Option Pricing Formulas based on a non-Gaussian Stock Price Model

Options are financial instruments that depend on the underlying stock. We explain their non-Gaussian fluctuations using the nonextensive thermodynamics parameter $q$. A generalized form of the Black-Scholes (B-S) partial differential equation, and some closed-form solutions are obtained. The standard B-S equation ($q=1$) which is used by economists to calculate option prices requires multiple values of the stock volatility (known as the volatility smile). Using $q=1.5$ which well models the empirical distribution of returns, we get a good description of option prices using a single volatility.Comment: final version (published

How Cover Crop Sowing Date Impacts upon Their Growth, Nutrient Assimilation and the Yield of the Subsequent Commercial Crop

Publication history: Accetpted - 24 January 2022; Published online - 1 February 2022Cover crops are typically sown post-harvest of commercial crops, prior to winter, which means that as sowing date is delayed, so will biomass production potential. The wide range of benefits associated with cover crops relies on them to produce sufficient biomass. Therefore, it must be identified how late certain species of cover crops can be sown. In the climatic conditions of Northern Ireland, not only has no research been conducted on how cover crops perform at various sowing dates but also their effect on the subsequent commercial crop yield has not been investigated. Addressing these issue will in turn help provide recommendations to maximise and encourage later sowing of cover crops. Consequently, five species of cover crops were chosen, from a range of families, then sown on 14 August, 7 September and 27 September. This is to mimic when land becomes fallow post-harvest of typical crops/rotations to this region. It was found that tillage radish (Raphanus sativus L.), when sown on the earliest date, could accumulate a maximum of 261 kg/ha of nitrogen (N), whereas, when sown on the last date, phacelia (Phacelia tanacetifolia L.) significantly outperformed all other species and assimilated 70 kg/ha of N. The cover crops were then incorporated into the soil and over-sown with spring barley (Hordeum vulgare L.). However, the spring barley yield was unaffected by any treatments. This trial shows that the non-leguminous species chosen are highly effective in assimilating nutrients when sown mid-August until early-SeptemberThis research was funded by DAERA grant number (17/1/01

Investigation of the Effect of Slurry, Combined with Inorganic N Rate and Timing, on the Yield of Spring Barley Post Cover Crop of Stubble Turnips

Publication history: Accepted - 19 January 2021; Published online - 27 January 2021ntegration of cover crops into arable rotations over winter results in difficulty in determining the nitrogen (N) requirement for the following commercial crop. The region of Northern Ireland (NI) has had no previous field research on cover crops and how they may affect N supply to the following commercial crop. Stubble turnips (Brassica rapa oleifera L.) were sown as a cover crop, after the harvest of winter barley (Hordeum vulgare L.) and retained over winter. Prior to planting the stubble turnips, pig slurry was applied to maximise cover crop growth. The stubble turnips accumulated 111 and 150 kg N/ha in their biomass. This equates to 79 and 107% of the N requirement of a 5 t/ha spring barley crop, if this N is released sufficiently. In this experiment, the cover crop of stubble turnips was over-sown with spring barley and supplemented with different rates of organic manures (either applied at 50 m3/ha of pig slurry or not applied), and inorganic N fertiliser (0, 70 and 140 kg N/ha), at two different timings (early or late). In the two experimental years, additional N supplied in the form of inorganic N or organic manures, did not significantly enhance spring barley yields. No control area of fallow was included in this trial. However, this study demonstrates that in this region there may be a greater rate of N release from the cover crop of stubble turnips than estimated due to agronomic management practices applied and conducive climatic conditions. This means that in this study location, a reduced N rate programme supplemented to the spring barley is possible, which lead to considerable financial savingsThis research was supported and funded by AFBI (Agri-Food and Biosciences Institute) in conjunction with DAERA (Department of Agriculture, Environment and Rural Affairs)

Assessment of water-limited winter wheat yield potential at spatially contrasting sites in Ireland using a simple growth and development model

Publication history: Published online - 19 September 2017Although Irish winter wheat yields are among the highest globally, increases in the profitability of this crop are required to maintain its economic viability. However, in order to determine if efforts to further increase Irish wheat yields are likely to be successful, an accurate estimation of the yield potential is required for different regions within Ireland. A winter wheat yield potential model (WWYPM) was developed, which estimates the maximum water-limited yield achievable, within the confines of current genetic resources and technologies, using parameters for winter wheat growth and development observed recently in Ireland and a minor amount of daily meteorological input (maximum and minimum daily temperature, total daily rainfall and total daily incident radiation). The WWYPM is composed of three processes: (i) an estimation of potential green area index, (ii) an estimation of light interception and biomass accumulation and (iii) an estimation of biomass partitioning to grain yield. Model validation indicated that WWYPM estimations of water-limited yield potential (YPw) were significantly related to maximum yields recorded in variety evaluation trials as well as regional average and maximum farm yields, reflecting the model’s sensitivity to alterations in the climatic environment with spatial and seasonal variations. Simulations of YPw for long-term average weather data at 12 sites located at spatially contrasting regions of Ireland indicated that the typical YPw varied between 15.6 and 17.9 t/ha, with a mean of 16.7 t/ha at 15% moisture content. These results indicate that the majority of sites in Ireland have the potential to grow high-yielding crops of winter wheat when the effects of very high rainfall and other stresses such as disease incidence and nutrient deficits are not considered.Funding for this study was provided by the Department of Agriculture, Food and the Marine, Ireland

The role of metaphor in shaping the identity and agenda of the United Nations: the imagining of an international community and international threat

This article examines the representation of the United Nations in speeches delivered by its Secretary General. It focuses on the role of metaphor in constructing a common ‘imagining’ of international diplomacy and legitimising an international organisational identity. The SG legitimises the organisation, in part, through the delegitimisation of agents/actions/events constructed as threatening to the international community and to the well-being of mankind. It is a desire to combat the forces of menace or evil which are argued to motivate and determine the organisational agenda. This is predicated upon an international ideology of humanity in which difference is silenced and ‘working towards the common good’ is emphasised. This is exploited to rouse emotions and legitimise institutional power. Polarisation and antithesis are achieved through the employment of metaphors designed to enhance positive and negative evaluations. The article further points to the constitutive, persuasive and edifying power of topic and situationally-motivated metaphors in speech-making

Bacterial antimicrobial metal ion resistance

Metals such as mercury, arsenic, copper and silver have been used in various forms as antimicrobials for thousands of years with until recently, little understanding of their mode of action. The discovery of antibiotics and new organic antimicrobial compounds during the twentieth century saw a general decline in the clinical use of antimicrobial metal compounds, with the exception of the rediscovery of the use of silver for burns treatments and niche uses for other metal compounds. Antibiotics and new antimicrobials were regarded as being safer for the patient and more effective than the metal-based compounds they supplanted. Bacterial metal ion resistances were first discovered in the second half of the twentieth century. The detailed mechanisms of resistance have now been characterized in a wide range of bacteria. As the use of antimicrobial metals is limited, it is legitimate to ask: are antimicrobial metal resistances in pathogenic and commensal bacteria important now? This review details the new, rediscovered and 'never went away' uses of antimicrobial metals; examines the prevalence and linkage of antimicrobial metal resistance genes to other antimicrobial resistance genes; and examines the evidence for horizontal transfer of these genes between bacteria. Finally, we discuss the possible implications of the widespread dissemination of these resistances on re-emergent uses of antimicrobial metals and how this could impact upon the antibiotic resistance problem

Rhesus TRIM5α disrupts the HIV-1 capsid at the inter-hexamer interfaces

TRIM proteins play important roles in the innate immune defense against retroviral infection, including human immunodeficiency virus type-1 (HIV-1). Rhesus macaque TRIM5α (TRIM5αrh) targets the HIV-1 capsid and blocks infection at an early post-entry stage, prior to reverse transcription. Studies have shown that binding of TRIM5α to the assembled capsid is essential for restriction and requires the coiled-coil and B30.2/SPRY domains, but the molecular mechanism of restriction is not fully understood. In this study, we investigated, by cryoEM combined with mutagenesis and chemical cross-linking, the direct interactions between HIV-1 capsid protein (CA) assemblies and purified TRIM5αrh containing coiled-coil and SPRY domains (CC-SPRYrh). Concentration-dependent binding of CC-SPRYrh to CA assemblies was observed, while under equivalent conditions the human protein did not bind. Importantly, CC-SPRYrh, but not its human counterpart, disrupted CA tubes in a non-random fashion, releasing fragments of protofilaments consisting of CA hexamers without dissociation into monomers. Furthermore, such structural destruction was prevented by inter-hexamer crosslinking using P207C/T216C mutant CA with disulfide bonds at the CTD-CTD trimer interface of capsid assemblies, but not by intra-hexamer crosslinking via A14C/E45C at the NTD-NTD interface. The same disruption effect by TRIM5αrh on the inter-hexamer interfaces also occurred with purified intact HIV-1 cores. These results provide insights concerning how TRIM5α disrupts the virion core and demonstrate that structural damage of the viral capsid by TRIM5α is likely one of the important components of the mechanism of TRIM5α-mediated HIV-1 restriction. © 2011 Zhao et al

Engaging stakeholder communities as body image intervention partners: The Body Project as a case example

© 2015 Elsevier Ltd Despite recent advances in developing evidence-based psychological interventions, substantial changes are needed in the current system of intervention delivery to impact mental health on a global scale (Kazdin & Blase, 2011). Prevention offers one avenue for reaching large populations because prevention interventions often are amenable to scaling-up strategies, such as task-shifting to lay providers, which further facilitate community stakeholder partnerships. This paper discusses the dissemination and implementation of the Body Project, an evidence-based body image prevention program, across 6 diverse stakeholder partnerships that span academic, non-profit and business sectors at national and international levels. The paper details key elements of the Body Project that facilitated partnership development, dissemination and implementation, including use of community-based participatory research methods and a blended train-the-trainer and task-shifting approach. We observed consistent themes across partnerships, including: sharing decision making with community partners, engaging of community leaders as gatekeepers, emphasizing strengths of community partners, working within the community's structure, optimizing non-traditional and/or private financial resources, placing value on cost-effectiveness and sustainability, marketing the program, and supporting flexibility and creativity in developing strategies for evolution within the community and in research. Ideally, lessons learned with the Body Project can be generalized to implementation of other body image and eating disorder prevention programs