Are exoplanetesimals differentiated?

Metals observed in the atmospheres of white dwarfs suggest that many have recently accreted planetary bodies. In some cases, the compositions observed suggest the accretion of material dominantly from the core (or the mantle) of a differentiated planetary body. Collisions between differentiated exoplanetesimals produce such fragments. In this work, we take advantage of the large numbers of white dwarfs where at least one siderophile (core-loving) and one lithophile (rock-loving) species have been detected to assess how commonly exoplanetesimals differentiate. We utilise N-body simulations that track the fate of core and mantle material during the collisional evolution of planetary systems to show that most remnants of differentiated planetesimals retain core fractions similar to their parents, whilst some are extremely core-rich or mantle-rich. Comparison with the white dwarf data for calcium and iron indicates that the data are consistent with a model in which $66^{+4}_{-6}\%$ have accreted the remnants of differentiated planetesimals, whilst $31^{+5}_{-5}\%$ have Ca/Fe abundances altered by the effects of heating (although the former can be as high as $100\%$, if heating is ignored). These conclusions assume pollution by a single body and that collisional evolution retains similar features across diverse planetary systems. These results imply that both collisions and differentiation are key processes in exoplanetary systems. We highlight the need for a larger sample of polluted white dwarfs with precisely determined metal abundances to better understand the process of differentiation in exoplanetary systems

Epigenetic alterations following early postnatal stress: a review on novel aetiological mechanisms of common psychiatric disorders

Stressor exposure during early life has the potential to increase an individual’s susceptibility to a number of neuropsychiatric conditions such as mood and anxiety disorders and schizophrenia in adulthood. This occurs in part due to the dysfunctional stress axis that persists following early adversity impairing stress responsivity across life. The mechanisms underlying the prolonged nature of this vulnerability remain to be established. Alterations in the epigenetic signature of genes involved in stress responsivity may represent one of the neurobiological mechanisms. The overall aim of this review is to provide current evidence demonstrating changes in the epigenetic signature of candidate gene(s) in response to early environmental adversity. More specifically, this review analyses the epigenetic signatures of postnatal adversity such as childhood abuse or maltreatment and later-life psychopathology in human and animal models of early life stress. The results of this review shows that focus to date has been on genes involved in the regulation of hypothalamic-pituitary-adrenal (HPA) axis and its correlation to subsequent neurobiology, for example, the role of glucocorticoid receptor gene. However, epigenetic changes in other candidate genes such as brain-derived neurotrophic factor (BDNF) and serotonin transporter are also implicated in early life stress (ELS) and susceptibility to adult psychiatric disorders. DNA methylation is the predominantly studied epigenetic mark followed by histone modifications specifically acetylation and methylation. Further, these epigenetic changes are cell/tissue-specific in regulating expression of genes, providing potential biomarkers for understanding the trajectory of early stress-induced susceptibility to adult psychiatric disorders

A mathematical modelling study of an athlete's sprint time when towing a weighted sled

This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s12283-013-0114-2.This study used a mathematical model to examine the effects of the sled, the running surface, and the athlete on sprint time when towing a weighted sled. Simulations showed that ratio scaling is an appropriate method of normalising the weight of the sled for athletes of different body size. The relationship between sprint time and the weight of the sled was almost linear, as long as the sled was not excessively heavy. The athlete’s sprint time and rate of increase in sprint time were greater on running surfaces with a greater coefficient of friction, and on any given running surface an athlete with a greater power-to-weight ratio had a lower rate of increase in sprint time. The angle of the tow cord did not have a substantial effect on an athlete’s sprint time. This greater understanding should help coaches set the training intensity experienced by an athlete when performing a sled-towing exercise

The many positive impacts of participating in outreach activities on postgraduate students

Postgraduate students are excellent role models for school students, where their passion and energy play a vital role in engaging younger students and spreading enthusiasm and excitement about science. However, participating in outreach is not a one way activity for these postgraduate students. Through focus groups we show that the postgraduate students perceive that there are many benefits for themselves. These benefits are identified and discussed. This paper also contrasts the postgraduate with their undergraduate counterpart in terms of their contributions to engagement activities

Comparison between gradients and parcellations for functional connectivity prediction of behavior

Resting-state functional connectivity (RSFC) is widely used to predict behavioral measures. To predict behavioral measures, representing RSFC with parcellations and gradients are the two most popular approaches. Here, we compare parcellation and gradient approaches for RSFC-based prediction of a broad range of behavioral measures in the Human Connectome Project (HCP) and Adolescent Brain Cognitive Development (ABCD) datasets. Among the parcellation approaches, we consider group-average “hard” parcellations (Schaefer et al., 2018), individual-specific “hard” parcellations (Kong et al., 2021a), and an individual-specific “soft” parcellation (spatial independent component analysis with dual regression; Beckmann et al., 2009). For gradient approaches, we consider the well-known principal gradients (Margulies et al., 2016) and the local gradient approach that detects local RSFC changes (Laumann et al., 2015). Across two regression algorithms, individual-specific hard-parcellation performs the best in the HCP dataset, while the principal gradients, spatial independent component analysis and group-average “hard” parcellations exhibit similar performance. On the other hand, principal gradients and all parcellation approaches perform similarly in the ABCD dataset. Across both datasets, local gradients perform the worst. Finally, we find that the principal gradient approach requires at least 40 to 60 gradients to perform as well as parcellation approaches. While most principal gradient studies utilize a single gradient, our results suggest that incorporating higher order gradients can provide significant behaviorally relevant information. Future work will consider the inclusion of additional parcellation and gradient approaches for comparison

Age-Related Reference Intervals of the Main Biochemical and Hematological Parameters in C57BL/6J, 129SV/EV and C3H/HeJ Mouse Strains

BACKGROUND: Although the mouse is the animal model most widely used to study the pathogenesis and treatment of human diseases, reference values for biochemical parameters are scanty or lacking for the most frequently used strains. We therefore evaluated these parameters in the C57BL/6J, 129SV/EV and C3H/HeJ mice. METHODOLOGY/PRINCIPAL FINDINGS: We measured by dry chemistry 26 analytes relative to electrolyte balance, lipoprotein metabolism, and muscle/heart, liver, kidney and pancreas functions, and by automated blood counter 5 hematological parameters in 30 animals (15 male and 15 female) of each mouse strain at three age ranges: 1-2 months, 3-8 months and 9-12 months. Whole blood was collected from the retro-orbital sinus. We used quality control procedures to investigate analytical imprecision and inaccuracy. Reference values were calculated by non parametric methods (median and 2.5(th) and 97.5(th) percentiles). The Mann-Whitney and Kruskal-Wallis tests were used for between-group comparisons. Median levels of GLU, LDH, Chol and BUN were higher, and LPS, AST, ALP and CHE were lower in males than in females (p range: 0.05-0.001). Inter-strain differences were observed for: (1) GLU, t-Bil, K+, Ca++, PO(4)- (p<0.05) and for TAG, Chol, AST, Fe++ (p<0.001) in 4-8 month-old animals; (2) for CK, Crea, Mg++, Na++, K+, Cl- (p<0.05) and BUN (p<0.001) in 2- and in 10-12 month-old mice; and (3) for WBC, RBC, HGB, HCT and PLT (p<0.05) during the 1 year life span. CONCLUSION/SIGNIFICANCE: Our results indicate that metabolic variations in C57BL/6J, 129SV/EV and C3H/HeJ mice after therapeutic intervention should be evaluated against gender- and age-dependent reference intervals

Secondary meningioma in a long-term survivor of atypical teratoid/rhabdoid tumour with a germline INI1 mutation

OBJECTIVE: We report on a patient who developed a meningioma more than two decades after removal at a young age of an atypical teratoid/rhabdoid tumour (AT/RT), which was due to a germline INI1 mutation, and radio- and chemotherapy. MATERIALS AND METHODS: We present genetic evidence that the meningioma is not a recurrence or metastasis of the AT/RT and not due to the INI1 mutation, but is a radiation-induced tumour. CONCLUSION: This is the first case illustrating that improved survival of young patients with an AT/RT after aggressive treatment may be gained at the cost of an increased risk for the development of radiation-induced, non-INI1-related tumours

Neuropsychiatric Symptoms in Patients with Aortic Aneurysms

BACKGROUND: Emerging evidence suggests that vascular disease confers vulnerability to a late-onset of depressive illness and the impairment of specific cognitive functions, most notably in the domains of memory storage and retrieval. Lower limb athero-thrombosis and abdominal aortic aneurysm (AAA) have both been previously associated with neuropsychiatric symptoms possibly due to associated intracerebral vascular disease or systemic inflammation, hence suggesting that these illnesses may be regarded as models to investigate the vascular genesis of neuropsychiatric symptoms. The aim of this study was to compare neuropsychiatric symptoms such as depression, anxiety and a variety of cognitive domains in patients who had symptoms of peripheral athero-thrombosis (intermittent claudication) and those who had an asymptomatic abdominal aortic aneurysm AAA. METHODOLOGY/PRINCIPAL FINDINGS: In a cross-sectional study, 26 participants with either intermittent claudication or AAA were assessed using a detailed neuropsychiatric assessment battery for various cognitive domains and depression and anxiety symptoms (Hamilton Depression and Anxiety Scales). Student t test and linear regression analyses were applied to compare neuropsychiatric symptoms between patient groups. AAA participants showed greater levels of cognitive impairment in the domains of immediate and delayed memory as compared to patients who had intermittent claudication. Cognitive dysfunction was best predicted by increasing aortic diameter. CRP was positively related to AAA diameter, but not to cognitive function. AAA and aortic diameter in particular were associated with cognitive dysfunction in this study. CONCLUSIONS/SIGNIFICANCE: AAA patients are at a higher risk for cognitive impairment than intermittent claudication patients. Validation of this finding is required in a larger study, but if confirmed could suggest that systemic factors peculiar to AAA may impact on cognitive function.Bernhard T. Baune, Steven J. Unwin, Frances Quirk and Jonathan Golledg

Spontaneous R-Parity Violation, A4A_4 Flavor Symmetry and Tribimaximal Mixing

We explore the possibility of spontaneous R parity violation in the context of $A_4$ flavor symmetry. Our model contains $SU(3)_c \times SU(2)_L \times U(1)_Y$ singlet matter chiral superfields which are arranged as triplet of $A_4$ and as well as few additional Higgs chiral superfields which are singlet under MSSM gauge group and belong to triplet and singlet representation under the $A_4$ flavor symmetry. R parity is broken spontaneously by the vacuum expectation values of the different sneutrino fields and hence we have neutrino-neutralino as well as neutrino-MSSM gauge singlet higgsino mixings in our model, in addition to the standard model neutrino- gauge singlet neutrino, gaugino-higgsino and higgsino-higgsino mixings. Because all of these mixings we have an extended neutral fermion mass matrix. We explore the low energy neutrino mass matrix for our model and point out that with some specific constraints between the sneutrino vacuum expectation values as well as the MSSM gauge singlet Higgs vacuum expectation values, the low energy neutrino mass matrix will lead to a tribimaximal mixing matrix. We also analyze the potential minimization for our model and show that one can realize a higher vacuum expectation value of the $SU(3)_c \times SU(2)_L \times U(1)_Y$ singlet sneutrino fields even when the other sneutrino vacuum expectation values are extremely small or even zero.Comment: 18 page

Testing the cognitive-behavioural maintenance models across DSM-5 bulimic-type eating disorder diagnostic groups: A multi-centre study

The original cognitive-behavioural (CB) model of bulimia nervosa, which provided the basis for the widely used CB therapy, proposed that specific dysfunctional cognitions and behaviours maintain the disorder. However, amongst treatment completers, only 40–50 % have a full and lasting response. The enhanced CB model (CB-E), upon which the enhanced version of the CB treatment was based, extended the original approach by including four additional maintenance factors. This study evaluated and compared both CB models in a large clinical treatment seeking sample (N = 679), applying both DSM-IV and DSM-5 criteria for bulimic-type eating disorders. Application of the DSM-5 criteria reduced the number of cases of DSM-IV bulimic-type eating disorders not otherwise specified to 29.6 %. Structural equation modelling analysis indicated that (a) although both models provided a good fit to the data, the CB-E model accounted for a greater proportion of variance in eating-disordered behaviours than the original one, (b) interpersonal problems, clinical perfectionism and low self-esteem were indirectly associated with dietary restraint through over-evaluation of shape and weight, (c) interpersonal problems and mood intolerance were directly linked to binge eating, whereas restraint only indirectly affected binge eating through mood intolerance, suggesting that factors other than restraint may play a more critical role in the maintenance of binge eating. In terms of strength of the associations, differences across DSM-5 bulimic-type eating disorder diagnostic groups were not observed. The results are discussed with reference to theory and research, including neurobiological findings and recent hypotheses