8,598 research outputs found
Expected-value bias in routine third-trimester growth scans.
OBJECTIVES: Operators performing fetal growth scans are usually aware of the gestational age of the pregnancy, which may lead to expected-value bias when performing biometric measurements. We aimed to evaluate the incidence of expected-value bias in routine fetal growth scans and assess its impact on standard biometric measurements. METHODS: We collected prospectively full-length video recordings of routine ultrasound growth scans coupled with operator eye tracking. Expected value was defined as the gestational age at the time of the scan, based on the estimated due date that was established at the dating scan. Expected-value bias was defined as occurring when the operator looked at the measurement box on the screen during the process of caliper adjustment before saving a measurement. We studied the three standard biometric planes on which measurements of head circumference (HC), abdominal circumference (AC) and femur length (FL) are obtained. We evaluated the incidence of expected-value bias and quantified the impact of biased measurements. RESULTS: We analyzed 272 third-trimester growth scans, performed by 16 operators, during which a total of 1409 measurements (354 HC, 703 AC and 352 FL; including repeat measurements) were obtained. Expected-value bias occurred in 91.4% of the saved standard biometric plane measurements (85.0% for HC, 92.9% for AC and 94.9% for FL). The operators were more likely to adjust the measurements towards the expected value than away from it (47.7% vs 19.7% of measurements; P < 0.001). On average, measurements were corrected by 2.3 ± 5.6, 2.4 ± 10.4 and 3.2 ± 10.4 days of gestation towards the expected gestational age for the HC, AC, and FL measurements, respectively. Additionally, we noted a statistically significant reduction in measurement variance once the operator was biased (P = 0.026). Comparing the lowest and highest possible estimated fetal weight (using the smallest and largest biased HC, AC and FL measurements), we noted that the discordance, in percentage terms, was 10.1% ± 6.5%, and that in 17% (95% CI, 12-21%) of the scans, the fetus could be considered as small-for-gestational age or appropriate-for-gestational age if using the smallest or largest possible measurements, respectively. Similarly, in 13% (95% CI, 9-16%) of scans, the fetus could be considered as large-for-gestational age or appropriate-for-gestational age if using the largest or smallest possible measurements, respectively. CONCLUSIONS: During routine third-trimester growth scans, expected-value bias frequently occurs and significantly changes standard biometric measurements obtained. © 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
Estimating Small Area Income Deprivation: An Iterative Proportional Fitting Approach
Small area estimation and in particular the estimation of small area income deprivation has
potential value in the development of new or alternative components of multiple deprivation
indices. These new approaches enable the development of income distribution threshold based
as opposed to benefit count based measures of income deprivation and so enable the
alignment of regional and national measures such as the Households Below Average Income
with small area measures. This paper briefly reviews a number of approaches to small area
estimation before describing in some detail an iterative proportional fitting based spatial
microsimulation approach. This approach is then applied to the estimation of small area HBAI
rates at the small area level in Wales in 2003-5. The paper discusses the results of this
approach, contrasts them with contemporary ‘official’ income deprivation measures for the
same areas and describes a range of ways to assess the robustness of the results
Sampling the Uppermost Surface of Airless Bodies
The uppermost surface of an airless body is a critical source of ground-truth information for the various remote sensing techniques that only penetrate nanometers to micrometers into the surface. Such samples will also be vital for understanding conditions at the surface and acquiring information about how the body interacts with its environment, including solar wind interaction, grain charging and levitation [1]. Sampling the uppermost surface while preserving its structure (e.g. porosity, grain-to-grain contacts) however, is a daunting task that has not been achieved on any sample return mission to date
Alcohol-related expectancies are associated with the D2 dopamine receptor and GABAa receptor B3 subunit genes
Molecular genetic research has identified promising markers of alcohol dependence, including alleles of the D2 dopamine receptor (DRD2) and the GABAA receptor ¬3 subunit (GABRB3) genes. Whether such genetic risk manifests itself in stronger alcohol-related outcome expectancies, or in difficulty resisting alcohol, is unknown. In the present study, A1+ (A1A1 and A1A2 genotypes) and A1- (A2A2 genotype) alleles of the DRD2 and G1+ (G1G1 and G1 non-G1 genotypes) and G1- (non-G1 non-G1 genotype) alleles of the GABRB3 were determined in a group of 56 medically-ill patients diagnosed with alcohol dependence. Mood-related Alcohol Expectancy (AE) and Drinking Refusal Self-Efficacy (DRSE) were assessed using the Drinking Expectancy Profile (Young and Oei, 1996). Patients with the DRD2 A1+ allele, compared to those with the DRD2 A1- allele, reported lower DRSE in situations of social pressure (p=. 009). Similarly, lower DRSE was reported under social pressure by patients with the GABRB3 G1+ allele when compared to those with the GABRB3 G1- allele (p=.027). Patients with the GABRB3 G1+ allele also revealed reduced DRSE in situations characterized by negative affect than patients with the GABRB3 G1- alleles (p=. 037). Patients carrying the GABRB3 G1+ allele showed stronger AE relating to negative affective change (for example, increased depression) than their GABRB3 G1- counterparts (p=. 006). Biological influence in the development of some classes of cognitions is hypothesized. The clinical implications, particularly with regard to patient-treatment matching and the development of an integrated psychological and pharmacogenetic approach are discussed
Nanoscale Compositional Relations in Lunar Rock Patina: Deciphering Sources for Patina Components on an Apollo 17 Station 6 Boulder
Space weathering on the Moon and other airless bodies modifies the surfaces of regolith grains as well as the space-exposed surfaces of larger rocks and boulders. As space weathering witness plates, rocks and boulders are distinguished from regolith grains based on their ability to persist as physically intact substrates over longer time scales before being disaggregated by impact processes. Because lunar surfaces, including exposed rocks, quickly develop an optically thick layer of patina, it is important to understand the compositional relationship between patinas and their underlying rock substrates, particularly to support remote-sensing of rocky lunar terrains. Based on analytical TEM techniques, supported by focused ion beam (FIB) cross-sectioning, we have begun to systematize the multi-layer microstructural complexity of patinas on rock samples with a range of space exposure histories. Our on-going work has particularly focused on lunar rock 76015, both because it has a long (approx. 22 my) exposure history, and because its surface was exposed to patina development approximately 1 m off the regolith surface on a boulder in the Apollo 17 Station 6 boulder field. Potential sources for the 76015 patina therefore include impact-melted and vaporized material derived from the local rock substrate, as well as from the mix of large boulders and regolith in the Station 6 area. While similar, there are differences in the mineralogy and chemistry of the rocks and regolith at Station 6. We were interested to see if these, or other sources, could be distinguished in the average composition, as well as the compositional nanostratigraphy of the 76015 patina. To date we have acquired a total of 9 TEM FIB cross-sections from the 76015 patina, giving us reasonable confidence of being able to arrive at an integrated average for the patina major element composition based on analytical TEM methods
Lateral Variations in Lunar Weathering Patina on Centimeter to Nanometer Scales
All materials exposed at the lunar surface undergo space weathering processes. On the Moon, boulders make up only a small percentage of the exposed surface, and areas where such rocks are exposed, like central peaks, are often among the least space weathered regions identified from remote sensing data. Yet space weathered surfaces (patina) are relatively common on returned rock samples, some of which directly sample the surface of larger boulders. Because, as witness plates to lunar space weathering, rocks and boulders experience longer exposure times compared to lunar soil grains, they allow us to develop a deeper perspective on the relative importance of various weathering processes as a function of time
Post-graduate education, training and extension at Central Marine Fisheries Research Institute, Cochin
In view of the increasing demand for trained personnel to meet the requirements of mariculture and brackishwater culture activities in
the country, the Central Marine Fisheries Research Institute took steps to institute a post-graduate education programme In mariculture at the
institute, leading to the M.Sc. and Ph.D. degrees awarded by the Cochin University of Science and Technology. Through this programme a
number of post-graduates have been turned out in the subject during the past seven years. The students were given both theoretical and practical
instructions in different aspects of mariculture including basic subjects like physiology, nutrition, genetics and pathology. The Scientists of the
Institute constitute the faculty for the programme and a number of members of the faculty have also been trained abroad in different specialisations.
The Programme also had the advantage of consultants from other countries who have contributed greatly to its improvement and also in the
development of Infrastructural facilities at the Institute. As a result of the consultancy, a number of manuals on special subjects have also been
published. The Krishi Vigyan Kendra and the Trainers' Training Centre handle a number of courses at the farmers level and at the trainers level
based on the technologies developed at the Institute. In addition, an integrated programme of training including subjects in agriculture, animal
husbandry and home management is also conducted
Space Weathering of Lunar Rocks
All materials exposed at the lunar surface undergo space weathering processes. On the Moon, boulders make up only a small percentage of the exposed surface, and areas where such rocks are exposed, like central peaks, are often among the least space weathered regions identified from remote sensing data. Yet space weathered surfaces (patina) are relatively common on returned rock samples, some of which directly sample the surface of larger boulders. Because, as witness plates to lunar space weathering, rocks and boulders experience longer exposure times compared to lunar soil grains, they allow us to develop a deeper perspective on the relative importance of various weathering processes as a function of time
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