A MODEST review

We present an account of the state of the art in the fields explored by the research community invested in 'Modeling and Observing DEnse STellar systems'. For this purpose, we take as a basis the activities of the MODEST-17 conference, which was held at Charles University, Prague, in September 2017. Reviewed topics include recent advances in fundamental stellar dynamics, numerical methods for the solution of the gravitational N-body problem, formation and evolution of young and old star clusters and galactic nuclei, their elusive stellar populations, planetary systems, and exotic compact objects, with timely attention to black holes of different classes of mass and their role as sources of gravitational waves. Such a breadth of topics reflects the growing role played by collisional stellar dynamics in numerous areas of modern astrophysics. Indeed, in the next decade, many revolutionary instruments will enable the derivation of positions and velocities of individual stars in the Milky Way and its satellites and will detect signals from a range of astrophysical sources in different portions of the electromagnetic and gravitational spectrum, with an unprecedented sensitivity. On the one hand, this wealth of data will allow us to address a number of long-standing open questions in star cluster studies; on the other hand, many unexpected properties of these systems will come to light, stimulating further progress of our understanding of their formation and evolution.Comment: 42 pages; accepted for publication in 'Computational Astrophysics and Cosmology'. We are much grateful to the organisers of the MODEST-17 conference (Charles University, Prague, September 2017). We acknowledge the input provided by all MODEST-17 participants, and, more generally, by the members of the MODEST communit

Optimal scaling of weight and waist circumference to height for adiposity and cardiovascular disease risk in individuals with spinal cord injury

Study design: Observational cross-sectional study. Objectives: Body mass index (BMI), measured as a ratio of weight (Wt) to the square of height (Wt/H

Gains and losses in C and N stocks of New Zealand pasture soils depend on land use

Previous re-sampling of 31 New Zealand pasture soil profiles to 1 m depth found large and significant losses of C and N over 2–3 decades. These profiles were predominantly on intensively grazed flat land. We have extended re-sampling to 83 profiles, to investigate whether changes in soil C and N stocks were related to land use. Over an average of 27 years, soils (0–30 cm) in flat dairy pastures lost 0.73 ± 0.16 Mg C ha⁻¹ y⁻¹ and 57 ± 16 kg N ha⁻¹ y⁻¹ but we observed no significant change in soil C or N in flat pasture grazed by “dry stock” (e.g., sheep, beef), or in grazed tussock grasslands. Grazed hill country soils (0–30 cm) gained 0.52 ± 0.18 Mg C ha⁻¹ y⁻¹and 66 ± 18 kg N ha⁻¹y⁻¹. The losses of C and N were strongly correlated, and C:N declined significantly. Further, results reported to 60 and 90 cm show that the pattern of losses and gains extend beyond the IPCC accounting depth of 30 cm. Specific causes for the soil C and N changes are unknown, but appear to be related to land use. In general, the losses under dairying correspond to systems with greater stocking rates, fertiliser inputs and removal of C and N in exported products. Gains in hill country pastures may be due to long-term recovery from erosion and disturbance following land clearance. The unexpected and contrary changes of C and N in different pasture systems (initially thought to be at steady state) demonstrates the need for global and national-scale collection of robust data investigating soil biogeochemical changes, not only for grasslands but also for other land uses. Re-sampling of soils can constrain the directions and magnitude of soil C and N change associated with land use and management to underpin C and N inventories and correctly identify mitigation options

Correcting bulk density measurements made with driving hammer equipment

Accurate measurement of dry bulk density is critical for determining stocks of elements such as carbon or nitrogen, in soils. During investigations of changes of soil carbon with time, we resampled soil profiles for bulk density using two methods, namely the driving hammer method and the carving method. The carving method involves gently pressing a metal ring down into a carved pedestal of soil while the hammer method uses percussion to insert a metal ring into the top of a soil layer. We consider the carving method to be more accurate because the soils are less disturbed using carving. The hammer method generally underestimated bulk density by about 5% in comparison with the carving method – depending on soil order and horizon. Most of the bulk density data in the New Zealand National Soils Database (originally collected in moist soils for water release characterisation) were obtained with the hammer method and can now be corrected to the equivalent of data obtained by carving. With data from 44 soil profiles comprising 388 horizons, we showed that a greater correction is needed for soils in the Allophanic (+ 10%) and Melanic soil orders than for other soil orders. The Brown Soils were separated from the remaining soils and a correction factor of about + 9% was required for their A and AB horizons and + 3% for their subsoil horizons. The remaining soils required a correction factor of + 6% for their A and AB horizons and + 3.5% for their subsoil horizons. The correction factor for the A horizons for the Allophanic Soils was similar to their subsoil horizons, suggesting that the influence of aluminium and allophane was overriding that of soil carbon. The Melanic Soils required a correction factor of + 13% for their A horizons but their subsoil horizons responded differently to other soils possibly because of high smectite contents. These differences in bulk density, attributed to change in sampling method, were often greater than changes in soil carbon that would be considered important. Although we used New Zealand soils, we believe that our conclusions will apply to many soils world-wide because most of our soils have equivalents within the FAO and USDA systems of soil classification. This study shows the importance of assessing bulk density methodology, and the possible need for other workers to amend the carbon stocks calculated from the hammer method

Alguns grupos de microrganismos em manteigas vendidas no município de São Paulo Microorganism groups found in butter sold in the City of S. Paulo, Brazil

Foram colhidas 105 amostras de manteiga de 5 marcas diferentes vendidas em supermercados da cidade de São Paulo (Brasil) com a finalidade de verificar as condições microbiológicas de manteigas e compará-las com os padrões recomendados. Semanalmente foi colhida uma amostra de cada marca, durante 21 semanas. A partir da parte aquosa de cada amostra, foram realizadas as contagens de bactérias mesófilas e psicrófilas (em ágar padrão e ágar gelisato), coliformes, proteolíticas e de bolores e leveduras e os resultados comparados com alguns parâmetros propostos por vários pesquisadores. Os valores obtidos nas contagens dos vários grupos de microrganismos estudados, em muitos casos podem ser considerados altos, os quais podem ser resultado do processamento e/ou conservação, realizados em condições não satisfatórias.<br>One hundred and five samples of five different brands of butter in the supermarkets of the City of S. Paulo, Brazil were brought in for testing every week for 21 weeks. From the aqueous phase, counts were made for mesophilic and psichrophilic (using the standard plate count, agar and gelysate agar), coliform, proteolytic, and lipolytic bacteria, as well as for yeasts and molds. Results were compared with parameters proposed by several researchers. In many cases, the count values can be considered high, but these high counts may be due to inadequate processing and/or inadequate storage