1,339 research outputs found
The role of post-Variscan extensional tectonics and mantle melting in the generation of the Lower Permian granites and the giant W-As-Sn-Cu-Zn-Pb orefield of SW England
Copyright © 2003 Maney Publishin
Single Cut Integration
We present an analytic technique for evaluating single cuts for one-loop
integrands, where exactly one propagator is taken to be on shell. Our method
extends the double-cut integration formalism of one-loop amplitudes to the
single-cut case. We argue that single cuts give meaningful information about
amplitudes when taken at the integrand level. We discuss applications to the
computation of tadpole coefficients.Comment: v2: corrected typo in abstrac
Prediction of the yield of grains through artificial intelligence
Grass turns out to be an appropriate food for cattle, mainly in tropical climate countries such as Latin American countries. This is due to the high number of species that can be used, the possibility of growing them year-round, the ability of the ruminant to use fibrous supplies and be an economic source (Sánchez et al., Data mining and big data. DMBD 2018. Lecture notes in computer science, vol 10943. Springer, Cham, 2018, [1]). In this work, an application of neural networks was carried out in the forecasting of more accurate values of production and quality of grasslands
Dwarf Galaxy Formation Was Suppressed By Cosmic Reionization
A large number of faint galaxies, born less than a billion years after the
big bang, have recently been discovered. The fluctuations in the distribution
of these galaxies contributed to a scatter in the ionization fraction of cosmic
hydrogen on scales of tens of Mpc, as observed along the lines of sight to the
earliest known quasars. Theoretical simulations predict that the formation of
dwarf galaxies should have been suppressed after cosmic hydrogen was reionized,
leading to a drop in the cosmic star formation rate. Here we present evidence
for this suppression. We show that the post-reionization galaxies which
produced most of the ionizing radiation at a redshift z~5.5, must have had a
mass in excess of ~10^{10.6+/-0.4} solar masses or else the aforementioned
scatter would have been smaller than observed. This limiting mass is two orders
of magnitude larger than the galaxy mass that is thought to have dominated the
reionization of cosmic hydrogen (~10^8 solar masses). We predict that future
surveys with space-based infrared telescopes will detect a population of
smaller galaxies that reionized the Universe at an earlier time, prior to the
epoch of dwarf galaxy suppression.Comment: 19 pages, 3 figures. Accepted for publication in Nature; press
embargo until publishe
Eliciting and prioritising determinants of improved care in multimorbidity: A modified online Delphi study.
BACKGROUND: Multimorbidity is a major challenge to health and social care systems around the world. There is limited research exploring the wider contextual determinants that are important to improving care for this cohort. In this study, we aimed to elicit and prioritise determinants of improved care in people with multiple conditions. METHODS: A three-round online Delphi study was conducted in England with health and social care professionals, data scientists, researchers, people living with multimorbidity and their carers. RESULTS: Our findings suggest a care system which is still predominantly single condition focused. 'Person-centred and holistic care' and 'coordinated and joined up care', were highly rated determinants in relation to improved care for multimorbidity. We further identified a range of non-medical determinants that are important to providing holistic care for this cohort. CONCLUSIONS: Further progress towards a holistic and patient-centred model is needed to ensure that care more effectively addresses the complex range of medical and non-medical needs of people living with multimorbidity. This requires a move from a single condition focused biomedical model to a person-based biopsychosocial approach, which has yet to be achieved
A Phase 1 Trial of CNDO-109-Activated Natural Killer Cells in Patients with High-Risk Acute Myeloid Leukemia
Natural killer (NK) cells are an emerging immunotherapy approach to acute myeloid leukemia (AML); however, the optimal approach to activate NK cells before adoptive transfer remains unclear. Human NK cells that are primed with the CTV-1 leukemia cell line lysate CNDO-109 exhibit enhanced cytotoxicity against NK cell–resistant cell lines. To translate this finding to the clinic, CNDO-109–activated NK cells (CNDO-109-NK cells) isolated from related HLA-haploidentical donors were evaluated in a phase 1 dose-escalation trial at doses of 3 × 105 (n = 3), 1 × 106 (n = 3), and 3 × 106 (n = 6) cells/kg in patients with AML in first complete remission (CR1) at high risk for recurrence. Before CNDO-109-NK cell administration, patients were treated with lymphodepleting fludarabine/cyclophosphamide. CNDO-109-NK cells were well tolerated, and no dose-limiting toxicities were observed at the highest tested dose. The median relapse-free survival (RFS) by dose level was 105 (3 × 105), 156 (1 × 106), and 337 (3 × 106) days. Two patients remained relapse-free in post-trial follow-up, with RFS durations exceeding 42.5 months. Donor NK cell microchimerism was detected on day 7 in 10 of 12 patients, with 3 patients having evidence of donor cells on day 14 or later. This trial establishes that CNDO-109-NK cells generated from related HLA haploidentical donors, cryopreserved, and then safely administered to AML patients with transient persistence without exogenous cytokine support. Three durable complete remissions of 32.6 to 47.6+ months were observed, suggesting additional clinical investigation of CNDO-109-NK cells for patients with myeloid malignancies, alone or in combination with additional immunotherapy strategies, is warranted
A study protocol to investigate the relationship between dietary fibre intake and fermentation, colon cell turnover, global protein acetylation and early carcinogenesis: the FACT study
Background: A number of studies, notably EPIC, have shown a descrease in colorectal cancer risk associated with increased fibre consumption. Whilst the underlying mechanisms are likely to be multifactorial, production of the short-chain fatty-acid butyrate fro butyratye is frequently cited as a major potential contributor to the effect. Butyrate inhibits histone deacetylases, which work on a wide range of proteins over and above histones. We therefore hypothesized that alterations in the acetylated proteome may be associated with a cancer risk phenotype in the colorectal mucosa, and that such alterations are candidate biomarkers for effectiveness of fibre interventions in cancer prevention.
Methods an design: There are two principal arms to this study: (i) a cross-sectional study (FACT OBS) of 90 subjects recruited from gastroenterology clinics and; (ii) an intervention trial in 40 subjects with an 8 week high fibre intervention. In both studies the principal goal is to investigate a link between fibre intake, SCFA production and global protein acetylation. The primary measure is level of faecal butyrate, which it is hoped will be elevated by moving subjects to a high fibre diet. Fibre intakes will be estimated in the cross-sectional group using the EPIC Food Frequency Questionnaire. Subsidiary measures of the effect of butyrate on colon mucosal function and precancerous phenotype will include measures of apoptosis, apoptotic regulators cell cycle and cell division.
Discussion: This study will provide a new level of mechanistic data on alterations in the functional proteome in response to the colon microenvironment which may underwrite the observed cancer preventive effect of fibre. The study may yield novel candidate biomarkers of fibre fermentation and colon mucosal function
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A demonstration of 'broken' visual space
It has long been assumed that there is a distorted mapping between real and ‘perceived’ space, based on demonstrations of systematic errors in judgements of slant, curvature, direction and separation. Here, we have applied a direct test to the notion of a coherent visual space. In an immersive virtual environment, participants judged the relative distance of two squares displayed in separate intervals. On some trials, the virtual scene expanded by a factor of four between intervals although, in line with recent results, participants did not report any noticeable change in the scene. We found that there was no consistent depth ordering of objects that can explain the distance matches participants made in this environment (e.g. A > B > D yet also A < C < D) and hence no single one-to-one mapping between participants’ perceived space and any real 3D environment. Instead, factors that affect pairwise comparisons of distances dictate participants’ performance. These data contradict, more directly than previous experiments, the idea that the visual system builds and uses a coherent 3D internal representation of a scene
The RING-CH ligase K5 antagonizes restriction of KSHV and HIV-1 particle release by mediating ubiquitin-dependent endosomal degradation of tetherin
Tetherin (CD317/BST2) is an interferon-induced membrane protein that inhibits the release of diverse enveloped viral particles. Several mammalian viruses have evolved countermeasures that inactivate tetherin, with the prototype being the HIV-1 Vpu protein. Here we show that the human herpesvirus Kaposi's sarcoma-associated herpesvirus (KSHV) is sensitive to tetherin restriction and its activity is counteracted by the KSHV encoded RING-CH E3 ubiquitin ligase K5. Tetherin expression in KSHV-infected cells inhibits viral particle release, as does depletion of K5 protein using RNA interference. K5 induces a species-specific downregulation of human tetherin from the cell surface followed by its endosomal degradation. We show that K5 targets a single lysine (K18) in the cytoplasmic tail of tetherin for ubiquitination, leading to relocalization of tetherin to CD63-positive endosomal compartments. Tetherin degradation is dependent on ESCRT-mediated endosomal sorting, but does not require a tyrosine-based sorting signal in the tetherin cytoplasmic tail. Importantly, we also show that the ability of K5 to substitute for Vpu in HIV-1 release is entirely dependent on K18 and the RING-CH domain of K5. By contrast, while Vpu induces ubiquitination of tetherin cytoplasmic tail lysine residues, mutation of these positions has no effect on its antagonism of tetherin function, and residual tetherin is associated with the trans-Golgi network (TGN) in Vpu-expressing cells. Taken together our results demonstrate that K5 is a mechanistically distinct viral countermeasure to tetherin-mediated restriction, and that herpesvirus particle release is sensitive to this mode of antiviral inhibition
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