Nitrogen transfer within and between plants through common mycorrhizal networks (CMNs)

Mycorthizae play a critical role in nutrient capture from soils. Arbuscular mycorrhizae (AM) and ectomycorrhizae (EM) are the most important mycorrhizae in agricultural and natural ecosystems. AM and EM fungi use inorganic NH4+ and NO3-, and most EM fungi are capable of using organic nitrogen. The heavier stable isotope N-15 is discriminated against during biogeochemical and biochemical processes. Differences in N-15 (atom%) or delta(15)N (parts per thousand) provide nitrogen movement information in an experimental system. A range of 20 to 50% of one-way N-transfer has been observed from legumes to nonlegumes. Mycorrhizal fungal mycelia can extend from one plant's roots to another plant's roots to form common mycorrhizal networks (CMNs). Individual species, genera, even families of plants can be interconnected by CMNs. They are capable of facilitating nutrient uptake and flux. Nutrients such as carbon, nitrogen and phosphorus and other elements may then move via either AM or EM networks from plant to plant. Both N-15 labeling and N-15 natural abundance techniques have been employed to trace N movement between plants interconnected by AM or EM networks. Fine mesh (25similar to45 mum) has been used to separate root systems and allow only hyphal penetration and linkages but no root contact between plants. In many studies, nitrogen from N-2-fixing mycorrhizal plants transferred to non-N-2-fixing mycorrhizal plants (one-way N-transfer). In a few studies, N is also transferred from non-N-2-fixing mycorrhizal plants to N-2-fixing mycorrhizal plants (two-way N-transfer). There is controversy about whether N-transfer is direct through CMNs, or indirect through the soil. The lack of convincing data underlines the need for creative, careful experimental manipulations. Nitrogen is crucial to productivity in most terrestrial ecosystems, and there are potential benefits of management in soil-plant systems to enhance N-transfer. Thus, two-way N-transfer warrants further investigation with many species and under field conditions.

Reciprocal N ((NH4+)-N-15 or (NO3-)-N-15) transfer between nonN(2)-fixing Eucalyptus maculata and N-2-fixing Casuarina cunninghamiana linked by the ectomycorrhizal fungus Pisolithus sp.

Two-way N transfers mediated by Pisolithus sp. were examined by excluding root contact and supplying (NH4+)-N-15 or (NO3-)-N-15 to 6-month-old Eucalyptus maculata or Casuarina cunninghamiana grown in two-chambered-pots separated by 37 m screens. Mycorrhizal colonization was 35% in Eucalyptus and 66% in Casuarina (c. 29% N-2-fixation). Using an environmental scanning electron microscope, living hyphae were observed to interconnect Eucalyptus and Casuarina. Biomass and N accumulation was greatest in nodulated mycorrhizal Casuarina/mycorrhizal Eucalyptus pairs, less in nonnodulated mycorrhizal Casuarina/mycorrhizal Eucalyptus pairs, and least in nonnodulated nonmycorrhizal Casuarina/nonmycorrhizal Eucalyptus pairs. In nonnodulated mycorrhizal pairs, N transfers to Eucalyptus or to Casuarina were similar (2.4-4.1 mg per plant in either direction) and were 2.6-4.0 times greater than in nonnodulated nonmycorrhizal pairs. In nodulated mycorrhizal pairs, N transfers were greater to Eucalyptus (5-7 times) and to Casuarina (12-18 times) than in nonnodulated mycorrhizal pairs. Net transfer to Eucalyptus or to Casuarina was low in both nonnodulated nonmycorrhizal (< 0.7 mg per plant) and nonnodulated mycorrhizal pairs (< 1.1 mg per plant). In nodulated mycorrhizal pairs, net transfer to Casuarina was 26.0 mg per plant. The amount and direction of two-way mycorrhiza-mediated N transfer was increased by the presence of Pisolithus sp. and Frankia, resulting in a net N transfer from low-N-demanding Eucalyptus to high-N-demanding Casuarina.

Nodulated N-2-fixing Casuarina cunninghamiana is the sink for net N transfer from non-N-2-fixing Eucalyptus maculata via an ectomycorrhizal fungus Pisolithus sp using (NH4+)-N-15 or (NO3-)-N-15 supplied as ammonium nitrate

To determine the effects of nitrogen source on rates of net N transfer between plants connected by a common mycorrhizal network, we measured transfer of N supplied as (NH4NO3)-N-15-N-14 or (NH4NO3)-N-14-N-15 in three Casuarina/Eucalyptus treatments interconnected by a Pisolithus sp. The treatments were nonnodulated nonmycorrhizal/nonmycorrhizal; nonnodulated mycorrhizal/mycorrhizal; and nodulated mycorrhizal/mycorrhizal. Mycorrhization was 67% in Eucalyptus and 36% in Casuarina. N-2 fixation supplied 38% of the N in Casuarina. Biomass, N and N-15 contents were lowest in nonmycorrhizal plants and greatest in plants in the nodulated/mycorrhizal treatment. Nitrogen transfer was enhanced by mycorrhization and by nodulation, and was greater when N was supplied as (NH4+)-N-15 than (NO3-)-N-15. Nitrogen transfer rates were lowest in the nonmycorrhizal treatment for either N-15 source, and greatest in the nodulated, mycorrhizal treatment. Transfer was greater to Casuarina than to Eucalyptus and where ammonium rather than nitrate was the N source. Irrespective of N-15 source and of whether Casuarina or Eucalyptus was the N sink, net N transfer was low and was similar in both nonnodulated treatments. However, when Casuarina was the N sink in the nodulated, mycorrhizal treatment, net N transfer was much greater with (NH4+)-N-15 than with (NO3-)-N-15. High N demand by Casuarina resulted in greater net N transfer from the less N-demanding Eucalyptus. Net transfer of N from a non-N-2-fixing to an N-2-fixing plant may reflect the very high N demand of N-2-fixing species.

Rooting theories of plant community ecology in microbial interactions

Predominant frameworks for understanding plant ecology have an aboveground bias that neglects soil micro-organisms. This is inconsistent with recent work illustrating the importance of soil microbes in terrestrial ecology. Microbial effects have been incorporated into plant community dynamics using ideas of niche modification and plant–soil community feedbacks. Here, we expand and integrate qualitative conceptual models of plant niche and feedback to explore implications of microbial interactions for understanding plant community ecology. At the same time we review the empirical evidence for these processes. We also consider common mycorrhizal networks, and propose that these are best interpreted within the feedback framework. Finally, we apply our integrated model of niche and feedback to understanding plant coexistence, monodominance and invasion ecology.

University Networking in Developing Countries based on C4D-Learning

In recent years, the establishment of cooperation networks between universities is one of the most important trends in higher education all over the world. Well recognized local and international university networks have been implemented in most educational institutions. It is common to find associations of various prestigious universities collaborating in a high-­‐technology research project including a very specialized teaching as well. This is the most common cooperation networks among higher education institutions in developed countries. An increasingly common type of networking between developed and developing universities is related to cooperation for development. This is the case of many universities in Africa that are needed for external help in order to improve its capabilities. Numerous memorandums of understanding regarding first world institutions that collaborate with universities in developing countries describe contributions of eventual visiting professors, teaching material and courses. But probably there exist another type of more important, but less explored association, such as networking among developing universities. The new goal, in this case, is not only the excellence but also the mutual development.

Introducción de las plataformas tecnológicas 2.0 y la innovación abierta en la estrategia empresarial: estudio del sector de componentes electrónicos

Este proyecto se encuadra dentro de los estudios de impacto que están produciendo en las empresas el desarrollo e incorporación de las nuevas tecnologías, y más concretamente la implantación de las aplicaciones provenientes de la denominada web 2.0. Se conoce con este nombre a las herramientas web que permiten una comunicación bidireccional, es decir, el usuario y la empresa pueden intercambiar opiniones, de manera que el usuario adquiere un nuevo papel más protagonista, presentando ideas, aclaraciones, gustos, críticas...que son tenidas en cuenta por la empresa para realizar su actividad. De esta manera se ha roto con el modelo anterior donde el usuario solo podía consultar la información de una página web, era simple receptor de la información. El objetivo de este estudio es conocer cómo las empresas están incorporando estas tecnologías 2.0 a su estrategia empresarial, y cómo términos como innovación abierta o co-creación están tomando mayor importancia en el entorno empresarial gracias a estas nuevas tecnologías. Si bien existen estudios a nivel de consultoría que generalmente aportan información sobre cuáles son las plataformas 2.0 más utilizadas en el mundo empresarial, no se han encontrado hasta ahora estudios que vinculen estas plataformas entre ellas y con la estructura empresarial, para poder definir un perfil de la organización que trabaja con ellas o el nivel de madurez de la incorporación de estas tecnologías en las organizaciones. Analizar cualitativamente estos aspectos, significa estudiar los nuevos conceptos incorporados a las tecnologías 2.0 en la empresa. Un análisis cuantitativo nos llevaría a estudiar de manera práctica que tipo de recursos y en qué cantidad se están utilizando y su vinculación con la estructura de la organización. Para ello: En una primera parte, nos centraremos en las diferentes formas en las que se puede acceder a Internet, y a continuación enfocaremos el estudio en los dispositivos móviles que nos permiten la conexión desde cualquier lugar y en cualquier instante. Con esto conseguiremos tener una situación actual del mercado de las TIC y veremos cómo las empresas han ido construyendo nuevas políticas para cambiar su estrategia con el fin de estar presentes en los nuevos dispositivos móviles y no perder cuota de mercado. Tras ello, veremos porqué conceptos como el de innovación abierta y proceso de co-creación han sido posibles gracias a la implantación de las tecnologías 2.0 en el ámbito empresarial, facilitando que la empresa y el usuario final cooperen y vayan de la mano en una misma dirección; la empresa se surte de las aportaciones que los usuarios ofrecen, y por otra parte el usuario se siente valorado por la empresa para conseguir la meta final. Es aquí donde comprobaremos la transformación que ha sufrido la empresa en sus distintos sectores departamentales (marketing, ventas, recursos humanos y atención al cliente) como consecuencia de la incorporación de las herramientas 2.0 al mundo laboral. Por todo ello, se enumerarán los distintos usos que realizan las empresas de las redes social más habituales, y además se describirán las principales herramientas y/o aplicaciones para monitorizar las redes sociales que servirán a la empresa para hacer un seguimiento de las mismas. La segunda parte del proyecto será un caso práctico y servirá para ofrecer una visión más real del estado actual de las empresas y su relación con las redes sociales. Para la recopilación de los datos se han escogido las empresas que pertenecen al sector de la “Fabricación de productos informáticos, electrónicos y ópticos”. En cuento a las redes sociales elegidas, han sido Facebook y Twitter. Este estudio práctico nos hará entender mejor el impacto directo que tienen las redes sociales en la actividad diaria de las empresas. Finalmente se realizarán una serie de consideraciones a modo de directrices que servirán para tratar de entender cómo se están utilizando las redes sociales en el entorno empresarial y cuál puede ser la manera más óptima de utilizarlas según el estudio presentado. ABSTRACT. This project is part of the impact studies arisen in companies by the development and incorporation of new technologies and, specifically, by the implementation of applications from the so-called web 2.0. That is how we call the web tools that allow bidirectional communication, this is, user and company can exchange opinions, in such a way that users acquire a leading role, submitting ideas, explanations, preferences, criticism... considered by the company when performing its activities. This way, we have broken with the previous model, where users could only check information from a web page and were simple information recipients. The objective of this study is to get to know how companies are incorporating these technologies 2.0 to their business strategy and how terms such as open innovation or co-creation are becoming more important in the business sphere thanks to these new technologies. Even if there are consulting studies that generally provide information about which are the platforms 2.0 more used in the business world, no studies have been found until now that link such platforms among them and with the business structure, in order to define a profile of the organization that works with them or the level of development of the incorporation of these technologies in the organizations. A qualitative analysis of these aspects involves studying the new concepts incorporated to technologies 2.0 by companies. A qualitative analysis would lead us to study in a practical manner what kind of resources and what amount are being used and their relation with the organization structure. Therefore: First, we will focus on the different ways to gain access to the Internet and, afterwards, we will focus the study on mobile devices that allow us to be connected everywhere any time. This way, we will manage to obtain a present situation of the ICT market and we will see how companies have constructed new policies to change their strategy in order to be present in the new mobile devices without losing their market share. Later, we will review why concepts such as open innovation and co-creation process have been possible thanks to the implementation of technologies 2.0 in the business environment, facilitating that companies and final users cooperate and walk hand in hand in the same direction; companies stock up on the contributions offered by users and, on the other hand, users feel appreciated by companies in the achievement of the final goal. Here we will confirm the transformation suffering by companies in different department sectors (marketing, sales, human resources and customer service) as a result of the incorporation of tools 2.0 to the work environment. Therefore, we will enumerate the different uses that companies make of the most common social networks, describing the main tools and/or applications to monitor social networks used by companies to follow them up. The second part of the project will be a case study to offer a more real vision of the present status of companies and their relation with social networks. To collect the data, we have selected companies from the “Manufacture of computer, electronic and optical products” industry. The social networks chosen are Facebook and Twitter. This case study will help us to get a better understanding of the direct impact of social networks in companies’ daily activity. Finally, we will offer a series of considerations and guidelines to try to understand how are social networks being used in the business environment and what can be the most suitable manner to use them according to this study.

Public support for the deployment of next generation access networks-Common themes, methodological caveats and further research

Next generation telecommunications infrastructures are considered as a principal example of a new technology for sustainable economic growth. From their deployment it is expected that a wealth of innovations – hopefully converted into economic growth – new sources of employment and improved quality of life will result. In line with these prospects, public administrations at supranational, national, regional and local levels have encouraged the development of these new infrastructures. Moreover, in times of economic crisis, public assistance to deploy such networks encompasses the promise of placing a weak economy on the road to prosperity. However, such arguments and political claims clearly require rigorous assessment. In particular, any such assessment must adequately address the appropriate form of modelling that best captures key elements for identifiable progress from next generation access networks (NGAN).

A reliable measure of similarity based on dependency for short time series: an application to gene expression networks

Background: Microarray techniques have become an important tool to the investigation of genetic relationships and the assignment of different phenotypes. Since microarrays are still very expensive, most of the experiments are performed with small samples. This paper introduces a method to quantify dependency between data series composed of few sample points. The method is used to construct gene co-expression subnetworks of highly significant edges. Results: The results shown here are for an adapted subset of a Saccharomyces cerevisiae gene expression data set with low temporal resolution and poor statistics. The method reveals common transcription factors with a high confidence level and allows the construction of subnetworks with high biological relevance that reveals characteristic features of the processes driving the organism adaptations to specific environmental conditions. Conclusion: Our method allows a reliable and sophisticated analysis of microarray data even under severe constraints. The utilization of systems biology improves the biologists ability to elucidate the mechanisms underlying celular processes and to formulate new hypotheses.

Social Networks Shape the Transmission Dynamics of Hepatitis C Virus

Hepatitis C virus (HCV) infects 170 million people worldwide, and is a major public health problem in Brazil, where over 1% of the population may be infected and where multiple viral genotypes co-circulate. Chronically infected individuals are both the source of transmission to others and are at risk for HCV-related diseases, such as liver cancer and cirrhosis. Before the adoption of anti-HCV control measures in blood banks, this virus was mainly transmitted via blood transfusion. Today, needle sharing among injecting drug users is the most common form of HCV transmission. Of particular importance is that HCV prevalence is growing in non-risk groups. Since there is no vaccine against HCV, it is important to determine the factors that control viral transmission in order to develop more efficient control measures. However, despite the health costs associated with HCV, the factors that determine the spread of virus at the epidemiological scale are often poorly understood. Here, we sequenced partial NS5b gene sequences sampled from blood samples collected from 591 patients in Sao Paulo state, Brazil. We show that different viral genotypes entered Sao Paulo at different times, grew at different rates, and are associated with different age groups and risk behaviors. In particular, subtype 1b is older and grew more slowly than subtypes 1a and 3a, and is associated with multiple age classes. In contrast, subtypes 1a and 3b are associated with younger people infected more recently, possibly with higher rates of sexual transmission. The transmission dynamics of HCV in Sao Paulo therefore vary by subtype and are determined by a combination of age, risk exposure and underlying social network. We conclude that social factors may play a key role in determining the rate and pattern of HCV spread, and should influence future intervention policies.

Correlation of Modified Natural Rubber Properties by Artificial Neural Networks

Natural rubber (NR) is a raw material largely used by the modern industry; however, it is common that chemical modifications must be made to NR in order to improve properties such as hydrophobicity or mechanical resistance. This work deals with the correlation of properties of NR modified with dimethylaminoethylmethacrylate or methylmethacrylate as grafting agents. Dynamic-mechanical behavior and stress/strain relations are very important properties because they furnish essential characteristics of the material such as glass transition temperature and rupture point. These properties are concerned with different physical principles; for this reason, normally they are not related to each other. This work showed that they can be correlated by artificial neural networks (ANN). So, from one type of assay, the properties that as a rule only could be obtained from the other can be extracted by ANN correlation. POLYM. ENG. SCI., 49:499-505, 2009. (c) 2009 Society of Plastics Engineers

Remote control of CNC machines using the CyberOPC communication system over public networks

During the last few years, the evolution of fieldbus and computers networks allowed the integration of different communication systems involving both production single cells and production cells, as well as other systems for business intelligence, supervision and control. Several well-adopted communication technologies exist today for public and non-public networks. Since most of the industrial applications are time-critical, the requirements of communication systems for remote control differ from common applications for computer networks accessing the Internet, such as Web, e-mail and file transfer. The solution proposed and outlined in this work is called CyberOPC. It includes the study and the implementation of a new open communication system for remote control of industrial CNC machines, making the transmission delay for time-critical control data shorter than other OPC-based solutions, and fulfilling cyber security requirements.