International standards for fetal brain structures based on serial ultrasound measurements from the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project.

OBJECTIVE: To create prescriptive growth standards for five fetal brain structures, measured by ultrasound, from healthy, well-nourished women, at low risk of impaired fetal growth and poor perinatal outcomes, taking part in the Fetal Growth Longitudinal Study (FGLS) of the INTERGROWTH-21st Project. METHODS: This was a complementary analysis of a large, population-based, multicentre, longitudinal study. We measured, in planes reconstructed from 3-dimensional (3D) ultrasound volumes of the fetal head at different time points in pregnancy, the size of the parieto-occipital fissure (POF), Sylvian fissure (SF), anterior horn of the lateral ventricle (AV), atrium of the posterior ventricle (PV) and cisterna magna (CM). The sample analysed was randomly selected from the overall FGLS population, ensuring an equal distribution amongst the eight diverse participating sites and of 3D ultrasound volumes across pregnancy (range: 15 - 36 weeks' gestation). Fractional polynomials were used to the construct standards. Growth and development of the infants were assessed at 1 and 2 years of age to confirm their adequacy for constructing international standards. RESULTS: From the entire FGLS cohort of 4321 women, 451 (10.4%) were randomly selected. After exclusions, 3D ultrasound volumes from 442 fetuses born without congenital malformations were used to create the charts. The fetal brain structures of interest were identified in 90% of cases. All structures showed increasing size with gestation and increasing variability for the POF, SF, PV and CM. The 3rd , 5th , 50th , 95th and 97th smoothed centile are presented. The 5th centile of POF and SF were 2.8 and 4.3 at 22 weeks and 4.2 and 9.4mm at 32 weeks respectively. The 95th centile of PV and CM were 8.5 and 7.4 at 22 weeks and 8.5 and 9.4mm at 32 weeks respectively. CONCLUSIONS: We have produced prescriptive size standards for fetal brain structures based on prospectively enrolled pregnancies at low risk of abnormal outcomes. We recommend these as international standards for the assessment of measurements obtained by ultrasound from fetal brain structures

Towards mobile learning deployment in higher learning institutions : a report on the qualitative inquiries conducted in four universities in Tanzania

Over the past two decades, mobile learning (m-learning) has been a purposeful area of research among educational technologists, educators and instructional designers whereby doubts and controversies over its relevancy and applicability have been keenly addressed. This paper explores stakeholders’ perceptions of m-learning deployment in Higher Learning Institutions (HLIs). Spe- cifically, we examine the potential of m-learning for HLIs in Tanzania and the challenges that hinder successful m-learning deployment. We adopt a comparative qualitative case study design in which four HLIs in Tanzania were purposefully selected. The study uses a combination of de- sign science research approach and qualitative methods including grounded theory, document re- views, and observation. The respondents included university lecturers, students and ICT experts, who were selected for the interviews through theoretical sampling. The transcripts were loaded, coded and analyzed in NVIVO software. The results indicate that mobiles (smartphone, tablets, laptops, feature-phones etc.) are widely used in the HLIs. Stakeholders perceive that m-learning deployment is important and useful because it improves the quality of the learning experience. The results further indicate that there are financial, pedagogical, technological, infrastructural, individuals – and policy – related challenges that hinder successful deployment of m-learning in HLIs in Tanzania, such as limited network coverage, some students ́ inability to afford mobiles, lack of qualified staff for preparation of mobile content and administration, gaps in the exist- ing policies, and faulty course design. However, our results show that participants are optimistic about the potential of m-learning in the HLIs of Tanzania. They expect that m-learning will im- prove access to learning resources, teacher-student and student-student interaction without being restricted by time or place. Thus, m-learning is considered to have the potential to address issues of crowded classrooms, expertise, access to learning materials, flexibility of the learners as well as remote connectivity.
 We recommend that HLIs should prioritize m-learning and commit resources to the success of the related projects. We also recommend that the governments and stakeholders provide policy interventions, subsidize mobile technologies, expand network coverage, build capacity within and outside HLIs, and improve digital literacy by integrating ICT education at all levels of education

Skin-Friction and Forced Convection from Rough and Smooth Plates

The current models for skin-friction drag from a plate with a rough surface are derived by analogy to flow within pipes having rough interiors. But this analogy fails at low Reynolds number (Re) flow rates because the boundary-layer must compress into the center of the pipe, while the plate boundary-layer is unbounded. A significant discrepancy from the pipe analogy at low Re was found by the rough plate experiments of Pimenta, Moffat, and Kays (1975) and by experiments conducted by the present author (2019). An additional problem is that the roughness parameter in pipe analogy theories is tied to the drag measurements of flows inside Nikuradse's assortment of sand-roughened pipes (1933). Prandtl and Schlichting (1934) caution that their theory applies only to sand-roughness. More useful would be a theory based on direct measurements of roughness profiles. The present work derives the formula for a plate's skin-friction drag coefficient given its root-mean-squared height-of-roughness, and Re bounds from the roughness spatial frequency spectrum. The present theory is in close agreement with the Mills-Hang (1983) theory, the Pimenta et al measurements, and the experiments conducted by the author over their respective Re ranges. From boundary conditions of its rough plate analysis, the present work also derives an exact formula for skin-friction from a smooth plate; this formula is in very close agreement with measurements from Smith and Walker (1959) and Spalding and Chi (1964) over 4 decades of Re.Comment: Rewritten to include skin-friction from smooth plates. 20 pages; 17 figures; 16 reference

Peopling landscapes, ethnographic and otherwise: European images of Asians from the 15th to the 19th centuries

This article examines European depictions of Asians during the early modern period, arguing that images were determined by the conditions of the relationship between Europe and Asia. Europe's marginal position and limited access in the 16th and 17th century encouraged invention rather than observation. Increasing access and dominance in the 18th and 19th did not necessarily encourage greater accuracy. It remained rare for an Asian to escape landscape and history: for portraits to allow the individual to emerge from the type that he or she illustrated, or for Asia to escape the past to which it had by then been consigned

International standards for early fetal size and pregnancy dating based on ultrasound measurement of crown-rump length in the first trimester of pregnancy.

OBJECTIVES: There are no international standards for relating fetal crown-rump length (CRL) to gestational age (GA), and most existing charts have considerable methodological limitations. The INTERGROWTH-21(st) Project aimed to produce the first international standards for early fetal size and ultrasound dating of pregnancy based on CRL measurement. METHODS: Urban areas in eight geographically diverse countries that met strict eligibility criteria were selected for the prospective, population-based recruitment, between 9 + 0 and 13 + 6 weeks' gestation, of healthy well-nourished women with singleton pregnancies at low risk of fetal growth impairment. GA was calculated on the basis of a certain last menstrual period, regular menstrual cycle and lack of hormonal medication or breastfeeding in the preceding 2 months. CRL was measured using strict protocols and quality-control measures. All women were followed up throughout pregnancy until delivery and hospital discharge. Cases of neonatal and fetal death, severe pregnancy complications and congenital abnormalities were excluded from the study. RESULTS: A total of 4607 women were enrolled in the Fetal Growth Longitudinal Study, one of the three main components of the INTERGROWTH-21(st) Project, of whom 4321 had a live singleton birth in the absence of severe maternal conditions or congenital abnormalities detected by ultrasound or at birth. The CRL was measured in 56 women at < 9 + 0 weeks' gestation; these were excluded, resulting in 4265 women who contributed data to the final analysis. The mean CRL and SD increased with GA almost linearly, and their relationship to GA is given by the following two equations (in which GA is in days and CRL in mm): mean CRL = -50.6562 + (0.815118 × GA) + (0.00535302 × GA(2) ); and SD of CRL = -2.21626 + (0.0984894 × GA). GA estimation is carried out according to the two equations: GA = 40.9041 + (3.21585 × CRL(0.5) ) + (0.348956 × CRL); and SD of GA = 2.39102 + (0.0193474 × CRL). CONCLUSIONS: We have produced international prescriptive standards for early fetal linear size and ultrasound dating of pregnancy in the first trimester that can be used throughout the world