The environmental control of development in winter wheat

1. The relevance of studies of development in crop-weather investigations is reviewed and the aims of the present work are outlined. 2. The procedures used in studying development in field crops of winter wheat are described. The developmental progress of the plants was ascertained by frequent dissections. 3. Primordium initiation at the stem apex is strongly dependent upon apex temperature, which could be accurately estimated from standard meteorological screen temperatures. Like numerous other complex biological processes, initiation has a markedly linear response to temperature: the number of primordia initiated is therefore in direct proportion to accumulated temperature (thermal time). To calculate this requires estimation of the base temperature (Tb). 4. The linear dependence upon temperature of the initiation rates of leaves, spikelets and florets (R1, Rs and Rf ) was evident. Spikelets were initiated faster than leaves ; rate changed at a distinct inflexion point, usually at about the end of leaf initiation but sometimes later. Tb = 0 grad. C for leaves but was higher for spikelets and florets. The shift in Tb apparent17 occurred because Rs and Rf were strongly influenced by the day length at inflexion point. When temperature was corrected for day length influence, Tb = 0°0 for each developmental phase. Inflexion point timing apparently depended upon interaction between vernalisation before crop emergence and photo thermal time afterwards. 5. Leaf appearance rate in thermal time was linear but apparently influenced by the direction and magnitude of day length change at emergence, with a possible secondary effect of current day length. Leaf extension was strongly related to temperature. The gradient of lamina size up the stem appeared to be ontogenetically determined. 6. Compared with early-sown or fully-fertilised crops, floret survival and grain yield was lower in those sown late or inadequately fertilised, probably on account of their smaller amount of growth per unit of developmental time

The environmental control of development in winter wheat

1. The relevance of studies of development in crop-weather investigations is reviewed and the aims of the present work are outlined. 2. The procedures used in studying development in field crops of winter wheat are described. The developmental progress of the plants was ascertained by frequent dissections. 3. Primordium initiation at the stem apex is strongly dependent upon apex temperature, which could be accurately estimated from standard meteorological screen temperatures. Like numerous other complex biological processes, initiation has a markedly linear response to temperature: the number of primordia initiated is therefore in direct proportion to accumulated temperature (thermal time). To calculate this requires estimation of the base temperature (Tb). 4. The linear dependence upon temperature of the initiation rates of leaves, spikelets and florets (R1, Rs and Rf ) was evident. Spikelets were initiated faster than leaves ; rate changed at a distinct inflexion point, usually at about the end of leaf initiation but sometimes later. Tb = 0 grad. C for leaves but was higher for spikelets and florets. The shift in Tb apparent17 occurred because Rs and Rf were strongly influenced by the day length at inflexion point. When temperature was corrected for day length influence, Tb = 0°0 for each developmental phase. Inflexion point timing apparently depended upon interaction between vernalisation before crop emergence and photo thermal time afterwards. 5. Leaf appearance rate in thermal time was linear but apparently influenced by the direction and magnitude of day length change at emergence, with a possible secondary effect of current day length. Leaf extension was strongly related to temperature. The gradient of lamina size up the stem appeared to be ontogenetically determined. 6. Compared with early-sown or fully-fertilised crops, floret survival and grain yield was lower in those sown late or inadequately fertilised, probably on account of their smaller amount of growth per unit of developmental time

Analysis of the genome sequence of an alpaca coronavirus

AbstractCoronaviral infection of New World camelids was first identified in 1998 in llamas and alpacas with severe diarrhea. In order to understand this infection, one of the coronavirus isolates was sequenced and analyzed. It has a genome of 31,076 nt including the poly A tail at the 3′ end. This virus designated as ACoV-00-1381 (ACoV) encodes all 10 open reading frames (ORFs) characteristic of Group 2 bovine coronavirus (BCoV). Phylogenetic analysis showed that the ACoV genome is clustered closely (>99.5% identity) with two BCoV strains, ENT and LUN, and was also closely related to other BCoV strains (Mebus, Quebec, DB2), a human corona virus (strain 043) (>96%), and porcine hemagglutinating encephalomyelitis virus (>93% identity). A total of 145 point mutations and one nucleotide deletion were found relative to the BCoV ENT. Most of the ORFs were highly conserved; however, the predicted spike protein (S) has 9 and 12 amino acid differences from BCoV LUN and ENT, respectively, and shows a higher relative number of changes than the other proteins. Phylogenetic analysis suggests that ACoV shares the same ancestor as BCoV ENT and LUN

Baryon phase-space density in heavy-ion collisions

The baryon phase-space density at mid-rapidity from central heavy-ion collisions is estimated from proton spectra with interferometry and deuteron coalescence measurements. It is found that the mid-rapidity phase-space density of baryons is significantly lower at the SPS than the AGS, while those of total particles (pion + baryon) are comparable. Thermal and chemical equilibrium model calculations tend to over-estimate the phase-space densities at both energies.Comment: 5 pages, 2 tables, no figure. RevTeX style. Accepted for publication in Phys. Rev. C Rapid Communicatio

‘As a woman…’; ‘As a Muslim…’: Subjects, positions and counter-terrorism powers in the United Kingdom

This article presents findings from original focus group research on the importance of identity claims within public understandings of counter-terrorism across the UK. Following a review of existing literature on the terrorism/counter-terrorism/identity nexus, the article introduces four prominent subject positions inhabited within public articulations of counter-terrorism powers: the ‘Muslim’, the ‘target’, the ‘woman’ and the ‘unaffected’. Positions such as these, we argue, both enable and inhibit particular normative, political and anecdotal claims about counter-terrorism frameworks and their impact upon the body politic. This, we suggest, is demonstrative of the co-constitutive role between counter-terrorism and identity claims. Thus, on the one hand, counter-terrorism initiatives work to position individuals socially, politically, and culturally: (re)producing various religious, ethnic and other identities. Yet, at the same time, specific subject positions are integral to the articulation of people’s attitudes toward developments in counter-terrorism. The article concludes by thinking through some of the implications of this, including for resistance toward securitising moves and for citizenship more generally

Diverse Beliefs and Time Variability of Risk Premia

Why do risk premia vary over time? We examine this problem theoretically and empirically by studying the effect of market belief on risk premia. Individual belief is taken as a fundamental primitive state variable. Market belief is observable; it is central to the empirical evaluation and we show how to measure it. Our asset pricing model is familiar from the noisy REE literature but we adapt it to an economy with diverse beliefs. We derive equilibrium asset prices and implied risk premium. Our approach permits a closed form solution of prices; hence we trace the exact effect of market belief on the time variability of asset prices and risk premia. We test empirically the theoretical conclusions. Our main result is that, above the effect of business cycles on risk premia, fluctuations in market belief have significant independent effect on the time variability of risk premia. We study the premia on long positions in Federal Funds Futures, 3- and 6-month Treasury Bills (T-Bills). The annual mean risk premium on holding such assets for 1-12 months is about 40-60 basis points and we find that, on average, the component of market belief in the risk premium exceeds 50% of the mean. Since time variability of market belief is large, this component frequently exceeds 50% of the mean premium. This component is larger the shorter is the holding period of an asset and it dominates the premium for very short holding returns of less than 2 months. As to the structure of the premium we show that when the market holds abnormally favorable belief about the future payoff of an asset the market views the long position as less risky hence the risk premium on that asset declines. More generally, periods of market optimism (i.e. "bull" markets) are shown to be periods when the market risk premium is low while in periods of pessimism (i.e. "bear" markets) the market's risk premium is high. Fluctuations in risk premia are thus inversely related to the degree of market optimism about future prospects of asset payoffs. This effect is strong and economically very significant

Toward a Multifaceted Heuristic of Digital Reading to Inform Assessment, Research, Practice, and Policy

In this commentary, the author explores the tension between almost 30 years of work that has embraced increasingly complex conceptions of digital reading and recent studies that risk oversimplifying digital reading as a singular entity analogous with reading text on a screen. The author begins by tracing a line of theoretical and empirical work that both informs and complicates our understanding of digital literacy and, more specifically, digital reading. Then, a heuristic is proposed to systematically organize, label, and define a multifaceted set of increasingly complex terms, concepts, and practices that characterize the spectrum of digital reading experiences. Research that informs this heuristic is used to illustrate how more precision in defining digital reading can promote greater clarity across research methods and advance a more systematic study of promising digital reading practices. Finally, the author discusses implications for assessment, research, practice, and policy