Deciduous enamel 3D microwear texture analysis as an indicator of childhood diet in medieval Canterbury, England

This study conducted the first three dimensional microwear texture analysis of human deciduous teeth to reconstruct the physical properties of medieval childhood diet (age 1-8yrs) at St Gregory's Priory and Cemetery (11th to 16th century AD) in Canterbury, England. Occlusal texture complexity surfaces of maxillary molars from juvenile skeletons (n=44) were examined to assess dietary hardness. Anisotropy values were calculated to reconstruct dietary toughness, as well as jaw movements during chewing. Evidence of weaning was sought, and variation in the physical properties of food was assessed against age and socio-economic status. Results indicate that weaning had already commenced in the youngest children. Diet became tougher from four years of age, and harder from age six. Variation in microwear texture surfaces was related to historical textual evidence that refers to lifestyle developments for these age groups. Diet did not vary with socio-economic status, which differs to previously reported patterns for adults. We conclude, microwear texture analyses can provide a non-destructive tool for revealing subtle aspects of childhood diet in the past

A Frequency-Controlled Magnetic Vortex Memory

Using the ultra low damping NiMnSb half-Heusler alloy patterned into vortex-state magnetic nano-dots, we demonstrate a new concept of non-volatile memory controlled by the frequency. A perpendicular bias magnetic field is used to split the frequency of the vortex core gyrotropic rotation into two distinct frequencies, depending on the sign of the vortex core polarity $p=\pm1$ inside the dot. A magnetic resonance force microscope and microwave pulses applied at one of these two resonant frequencies allow for local and deterministic addressing of binary information (core polarity)

Possible Detection of OVI from the LMC Superbubble N70

We present FUSE observations toward four stars in the LMC superbubble N70 and compare these spectra to those of four comparison targets located in nearby field and diffuse regions. The N70 sight lines show OVI 1032 absorption that is consistently stronger than the comparison sight lines by ~60%. We attribute the excess column density (logN_OVI=14.03 cm^-2) to hot gas within N70, potentially the first detection of OVI associated with a superbubble. In a survey of 12 LMC sight lines, Howk et al. (2002a) concluded that there was no correlation between ISM morphology and N_OVI. We present a reanalysis of their measurements combined with our own and find a clear difference between the superbubble and field samples. The five superbubbles probed to date with FUSE show a consistently higher mean N_OVI than the 12 non-superbubble sight lines, though both samples show equivalent scatter from halo variability. Possible ionization mechanisms for N70 are discussed, and we conclude that the observed OVI could be the product of thermal conduction at the interface between the hot, X-ray emitting gas inside the superbubble and the cooler, photoionized material making up the shell seen prominently in Halpha. We calculate the total hydrogen density n_H implied by our OVI measurements and find a value consistent with expectations. Finally, we discuss emission-line observations of OVI from N70.Comment: 9 pages in emulateapj style. Accepted to Ap

Exclusion of Tiny Interstellar Dust Grains from the Heliosphere

The distribution of interstellar dust grains (ISDG) observed in the Solar System depends on the nature of the interstellar medium-solar wind interaction. The charge of the grains couples them to the interstellar magnetic field (ISMF) resulting in some fraction of grains being excluded from the heliosphere while grains on the larger end of the size distribution, with gyroradii comparable to the size of the heliosphere, penetrate the termination shock. This results in a skewing the size distribution detected in the Solar System. We present new calculations of grain trajectories and the resultant grain density distribution for small ISDGs propagating through the heliosphere. We make use of detailed heliosphere model results, using three-dimensional (3-D) magnetohydrodynamic/kinetic models designed to match data on the shape of the termination shock and the relative deflection of interstellar neutral H and He flowing into the heliosphere. We find that the necessary inclination of the ISMF relative to the inflow direction results in an asymmetry in the distribution of the larger grains (0.1 micron) that penetrate the heliopause. Smaller grains (0.01 micron) are completely excluded from the Solar System at the heliopause.Comment: 5 pages, 5 figures, accepted for publication in the Solar Wind 12 conference proceeding

Putting theory oriented evaluation into practice

Evaluations of gaming simulations and business games as teaching devices are typically end-state driven. This emphasis fails to detect how the simulation being evaluated does or does not bring about its desired consequences. This paper advances the use of a logic model approach which possesses a holistic perspective that aims at including all elements associated with the situation created by a game. The use of the logic model approach is illustrated as applied to Simgame, a board game created for secondary school level business education in six European Union countries

Mercury Orbiter: Report of the Science Working Team

The results are presented of the Mercury Orbiter Science Working Team which held three workshops in 1988 to 1989 under the auspices of the Space Physics and Planetary Exploration Divisions of NASA Headquarters. Spacecraft engineering and mission design studies at the Jet Propulsion Lab were conducted in parallel with this effort and are detailed elsewhere. The findings of the engineering study, summarized herein, indicate that spin stabilized spacecraft carrying comprehensive particles and fields experiments and key planetology instruments in high elliptical orbits can survive and function in Mercury orbit without costly sun shields and active cooling systems

Characteristics of the terrestrial field-aligned current system

We present the first ever comprehensive statistical study of the spatiotemporal characteristics of field-aligned currents in the terrestrial magnetosphere-ionosphere system using multi point measurements. We determine how the FAC density, variability and scale size are coupled. The three ST 5 satellites were in a pearls-on-a-string formation making measurements of the magnetic field with variable inter-spacecraft separations ranging from a few seconds to about 10 min. More than 4700 sets of satellite passes are analyzed using a robust correlation analysis aimed at determining the variability of the FAC system as a function of scale size and satellite spacing. We find significant differences between the FAC characteristics on the dayside and on the nightside in terms of dynamics of the current systems. On the dayside the FAC characteristics are found to be independent of IMF <I>B</I>_z and geomagnetic activity while the nightside indicates increased variability during disturbed conditions. The boundary separating highly and poorly correlated FACs can be fitted by a linear line for satellite separations shorter than 60 s (dayside) and 160 s (nightside). We interpret this as the dayside and nightside magnetospheric reconfiguration times respectively. For times exceeding this the FAC characteristics are suggested to be controlled by the solar wind (dayside) and plasma sheet (nightside) dynamics. Finally, the characteristics of FAC system with scale sizes larger than ~200 km (at ionospheric altitude) appear to be stable and repeatable on time scales of the order of a minute (i.e. comparable to the low-altitude orbiting satellite's traverse time across the auroral belt). In this sense, our results effectively validate the Iijima and Potemra (1978) assumption that on average the large-scale currents with scale sizes of the Region1 and Region2 are quasi-persistently significant in the transport of energy and momentum between the magnetosphere and the ionosphere

MMS Observations of Plasma Heating Associated With FTE Growth

Upon formation, flux transfer events (FTEs) in the subsolar magnetosheath have been observed to grow in diameter, λ, while convecting along the magnetopause. Plasma pressure has also been found to decrease subâ adiabatically with increasing λ, indicating the presence of internal plasma acceleration and heating processes. Here, the Magnetospheric Multiscale (MMS) fields and plasma measurements are used to determine the relative roles of parallel electric fields, betatron, and Fermi processes in plasma heating inside an ensemble of 55 subsolar FTEs. Plasma heating is shown asymmetric inside FTEs. Parallel electric fields dominate (>75%) ion and electron heating at the leading edge of FTEs. At the trailing edge, betatron and Fermi processes overtake (>50%), resulting in ion cooling and electron heating, respectively. The observed strong net heatings inside FTEs are proportional to λâ 1/2. It is concluded that reconnectionâ driven heating continues inside FTEs far from the subsolar electron and ion diffusion regions.Plain Language SummaryEnergetic charged particles are observed in many space and astrophysical environments, including our solar system. However, the acceleration and heating mechanisms responsible for generating these energetic charged particles remain to be discovered. Simulations and in situ observations have shown that magnetic reconnection, a process through which magnetic field lines â reconnectâ and release magnetic energy, plays a major role in generating energetic charged particles. The primary sites for magnetic energy transfer to charged particle acceleration and heating are the twin exhaust regions that emanate from the reconnection Xâ line. However, the amount of kinetic energy gained by charged particles in the exhaust regions represents only a small fraction of the total energy released by magnetic reconnection. Here, the Magnetospheric Multiscale (MMS) multipoint fields and plasma measurements are used to determine the contributions of acceleration mechanisms operating inside flux transfer events (FTEs), which are formed in the reconnection exhaust regions. We observe that acceleration mechanisms contribute to the charged particles’ energy gain inside FTEs. We further reveal that while acceleration mechanisms are most significant inside smaller FTEs, they continue to accelerate charged particles inside larger FTEs. We conclude that magnetic reconnectionâ driven charged particle acceleration is longâ lasting and can take place far from the exhaust regions.Key PointsThe relative roles of parallel electric fields, betatron, and Fermi processes in plasma heating inside 55 subsolar FTEs are determinedParallel electric fields dominate plasma energization at FTEs’ leading edge. Betatron and Fermi processes overtake at FTEs’ trailing edgeMMS observations reveal strong plasma acceleration inside FTEs that is inversely proportional to the square root of FTE diameterPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152496/1/grl59844_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152496/2/grl59844-sup-0001-2019GL084843-SI.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152496/3/grl59844.pd