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Investigating the effects of inter-annual weather variation (1968- 2016) on the functional response of cereal grain yield to applied nitrogen, using data from the Rothamsted Long-Term experiments
The effect of weather on inter-annual variation in the crop yield response to nitrogen (N) fertilizer for winter wheat (Triticum aestivvum L.) and spring barley (Hordeum vulgare L.) was investigated using yield data from the Broadbalk Wheat and Hoosfield Spring Barley long-term experiments at Rothamsted Research. Grain yields of crops from 1968 to 2016 were modelled as a function of N rates using a linear-plus-exponential (LEXP) function. The extent to which inter-annual variation in the parameters of these responses was explained by variations in weather (monthly summarized temperatures and rainfall), and by changes in the cultivar grown, was assessed. The inter-annual variability in rainfall and underlying temperature influenced the crop N response and hence grain yields in both crops. Asymptotic yields in wheat were particularly sensitive to mean temperature in November, April and May, and to total rainfall in October, February and June. In spring barley asymptotic yields were sensitive to mean temperature in February and June, and to total rainfall in April to July inclusive and September.
The method presented here explores the separation of agronomic and environmental (weather) influences on crop yield over time. Fitting N response curves across multiple treatments can support an informative analysis of the influence of weather variation on the yield variability. Whilst there are issues of the confounding and collinearity of explanatory variables within such models, and that other factors also influence yields over time, our study confirms the considerable impact of weather variables at certain times of the year. This emphasizes the importance of including weather temporal variation when evaluating the impacts of climate change on crops
Effects of Nitrogen Supply and Nitrogen Form on Intrinsic Water-Use Efficiency in Temperate, Semi-Natural Grasslands under Rising Atmospheric CO\u3csub\u3e2\u3c/sub\u3e
Carbon uptake and water loss of plants are controlled by the regulation of carbon assimilation rate (A) and stomatal conductance (gs). Any changes in these parameters under rising atmospheric CO2 concentration (ca) influence plant water-use efficiency and can affect carbon and water relations in grassland ecosystems. Time-series analyses of intrinsic water-use efficiency (Wi) of C3 grassland vegetation during the 20th century have shown that carbon uptake relative to water loss generally increased (KĂśhler et al. 2010, 2012; Barbosa et al. 2010). Short-term experiments suggest that nitrogen (N) supply (Stitt and Krapp 1999) and N form (Bloom et al. 2011) also play a role.
We hypothesize that any increase in Wi should be stronger in swards with high N availability and with ammonium (NH4)-N instead of nitrate (NO3)-N fertilization
Culture moderates the pliability of ambivalent attitudes
Ambivalent attitudes are comprised of conflicting components. In response to this evaluative conflict, North Americans are more likely to change high ambivalent attitudes than low ambivalent attitudes. However, East Asians exhibit greater tolerance for inconsistencies than do North Americans. Hence, we hypothesized that culture would interact with ambivalence in influencing the degree of attitude change in response to a persuasive attempt. Results indicated that culture significantly moderated the relationship between ambivalence and attitude pliability, such that ambivalence and the degree of attitude change were positively associated for European Canadians but not for East Asian Canadians. These results add to the extant literature on attitudinal ambivalence, demonstrating cultural variability in the pliability of ambivalent attitudes
Are âcultures of worklessness' passed down the generations?
This report critically investigates the idea of âintergenerational cultures of worklessness â and that there may be families where âthree generations have never workedâ. Although there is relatively little solid research evidence to support them, these ideas are said to help explain worklessness in the UK and continue to inform recent and current government policy agendas. Our study used qualitative research methods, with families in Middlesbrough and Glasgow. The report: ⢠explores the existence of permanent worklessness across generations within families; ⢠concludes that even two generations of extensive or permanent worklessness in the same family is a rare phenomenon; ⢠examines whether families experiencing long-term worklessness can be described as having a âculture of worklessnessâ; ⢠shows how the impact of complex and multiple problems, rooted in long-term experiences of deep poverty, can distance people from the labour market; and ⢠argues that policy makers should abandon theories â and policies that flow from them â that see worklessness as primarily the outcome of a âculture of worklessnessâ, held in families and passed down the generations
The relationship between living in urban and rural areas of Scotland and childrenâs physical activity and sedentary levels: A country-wide cross-sectional analysis.
Background: Living in urban or rural environments may influence childrenâs levels of physical activity and sedentary behaviours. We know little about variations in device-measured physical activity and sedentary levels of urban and rural children using nationally representative samples, or if these differences are moderated by socioeconomic factors or seasonal variation. Moreover, little is known about the influence of âwalkabilityâ in the UK context. A greater understanding of these can better inform intervention strategies or policy initiatives at the population level. Methods: Country-wide cross-sectional study in Scotland in which 774 children (427 girls, 357 boys), aged 10/11 years, wore an accelerometer on one occasion for at least four weekdays and one weekend day. Mean total physical activity, time spent in sedentary, light, and moderate-to-vigorous physical activity (MVPA), per day were extracted for weekdays, weekend days, and all days combined. Regression analyses explored associations between physical activity outcomes, urban/rural residence, and a modified walkability index (dwelling density and intersection density); with interactions fitted for household equivalised income and season of data collection. Sensitivity analyses assessed variation in findings by socioeconomic factors and urbanicity. Results: Rural children spent an average of 14 minutes less sedentary (95% CI of difference: 2.23, 26.32) and 13 minutes more (95% CI of difference: 2.81, 24.09) in light intensity activity per day than those from urban settlements. No urban-rural differences were found for time spent in MVPA or in total levels of activity. Our walkability index was not associated with any outcome measure. We found no interactions with household equivalised income, but there were urban/rural differences in seasonal variation; urban children engaged in higher levels of MVPA in the spring months (difference: 10 mins, p=0.06, n.s) and significantly lower levels in winter (difference: 8.7 mins, p=0.036). Conclusions: Extrapolated across one-year, rural children would accumulate approximately 79 hours (or just over three days) less sedentary time than urban children, replacing this for light intensity activity. With both outcomes having known implications for health, this finding is particularly important. Future work should prioritise exploring the patterns and context in which these differences occur to allow for more targeted intervention/policy strategies
Natural flood management, lag time and catchment scale:Results from an empirical nested catchment study
Natural flood management (NFM) techniques attract much interest in flood risk management science, not least because their effectiveness remains subject to considerable uncertainty, particularly at larger catchment and event scales. This derives from a paucity of empirical studies which can offer either longitudinal or comparison data sets in which changes can be observed. The Eddleston catchment study, with 13 stream gauges operated continuously over 9âyears, is based on both longitudinal and comparison data sets. Two years of baseline monitoring have been followed by 7âyears of further monitoring after a range of NFM interventions across the 69âkm2 catchment. This study has examined changes in lag as an index of hydrological response which avoids dependence on potentially significant uncertainties in flow data. Headwater catchments up to 26âkm2 showed significant delays in lag of 2.6â7.3 hr in catchments provided with leaky wood structures, onâline ponds and riparian planting, while larger catchments downstream and those treated with riparian planting alone did not. Two control catchments failed to show any such changes. The findings provide important evidence of the catchment scale at which NFM can be effective and suggest that effects may increase with event magnitude
Changes of oxygen isotope values of soil P pools associated with changes in soil pH
Field data about the effect of soil pH on phosphorus (P) cycling is limited. A promising tool to study P cycling under field conditions is the 18O:16O ratio of phosphate (δ18OP). In this study we investigate whether the δ18OP can be used to elucidate the effect of soil pH on P cycling in grasslands. Soils and plants were sampled from different fertilisation and lime treatments of the Park Grass long term experiment at Rothamsted Research, UK. The soils were sequentially extracted to isolate different soil P pools, including available P and corresponding δ18OP values were determined. We did not observe changes in plant δ18OP value, but soil P δ18OP values changed, and lower δ18OP values were associated with higher soil pH values. At sites where P was not limiting, available P δ18OP increased by up to 3Ⱐwhen lime was applied. We show that the δ18OP method is a useful tool to investigate the effect of pH on soil P cycling under field conditions as it highlights that different soil processes must govern P availability as pH shifts. The next challenge is now to identify these underlying processes, enabling better management of soil P at different pH
The bulk-surface finite element method for reaction-diffusion systems on stationary volumes
In this work we present the bulk-surface finite element method (BSFEM) for solving coupled systems of bulk-surface reaction-diffusion equations (BSRDEs) on stationary volumes. Such systems of coupled bulk-surface partial differential equations arise naturally in biological applications and fluid dynamics, for example, in modelling of cellular dynamics in cell motility and transport and diffusion of surfactants in two phase flows. In this proposed framework, we define the surface triangulation as a collection of the faces of the elements of the bulk triangulation whose vertices lie on the surface. This implies that the surface triangulation is the trace of the bulk triangulation. As a result, we construct two finite element spaces for the interior and surface respectively. To discretise in space we use piecewise bilinear elements and the implicit second order fractional-step scheme is employed to discretise in time. Furthermore, we use the Newton method to treat the nonlinearities. The BSFEM applied to a coupled system of BSRDEs reveals interesting patterning behaviour. For a set of appropriate model parameter values, the surface reaction-diffusion system is not able to generate patterns everywhere in the bulk except for a small region close to the surface while the bulk reaction-diffusion system is able to induce patterning almost everywhere. Numerical experiments are presented to reveal such patterning processes associated with reaction-diffusion theory
The perseveration of checking thoughts and moodâasâinput hypothesis
This paper describes two experiments designed to investigate how a current model of task perseveration, the mood-as-input hypothesis, might be applied to activities relevant to compulsive checking. The mood-as-input hypothesis predicts that perseveration at an open-ended task will be determined by a combination of the âstop rulesâ adopted for the task, and the valency of the mood state in which the task is conducted. Experiment 1 required participants to generate items that should be checked for safety/security if they were leaving their home unattended. Experiment 2 used an analogue recall task, in which participants were asked to recall items from a comprehensive list of items that should be checked if they were to leave their home safe/secure. Both experiments found that perseveration at the tasks was determined by particular configurations of mood and stop rules for the task. Of most relevance to compulsive checking was the fact that facilitated perseveration occurred when participants were asked to undertake the tasks in a negative mood using âas many as canâ stop rules. Implications for the factors that develop and maintain compulsive checking are discussed
Defined covalent assembly of protein molecules on graphene using a genetically encoded photochemical reaction handle
We have created modified protein variants by introducing a non-canonical amino acid p-azido-Lphenylalanine
(azF) into defined positions for photochemically-induced covalent attachment to
graphene. Attachment of GFP, TEM and cyt b562 proteins was verified through a combination of atomic
force and scanning tunnelling microscopy, resistance measurements, Raman data and fluorescence
measurements. This method can in principle be extended to any protein which can be engineered in this
way without adversely affecting its structural stabilit
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