Further evidence for early lunar magnetism from troctolite 76535

The earliest history of the lunar dynamo is largely unknown and has important implications for the thermal state of the Moon and the physics of dynamo generation. The lunar sample with the oldest known paleomagnetic record is the 4.25 billion year old (Ga) troctolite 76535. Previous studies of unoriented subsamples of 76535 found evidence for a dynamo field with a paleointensity of several tens of microteslas. However, the lack of mutual subsample orientation prevented a demonstration that the magnetization was unidirectional, a key property of thermoremanent magnetization. Here we report further alternating field demagnetization on three mutually oriented subsamples of 76535, as well as new pressure remanent magnetization experiments to help rule out shock magnetization. We also describe new 40Ar/39Ar thermochronometry and cosmogenic neon measurements that better constrain the rock's thermal history. Although the rock is unbrecciated, unshocked, and slowly cooled, its demagnetization behavior is not ideal due to spurious remanence acquisition. Despite this limitation, all three subsamples record a high coercivity magnetization oriented in nearly the same direction, implying that they were magnetized by a unidirectional field on the Moon. We find no evidence for shock remanence, and our thermochronometry calculations show no significant reheating events since 4249 ± 12 million years ago (Ma). We infer a field paleointensity of approximately 20–40 μT, supporting the previous conclusion that a lunar dynamo existed at 4.25 Ga. The timing of this field supports an early dynamo powered by thermal or thermochemical core convection and/or a mechanical dynamo but marginally excludes a dynamo delayed by thermal blanketing from radiogenic element-rich magma ocean cumulates

Panel Discussion On The Clinical Management Of Blood Dyscrasias In The Older Age Group†

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111245/1/jgs00338.pd

Dust heating by the interstellar radiation field in models of turbulent molecular clouds

We have calculated the radiation field, dust grain temperatures, and far infrared emissivity of numerical models of turbulent molecular clouds. When compared to a uniform cloud of the same mean optical depth, most of the volume inside the turbulent cloud is brighter, but most of the mass is darker. There is little mean attenuation from center to edge, and clumping causes the radiation field to be somewhat bluer. There is also a large dispersion, typically by a few orders of magnitude, of all quantities relative to their means. However, despite the scatter, the 850 micron emission maps are well correlated with surface density. The fraction of mass as a function of intensity can be reproduced by a simple hierarchical model of density structure.Comment: 32 pages, 14 figures, submitted to Ap

Outcomes 1 year after non-operative management of uncomplicated appendicitis in children : Children with AppendicitiS during the CoronAvirus panDEmic (CASCADE) study

Peer reviewedPublisher PD

The Gas Temperature of Starless Cores in Perseus

In this paper we study the determinants of starless core temperatures in the Perseus molecular cloud. We use NH3 (1,1) and (2,2) observations to derive core temperatures (T_kin) and data from the COMPLETE Survey of Star Forming Regions and the c2d Spitzer Legacy Survey for observations of the other core and molecular cloud properties. The kinetic temperature distribution probed by NH3 is in the fairly narrow range of 9 - 15 K. We find that cores within the clusters IC348 and NGC1333 are significantly warmer than "field" starless cores, and T_kin is higher within regions of larger extinction-derived column density. Starless cores in the field are warmer when they are closer to class O/I protostars, but this effect is not seen for those cores in clusters. For field starless cores, T_kin is higher in regions in which the 13CO linewidth and the 1.1mm flux from the core are larger, and T_kin is lower when the the peak column density within the core and average volume density of the core are larger. There is no correlation between T_kin and 13CO linewidth, 1.1mm flux, density or peak column density for those cores in clusters. The temperature of the cloud material along the line of sight to the core, as measured by CO or far-infrared emission from dust, is positively correlated with core temperature when considering the collection of cores in the field and in clusters, but this effect is not apparent when the two subsamples of cores are considered separately.Comment: Accepted to ApJ; 13 pages, including 3 tables and three figure

A shortened protocol for assessing cognitive bias in rats

Reliable measurement of affective state in animals is a significant goal of animal welfare. Such measurements would also improve the validity of pre-clinical mental health research which relies on animal models. However, at present, affective states in animals are inaccessible to direct measurement. In humans, changes in cognitive processing can give reliable indications of emotional state. Therefore, similar techniques are increasingly being used to gain proxy measures of affective states in animals. In particular, the ‘cognitive bias’ assay has gained popularity in recent years. Major disadvantages of this technique include length of time taken for animals to acquire the task (typically several weeks), negative experiences associated with task training, and issues of motivation. New method Here we present a shortened cognitive bias protocol using only positive reinforcers which must actively be responded to. Results The protocol took an average of 4 days to complete, and produced similar results to previous, longer methods (minimum 30 days). Specifically, rats housed in standard laboratory conditions demonstrated negative cognitive biases when presented with ambiguous stimuli, and took longer to make a decision when faced with an ambiguous stimulus. Comparison with existing methods Compared to previous methods, this protocol is significantly shorter (average 4 days vs. minimum 30 days), utilises only positive reinforcers to avoid inducing negative affective states, and requires active responses to all cues, avoiding potential confounds of motivational state. Conclusions We have successfully developed a shortened cognitive bias protocol, suitable for use with laboratory rats. Keywords Cognitive bias; Emotion; Affect; Rat; Protoco

A “How-To” Guide for Designing Judgment Bias Studies to Assess Captive Animal Welfare

Robust methods to assess nonhuman animal emotion are essential for ensuring good welfare in captivity. Cognitive bias measures such as the judgment bias task have recently emerged as promising tools to assess animal emotion. The simple design and objective response measures make judgment bias tasks suitable for use across species and contexts. In reviewing 64 studies published to date, it emerged that (a) judgment biases have been measured in a number of mammals and birds and an invertebrate; (b) no study has tested judgment bias in any species of fish, amphibian, or reptile; and (c) no study has yet investigated judgment bias in a zoo or aquarium. This article proposes that judgment bias measures are highly suitable for use with these understudied taxa and can provide new insight into welfare in endangered species housed in zoos and aquariums, where poor welfare impacts breeding success and, ultimately, species survival. The article includes a “how-to” guide to designing judgment bias tests with recommendations for working with currently neglected “exotics” including fishes, amphibians, and reptiles