962 resultados para complex issues
Resumo:
Self-organising pervasive ecosystems of devices are set to become a major vehicle for delivering infrastructure and end-user services. The inherent complexity of such systems poses new challenges to those who want to dominate it by applying the principles of engineering. The recent growth in number and distribution of devices with decent computational and communicational abilities, that suddenly accelerated with the massive diffusion of smartphones and tablets, is delivering a world with a much higher density of devices in space. Also, communication technologies seem to be focussing on short-range device-to-device (P2P) interactions, with technologies such as Bluetooth and Near-Field Communication gaining greater adoption. Locality and situatedness become key to providing the best possible experience to users, and the classic model of a centralised, enormously powerful server gathering and processing data becomes less and less efficient with device density. Accomplishing complex global tasks without a centralised controller responsible of aggregating data, however, is a challenging task. In particular, there is a local-to-global issue that makes the application of engineering principles challenging at least: designing device-local programs that, through interaction, guarantee a certain global service level. In this thesis, we first analyse the state of the art in coordination systems, then motivate the work by describing the main issues of pre-existing tools and practices and identifying the improvements that would benefit the design of such complex software ecosystems. The contribution can be divided in three main branches. First, we introduce a novel simulation toolchain for pervasive ecosystems, designed for allowing good expressiveness still retaining high performance. Second, we leverage existing coordination models and patterns in order to create new spatial structures. Third, we introduce a novel language, based on the existing ``Field Calculus'' and integrated with the aforementioned toolchain, designed to be usable for practical aggregate programming.
Resumo:
With advances in pediatric cardiology and cardiac surgery, the population of adults with congenital heart disease (CHD) has increased. In the current era, there are more adults with CHD than children. This population has many unique issues and needs. They have distinctive forms of heart failure and their cardiac disease can be associated with pulmonary hypertension, thromboemboli, complex arrhythmias and sudden death. Medical aspects that need to be considered relate to the long-term and multisystemic effects of single ventricle physiology, cyanosis, systemic right ventricles, complex intracardiac baffles and failing subpulmonary right ventricles. Since the 2001 Canadian Cardiovascular Society Consensus Conference report on the management of adults with CHD, there have been significant advances in the field of adult CHD. Therefore, new clinical guidelines have been written by Canadian adult CHD physicians in collaboration with an international panel of experts in the field. Part III of the guidelines includes recommendations for the care of patients with complete transposition of the great arteries, congenitally corrected transposition of the great arteries, Fontan operations and single ventricles, Eisenmenger's syndrome, and cyanotic heart disease. Topics addressed include genetics, clinical outcomes, recommended diagnostic workup, surgical and interventional options, treatment of arrhythmias, assessment of pregnancy risk and follow-up requirements. The complete document consists of four manuscripts, which are published online in the present issue of The Canadian Journal of Cardiology. The complete document and references can also be found at www.ccs.ca or www.cachnet.org.
Resumo:
The Mediterranean Region has many morphologic, geographical, historical, and societal characteristics, which make its climate scientifically interesting. The concept of Mediterranean climate is characterized by mild wet winters and warm to hot, dry summers and occur on the west side of continents between about 30° and 40° latitude. However, the presence of a relatively large mass of water is unique to the actual Mediterranean region. The Mediterranean Sea is a marginal and semi-enclosed sea; it is located on the western side of a large continental area and is surrounded by Europe to the North, Africa to the South, and Asia to the East. The chapter discusses that the climate of the Mediterranean region is to a large extent forced by planetary scale patterns. The time and space behavior of the regional features associated with such large-scale forcing is complex. Orography and land–sea distribution play an important role establishing the climate at basin scale and its teleconnections with global patterns. Different levels of services of readiness to emergencies, technological, and economic resources are likely to result in very different adaptation capabilities to environmental changes and new problems. The different economic situations and demographic trends are likely to produce contrasts and conflicts in a condition of limited available resources and environmental stress.
Resumo:
Balancing the frequently conflicting priorities of conservation and economic development poses a challenge to management of the Swiss Alps Jungfrau-Aletsch World Heritage Site (WHS). This is a complex societal problem that calls for a knowledge-based solution. This in turn requires a transdisciplinary research framework in which problems are defined and solved cooperatively by actors from the scientific community and the life-world. In this article we re-examine studies carried out in the region of the Swiss Alps Jungfrau-Aletsch WHS, covering three key issues prevalent in transdisciplinary settings: integration of stakeholders into participatory processes; perceptions and positions; and negotiability and implementation. In the case of the Swiss Alps Jungfrau-Aletsch WHS the transdisciplinary setting created a situation of mutual learning among stakeholders from different levels and backgrounds. However, the studies showed that the benefits of such processes of mutual learning are continuously at risk of being diminished by the power play inherent in participatory approaches.
Resumo:
An exponential increase in the use of transcatheter aortic valve implantation (TAVI) in patients with severe aortic stenosis has been witnessed over the recent years. The current article reviews different areas of uncertainty related to patient selection. The use and limitations of risk scores are addressed, followed by an extensive discussion on the value of three-dimensional imaging for prosthesis sizing and the assessment of complex valve anatomy such as degenerated bicuspid valves. The uncertainty about valvular stenosis severity in patients with a mismatch between the transvalvular gradient and the aortic valve area, and how integrated use of echocardiography and computed tomographic imaging may help, is also addressed. Finally, patients referred for TAVI may have concomitant mitral regurgitation and/or coronary artery disease and the management of these patients is discussed.
Resumo:
The value of wildlife has long been ignored or under-rated. However, growing concerns about biodiversity loss and emerging diseases of wildlife origin have enhanced debates about the importance of wildlife. Wildlife-related diseases are viewed through these debates as a potential threat to wildlife conservation and domestic animal and human health. This article provides an overview of the values we place on wildlife (positive: socio-cultural, nutritional, economic, ecological; and negative: damages, health issues) and of the significance of diseases for biodiversity conservation. It shows that the values of wildlife, the emergence of wildlife diseases and biodiversity conservation are closely linked. The article also illustrates why investigations into wildlife diseases are now recognized as an integral part of global health issues. The modern One Health concept requires multi-disciplinary research groups including veterinarians, human physicians, ecologists and other scientists collaborating towards a common goal: prevention of disease emergence and preservation of ecosystems, both of which are essential to protect human life and well-being.
Resumo:
This paper makes reference to the importance lying, at present, on the professional education of counselors. It goes through the history of the different pre-scientific and scientific stages of counseling, and it points out the main representatives in Latin America . It also shows the current state of the specialization, taking as an antecedent some in-depth, widely encompassing research carried out in the European Union in this area. Coincidences and differences are exposed here in terms of professional profiles, university degrees, institutional dependence, up-dating processes and modes of intervention. The current state of postgraduate studies at university is also touched upon, and the different proposals for further education in Latin America are analyzed as well as their dependence upon an undergraduate degree in Psychology, Educational Sciences or Psycho-pedagogy. Finally, this paper places counseling within the complexity and the need to provide all-encompassing and integrative answers which require a wide and deep enough education so as to answer all these issues and problems.
Resumo:
This paper makes reference to the importance lying, at present, on the professional education of counselors. It goes through the history of the different pre-scientific and scientific stages of counseling, and it points out the main representatives in Latin America . It also shows the current state of the specialization, taking as an antecedent some in-depth, widely encompassing research carried out in the European Union in this area. Coincidences and differences are exposed here in terms of professional profiles, university degrees, institutional dependence, up-dating processes and modes of intervention. The current state of postgraduate studies at university is also touched upon, and the different proposals for further education in Latin America are analyzed as well as their dependence upon an undergraduate degree in Psychology, Educational Sciences or Psycho-pedagogy. Finally, this paper places counseling within the complexity and the need to provide all-encompassing and integrative answers which require a wide and deep enough education so as to answer all these issues and problems.
Resumo:
This paper makes reference to the importance lying, at present, on the professional education of counselors. It goes through the history of the different pre-scientific and scientific stages of counseling, and it points out the main representatives in Latin America . It also shows the current state of the specialization, taking as an antecedent some in-depth, widely encompassing research carried out in the European Union in this area. Coincidences and differences are exposed here in terms of professional profiles, university degrees, institutional dependence, up-dating processes and modes of intervention. The current state of postgraduate studies at university is also touched upon, and the different proposals for further education in Latin America are analyzed as well as their dependence upon an undergraduate degree in Psychology, Educational Sciences or Psycho-pedagogy. Finally, this paper places counseling within the complexity and the need to provide all-encompassing and integrative answers which require a wide and deep enough education so as to answer all these issues and problems.
Resumo:
The development of a global instability analysis code coupling a time-stepping approach, as applied to the solution of BiGlobal and TriGlobal instability analysis 1, 2 and finite-volume-based spatial discretization, as used in standard aerodynamics codes is presented. The key advantage of the time-stepping method over matrix-formulation approaches is that the former provides a solution to the computer-storage issues associated with the latter methodology. To-date both approaches are successfully in use to analyze instability in complex geometries, although their relative advantages have never been quantified. The ultimate goal of the present work is to address this issue in the context of spatial discretization schemes typically used in industry. The time-stepping approach of Chiba 3 has been implemented in conjunction with two direct numerical simulation algorithms, one based on the typically-used in this context high-order method and another based on low-order methods representative of those in common use in industry. The two codes have been validated with solutions of the BiGlobal EVP and it has been showed that small errors in the base flow do not have affect significantly the results. As a result, a three-dimensional compressible unsteady second-order code for global linear stability has been successfully developed based on finite-volume spatial discretization and time-stepping method with the ability to study complex geometries by means of unstructured and hybrid meshes
Resumo:
The dynamic effects of high-speed trains on viaducts are important issues for the design of the structures, as well as for the consideration of safe running conditions for the trains. In this work we start by reviewing the relevance of some basic design aspects. The significance of impact factor envelopes for moving loads is considered first. Resonance which may be achieved for high-speed trains requires dynamic analysis, for which some key aspects are discussed. The relevance of performing a longitudinal distribution of axle loads, the number of modes taken in analysis, and the consideration of vehicle-structure interaction are discussed with representative examples. The lateral dynamic effects of running trains on bridges is of importance for laterally compliant viaducts, such as some very tall structures erected in new high-speed lines. The relevance of this study is mainly for the safety of the traffic, considering both internal actions such as the hunting motion as well as external actions such as wind or earthquakes [1]. These studies require three-dimensional dynamic coupled vehicle-bridge models, and consideration of wheel to rail contact, a phenomenon which is complex and costly to model in detail. We describe here a fully nonlinear coupled model, described in absolute coordinates and incorporated into a commercial finite element framework [2]. The wheel-rail contact has been considered using a FastSim algorithm which provides a compromise between accuracy and computational cost, and captures the main nonlinear response of the contact interface. Two applications are presented, firstly to a vehicle subject to a strong wind gust traversing a bridge, showing the relevance of the nonlinear wheel-rail contact model as well as the dynamic interaction between bridge and vehicle. The second application is to a real HS viaduct with a long continuous deck and tall piers and high lateral compliance [3]. The results show the safety of the traffic as well as the importance of considering features such as track alignment irregularities.
Resumo:
Scaling is becoming an increasingly important topic in the earth and environmental sciences as researchers attempt to understand complex natural systems through the lens of an ever-increasing set of methods and scales. The guest editors introduce the papers in this issue’s special section and present an overview of some of the work being done. Scaling remains one of the most challenging topics in earth and environmental sciences, forming a basis for our understanding of process development across the multiple scales that make up the subsurface environment. Tremendous progress has been made in discovery, explanation, and applications of scaling. And yet much more needs to be done and is being done as part of the modern quest to quantify, analyze, and manage the complexity of natural systems. Understanding and succinct representation of scaling properties can unveil underlying relationships between system structure and response functions, improve parameterization of natural variability and heterogeneity, and help us address societal needs by effectively merging knowledge acquired at different scales.
Resumo:
The plastid genomes of some nonphotosynthetic parasitic plants have experienced an extreme reduction in gene content and an increase in evolutionary rate of remaining genes. Nothing is known of the dynamics of these events or whether either is a direct outcome of the loss of photosynthesis. The parasitic Scrophulariaceae and Orobanchaceae, representing a continuum of heterotrophic ability ranging from photosynthetic hemiparasites to nonphotosynthetic holoparasites, are used to investigate these issues. We present a phylogenetic hypothesis for parasitic Scrophulariaceae and Orobanchaceae based on sequences of the plastid gene rps2, encoding the S2 subunit of the plastid ribosome. Parasitic Scrophulariaceae and Orobanchaceae form a monophyletic group in which parasitism can be inferred to have evolved once. Holoparasitism has evolved independently at least five times, with certain holoparasitic lineages representing single species, genera, and collections of nonphotosynthetic genera. Evolutionary loss of the photosynthetic gene rbcL is limited to a subset of holoparasitic lineages, with several holoparasites retaining a full length rbcL sequence. In contrast, the translational gene rps2 is retained in all plants investigated but has experienced rate accelerations in several hemi- as well as holoparasitic lineages, suggesting that there may be substantial molecular evolutionary changes to the plastid genome of parasites before the loss of photosynthesis. Independent patterns of synonymous and nonsynonymous rate acceleration in rps2 point to distinct mechanisms underlying rate variation in different lineages. Parasitic Scrophulariaceae (including the traditional Orobanchaceae) provide a rich platform for the investigation of molecular evolutionary process, gene function, and the evolution of parasitism.
Resumo:
Beyond free trade agreements governing cross-border commerce, the source of most global economic growth is attributed to business across interconnecting markets. Among the most attractive and complex markets, China stands out. Despite its appeal, American businesses are more likely to fail in China due to an overwhelming desire for an immediate return on investment while neglecting to consider or completely disregarding China's unique legal, ethical and cultural environment. This capstone project will give recommendations to help businesses succeed when entering China and avoid legal, ethical and cultural issues such as the ones that Google, Apple, and Yahoo experienced.
Resumo:
Frequent calls for more male teachers are being made in English-speaking countries. Many of these calls are based upon the fact that the teaching profession has become (even more) 'feminized' and the presumption that this has had negative effects for the education of boys. The employment of more male teachers is sometimes suggested as a way to re-masculinize schools so they become more 'boy-friendly' and thus contribute to improving boys' school performance. The focus of this paper is on an Australian education policy document in the state of Queensland that is concerned with the attraction, recruitment and retention of male teachers in the government education system. It considers the failure of this document, as with many of the calls for more male teachers, to take into account complex matters of gender raised by feminism and the sociology of masculinities. The paper then critiques the primary argument given for the need for more male teachers: that is, that male teachers provide boys with much needed role models.