729 research outputs found
Multiple parapatric pollinators have radiated across a continental fig tree displaying clinal genetic variation
The ways that plant‐feeding insects have diversified is central to our understanding of terrestrial ecosystems. Obligate nursery pollination mutualisms provide highly relevant model systems of how plants and their insect associates have diversified and the over 800 species of fig trees (Ficus) allow comparative studies. Fig trees can have one or more pollinating fig wasp species (Agaonidae) that breed within their figs, but factors influencing their number remain to be established. In some widely distributed fig trees, the plants form populations isolated by large swathes of sea, and the different populations are pollinated by different wasp species. Other Ficus species with continuous distributions may present genetic signatures of isolation by distance, suggesting more limited pollinator dispersal, which may also facilitate pollinator speciation. We tested the hypothesis that Ficus hirta, a species for which preliminary data showed genetic isolation by distance, would support numerous pollinator species across its range. Our results show that across its range Ficus hirta displays clinal genetic variation and is pollinated by nine parapatric species of Valisia. This is the highest number of pollinators reported to date for any Ficus species and it is the first demonstration of the occurrence of parapatric pollinator species on a fig host displaying continuous genetic structure. Future comparative studies across Ficus species should be able to establish the plant traits that have driven the evolution of pollinator dispersal behaviour, pollinator speciation and host plant spatial genetic structure
Emergence in marketing: an institutional and ecosystem framework
Many core marketing concepts (e.g., markets, relationships, customer experience, brand meaning, value) concern phenomena
that are difficult to understand using linear and dyadic approaches, because they are emergent. That is, they arise, often
unpredictably, from interactions within complex and dynamic contexts. This paper contributes to the marketing discipline
through an explication of the concept of emergence as it applies to marketing theory. We accomplish this by first drawing on
the existing literature on emergence in philosophy, sociology, and the theory of complex adaptive systems, and then link and
extend this understanding to marketing using the theoretical framework of service-dominant (S-D) logic, particularly as enhanced
by its service-ecosystems and institutionalization perspectives. Our work recognizes both emergence and institutionalization as
integral or interrelated processes in the creation, maintenance, and disruption of markets and marketing phenomena. We conclude
by discussing implications for marketing research and practice
Smoking, diet, pregnancy and oral contraceptive use as risk factors for cervical intra-epithelial neoplasia in relation to human papillomavirus infection
Smoking, nutrition, parity and oral contraceptive use have been reported as major environmental risk factors for cervical cancer. After the discovery of the very strong link between human papillomavirus (HPV) infection and cervical cancer, it is unclear whether the association of these environmental factors with cervical cancer reflect secondary associations attributable to confounding by HPV, if they are independent risk factors or whether they may act as cofactors to HPV infection in cervical carcinogenesis. To investigate this issue, we performed a population-based case–control study in the Västerbotten county of Northern Sweden of 137 women with high-grade cervical intra-epithelial neoplasia (CIN 2–3) and 253 healthy age-matched women. The women answered a 94-item questionnaire on diet, smoking, oral contraceptive use and sexual history and donated specimens for diagnosis of present HPV infection (nested polymerase chain reaction on cervical brush samples) and for past or present HPV infections (HPV seropositivity). The previously described protective effects of dietary micronutrients were not detected. Pregnancy appeared to be a risk factor in the multivariate analysis (P< 0.0001). Prolonged oral contraceptive use and sexual history were associated with CIN 2–3 in univariate analysis, but these associations lost significance after taking HPV into account. Smoking was associated with CIN 2–3 (odds ratio (OR) 2.6, 95% confidence interval (CI) 1.7–4.0), the effect was dose-dependent (P = 0.002) and the smoking-associated risk was not affected by adjusting for HPV, neither when adjusting for HPV DNA (OR 2.5, CI 1.3–4.9) nor when adjusting for HPV seropositivity (OR 3.0, CI 1.9–4.7). In conclusion, after taking HPV into account, smoking appeared to be the most significant environmental risk factor for cervical neoplasia. © 2000 Cancer Research Campaig
Culinary communication practices:The role of retail spaces in producing field-specific cultural capital
Purpose: This chapter explores the practices underpinning the production of field-specific cultural capital at festivals, understood here as retail spaces that gather a plethora of distinct market actors. Methodology/Approach: This research presents evidence from an ethnographic study employing an interpretative paradigm and multiple data collection processes. The empirical research has been undertaken in the context of food festivals associated with the foodie taste regime. Findings: Three categories of practices that play a role in the production of field-specific cultural capital, namely representational, exchange, and experiential practices, are presented. Practical Implications: Our chapter provides recommendations for food festival organizers and participants who need to improve their practices when facing challenges such as increasing international competition and costs or declining sponsorship. Research Limitations/Implications: This chapter contributes to the growing body of field-level market analysis by showing how practices enabled by complex retail spaces contribute to the production of field-specific cultural capital. However, this chapter is limited by its focus on food festivals. Originality/Value of the Paper: This chapter theorizes how practices enable the acceleration and diversification of field-specific capital exchange, as well as its integration with other forms of capital
Are smoking and chlamydial infection risk factors for CIN? Different results after adjustment for HPV DNA and antibodies
To identify the risk factors for cervical intraepithelial neoplasia (CIN), we reanalysed the data from our previous case-control study by adjusting for human papillomavirus (HPV) antibodies. Unlike our previous study based only on HPV DNA, smoking and Chlamydia trachomatis infection were revealed as significant risk factors for CIN after adjustment for HPV antibodies
Excitation Dynamics and Relaxation in a Molecular Heterodimer
The exciton dynamics in a molecular heterodimer is studied as a function of
differences in excitation and reorganization energies, asymmetry in transition
dipole moments and excited state lifetimes. The heterodimer is composed of two
molecules modeled as two-level systems coupled by the resonance interaction.
The system-bath coupling is taken into account as a modulating factor of the
energy gap of the molecular excitation, while the relaxation to the ground
state is treated phenomenologically. Comparison of the description of the
excitation dynamics modeled using either the Redfield equations (secular and
full forms) or the Hierarchical quantum master equation (HQME) is demonstrated
and discussed. Possible role of the dimer as an excitation quenching center in
photosynthesis self-regulation is discussed. It is concluded that the
system-bath interaction rather than the excitonic effect determines the
excitation quenching ability of such a dimer
Leveraging the sport participation legacy of the London 2012 Olympics: Senior managers’ perceptions
The purpose of this study was to understand how a sports mega event (SME) was leveraged to try and increase participation, through the investigation of national governing bodies (NGBs) opinions and atti- tudes. Critical realism (CR) was used as a tool to aid understanding of leveraging and legacy conceptualisation, through an empirical investiga- tion. An extensive, mixed method online survey was conducted post London 2012 with senior staff members of NGBs, the main delivery agent chosen to support the participation initiatives associated with the London 2012 Olympics. This research provides valuable findings surrounding the use of CR as a tool to investigate legacy creation, whilst at the same time offering insights to enhance the policy implementation process within the sports development sector. The importance of com- munication, competitive nature of sports system, media, club engage- ment, organisational capacity and monitoring and evaluation were highlighted, which provided useful insights into the multidimensional constructs that can aid future leveraging strategies prior to hosting SMEs
Searches at HERA for Squarks in R-Parity Violating Supersymmetry
A search for squarks in R-parity violating supersymmetry is performed in e^+p
collisions at HERA at a centre of mass energy of 300 GeV, using H1 data
corresponding to an integrated luminosity of 37 pb^(-1). The direct production
of single squarks of any generation in positron-quark fusion via a Yukawa
coupling lambda' is considered, taking into account R-parity violating and
conserving decays of the squarks. No significant deviation from the Standard
Model expectation is found. The results are interpreted in terms of constraints
within the Minimal Supersymmetric Standard Model (MSSM), the constrained MSSM
and the minimal Supergravity model, and their sensitivity to the model
parameters is studied in detail. For a Yukawa coupling of electromagnetic
strength, squark masses below 260 GeV are excluded at 95% confidence level in a
large part of the parameter space. For a 100 times smaller coupling strength
masses up to 182 GeV are excluded.Comment: 32 pages, 14 figures, 3 table
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