961 research outputs found
Preliminary study of thermomechanical fatigue of polycrystalline MAR-M 200
Thermomechanical fatigue (TMF) experiments were conducted on polycrystalline MAR-M 200 over a cyclic temperature range of 500 to 1000 C. Inelastic strain ranges of 0.03 to 0.2 percent were imposed on the specimens. The TMF lives were found to be significantly shorter than isothermal low-cycle-fatigue (LCF) life at the maximum cycle temperature, and in-phase cycling was more damaging than out-of-phase cycling. Extensive crack tip oxidation appeared to play a role in promoting the severity of in-phase cycling. Carbide particle - matrix interface cracking was also observed after in-phase TMF cycling. The applicability of various life prediction models to the TMF results obtained was assessed. It was concluded that current life prediction models based on isothermal data as input must be modified to be applicable to the TMF results
New first integral for twisting type-N vacuum gravitational fields with two non-commuting Killing vectors
A new first integral for the equations corresponding to twisting type-N
vacuum gravitational fields with two non-commuting Killing vectors is
introduced. A new reduction of the problem to a complex second-order ordinary
differential equation is given. Alternatively, the mentioned first integral can
be used in order to provide a first integral of the second-order complex
equation introduced in a previous treatment of the problem.Comment: 7 pages, LaTeX, uses ioplppt.sty and iopl12.sty; to be published in
Class. Quantum Gra
Field assessment of genome edited, low asparagine wheat: Europe's first CRISPR wheat field trial.
We reported in this journal in 2021 the generation of wheat genotypes in which the asparagine synthetase gene, TaASN2, had been ‘knocked out’ using CRISPR-Cas9 (Raffan et al. 2021). The editing had been achieved by introducing genes encoding the Cas9 nuclease, four guide RNAs (gRNAs) and a Bar marker gene into wheat (Triticum aestivum) cv. Cadenza. Here we report the results of a field trial of Line 178.35, an A genome null for TaASN2, and total nulls, 23.60 and 23.75 (Raffan et al., 2021). Also included were four AB genome nulls, referred to as TILLING lines 1-4, derived from a selected line of a mutant population produced by ethyl methanesulphonate treatment of wheat cv. Cadenza seeds (Rakszegi et al., 2010). The mutated TaASN2-A2 gene from this line was backcrossed into the cv. Claire background to generate AB genome nulls (cv. Claire lacks a B genome TaASN2 gene due to a ‘natural’ deletion (Oddy et al., 2021))
Novel low-nitrogen stress-responsive long non-coding RNAs (lncRNA) in barley landrace B968 (Liuzhutouzidamai) at seedling stage
Background: Reducing the dependence of crop production on chemical fertilizer with its associated costs, carbon footprint and other environmental problems is a challenge for agriculture. New solutions are required to solve this problem, and crop breeding for high nitrogen use efficiency or tolerance of low nitrogen availability has been
widely considered to be a promising approach. However, the molecular mechanisms of high nitrogen use efficiency or low-nitrogen tolerance in crop plants are still to be elucidated, including the role of long non-coding RNAs (lncRNAs.
Results: In this study, we identified 498 lncRNAs in barley (Hordeum vulgare) landrace B968 (Liuzhutouzidamai), of which 487 were novel, and characterised 56 that were responsive to low-nitrogen stress. For functional analysis of differentially-expressed lncRNAs, the gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment of co-expressed and co-located protein-coding genes were analyzed, and interactions with annotated co-expressed protein coding genes or micro RNAs (miRNAs) were further predicted. Target mimicry prediction between differentially-expressed lncRNAs and miRNAs identified 40 putative target mimics of lncRNAs and 58 target miRNAs. Six differentially-expressed lncRNAs were further validated by qPCR, and one in particular showed consistent differential expression using both techniques. Expression levels of most of the lncRNAs were found to be very low, and this may be the reason for the apparent inconsistency between RNA-seq and qPCR data.
Conclusions: The analysis of lncRNAs that are differentially-expressed under low-nitrogen stress, as well as their coexpressed or co-located protein coding genes and target mimics, could elucidate complex and hitherto uncharacterised mechanisms involved in the adaptation to low-nitrogen stress in barley and other crop plants
Associations between hedonic hunger and BMI during a two-year behavioural weight loss trial.
ObjectiveProspective studies on relationships between hedonic hunger and BMI (Body Mass Index) during weight management are lacking. This study examined if hedonic hunger reduced during a behavioural weight management programme, and if hedonic hunger predicted future BMI.MethodsParticipants were 594 community-dwelling, UK-based adults(396 female; age 56.43 years, s.d. = 12.50, range 20-83 years); 490 participants (82.5%) had obesity. Participants were randomised to a 12- or 52-week behavioural weight management intervention (WW12 or WW52, respectively) or a brief self-help intervention (BI). Relationships between hedonic hunger and BMI over 24 months (baseline, 3, 12, 24 months) were analysed using an autoregressive cross-lagged model.ResultsHedonic hunger scores decreased from 2.71 (s.d. = .91) at baseline to 2.41 (s.d. = .88) at 3 months (p .05). Baseline hedonic hunger scores predicted 3-month scores (B = .76, SE = .03, p .05). BMI at 12 months was lower in WW52 30.87kg/m2, s.d. = 5.02) than WW12 (32.12 kg/m2, s.d. = 5.58, p = .02, CI .16 to 2.34) and BI (32.74 kg/m2, s.d. = 4.15, p = .01, CI .30 to 3.45). BMI was not affected by intervention at any other time point (p's>.05).ConclusionHedonic hunger reduced during weight management irrespective of intervention. Early reductions in hedonic hunger appear to be associated with lower BMI in the medium-term. Identifying ways to reduce hedonic hunger during weight loss could aid weight management for some people
Spin Foam Models of Riemannian Quantum Gravity
Using numerical calculations, we compare three versions of the Barrett-Crane
model of 4-dimensional Riemannian quantum gravity. In the version with face and
edge amplitudes as described by De Pietri, Freidel, Krasnov, and Rovelli, we
show the partition function diverges very rapidly for many triangulated
4-manifolds. In the version with modified face and edge amplitudes due to Perez
and Rovelli, we show the partition function converges so rapidly that the sum
is dominated by spin foams where all the spins labelling faces are zero except
for small, widely separated islands of higher spin. We also describe a new
version which appears to have a convergent partition function without drastic
spin-zero dominance. Finally, after a general discussion of how to extract
physics from spin foam models, we discuss the implications of convergence or
divergence of the partition function for other aspects of a spin foam model.Comment: 23 pages LaTeX; this version to appear in Classical and Quantum
Gravit
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Effects of water availability on free amino acids, sugars, and acrylamide-forming potential in potato
Irrigation is used frequently in potato cultivation to maximize yield, but water availability may also affect the composition of the crop, with implications for processing properties and food safety. Five varieties of potatoes, including drought-tolerant and -sensitive types, which had been grown with and without irrigation, were analyzed to show the effect of water supply on concentrations of free asparagine, other free amino acids, and sugars and on the acrylamide-forming potential of the tubers. Two varieties were also analyzed under more severe drought stress in a glasshouse. Water availability had profound effects on tuber free amino acid and sugar concentrations, and it was concluded that potato farmers should irrigate only if necessary to maintain the health and yield of the crop, because irrigation may increase the acrylamide-forming potential of potatoes. Even mild drought stress caused significant changes in composition, but these differed from those caused by more extreme drought stress. Free proline concentration, for example, increased in the field-grown potatoes of one variety from 7.02 mmol/kg with irrigation to 104.58 mmol/kg without irrigation, whereas free asparagine concentration was not affected significantly in the field but almost doubled from 132.03 to 242.26 mmol/kg in response to more severe drought stress in the glasshouse. Furthermore, the different genotypes were affected in dissimilar fashion by the same treatment, indicating that there is no single, unifying potato tuber drought stress response
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Nursing work and sensory experiences of hospital design: A before and after qualitative study following a move to all-single room inpatient accommodation
The embodied experience of nursing practice is rarely studied. Drawing on data from an internationally relevant larger study conducted in 2013–14, here we explore the sensory dimension of the embodied experiences of nursing staff working on two acute NHS hospital wards before and after a move to all-single room inpatient accommodation. We undertook a secondary analysis of 25 interviews with nursing staff (12 before and 13 after the move with half [13/25] using photographs taken by participants) from a mixed-method before-and-after study. This analysis focused on the sensory dimensions of nursing staff's experiences of their working practices and the effect of the built environment upon these. Drawing on Pallasmaa's theoretocal insights, we report how the all-single room ward design prioritises ‘focused vision’ and hinders peripheral perception, whilst the open ward environment is rich in contextual and preconscious information. We suggest all-single room accommodation may offer staff an impoverished experience of caring for patients and of working with each other
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