A mathematical model for the onset of avascular tumor growth in response to the loss of p53 function

We present a mathematical model for the formation of an avascular tumor based on the loss by gene mutation of the tumor suppressor function of p53. The wild type p53 protein regulates apoptosis, cell expression of growth factor and matrix metalloproteinase, which are regulatory functions that many mutant p53 proteins do not possess. The focus is on a description of cell movement as the transport of cell population density rather than as the movement of individual cells. In contrast to earlier works on solid tumor growth, a model is proposed for the initiation of tumor growth. The central idea, taken from the mathematical theory of dynamical systems, is to view the loss of p53 function in a few cells as a small instability in a rest state for an appropriate system of differential equations describing cell movement. This instability is shown (numerically) to lead to a second, spatially inhomogeneous, solution that can be thought of as a solid tumor whose growth is nutrient diffusion limited. In this formulation, one is led to a system of nine partial differential equations. We show computationally that there can be tumor states that coexist with benign states and that are highly unstable in the sense that a slight increase in tumor size results in the tumor occupying the sample region while a slight decrease in tumor size results in its ultimate disappearance

An investigation into E-business service in the UK telecommunication manufacturing industry

Nowadays, suppliers’ product and service quality has risen in importance with a manufacturer’s push to develop core competencies and capitalise on global operations and markets. However, due to the complex features of business service, suppliers are facing significant challenges in providing service effectively and developing business collaboration. This is further complicated by the development of information and communication technologies (ICTs). This paper thus attempts to investigate the factors influencing buyers’ e-service (EBS) requirements and the impact of these requirements on business collaboration. Based on a questionnaire survey with 500 UK telecommunication manufacturers, this research identifies buyers’ different EBS requirements for different types of suppliers and the impact of ICTs on EBS requirements. While for suppliers our findings provide insights into buyers’ EBS requirements, they can help buyers to develop appropriate supplier selection criteria. The findings also contribute to a better understanding of the development of buyer and supplier business collaboration

The impacts of IT capability and marketing capability on supply chain integration: A resource-based perspective

Although previous research has addressed the interface and logical association among marketing, information technology (IT) and supply chain management, there have been few, if any, attempts to investigate how IT capability and marketing capability influence supply chain integration (SCI). Thus, this study investigates the direct and interacting effects of IT capability and marketing capability on SCI. The hypothesised relationships were tested using survey data gathered from 329 firms in China’s manufacturing industry. The results reveal that both IT capability and marketing capability have a significant positive effect on SCI. Interestingly, no significant interaction effect was found, indicating that marketing IT capability and marketing capability influence SCI independently, and not synergistically. However, while IT capability and marketing capability do not interact, IT capability does mediate the impact of marketing capability on SCI

Global and regional trends of atmospheric sulfur

The profound changes in global SO2 emissions over the last decades have affected atmospheric composition on a regional and global scale with large impact on air quality, atmospheric deposition and the radiative forcing of sulfate aerosols. Reproduction of historical atmospheric pollution levels based on global aerosol models and emission changes is crucial to prove that such models are able to predict future scenarios. Here, we analyze consistency of trends in observations of sulfur components in air and precipitation from major regional networks and estimates from six different global aerosol models from 1990 until 2015. There are large interregional differences in the sulfur trends consistently captured by the models and observations, especially for North America and Europe. Europe had the largest reductions in sulfur emissions in the first part of the period while the highest reduction came later in North America and East Asia. The uncertainties in both the emissions and the representativity of the observations are larger in Asia. However, emissions from East Asia clearly increased from 2000 to 2005 followed by a decrease, while in India a steady increase over the whole period has been observed and modelled. The agreement between a bottom-up approach, which uses emissions and process-based chemical transport models, with independent observations gives an improved confidence in the understanding of the atmospheric sulfur budget

Producers Responding to Environmental Turbulence in the Greek Agricultural Supply Chain:Does Buyer Type Matter?

There are many changes in the EU Agricultural Supply Chain (ASC). These changes cause environmental turbulence for supply chain entities operating in this sector. In the Greek ASC, there is a significant decline in its performance in particular at producers’ level. Based on the Contingency Theory this paper aims to identify the relevant environmental turbulence factors in Greek ASC context from the producers’ perspective and ascertain their impact on producers based on their choice of buyer type i.e. collaboration type. Twenty in-depth semi-structured interviews were conducted with Greek ASC producers. Thematic analysis was used to analyse the interviews. The findings suggest the existence of six major environmental turbulence factors at producers’ level which are: regulatory, market, competitive, weather, economic and political turbulence factors. Producers selling their products to cooperatives were found to be significantly impacted by the different environmental turbulence factors. Future research directions as well as managerial and policy implications are identified

Enabling sustainable energy futures: Factors influencing green supply chain collaboration

In order to explore the relationship between sustainability strategies and future energy needs and demands (hence energy futures), supply chains (SCs) need to continue to reduce their CO2 emissions through developing their green credentials and improving overall performance; noting that the assimilation of such environmental aspects into production, SCs and logistics are considered as complex processes. Knowledge management (KM) has long been seen as an enabler to support intensive collaboration efforts – on which green initiatives are largely based. The supply chain management (SCM) and KM areas have largely focused on improving organisational performance. While the latter research has yielded successful outcomes in many different sectors, there is still a scarcity of research studies focusing on identifying influential factors that highlight those aspects which may enable green supply chain collaboration (GrSCC) to occur, thus leading to sustainable energy futures and carbon-efficient production. To increase inter-organisational synchronisation, organisations often call for SC partners to implement common business processes and sources of knowledge. This paper therefore aims to contribute to the research domain by examining the role of KM in facilitating GrSCC. Through the identification of key factors extrapolated from the normative literature, a model for implementing GrSCC using a futures-based perspective is proposed. This paper inductively demonstrates the relationship between identified GrSCC factors through the application of a fuzzy cognitive mapping (FCM) technique. Findings from this research support a futures-based perspective that enhances understanding and refines forward-looking strategies for GrSCC. Through the exploration of two GrSCC scenarios using the given technique, this paper reports a granular perspective of positive and negative causal factors that support enabling energy futures that enhance green supply credentials