Existence of Solution for a Class of Quasilinear Systems

This paper proves the existence of nontrivial solution for a class of quasilinear systems oil bounded domains in R(N), N >= 2, whose nonlinearity has a double criticality. The proof is based oil a linking theorem without the Palais-Smale condition.

A new scale-invariant ratio and finite-size scaling for the stochastic susceptible-infected-recovered model

The critical behavior of the stochastic susceptible-infected-recovered model on a square lattice is obtained by numerical simulations and finite-size scaling. The order parameter as well as the distribution in the number of recovered individuals is determined as a function of the infection rate for several values of the system size. The analysis around criticality is obtained by exploring the close relationship between the present model and standard percolation theory. The quantity UP, equal to the ratio U between the second moment and the squared first moment of the size distribution multiplied by the order parameter P, is shown to have, for a square system, a universal value 1.0167(1) that is the same for site and bond percolation, confirming further that the SIR model is also in the percolation class.

CRITICAL BEHAVIOR AND THRESHOLD OF COEXISTENCE OF A PREDATOR-PREY STOCHASTIC MODEL IN A 2D LATTICE

We investigate the critical behavior of a stochastic lattice model describing a predator-prey system. By means of Monte Carlo procedure we simulate the model defined on a regular square lattice and determine the threshold of species coexistence, that is, the critical phase boundaries related to the transition between an active state, where both species coexist and an absorbing state where one of the species is extinct. A finite size scaling analysis is employed to determine the order parameter, order parameter fluctuations, correlation length and the critical exponents. Our numerical results for the critical exponents agree with those of the directed percolation universality class. We also check the validity of the hyperscaling relation and present the data collapse curves.

An asymmetric sandpile model with height restriction

We analyze by numerical simulations and mean-field approximations an asymmetric version of the stochastic sandpile model with height restriction in one dimension. Each site can have at most two particles. Single particles are inactive and do not move. Two particles occupying the same site are active and may hop to neighboring sites following an asymmetric rule. Jumps to the right or to the left occur with distinct probabilities. In the active state, there will be a net current of particles to the right or to the left. We have found that the critical behavior related to the transition from the active to the absorbing state is distinct from the symmetrical case, making the asymmetry a relevant field.

Soluble one-dimensional particle conservation models with infinitely many absorbing states

Particle conservation lattice-gas models with infinitely many absorbing states are studied on a one-dimensional lattice. As one increases the particle density, they exhibit a phase transition from an absorbing to an active phase. The models are solved exactly by the use of the transfer matrix technique from which the critical behavior was obtained. We have found that the exponent related to the order parameter, the density of active sites, is 1 for all studied models except one of them with exponent 2.

Fock space for fermion-like lattices and the linear Glauber model

The concept of Fock space representation is developed to deal with stochastic spin lattices written in terms of fermion operators. A density operator is introduced in order to follow in parallel the developments of the case of bosons in the literature. Some general conceptual quantities for spin lattices are then derived, including the notion of generating function and path integral via Grassmann variables. The formalism is used to derive the Liouvillian of the d-dimensional Linear Glauber dynamics in the Fock-space representation. Then the time evolution equations for the magnetization and the two-point correlation function are derived in terms of the number operator. (C) 2008 Elsevier B.V. All rights reserved.

Hierarchical spherical model from a geometric point of view

A continuous version of the hierarchical spherical model at dimension d=4 is investigated. Two limit distributions of the block spin variable X(gamma), normalized with exponents gamma = d + 2 and gamma=d at and above the critical temperature, are established. These results are proven by solving certain evolution equations corresponding to the renormalization group (RG) transformation of the O(N) hierarchical spin model of block size L(d) in the limit L down arrow 1 and N ->infinity. Starting far away from the stationary Gaussian fixed point the trajectories of these dynamical system pass through two different regimes with distinguishable crossover behavior. An interpretation of this trajectories is given by the geometric theory of functions which describe precisely the motion of the Lee-Yang zeroes. The large-N limit of RG transformation with L(d) fixed equal to 2, at the criticality, has recently been investigated in both weak and strong (coupling) regimes by Watanabe (J. Stat. Phys. 115:1669-1713, 2004) . Although our analysis deals only with N = infinity case, it complements various aspects of that work.

Critical reflections on professional education for the environment

Evidence exists to suggest that in Australia many environmental issues remain unresolved even though the community has apparently become more environmentally aware. Although universities have undertaken responsibility to educate future environmental professionals to address this concern, there are numerous tensions underpinning professional environmental education. This folio explores my perceptions of these tensions and their effect on my professional practice as an academic. I refer to this as the relationships among theories and practices experienced in my work. Four perspectives are taken in this research as I appraise professional environmental education. This Dissertation (Vol. 1) focuses on views informing my professional environmental education, inclusive of my own reflexivity. From interviews with students, academics, professionals and environmentalists, and other sources of information, I consider various tensions arising from what I regard as dehumanising social and political forces. The conventional elite and authoritative roles for universities and professionals dominate most participants' understanding of professional activities. Professional practices often endorse these conventions. Juxtaposed to this authoritative view of professional education, and prescribing a different interpretation for professional practice, is my theoretical position informed by criticality and a need to challenge the status quo. I suggest that Leopold's The Land Ethic is an exemplar of criticality and a suitable basis for examining professional environmental education. The Land Ethic is used as a foundation to my thesis because it encapsulates suitable arguments to examine ideologies supportive of my understanding of professional environmental education. My thesis investigates the nature of participants' (including my own) understanding of their land ethic or land ethics suggesting that interpretations of 'place' provide an emotional and ethical appreciation of the land. I suggest that 'place', as a culturally derived construct, is central to the concept of a land ethic or land ethics, and a characteristic of an environmental ethic or ethics. To incorporate these different perspectives into professional environmental education perhaps land could be viewed, not just as a 'client' as in Schön's (1983) reflective contract, but expanded so that professionals form ethical partnerships with the land, which implies a greater equity between roles and responsibilities. This perspective challenges elite interpretations of the roles for environmental professionals by asking them to be advocates for their land, and to work with the land. Searching for my own land ethic or land ethics has promoted a discourse that encompasses a language of possibility and opportunity. This language of possibility and opportunity stands in contrast to the constraining language of reproduction that has promoted stasis. My reflexivity, a holistic and ecological view that in this thesis is an expression of my searching for a land ethic or land ethics, has encouraged me to develop critical and ethical questions to challenge my professional environmental education practice. As such the process of theorising about my theory and practice has been personally transformative as it encourages my development as a 'critical person'. Elective 1 (Vol. 2 ) reviews public information promoting a selected range of Australian environmental courses. Analysis demonstrates environmental courses are mainly technocratic, promoting technical-scientific and vocational perspectives. This orientation, I consider, is aligned to an emerging corporate agenda as universities attempt to be more accountable to the government within a competitive market dominated by economic interests. Elective 2 (Vol. 2 ) considers the providers of professional environmental education where I explore a diversity of tensions undermining current academic life found in many Australian universities. I suggest that corporatisation and vocationalisation dominate university culture to such an extent that any examination of professional environmental education is prejudiced. Professional environmental education appears to be biased toward maintaining the status quo. My conclusion is that professional environmental education does not promote graduates as 'critical persons' (Barnett 1997), and this may affect graduates' understandings of the purpose and aspirations of environmental professionalism. I suggest that elite and technical understandings of professionalism may affect the professionals' ability to implement environmental policy. Australia has an admirable record of developing environmental policy. However, public concern about a lack of resolution for many environmental issues suggests that professionals may be struggling to successfully implement policy in any meaningful way. Such challenges for environmental professionals may be a result of a professional environmental education that does not engage graduates within ideas that professional practice may require community participation and collaboration as key themes. Elective 3 (Vol. 2) is a case study investigating the development of conservation policies by the Ballarat community. The case demonstrates how the dominant social paradigm informs community views about environmental issues emphasising a technical emphasis and hierarchical arrangements of power and authority between local government and the community. The community view appears to be that environmental action should be mainly individualistic and behaviourist, which I suggest may have resulted from a technical framework for environmental knowledge. The community view of environmental issues resonates with the dominant view promoted by professional environmental education in most universities. In conclusion, my thesis is a representation of my challenges to critically engage in possible relationships among theories, practices and circumstances in my workplace, with a view to addressing what I perceive as a 'gap' between my own theory and practice. The motivation for this critical examination is to question the purpose of my professional environmental education practice in relation to the challenges of my emergent environmental ideology. The difficulty of promoting my critical theorising in a traditional small science faculty, within a corporate university, with my scientific background, is acknowledged. Nevertheless, based on my own experiences, I recommend that academics involved in professional environmental education should be encouraged to explore relationships between their own theories and practices in their own professional settings. I suggest that the search for a land ethic or land ethics, and one's 'place' in the 'land', can be an effective platform for this process.

An overview of the ecology, management and conservation of Australia's temperate woodlands

Australia’s temperate woodlands are environments of cultural and ecological importance and significant repositories of Australia’s biodiversity. Despite this, they have been heavily cleared, much remaining vegetation is in poor condition and many species of plants and animals are threatened. Here, we provide a brief overview of key issues relating to the ecology, management and policy directions for temperate woodlands, by identifying and discussing ten themes. When addressing issues relating to the conservation and management of temperate woodlands, spatial scale is very important, as are the needs for a temporal perspective and a complementary understanding of pattern and process. The extent of landscape change in many woodland environments means that woodland patches, linear networks and paddock trees are critical elements, and that there can be pervasive effects from ‘problem’ native species such as the Noisy Miner (Manorina melanocephala). These consequences of landscape change highlight the challenge to undertake active management and restoration as well as effective monitoring and long-term data collection. In developing approaches for conservation and management of temperate woodlands, it is essential to move our thinking beyond reserves to woodland conservation and management on private land, and recognise the criticality of cross-disciplinary linkages. We conclude by identifying some emerging issues in woodland conservation and management. These include the need to further develop non-traditional approaches to conservation particularly off-reserve management; the value of documenting approaches and programmes that demonstrably lead to effective change; new lessons that can be learned from intact examples of temperate woodlands; and the need to recognise how climate change and human population growth will interact with conservation and management of temperate woodlands in future decades

Is this a meaningful learning experience? Interactive critical self-inquiry as investigation

What conditions enable educators to engage in meaningful learning experiences with peers and beginning practitioners? This article documents a self-study on our actions-in-practice in a peer mentoring project. The investigation involved an iterative process to improve our knowledge as teacher educators, reflective practitioners, and researchers. Data sets included: video-stimulated reflections; audiotaped reflexive dialogue; individual and shared reflective writings. Data analyzed through the iterative process revealed competing tensions that were not addressed by the triad, leading to a less than meaningful learning experience. We sought to name the dilemmas and document how they impeded meaningful learning; identifying tensions proved useful in data interpretation. The research led us to focus on the tension between collegiality and criticality. Managing this tension requires being authentic with and accepting of the other and working with cognitive dissonances. Collegiality and criticality together promote reflexivity and increase growth, leading to new professional knowledge.

The impact of ITIL (information technology infrastructure library) recommended practices on the IT outsourcing relationship

Over the last two decades, the outsourcing of IT services has become a popular topic for many IS researchers. Furthermore, managing IT services (both internally and externally provided) has become an emerging area for academic research, given the criticality of IT services in modern organizations. One of the better known IT service management frameworks is the Information Technology Infrastructure Library (ITIL) framework. While there are many claims made about the relationship between ITIL and IT outsourcing, these claims still need further empirical research. Using data gathered from a preliminary focus group, this study investigates how ITIL impacts recommended practices on the success of IT outsourcing arrangement.

Structural equation modeling for evaluating the user perceptions of E-learning effectiveness in higher education

A crucial prerequisite for sustainable e-learning is the understanding of learners’ preferences for various pedagogical strategies, technologies, and the management of learning resources. This paper presents an empirical study aiming to empirically test the theoretical (pedagogies, technologies and management) (PTM) model on the preference of learners and on the perceived impact of the effectiveness of e-learning. This study uses structural equation modelling (SEM) to identify the critical dimensions in the PTM model for augmenting the effectiveness of e-learning. This leads to the development of a PTM model with the path coefficients showing weak to strong relationships ranging from 0.15 to 0.42 with acceptable significance levels. The results support the hypothesis that management, technology, resources and metadata ontology dimensions affect the effectiveness of elearning both directly and indirectly through enhancing the management effectiveness of learning resources. However, the result does not support positive influence of pedagogical strategy per se on e-learning effectiveness. The implications of this study indicate the criticality of effective management of learning resources to enhance e-learning effectiveness.

Critical success factors in e‐learning ecosystems: a qualitative study

Abstract
Purpose – The purpose of this paper is to evaluate the critical success factors for sustainable e-learning in an e-learning ecosystem framework. Three critical components of the e-learning ecosystem including principles and methods, processes and systems, and substance and content are considered based on a comprehensive review of the relevant literature in e-learning.
Design/methodology/approach – Systematic interviews are conducted with experts in e-learning for identifying the critical success factors to sustainable e-learning within an e-learning ecosystem framework. This leads to the development of an e-learning success model that describes the underlying relationship between and among the identified critical success factors.
Findings – A comprehensive analysis of the interview results shows that there are several barriers to the effective adoption of the proposed e-learning success model for improving the effectiveness of e- learning. These barriers include a lack of understanding of the technologies behind various pedagogies, insufficiencies of the popular learning management systems, and the sustainability of the learning objects repositories.
Research limitations/implications – The paper highlights the criticality of synergizing the three components of e-learning ecosystems namely pedagogies, technologies and management of learning resources for achieving a sustainable e-learning success.
Practical implications – A better understanding of these barriers would help e-learning stakeholders develop appropriate strategies and policies for the implementation of the proposed e-learning success model towards creating a sustainable e-learning environment.
Originality/value – Specific contributions of this research to the entire e-learning community are discussed with recommendations for concerted policy measures to eliminate the identified barriers in the process of adopting the developed e-learning success model.

Undersampled Critical Branching Processes on Small-World and Random Networks Fail to Reproduce the Statistics of Spike Avalanches

The power-law size distributions obtained experimentally for neuronal avalanches are an important evidence of criticality in the brain. This evidence is supported by the fact that a critical branching process exhibits the same exponent t~3=2. Models at criticality have been employed to mimic avalanche propagation and explain the statistics observed experimentally. However, a crucial aspect of neuronal recordings has been almost completely neglected in the models: undersampling. While in a typical multielectrode array hundreds of neurons are recorded, in the same area of neuronal tissue tens of thousands of neurons can be found. Here we investigate the consequences of undersampling in models with three different topologies (two-dimensional, small-world and random network) and three different dynamical regimes (subcritical, critical and supercritical). We found that undersampling modifies avalanche size distributions, extinguishing the power laws observed in critical systems. Distributions from subcritical systems are also modified, but the shape of the undersampled distributions is more similar to that of a fully sampled system. Undersampled supercritical systems can recover the general characteristics of the fully sampled version, provided that enough neurons are measured. Undersampling in two-dimensional and small-world networks leads to similar effects, while the random network is insensitive to sampling density due to the lack of a well-defined neighborhood. We conjecture that neuronal avalanches recorded from local field potentials avoid undersampling effects due to the nature of this signal, but the same does not hold for spike avalanches. We conclude that undersampled branching-process-like models in these topologies fail to reproduce the statistics of spike avalanches.

Projeto, construção e análise de um prototipo vibracional em escala de bancada aplicável ao tratamento de água de produção de petróleo bruto, mediante inovadora operação híbrida de adsorção e auto-flotação

A self-flotator vibrational prototype electromechanical drive for treatment of oil and water emulsion or like emulsion is presented and evaluated. Oil production and refining to obtain derivatives is carried out under arrangements technically referred to as on-shore and off-shore, ie, on the continent and in the sea. In Brazil 80 % of the petroleum production is taken at sea and area of deployment and it cost scale are worrisome. It is associated, oily water production on a large scale, carrier 95% of the potential pollutant of activity whose final destination is the environment medium, terrestrial or maritime. Although diversified set of techniques and water treatment systems are in use or research, we propose an innovative system that operates in a sustainable way without chemical additives, for the good of the ecosystem. Labyrinth adsor-bent is used in metal spirals, and laboratory scale flow. Equipment and process patents are claimed. Treatments were performed at different flow rates and bands often monitored with control systems, some built, other bought for this purpose. Measurements of the levels of oil and grease (OGC) of efluents treaty remained within the range of legal framework under test conditions. Adsorbents were weighed before and after treatment for obtaining oil impregna-tion, the performance goal of vibratory action and treatment as a whole. Treatment technolo-gies in course are referenced, to compare performance, qualitatively and quantitatively. The vibration energy consumption is faced with and without conventional flotation and self-flotation. There are good prospects for the proposed, especially in reducing the residence time, by capillary action system. The impregnation dimensionless parameter was created and confronted with consecrated dimensionless parameters, on the vibrational version, such as Weber number and Froude number in quadratic form, referred to as vibrational criticality. Re-sults suggest limits to the vibration intensity