of the Sun. On the other hand, based on the study of the evolution of the spot area, a magnetic flip-flop cycle with a duration of about 3.7 years was also detected on the Sun. It is relevant that the ratio of the periods of both types of cycles for young dwarfs and the Sun is the same: the flip-flop cycle is approximately 3–4 times shorter than the cycle of the solar type. That is, the structure and evolution of active longitudes on the Sun is similar to the observed active longitudes on the surface of cold stars that rotate quickly and have outer convective shells. Mechanisms of excitation of magnetically active longitudes proposed by the researchers were analyzed. Dynamo-excitation models of axially asymmetric magnetic harmonics look promising. Our calculations showed that the αΩ-dynamo models with the involvement of helioseismological data on the internal rotation of the Sun ensure the coexistence of dipole and quadrupole harmonics of the global magnetic field, which are necessary for the reproduction of selected longitudinal sectors of increased magnetic activity.

High-dimensional coding/decoding information with braiding period in free-space optical communication link

We present in principle a free-space optical coding/decoding method that based on the longitudinal braiding period of the structured laser beam. Different from the conventional techniques that mainly focuses on the field of time, frequency, amplitude, polarization and spatial structure, the longitudinal structure is added as a new freedom in our optical link. By combining the topological charge and propagation angle in the transmitter, the longitudinal intervals between the detectors are utilized as the key for decoding. The system using the braiding period as the information carrier has an advantage in security for it is difficult to be eavesdropped. The realization of the hexadecimal coding/decoding suggests that employing the braiding period as a new dimension may have a potential in increasing the capacity or security of the OAM-based free-space data transmission.

Numerical analysis of transient cavitating pipe flow by Quasi 2D and 1D models

Quasi two dimensional (2D) and one dimensional (1D) numerical simulations of transient flow with column separation are conducted using the discrete vaporous and gaseous cavitation models (DVCM and DGCM) in a simple reservoir-pipeline-valve system. In the quasi 2D transient model, the governing equations are solved by the method of characteristics along the pipe and by finite difference across the pipe cross section to consider the velocity profile, and the final model is coupled with the cavitating models. The comparison between the numerical and experimental results shows that the quasi 2D DGCM is more successful in predicting the maximum head pressures and reproducing the pressure spikes at different water hammer cycles. The quasi 2D model of DGCM correlates better with the experimental data than the quasi 2D DVCM, 1D DVCM and 1D DGCM in terms of pressure magnitude. In sensitivity analysis, the 2D DGCM shows more grid convergence than the 1D models of DGCM and DVCM and 2D DVCM by increasing the number of longitudinal and radial intervals.

Reference ranges of fetal superior vena cava blood flow velocities and pulsatility index in the second half of pregnancy: a longitudinal study

BackgroundFetal superior vena cava (SVC) is essentially the single vessel returning blood from the upper body to the heart. With approximately 80-85% of SVC blood flow representing cerebral venous return, its interrogation may provide clinically relevant information about fetal brain circulation. However, normal reference values for fetal SVC Doppler velocities and pulsatility index are lacking. Our aim was to establish longitudinal reference intervals for blood flow velocities and pulsatility index of the SVC during the second half of pregnancy.MethodsThis was a prospective study of low-risk singleton pregnancies. Serial Doppler examinations were performed approximately every 4 weeks to obtain fetal SVC blood velocity waveforms during 20–41 weeks. Peak systolic (S) velocity, diastolic (D) velocity, time-averaged maximum velocity (TAMxV), time-averaged intensity-weighted mean velocity (TAMeanV), and end-diastolic velocity during atrial contraction (A-velocity) were measured. Pulsatility index for vein (PIV) was calculated.ResultsSVC blood flow velocities were successfully recorded in the 134 fetuses yielding 510 sets of observations. The velocities increased significantly with advancing gestation: mean S-velocity increased from 24.0 to 39.8 cm/s, D-velocity from 13.0 to 19.0 cm/s, and A-velocity from 4.8 to 7.1 cm/s. Mean TAMxV increased from 12.7 to 23.1 cm/s, and TAMeanV from 6.9 to 11.2 cm/s. The PIV remained stable at 1.5 throughout the second half of pregnancy.ConclusionsLongitudinal reference intervals of SVC blood flow velocities and PIV were established for the second half of pregnancy. The SVC velocities increased with advancing gestation, while the PIV remained stable from 20 weeks to term.

Building Psychological Safety Through Training Interventions: Manage the Team, Not Just the Project

Background: Successful team collaborations require psychological safety (PS)—a measure that addresses how individuals perceive their own behaviors in a team, allowing members to be comfortable being themselves. Technical communication curricula do not engage deeply with managing the socioemotional components of collaboration. Literature review: Scholarship addressing hundreds of teams with thousands of members concludes that psychological safety has a direct influence on task performance. Few studies track psychological safety across a team's lifecycle, and different professions exhibit a wide range of PS values. Extensive research indicates that collaboration can be improved by training. Research questions: 1. Will a targeted training intervention produce higher levels of psychological safety? 2. Does team duration affect teaming success as exemplified by psychological safety, satisfaction, and cohesion? Methods: Our multisite longitudinal study surveyed 215 students in 50+ short- and long-term teams to understand the effects of a specific training intervention (a PS learning module). Results and discussion: Training had no significant impact, but targeted training might still increase psychological safety. Short-term teams experienced significantly better psychological safety over long-term teams, and psychological safety improved the more time members spent in teams. Comparisons within longitudinal intervals were also significant, indicating that different team contexts influenced our results. Implications and future research: Results suggest that incorporating team-specific training may facilitate building a personal awareness of interdependence among team members. Moreover, research should account for contextual differences and use longitudinal team self-assessments. Future research should concentrate on identifying a range of viability for PS useful in benchmarking.

Sex-specific reference ranges of cerebroplacental and umbilicocerebral ratios: longitudinal study.

Observational studies have shown that low cerebroplacental ratio (CPR) values predict an increased risk of adverse perinatal outcome. The inverse ratio, i.e. the umbilicocerebral ratio (UCR), has been suggested to be a better predictor as it rises with increasing degree of fetal compromise. However, longitudinal reference ranges for UCR have not been established, and whether gestational-age-dependent changes in CPR or UCR differ between male and female fetuses has not been studied. Thus, the aims of this study were to investigate sex-specific, gestational-age-associated serial changes in CPR and UCR during the second half of pregnancy and to establish longitudinal reference ranges. This was a secondary analysis of prospectively collected data from a dual-center longitudinal observational cohort study of low-risk singleton pregnancies. Doppler blood-flow velocity waveforms were obtained serially from the umbilical artery (UA) and fetal middle cerebral artery (MCA) from 19-41 weeks' gestation, and pulsatility indices (PIs) were determined. CPR and UCR were calculated as the ratios MCA-PI/UA-PI and UA-PI/MCA-PI, respectively. The course and outcome of pregnancies were recorded, and the sex of the fetus was determined after delivery. Reference intervals for CPR and UCR were constructed using multilevel modeling, and gestational-age-specific Z-scores in male and female fetuses were compared. Of a total of 299 pregnancies enrolled, 284 (148 male and 136 female fetuses) were included in the final analysis, and 979 paired measurements of UA-PI and MCA-PI were used to construct sex-specific longitudinal reference intervals. The relationship of both CPR and UCR with gestational age was U-shaped, but in opposite directions. There was a small but significant difference in Z-scores of CPR and UCR between male and female fetuses throughout the second half of pregnancy (P = 0.007). We have established longitudinal reference ranges for CPR and UCR suitable for serial monitoring, with the possibility of refining assessment by using fetal sex-specific ranges and conditioning by a previous measurement. The clinical significance of such refinements needs further evaluation. © 2019 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Technical Note: Dosimetric feasibility of lattice radiotherapy for breast cancer using GammaPod.

Studies on Lattice radiotherapy (LRT) for breast cancer have been largely lacking. This study investigates the dosimetric feasibility of using Gamma Pod, a stereotactic radiotherapy apparatus originally designed for breast SBRT, to deliver LRT to large, bulky breast tumor as a noninvasive treatment option. The GammaPod-based LRT was simulated using Geant4 Gate Monte Carlo software. The simulated GammaPod was equipped with 5mm diameter non-coplanar circular beams that span 28° latitudinally from 18° to 43° off the horizontal plane. Two degrees longitudinal intervals were used to simulate rotating sources. To simulate the treatments to different breast sizes, three water-equivalent hemisphere volumes with diameters of 10, 15, and 20cm were analyzed. The lattice was planned by spacing focal points 2cm apart in the transverse and sagittal planes and 2.5cm in the coronal plane. This resulted in 22-172 shots for full breast treatment. The maximum dose for each individual shot was 20Gy. The peak-to-valley dose differences and skin dose were analyzed. To verify the feasibility of delivering LRT, a test plan was created and delivered to a commercial diode array dose verification device using a clinical GammaPod system with 15mm collimators. The dose profiles showed the average peak-to-valley dose percent differences of 94.10% in the 10cm hemispherical volume, 88.95% in the 15cm hemispherical volume, and 83.60% in the 20cm hemispherical volume. Average skin dose was 1.27, 1.72, and 2.13Gy for the 10, 15, and 20cm irradiation volumes, respectively. The LRT plan delivered using a clinical GammaPod system with larger collimators verified the feasibility of LRT plan delivery. GammaPod-based lattice radiotherapy is a viable treatment option and its application can be extended to treating large bulky breast tumors.

Volume blood flow-based indices of fetal brain sparing in the second half of pregnancy: A longitudinal study.

Cerebroplacental ratio (CPR) and umbilicocerebral ratio (UCR) are clinically used as a measure of fetal brain sparing. These are calculated as the ratios between the pulsatility indices (PIs) of middle cerebral (MCA) and umbilical (UA) arteries, and are an indirect representation of the balance between cerebral and placental perfusion. Volume blood flow (Q)-based ratios, ie Q-CPR or Q-UCR, would directly reflect the distribution of fetal cardiac output to the placenta and brain. Thus, we aimed to determine the development pattern of Q-CPR and Q-UCR during the second half of pregnancy, construct reference intervals, and evaluate their association with CPR and UCR. In a longitudinal cohort study of low-risk pregnancies, the inner diameter of the fetal superior vena cava (SVC) and umbilical vein (UV) was measured and velocity waveforms were obtained from the MCA, UA, UV and SVC using ultrasound at approximately 4-weekly intervals from 20 to 41weeks. The CPR was calculated as PIMCA /PIUA and the inverse ratio was the UCR. Cerebral and placental blood flows were estimated as the product of mean velocity and cross-sectional area of the SVC and UV, respectively. Q-CPR was calculated as QSVC /QUV and the inverse as the Q-UCR. Gestational age-specific reference intervals were calculated and associations between variables were tested using multilevel regression modeling. Longitudinal reference intervals of Q-CPR and Q-UCR were established based on 471 paired measurements of QSVC and QUV obtained serially from 134 singleton pregnancies. The mean Q-CPR increased from 0.4 to 0.8 during the second half of pregnancy and Q-UCR declined from 2.5 to 1.3, while the CPR and UCR had U-shaped curves but in opposite directions. No significant correlation was found between CPR and Q-CPR (R=0.10; P=.051), or UCR and Q-UCR (R=0.09; P=.11), and the agreement between PI-based and Q-based indices of fetal brain sparing was poor. Indices of fetal brain sparing based on placental and cerebral volume blood flow differ from those calculated from UA and MCA PIs. They correlated poorly with conventional CPR and UCR, indicating that they may provide additional/different physiological information. Reference values of Q-CPR and Q-UCR established here can be useful to investigate their clinical value further.

Optical Coherence Tomography Tissue Coverage and Characterization with Grey-Scale Signal Intensity Analysis After Bifurcation Stenting with a New Generation Bioabsorbable Polymer Drug-Eluting Stent

Bifurcation stenting is thought to be associated with delayed healing and a subsequent risk of stent failure. The aim of this study was to further evaluate healing of thin-strut bioabsorbable polymer everolimus-eluting stents (EES) post bifurcation stenting by optical coherence tomography (OCT) including grey-scale signal intensity (GSI) analysis. Patients undergoing bifurcation stenting with a planned two-stent approach using EES with OCT follow-up at 3-6 months post-stenting were included in this study. Morphometric analysis of contiguous cross-sections was performed at 1 mm longitudinal intervals within the stented segment. GSI analysis of neointimal regions of interest (ROI) overlying stent struts was performed for each of these cross-sections. Tissue coverage was classified as mature or immature. Data on a total of 31 lesions (17 cases) was available at a median of 168 days post stenting. Mean length of stented segments was 27.7 ± 16.6 mm. The mean minimum stent area was 6.50 ± 2.71 mm2 while the mean stent area was 8.69 ± 3.08 mm2. Amongst a total of 847 assessed frames, 9716 struts were visible. Overall strut coverage was 95.9%; 0.3% of struts were malapposed. The mean thickness of neointimal coverage was 100.95 ± 42.03 μm and the mean percentage area stenosis was 9.03 ± 7.80%. A total of 53.79% of ROIs were classified as mature. After implantation of EES in bifurcation lesions, rates of uncovered and malapposed struts were low. GSI analysis showed that more than half of neointimal areas analyzed were classified as mature in keeping with advanced vessel healing.

Lasing in organic mixed-crystal thin films with cavities composed of naturally formed cracks.

This study investigates the possibility that a crack pair that is naturally formed in the course of sample preparation functions as a laser cavity. Lasing with longitudinal mode structures has been reported in mixed-crystal thin films composed of fluorene and anthracene without artificial cavity structure. In the present study, it was shown that lasing is observed only when an excitation spot covers parallel pairs of cracks. The longitudinal mode intervals of the stimulated emission spectra for several crack pairs were found to be proportional to the inverse of the crack spacing. Furthermore, the interval for the artificially fabricated metal cavity followed the same linear relation. These results indicate that the crack pairs can function as laser cavities.

Mutual spatiotemporal coherence of optical fields in an amplitude-splitting interferometer

We have considered cross correlations of wave perturbations formed by optical fields at different points of space at the exit of an interferometer with the splitting of the amplitude of the initial wave field. Expressions for the longitudinal spatiotemporal cross-correlation function of perturbations on the optical axis of a Michelson interferometer have been obtained and analyzed. We have determined spatial and temporal intervals in which the wave fields excite mutually coherent perturbations in the exit channel of the interferometer in the free space and in the image space of the lens system. We have found that, in the free space, mutually correlated perturbations arise simultaneously in identical longitudinal intervals, whereas, in the image space, they arise at different times in spatial and temporal intervals varying along the optical axis of the lens. The influence of cross correlations of the wave fields on the interferometer signal has been analyzed.

The World Health Organization Fetal Growth Charts: A Multinational Longitudinal Study of Ultrasound Biometric Measurements and Estimated Fetal Weight.

BackgroundPerinatal mortality and morbidity continue to be major global health challenges strongly associated with prematurity and reduced fetal growth, an issue of further interest given the mounting evidence that fetal growth in general is linked to degrees of risk of common noncommunicable diseases in adulthood. Against this background, WHO made it a high priority to provide the present fetal growth charts for estimated fetal weight (EFW) and common ultrasound biometric measurements intended for worldwide use.Methods and FindingsWe conducted a multinational prospective observational longitudinal study of fetal growth in low-risk singleton pregnancies of women of high or middle socioeconomic status and without known environmental constraints on fetal growth. Centers in ten countries (Argentina, Brazil, Democratic Republic of the Congo, Denmark, Egypt, France, Germany, India, Norway, and Thailand) recruited participants who had reliable information on last menstrual period and gestational age confirmed by crown–rump length measured at 8–13 wk of gestation. Participants had anthropometric and nutritional assessments and seven scheduled ultrasound examinations during pregnancy. Fifty-two participants withdrew consent, and 1,387 participated in the study.At study entry, median maternal age was 28 y (interquartile range [IQR] 25–31), median height was 162 cm (IQR 157–168), median weight was 61 kg (IQR 55–68), 58% of the women were nulliparous, and median daily caloric intake was 1,840 cal (IQR 1,487–2,222).The median pregnancy duration was 39 wk (IQR 38–40) although there were significant differences between countries, the largest difference being 12 d (95% CI 8–16). The median birthweight was 3,300 g (IQR 2,980–3,615). There were differences in birthweight between countries, e.g., India had significantly smaller neonates than the other countries, even after adjusting for gestational age. Thirty-one women had a miscarriage, and three fetuses had intrauterine death.The 8,203 sets of ultrasound measurements were scrutinized for outliers and leverage points, and those measurements taken at 14 to 40 wk were selected for analysis. A total of 7,924 sets of ultrasound measurements were analyzed by quantile regression to establish longitudinal reference intervals for fetal head circumference, biparietal diameter, humerus length, abdominal circumference, femur length and its ratio with head circumference and with biparietal diameter, and EFW. There was asymmetric distribution of growth of EFW: a slightly wider distribution among the lower percentiles during early weeks shifted to a notably expanded distribution of the higher percentiles in late pregnancy.Male fetuses were larger than female fetuses as measured by EFW, but the disparity was smaller in the lower quantiles of the distribution (3.5%) and larger in the upper quantiles (4.5%). Maternal age and maternal height were associated with a positive effect on EFW, particularly in the lower tail of the distribution, of the order of 2% to 3% for each additional 10 y of age of the mother and 1% to 2% for each additional 10 cm of height. Maternal weight was associated with a small positive effect on EFW, especially in the higher tail of the distribution, of the order of 1.0% to 1.5% for each additional 10 kg of bodyweight of the mother. Parous women had heavier fetuses than nulliparous women, with the disparity being greater in the lower quantiles of the distribution, of the order of 1% to 1.5%, and diminishing in the upper quantiles. There were also significant differences in growth of EFW between countries. In spite of the multinational nature of the study, sample size is a limiting factor for generalization of the charts.ConclusionsThis study provides WHO fetal growth charts for EFW and common ultrasound biometric measurements, and shows variation between different parts of the world.

Active longitudes in the period of overlap of 11-year cycles

It is shown that “active longitudes” for the sunspots of old and new cycles manifest themselves approximately in the same longitudinal intervals and remain for several 11-year cycles. To be more accurate, they vanish in some cycles but then appear again at the same longitudinal intervals in the other cycles. The entire period is characterized by a total of four active longitudes. The old-cycle sunspots observed at low equatorial latitudes in the Northern and Southern Hemispheres are characterized by a shift by ≈180°, which indicates antipodality of the active longitudes in the Northern and Southern Hemispheres. In the case of highlatitude sunspots (new-cycle sunspots), the best correlation is observed for the shift of ≈90°. There is supposedly a dependence of the rotation speed of active longitudes on the secular cycle.

Implantation of bioresorbable vascular scaffolds following acute coronary syndrome is associated with reduced early neointimal growth and strut coverage.

Registry data have suggested higher than anticipated rates of scaffold thrombosis following bioresorbable vascular scaffold (BVS) implantation. We examined early neointimal growth and strut coverage in BVS to ascertain whether this was affected by clinical presentation. Patients undergoing optical coherence tomography (OCT)-guided BVS implantation, either for stable angina (SA) or acute coronary syndrome (ACS), were recruited to this observational study. Repeat OCT was performed at follow-up (median 74 days), and scaffolds analysed at 1 mm longitudinal intervals for scaffold/flow area, scaffold apposition, neointimal growth and strut coverage. Twenty-nine BVS were included in the analysis (62% implanted following ACS). There were no differences in baseline patient/lesion characteristics. All BVS achieved >90% predicted scaffold area with only 1.64% of struts classified as incompletely apposed, compared with 0.47% at follow-up (p=0.006). Reductions in mean scaffold (-4.0%, p=0.01) and flow (-8.4%, p<0.001) areas were observed at follow-up, with larger reductions in mean flow area in stable patients (-14.5±14.2 vs. -4.9±7.9%, p=0.03). ACS patients had reduced neointimal growth (0.51±0.18 vs. 0.87±0.37 mm2, p=0.002), and increased percentage of uncovered struts (2.68±1.67 vs. 1.43±0.87%, p=0.015). Early neointimal growth and strut coverage are reduced following ACS in patients receiving BVS. These results may, in part, explain the high rates of ST in registry data.

Optical coherence tomography imaging of coronary atherosclerosis is affected by intraobserver and interobserver variability.

Optical coherence tomography (OCT) has emerged as a novel imaging modality that allows plaque classification through identification of features including lipid, calcification and fibrous cap. However, subtle changes in light attenuation as the optical beam traverses the plaque in vivo are challenging to interpret and data on strength of observer agreement are minimal. Thus, we sought to assess both the intra and interobserver variability for plaque composition/classification using OCT. OCT imaging was performed in 50 patients prior to percutaneous coronary intervention. Analysis was performed offline by two independent, experienced OCT operators. Target lesion luminal dimensions and plaque composition were assessed at minimal luminal area (MLA) and at five 1-mm longitudinal intervals proximal and distal to the MLA. An OCT thin-capped fibroatheroma (OCT-TCFA) was defined as greater than 90 degree lipid arc with minimal fibrous cap thickness less than 0.85 μm. Overall, 540 frames of OCT were included and exceptional consistency was seen for all measures of luminal geometry [all intraclass correlation coefficients (ICC) >0.97, P < 0.001]. Intraobserver agreements for calcification and lipid arc were strong (both ICC >0.84, P < 0.001), whereas interobserver agreement was higher for calcium (ICC 0.76) than lipid (ICC 0.69). Interobserver agreement of minimal fibrous cap thickness was moderate (ICC 0.52, 95% confidence interval 0.45-0.58, P < 0.001], but improved as cap thickness decreased. Overall, intra and interobserver agreements for OCT-defined plaque classification were strong (K = 0.86 and 0.71, respectively). Luminal dimensions and plaque compositional features identified by OCT are minimally affected by observer variability, permitting dependable plaque classification.

Establishment of reference ranges for thyroid-related indicators in normal pregnant women

To establish the gestational age-specific reference ranges for thyroid-related indicators of pregnant women in our hospital, especially for serum thyroid stimulating hormone (TSH) in the first trimester. A total of 548 pregnant women in the first trimester were collected in Peking University First Hospital from June 2013 to April 2014. Among them, 254 pregnant women with single fetus who conformed to the National Academy of Clinical Biochemistry criteria, without adverse pregnancy outcomes and obstetric complications, were enrolled in the current study. To establish their own self-sequential longitudinal reference intervals, serum TSH, total thyroxine (TT4) and free thyroxine (FT4) levels were measured using Siemens detection kits during three different trimesters. Urine iodine (UI) was measured using digestion instrument in some of the pregnant women. The gestational age-specific reference ranges for thyroid-related indicators of pregnant women in our hospital were as follows: in the first trimester: TSH 0.23-4.08 mU/L, TT4 92.59-186.25 nmol/L, FT4 13.36-20.81 pmol/L; in the second trimester: TSH 0.78-4.25 mU/L, TT4 103.20-180.95 nmol/L, FT4 11.57-16.62 pmol/L; in the third trimester: TSH 0.65-4.52 mU/L, TT4 78.20-174.70 nmol/L, FT4 10.01-20.57 pmol/L. The median level of TSH during 7 to 12 weeks of gestational age was lower than that of 4 to 6 weeks, but with no significant statistical difference (P=0.063). The medians of UI during three trimesters of pregnancy were 211.60 μg/L, 195.55 μg/L and 198.65 μg/L, respectively, which were all classified as adequate iodine status. The gestational age-specific reference ranges for thyroid-related indicators are different from the kits' reference ranges, which are also different among the three trimesters. It may be more reasonable to establish different reference ranges for thyroid-related indicators at 4 to 6 weeks and 7 to 12 weeks in the first trimester separately.

Fetal Hemodynamic Parameters in Low Risk Pregnancies: Doppler Velocimetry of Uterine, Umbilical, and Middle Cerebral Artery.

Objective. To elaborate curves of longitudinal reference intervals of pulsatility index (PI) and systolic velocity (SV) for uterine (UtA), umbilical (UA), and middle cerebral arteries (MCA), in low risk pregnancies. Methods. Doppler velocimetric measurements of PI and SV from 63 low risk pregnant women between 16 and 41 weeks of gestational age. Means (±SD) for intervals of gestational age and percentiles 5, 50, and 95 were calculated for each parameter. The Intraclass Correlation Coefficients (ICC) were also estimated for assessing intra- and intervariability of measurements. Results. Mean PI of UtA showed decreasing values during pregnancy, but no regular pattern was identified for mean SV. For UA, PI decreased and SV increased along gestation. MCA presented PI increasing values until 32–35 weeks. SV showed higher levels with increasing gestation. High ICC values indicated good reproducibility. Conclusions. Reference intervals for the assessment of SV and PI of UtA, UA, and MCA were established. These reference intervals showed how a normal pregnancy is expected to progress regarding these Doppler velocimetric parameters and are useful to follow high risk pregnancies. The comparison between results using different curves may provide insights about the best patterns to be used.

Duskside enhancement of equatorial zonal electric field response to convection electric fields during the St. Patrick's Day storm on 17 March 2015

AbstractThe equatorial zonal electric field responses to prompt penetration of eastward convection electric fields (PPEF) were compared at closely spaced longitudinal intervals at dusk to premidnight sectors during the intense geomagnetic storm of 17 March 2015. At dusk sector (Indian longitudes), a rapid uplift of equatorial F layer to &gt;550 km and development of intense equatorial plasma bubbles (EPBs) were observed. These EPBs were found to extend up to 27.13°N and 25.98°S magnetic dip latitudes indicating their altitude development to ~1670 km at apex. In contrast, at few degrees east in the premidnight sector (Thailand‐Indonesian longitudes), no significant height rise and/or EPB activity has been observed. The eastward electric field perturbations due to PPEF are greatly dominated at dusk sector despite the existence of background westward ionospheric disturbance dynamo (IDD) fields, whereas they were mostly counter balanced by the IDD fields in the premidnight sector. In situ observations from SWARM‐A and SWARM‐C and Communication/Navigation Outage Forecasting System satellites detected a large plasma density depletion near Indian equatorial region due to large electrodynamic uplift of F layer to higher than satellite altitudes. Further, this large uplift is found to confine to a narrow longitudinal sector centered on sunset terminator. This study brings out the significantly enhanced equatorial zonal electric field in response to PPEF that is uniquely confined to dusk sector. The responsible mechanisms are discussed in terms of unique electrodynamic conditions prevailing at dusk sector in the presence of convection electric fields associated with the onset of a substorm under southward interplanetary magnetic field Bz.

Examining the reliability of alcohol/drug use and HIV-risk behaviors using Timeline Follow-Back in a pilot sample

Research on the course of substance use disorders (SUDs) faces challenges in assessing behavior over lengthy time periods. Calendar-based methods, like the Timeline Follow-Back (TLFB), may overcome these challenges. This study assessed the reliability of self-reported weekly alcohol use, drug use and HIV-risk behaviors over the past 90 days using an interview TLFB. Individuals with SUD in outpatient treatment (N = 26) completed the TLFB at baseline and then a week later with separate interviewers. Weekly ratings were aggregated across 4-week intervals for each administration. Intra-class correlations were used to compare agreement between the two administrations. Reliabilities for alcohol and drug use ratings ranged from good to excellent for most drug categories (ICCs = 0.76–1.00), except opioid use (other than heroin) and sedative use produced sub-standard reliabilities (ICCs = 0.29–0.74). HIV-risk behavior reliabilities also ranged from good to excellent (ICCs = 0.70–0.97), but were substandard for the number of casual sex partners for some intervals (ICCs = 0.29, 0.63). Findings extend support for the use of TLFB to produce reliable assessments of many drugs and HIV-risk behaviors across longitudinal intervals.

Longitudinal reference intervals for Doppler velocimetric parameters of the fetal renal artery correlated with amniotic fluid index among low-risk pregnancies.

To establish longitudinal reference intervals for pulsatility index (PI) and systolic velocity (SV) of the fetal renal artery, and to evaluate their correlation with the amniotic fluid index (AFI). A prospective longitudinal study was conducted among women with low-risk pregnancies who attended outpatient clinics at the University of Campinas Medical School, Brazil, at 16-19 weeks of pregnancy between April 1, 2008, and March 31, 2010. Doppler velocimetric measurements of the fetal renal artery and assessments of the AFI were undertaken at 4-week intervals to 36 weeks, and every 2 weeks thereafter until delivery. A total of 63 women were enrolled. The PI of the fetal renal artery showed little variation during pregnancy, whereas SV values increased to 36-37 weeks of pregnancy and decreased thereafter. No correlations were found between the AFI and the fetal renal artery Doppler velocimetric parameters (P>0.05 for all). The intraclass correlation coefficients for intra-observer and inter-observer variability indicated good reproducibility of SV, but the reproducibility of PI was lower. The AFI did not correlate with fetal renal artery Doppler velocimetric measures among low-risk pregnancies. However, investigations are needed among high-risk pregnancies.