ABSTRACT
The (α/Fe, Fe/H) distribution of Milky Way stars shows at least two distinct sequences, which have traditionally been associated with the thin and thick disc components. The abundance ...distribution varies systematically with location R and |z| across the Galaxy. We reproduce this using an analytical chemodynamical model that includes the effects of radial migration and kinematic heating. Unlike some earlier models, our scheme does not require a distinct thick disc component emerging from a separate evolutionary path. The proposed model has a continuous star formation history and a continuous age velocity dispersion relation. Moreover, α/Fe is constant for stellar ages less than 8 Gyr, but increases sharply for older stars over a time-scale of 1.5 Gyr. The gap between the two sequences is due to this sharp transition. We show that the high-α/Fe sequence at the low-metallicity end is simply a pile-up of old stars, but towards the high-metallicity end, the age progressively decreases and stars have small birth radii. Our model successfully explains the uniformity of the locus of the high-α/Fe sequence across different locations. The low-α/Fe sequence contains stars with different birth radii that owes its existence to radial migration. For the low-α/Fe stars, angular momentum is anticorrelated with Fe/H, while the opposite is true for high-α/Fe stars. We show that the later trend can be explained by the increase of circular velocity with time. If radial migration is not included, the model fails to generate the double sequence and instead shows only a single sequence. Our simple scheme has major advantages over earlier chemodynamical models, as we show.
The budget for the Common Agricultural Policy (CAP) is €365bn (European Commission, 2018) for 2021–2027, with the majority allocated to farmers through direct payments. Given the economic ...vulnerability of many farm enterprises, and the concern about the sustainability of food supply for a growing worldwide population, these payments are provided to encourage food production. Despite this economic vulnerability, many farmers do not appear to run their business with the sole intention of profit maximisation. This paper explores various financial and non-financial influencing factors on the strategic farm expansion decision-making process of farmers with the aim of assisting policymakers and farm advisors to develop a deeper understanding of that process. As a result, agricultural policy may be more effectively formulated and advisory services to farmers may be improved. Semi-structured interviews were undertaken with 27 farmers who have undertaken strategic farm expansion decisions. Subsequently, the interview findings were presented to a focus group to probe them in more detail. A wide range of financial and non-financial influencing factors on the strategic farm expansion decision-making process of farmers emerge. Analysis of the influencing factors by the specific type of farm expansion decision undertaken and by farm type provides further insights. It is proposed that these influencing factors act as a cue which trigger a sensebreaking activity and cause the farmer to enter a process of sensemaking, culminating in a strategic farm expansion decision being undertaken.
•A wide range of financial and non-financial factors which influence strategic farm expansion decisions are profiled.•A management accounting approach of profiling influencing factors as financial or non-financial brings a new prospective.•Influencing factors appear to be most associated with specific farm types and specific types of farm expansion decision.•Influencing factors act as cues which trigger a sensebreaking activity and cause farmers to enter a process of sensemaking.•If stakeholders gain a deeper understanding of farmer decision-making it will contribute to sustainable farm enterprises.
The GALAH+ survey: Third data release Buder, Sven; Sharma, Sanjib; Kos, Janez ...
Monthly Notices of the Royal Astronomical Society,
2021, Letnik:
506, Številka:
1
Journal Article
Recenzirano
Odprti dostop
ABSTRACT
The ensemble of chemical element abundance measurements for stars, along with precision distances and orbit properties, provides high-dimensional data to study the evolution of the Milky ...Way. With this third data release of the Galactic Archaeology with HERMES (GALAH) survey, we publish 678 423 spectra for 588 571 mostly nearby stars (81.2 per cent of stars are within <2 kpc), observed with the HERMES spectrograph at the Anglo-Australian Telescope. This release (hereafter GALAH+ DR3) includes all observations from GALAH Phase 1 (bright, main, and faint survey, 70 per cent), K2-HERMES (17 per cent), TESS-HERMES (5 per cent), and a subset of ancillary observations (8 per cent) including the bulge and >75 stellar clusters. We derive stellar parameters Teff, log g, Fe/H, vmic, vbroad, and vrad using our modified version of the spectrum synthesis code Spectroscopy Made Easy (sme) and 1D marcs model atmospheres. We break spectroscopic degeneracies in our spectrum analysis with astrometry from Gaia DR2 and photometry from 2MASS. We report abundance ratios X/Fe for 30 different elements (11 of which are based on non-LTE computations) covering five nucleosynthetic pathways. We describe validations for accuracy and precision, flagging of peculiar stars/measurements and recommendations for using our results. Our catalogue comprises 65 per cent dwarfs, 34 per cent giants, and 1 per cent other/unclassified stars. Based on unflagged chemical composition and age, we find 62 per cent young low-$\alpha$, 9 per cent young high-$\alpha$, 27 per cent old high-$\alpha$, and 2 per cent stars with Fe/H ≤ −1. Based on kinematics, 4 per cent are halo stars. Several Value-Added-Catalogues, including stellar ages and dynamics, updated after Gaia eDR3, accompany this release and allow chrono-chemodynamic analyses, as we showcase.
Huntington's disease (HD) is caused by an expansion of the polyglutamine tract at the N terminus of huntingtin. This mutation reduces levels of BDNF in the striatum, likely by inhibiting cortical ...Bdnf gene expression and anterograde transport of BDNF from the cerebral cortex to the striatum. Substantial evidence suggests that this reduction of striatal BDNF plays a crucial role in HD pathogenesis. Here we report that overexpression of BDNF in the forebrain rescues many disease phenotypes in YAC128 mice that express a full-length human huntingtin mutant with a 128-glutamine tract. The Bdnf transgene, under the control of the promoter for α subunit of Ca(2+)/calmodulin-dependent protein kinase II, greatly increased BDNF levels in the cerebral cortex and striatum. BDNF overexpression in YAC128 mice prevented loss and atrophy of striatal neurons and motor dysfunction, normalized expression of the striatal dopamine receptor D2 and enkephalin, and improved procedural learning. Furthermore, quantitative analyses of Golgi-impregnated neurons revealed a decreased spine density and abnormal spine morphology in striatal neurons of YAC128 mice, which was also reversed by increasing BDNF levels in the striatum. These results demonstrate that reduced striatal BDNF plays a crucial role in the HD pathogenesis and suggest that attempts to restore striatal BDNF level may have therapeutic effects to the disease.
Palmitoylation involves the reversible posttranslational addition of palmitate to cysteines and promotes membrane binding and subcellular localization. Recent advancements in the detection and ...identification of palmitoylated proteins have led to multiple palmitoylation proteomics studies but these datasets are contained within large supplemental tables, making downstream analysis and data mining time-consuming and difficult. Consequently, we curated the data from 15 palmitoylation proteomics studies into one compendium containing 1,838 genes encoding palmitoylated proteins; representing approximately 10% of the genome. Enrichment analysis revealed highly significant enrichments for Gene Ontology biological processes, pathway maps, and process networks related to the nervous system. Strikingly, 41% of synaptic genes encode a palmitoylated protein in the compendium. The top disease associations included cancers and diseases and disorders of the nervous system, with Schizophrenia, HD, and pancreatic ductal carcinoma among the top five, suggesting that aberrant palmitoylation may play a pivotal role in the balance of cell death and survival. This compendium provides a much-needed resource for cell biologists and the palmitoylation field, providing new perspectives for cancer and neurodegeneration.
Since the identification of the causative gene in Huntington's disease (HD), a number of animal models of this disorder have been developed. A frequently asked question is: which of these models most ...closely recapitulates the human disease? In this Review, we provide an overview of the currently available animal models of HD in the context of the clinical features of the disease. In doing so, we highlight their strengths and limitations for modelling specific symptoms of the disease. This should highlight the animal model that is best suited to address a particular question of interest and, ultimately, to expedite the discovery of treatments that will prevent or slow the progression of HD.
In 2009 we reported the fatal case of a toddler who had received codeine after adenotonsillectomy for obstructive sleep apnea syndrome. The child was an ultra-rapid metabolizer of cytochrome P4502D6 ...(CYP2D6). We now report 3 additional fatal or life-threatening cases from North America. In the 2 fatal cases, functional gene duplications encoding for CYP2D6 caused a significantly greater production of potent morphine from its parent drug, codeine. A severe case of respiratory depression in an extensive metabolizer is also noted. These cases demonstrate that analgesia with codeine or other opioids that use the CYP2D6 pathway after adenotonsillectomy may not be safe in young children with obstructive sleep apnea syndrome.
Highlights • HTT is an important regulator of autophagy that is, in turn, degraded by autophagy. • Genes regulating protein clearance show altered expression in HD brains. • Defining HD-specific ...alterations in autophagy is crucial for the development of therapeutics. • Post-translational modifications influence the role of HTT as a regulator of autophagy.
Huntington disease (HD) is caused by a CAG repeat expansion in the huntingtin (HTT) gene. Although the length of this repeat is inversely correlated with age of onset (AOO), it does not fully explain ...the variability in AOO. We assessed the sequence downstream of the CAG repeat in HTT reference: (CAG)n-CAA-CAG, since variants within this region have been previously described, but no study of AOO has been performed. These analyses identified a variant that results in complete loss of interrupting (LOI) adenine nucleotides in this region (CAG)n-CAG-CAG. Analysis of multiple HD pedigrees showed that this LOI variant is associated with dramatically earlier AOO (average of 25 years) despite the same polyglutamine length as in individuals with the interrupting penultimate CAA codon. This LOI allele is particularly frequent in persons with reduced penetrance alleles who manifest with HD and increases the likelihood of presenting clinically with HD with a CAG of 36–39 repeats. Further, we show that the LOI variant is associated with increased somatic repeat instability, highlighting this as a significant driver of this effect. These findings indicate that the number of uninterrupted CAG repeats, which is lengthened by the LOI, is the most significant contributor to AOO of HD and is more significant than polyglutamine length, which is not altered in these individuals. In addition, we identified another variant in this region, where the CAA-CAG sequence is duplicated, which was associated with later AOO. Identification of these cis-acting modifiers have potentially important implications for genetic counselling in HD-affected families.
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