Lotte Jacobi: A Composite Portrait

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Relationships between class size and teaching: a multi-method analysis of English infant schools

Research and debate on class size differences has focused on relations with achievement, and there is little relevant research on what mediating classroom processes might be involved. In this article we investigate connections between class size and teaching interactions. We adopt a multimethod approach, integrating qualitative in formation from teachers' end-of-year accounts and data from case studies with quantitative information from time-allocation estimates and systematic observations. Our data come from a longitudinal study of two cohorts of more than 10,000 children altogether for 3 years after enrollment in English infant schools (aged 4-7 years). Our results show, overall, that in smaller classes there is more individualized teacher support for learning. We interpret the results in the context of teacher time allocation, research on effective teaching, and post-Vygotskian approaches to teaching. It is suggested that direct models of teacher influences on pupils need to be adapted to allow for class size as a contextual factor that influences both teachers and pupils

Turbulence Measurements on a Flap-Edge Model

Turbulence measurements have been made on a flap-edge and leading-edge slat model using hot-wire anemometry, and, later, particle image velocimetry. The properties of hot-wire anemometry were studied using facilities at NASA Ames Research Center. Hot-film probes were used because of their durability, but cross-films were limited by non-linear end effects. As a warm-up exercise, hot-film probes were used to measure velocities in the farfield wake of a cylinder with an airfoil in the near-field wake. The airfoil reduced the drag coefficient of the system by 10%. A single-wire hot-film probe was used to measure velocity profiles over the top of a NACA 63(sub 2)-215 Mod. B wing with a Fowler flap and leading,-edge slat. Results showed the size of slat wake was dependent upon the slat deflection angle. Velocity increased through the slat gap with increased deflection. The acoustically modified slat decreased the chance of separation. Measurements were taken at the flap edge with a single hot-film. Trends in the data indicate velocity and turbulence levels increase at the flap edge. The acoustically modified flap modifies the mean flow near the flap edge. Correlations were made between the hot-film signal and the unsteady pressure transducers on the wing which were published in a NASA CDTM. The principles of Particle Image Velocimetry (PIV) were studied at Florida State University. Spectral PIV was used to measure the spectra of a subsonic jet. Measured frequencies were close to the predicted frequency of jet shedding. Spectral PIV will be used to measure the spectra of the slat flow in the second 7 x lO-ft. wind tunnel test. PIV has an advantage that it can measure velocity and spectra of the entire flowfield instantaneously. However, problems arise when trying, to store this massive amount of PIV data. Support for this research has continued through a NASA Graduate Student Program Fellowship which will end in June 1999. The thesis should be completed by this time

Diversity and Progression among Students Starting Social Work Qualifying Programmes in England between 1995 and 1998: a quantitative study

There has been no large-scale study looking at the proportion of social work students in the UK who achieve the professional qualification, although there is some evidence that different groups experience different rates of progression. This article examines progression rates among students studying for the DipSW in England and analyses the factors that influence whether students achieve an award on time (defined as achieving an award without being referred, deferred, failing or withdrawing). The results show that male students, students from a black and minority ethnic group, and students with a self-reported disability have poorer progression rates. However, contrary to the picture in higher education as a whole, older students and students with previously lower levels of educational attainment do not have poorer progression rates. Social work education has important lessons to share with higher-education colleagues in terms of working with an increasingly diverse student group. However, work is needed to identify students at greater risk of non-progression than others and to develop more effective student support strategies

Automated extraction of single H atoms with STM: tip state dependency

The atomistic structure of the tip apex plays a crucial role in performing reliable atomic-scale surface and adsorbate manipulation using scanning probe techniques. We have developed an automated extraction routine for controlled removal of single hydrogen atoms from the H:Si(100) surface. The set of atomic extraction protocols detect a variety of desorption events during scanning tunneling microscope (STM)-induced modification of the hydrogen-passivated surface. The influence of the tip state on the probability for hydrogen removal was examined by comparing the desorption efficiency for various classifications of STM topographs (rows, dimers, atoms, etc). We find that dimer-row-resolving tip apices extract hydrogen atoms most readily and reliably (and with least spurious desorption), while tip states which provide atomic resolution counter-intuitively have a lower probability for single H atom removal

GAMBARAN TINGKAT PENGETAHUAN MASYARAKAT TENTANG PENYAKIT ASAM URAT DI RT 04 RW 04 DESA KRANJI KECAMATAN PACIRAN KABUPATEN LAMONGAN

Penyakit asam urat menyerang masyarakat yang mempunyai kadar asam urat tinggi, masyarakat yang terkena asam urat biasanya mengeluh badan capek, linu-linu dan nyeri sendi. Tujuan penelitian ini adalah mengetahui gambaran tingkat pengetahuan warga tentang penyakit asam urat pada warga RT 04 RW 04 Desa Kranji Kecamatan Paciran Kabupaten Lamongan. Desain penelitian ini diskriptif. Populasinya semua warga yang mengeluh badan capek, linu-linu dan nyeri sendi sebesar 25 orang. Cara pengambilan sampel dengan menggunakan tehnik total sampling. Dengan jumlah sampel 25 responden. Variabelnya adalah tingkat pengetahuan warga tentang penyakit asam urat di RT 04 RW 04 Desa Kranji Kecamatan Paciran Kabupaten Lamongan. Pengumpulan data dengan menggunakan instrumen kuesioner dianalisis data dengan distribusi frekuensi. Hasil penelitian didapatkan dari 25 responden sebagian besar (56%) responden memiliki tingkat pengetahuan yang kurang, (24%) responden memiliki tingkat pengetahuan yang cukup dan (20%) memiliki tingkat pengetahuan yang baik. Disimpulkan bahwa warga di RT 04 sebagian besar memiliki tingkat pengetahuan tentang penyakit asam urat yang kurang. Sehingga bagi warga yang sudah mempunyai keluhan badan capek, linu-linu dan nyeri sendi diharapkan untuk menghindari semua makanan yang mengandung kadar purin tinggi

Estimating the recharge properties of the deep ocean using noble gases and helium isotopes

The distribution of noble gases and helium isotopes in the dense shelf waters of Antarctica reflect the boundary conditions near the ocean surface: air-sea exchange, sea ice formation and subsurface ice melt. We use a non-linear least-squares solution to determine the value of the recharge temperature and salinity, as well as the excess air injection and glacial meltwater content throughout the water column and in the precursor to Antarctic Bottom Water. The noble gas-derived recharge temperature and salinity in the Weddell Gyre are -1.95 °C and 34.95 psu near 5500 m; these cold, salty recharge values are a result of surface cooling as well as brine rejection during sea ice formation in Antarctic polynyas. In comparison, the global value for deep water recharge temperature is -0.44 °C at 5500 m, which is 1.5 °C warmer than the southern hemisphere deep water recharge temperature, reflecting the contribution from the north Atlantic. The contrast between northern and southern hemisphere recharge properties highlight the impact of sea ice formation on setting the gas properties in southern sourced deep water. Below 1000 m, glacial meltwater averages 3.5 ‰ by volume and represents greater than 50% of the excess neon and argon found in the water column. These results indicate glacial melt has a non-negligible impact on the atmospheric gas content of Antarctic Bottom Water

Iterative-build OMIT maps: map improvement by iterative model building and refinement without model bias.

A procedure for carrying out iterative model building, density modification and refinement is presented in which the density in an OMIT region is essentially unbiased by an atomic model. Density from a set of overlapping OMIT regions can be combined to create a composite 'iterative-build' OMIT map that is everywhere unbiased by an atomic model but also everywhere benefiting from the model-based information present elsewhere in the unit cell. The procedure may have applications in the validation of specific features in atomic models as well as in overall model validation. The procedure is demonstrated with a molecular-replacement structure and with an experimentally phased structure and a variation on the method is demonstrated by removing model bias from a structure from the Protein Data Bank

Interpretation of ensembles created by multiple iterative rebuilding of macromolecular models.

Automation of iterative model building, density modification and refinement in macromolecular crystallography has made it feasible to carry out this entire process multiple times. By using different random seeds in the process, a number of different models compatible with experimental data can be created. Sets of models were generated in this way using real data for ten protein structures from the Protein Data Bank and using synthetic data generated at various resolutions. Most of the heterogeneity among models produced in this way is in the side chains and loops on the protein surface. Possible interpretations of the variation among models created by repetitive rebuilding were investigated. Synthetic data were created in which a crystal structure was modelled as the average of a set of ;perfect' structures and the range of models obtained by rebuilding a single starting model was examined. The standard deviations of coordinates in models obtained by repetitive rebuilding at high resolution are small, while those obtained for the same synthetic crystal structure at low resolution are large, so that the diversity within a group of models cannot generally be a quantitative reflection of the actual structures in a crystal. Instead, the group of structures obtained by repetitive rebuilding reflects the precision of the models, and the standard deviation of coordinates of these structures is a lower bound estimate of the uncertainty in coordinates of the individual models