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Showing papers on "Literature survey published in 2009"


01 Jan 2009
TL;DR: This report provides a general introduction to active learning and a survey of the literature, including a discussion of the scenarios in which queries can be formulated, and an overview of the query strategy frameworks proposed in the literature to date.
Abstract: The key idea behind active learning is that a machine learning algorithm can achieve greater accuracy with fewer training labels if it is allowed to choose the data from which it learns. An active learner may pose queries, usually in the form of unlabeled data instances to be labeled by an oracle (e.g., a human annotator). Active learning is well-motivated in many modern machine learning problems, where unlabeled data may be abundant or easily obtained, but labels are difficult, time-consuming, or expensive to obtain. This report provides a general introduction to active learning and a survey of the literature. This includes a discussion of the scenarios in which queries can be formulated, and an overview of the query strategy frameworks proposed in the literature to date. An analysis of the empirical and theoretical evidence for successful active learning, a summary of problem setting variants and practical issues, and a discussion of related topics in machine learning research are also presented.

5,227 citations


Journal ArticleDOI
TL;DR: The potentials and limitations of analysis with lateral flow (immuno)assays are illustrated using a literature survey and a SWOT analysis (acronym for “strengths, weaknesses, opportunities, threats”).
Abstract: Lateral flow (immuno)assays are currently used for qualitative, semiquantitative and to some extent quantitative monitoring in resource-poor or non-laboratory environments. Applications include tests on pathogens, drugs, hormones and metabolites in biomedical, phytosanitary, veterinary, feed/food and environmental settings. We describe principles of current formats, applications, limitations and perspectives for quantitative monitoring. We illustrate the potentials and limitations of analysis with lateral flow (immuno)assays using a literature survey and a SWOT analysis (acronym for “strengths, weaknesses, opportunities, threats”). Articles referred to in this survey were searched for on MEDLINE, Scopus and in references of reviewed papers. Search terms included “immunochromatography”, “sol particle immunoassay”, “lateral flow immunoassay” and “dipstick assay”.

1,296 citations


Journal ArticleDOI
TL;DR: A survey of the literature related to airborne laser scanning techniques, with emphasis on the new sensors called full-waveform lidar systems, is presented, with special interest on vegetated and urban areas.
Abstract: Airborne laser scanning (ALS) is an active remote sensing technique providing range data as 3D point clouds. This paper aims at presenting a survey of the literature related to such techniques, with emphasis on the new sensors called full-waveform lidar systems. Indeed, an emitted laser pulse interacts with complex natural and man-made objects leading to a temporal distortion of the returned energy profile. The new technology of full-waveform laser scanning systems permits one to digitize the complete waveform of each backscattered pulse. Full-waveform lidar data give more control to an end user in the interpretation process of the physical measurement and provide additional information about the structure and the physical backscattering characteristics of the illuminated surfaces. In this paper, the theoretical principles of full-waveform airborne laser scanning are first described. Afterwards, a review of the main sensors as well as signal processing techniques are presented. We then discuss the interpretation of full-waveform measures with special interest on vegetated and urban areas.

757 citations


Journal ArticleDOI
John Krumm1
01 Aug 2009
TL;DR: This is a literature survey of computational location privacy, meaning computation-based privacy mechanisms that treat location data as geometric information, which includes privacy-preserving algorithms like anonymity and obfuscation as well as privacy-breaking algorithms that exploit the geometric nature of the data.
Abstract: This is a literature survey of computational location privacy, meaning computation-based privacy mechanisms that treat location data as geometric information. This definition includes privacy-preserving algorithms like anonymity and obfuscation as well as privacy-breaking algorithms that exploit the geometric nature of the data. The survey omits non-computational techniques like manually inspecting geotagged photos, and it omits techniques like encryption or access control that treat location data as general symbols. The paper reviews studies of peoples' attitudes about location privacy, computational threats on leaked location data, and computational countermeasures for mitigating these threats.

732 citations


Journal ArticleDOI
TL;DR: In this article, a literature survey shows potential advantages such as higher overall productivity, better control of pests and diseases, enhanced ecological services and greater economic profitability for mixed species cropping systems.
Abstract: The evolution of natural ecosystems is controled by a high level of biodiversity, In sharp contrast, intensive agricultural systems involve monocultures associated with high input of chemical fertilisers and pesticides. Intensive agricultural systems have clearly negative impacts on soil and water quality and on biodiversity conservation. Alternatively, cropping systems based on carefully designed species mixtures reveal many potential advantages under various conditions, both in temperate and tropical agriculture. This article reviews those potential advantages by addressing the reasons for mixing plant species; the concepts and tools required for understanding and designing cropping systems with mixed species; and the ways of simulating multispecies cropping systems with models. Multispecies systems are diverse and may include annual and perennial crops on a gradient of complexity from 2 to n species. A literature survey shows potential advantages such as (1) higher overall productivity, (2) better control of pests and diseases, (3) enhanced ecological services and (4) greater economic profitability. Agronomic and ecological conceptual frameworks are examined for a clearer understanding of cropping systems, including the concepts of competition and facilitation, above- and belowground interactions and the types of biological interactions between species that enable better pest management in the system. After a review of existing models, future directions in modelling plant mixtures are proposed. We conclude on the need to enhance agricultural research on these multispecies systems, combining both agronomic and ecological concepts and tools.

709 citations


Journal ArticleDOI
TL;DR: The use of chitosan in antimicrobial systems should be based on sufficient knowledge of the complex mechanisms of its antimicrobial mode of action, which in turn would help to arrive at an appreciation of its entire antimicrobial potential.
Abstract: Chitosan, an aminopolysaccharide biopolymer, has a unique chemical structure as a linear polycation with a high charge density, reactive hydroxyl and amino groups as well as extensive hydrogen bonding. It displays excellent biocompatibility, physical stability and processability. The term 'chitosan' describes a heterogeneous group of polymers combining a group of physicochemical and biological characteristics, which allow for a wide scope of applications that are both fascinating and as yet uncharted. The increased awareness of the potentials and industrial value of this biopolymer lead to its utilization in many applications of technical interest, and increasingly in the biomedical arena. Although not primarily used as an antimicrobial agent, its utility as an ingredient in both food and pharmaceutical formulations lately gained more interest, when a scientific understanding of at least some of the pharmacological activities of this versatile carbohydrate began to evolve. However, understanding the various factors that affect its antimicrobial activity has become a key issue for a better usage and a more efficient optimization of chitosan formulations. Moreover, the use of chitosan in antimicrobial systems should be based on sufficient knowledge of the complex mechanisms of its antimicrobial mode of action, which in turn would help to arrive at an appreciation of its entire antimicrobial potential.

671 citations


Journal ArticleDOI
TL;DR: The effects caused by different insect invaders are reviewed according to their ecosystem roles, i.e. herbivores, predators, parasites, parasitoids and pollinators; the level of biological organisation at which they occur; and the direct and indirect mechanisms underlying these effects.
Abstract: A literature survey identified 403 primary research publications that investigated the ecological effects of invasive alien insects and/or the mechanisms underlying these effects. The majority of these studies were published in the last 8 years and nearly two-thirds were carried out in North America. These publications concerned 72 invasive insect species, of which two ant species, Solenopsis invicta and Linepithema humile, accounted for 18% and 14% of the studies, respectively. Most publications investigated effects on native biodiversity at population or community level. Genetic effects and, to a lesser extent, effects on ecosystem services and processes were rarely explored. We review the effects caused by different insect invaders according to: their ecosystem roles, i.e. herbivores, predators, parasites, parasitoids and pollinators; the level of biological organisation at which they occur; and the direct and indirect mechanisms underlying these effects. The best documented effects occur in invasive ants, Eurasian forest herbivores invasive in North America, and honeybees. Impacts may occur through simple trophic interactions such as herbivory, predation or parasitism. Alien species may also affect native species and communities through more complex mechanisms such as competition for resources, disease transmission, apparent competition, or pollination disruption, among others. Finally, some invasive insects, particularly forest herbivores and ants, are known to affect ecosystem processes through cascading effects. We identify biases and gaps in our knowledge of ecological effects of invasive insects and suggest further opportunities for research.

648 citations


Journal ArticleDOI
TL;DR: An overview of the principal results obtained during the treatment of water and wastewater utilizing chitin and chitosan-derivatives for the removal of metal cations and metal anions and other miscellaneous pollutants is given.

614 citations


Journal ArticleDOI
TL;DR: In this paper, the authors provide nonspecialists working in the general area of digital communications with a comprehensive overview of this exciting research field, with focus on spatial multiplexing and spatial diversity techniques.
Abstract: The use of multiple antennas for wireless communication systems has gained overwhelming interest during the last decade - both in academia and industry. Multiple antennas can be utilized in order to accomplish a multiplexing gain, a diversity gain, or an antenna gain, thus enhancing the bit rate, the error performance, or the signal-to-noise-plus-interference ratio of wireless systems, respectively. With an enormous amount of yearly publications, the field of multiple-antenna systems, often called multiple-input multiple-output (MIMO) systems, has evolved rapidly. To date, there are numerous papers on the performance limits of MIMO systems, and an abundance of transmitter and receiver concepts has been proposed. The objective of this literature survey is to provide non-specialists working in the general area of digital communications with a comprehensive overview of this exciting research field. To this end, the last ten years of research efforts are recapitulated, with focus on spatial multiplexing and spatial diversity techniques. In particular, topics such as transmitter and receiver structures, channel coding, MIMO techniques for frequency-selective fading channels, diversity reception and space-time coding techniques, differential and non-coherent schemes, beamforming techniques and closed-loop MIMO techniques, cooperative diversity schemes, as well as practical aspects influencing the performance of multiple-antenna systems are addressed. Although the list of references is certainly not intended to be exhaustive, the publications cited will serve as a good starting point for further reading.

582 citations


Journal ArticleDOI
TL;DR: An extensive literature review on existing analytical models for both single and double-lap joints has been made to assist the designer to choose the right model for a particular application as discussed by the authors, which is generally sufficient because the stresses in the width direction are significantly lower than in the direction of the loading.

558 citations


Journal ArticleDOI
TL;DR: In this article, the coordination chemistry of thiosemicarbazones and all the metals for which complexes are reported are discussed with respect to their bonding and structures, variable bonding properties, metallation, metal-metal interactions, role of solvents/other factors in stabilization of sulfur-bridging in coinage metals, and the nature of substituents at azomethine carbon.

Journal ArticleDOI
TL;DR: This work applies a classification technique to IVC applications to provide a taxonomy for detailed study of their communication requirements, and divides them into type classes which share common communication organization and performance requirements.
Abstract: Inter-vehicle communication (IVC) protocols have the potential to increase the safety, efficiency, and convenience of transportation systems involving planes, trains, automobiles, and robots. The applications targeted include peer-to-peer networks for web surfing, coordinated braking, runway incursion prevention, adaptive traffic control, vehicle formations, and many others. The diversity of the applications and their potential communication protocols has challenged a systematic literature survey. We apply a classification technique to IVC applications to provide a taxonomy for detailed study of their communication requirements. The applications are divided into type classes which share common communication organization and performance requirements. IVC protocols are surveyed separately and their fundamental characteristics are revealed. The protocol characteristics are then used to determine the relevance of specific protocols to specific types of IVC applications.

Book
01 Jan 2009
TL;DR: This chapter discusses the literature review process, the body of the Literature Review, and the Background of the Study, as well as some common Outlining Mistakes.
Abstract: Preface Acknowledgments About the Authors 1. The Literature Review Process: Getting Started The Purpose of a Literature Review The Literature Review Definition The Literature Review Process Inquiry: The Necessary Precondition Pack Wisely Before You Begin Tips Summary Checklist 2. Selecting the Topic: Everyday Interest to Research Interest Introduction: Selecting a Research Topic Step 1: Choosing a Research Interest Exercises Researcher Bias Step 2: Specifying a Research Interest Focusing the Interest Selecting a Vantage Point Reflection: The Key to Interest Selection Step 3: From Research Interest to Research Topic Accessing the Research Conversation: Formalizing the Research Topic Tips Summary Checklist 3. Searching the Literature: Tasks and Tools Introduction: Searching the Literature Discovering the Literature to Review Conducting a Literature Search Previewing the Data: Scanning the Literature Using the Internet Managing Your Data Selecting the Data: Skimming the Literature Mapping: An Overview Mapping by Core Concept Mapping by Author Contribution Refining the Topic Expanding the Topic Tips Summary Checklist 4. Developing the Argument: Making the Case for the Literature Review Introduction: Arguments and the Literature Review Building the Case for the Literature Review Arguments Evaluating the Basic Parts of an Argument Claims Types of Claims Acceptability of Claims Data Versus Evidence Data Quality Data Relevance Qualifying the Claim Warranting: Building the Rationale for the Argument Multiple Claims Arguments Tips Summary Checklist 5. Doing the Literature Survey: Building the Argument of Discovery Introduction: The Next Steps The Survey of the Literature Stage 1: Assembly Assembling the Data Recording the Data Stage 2: Synthesis Synthesizing the Information, Building Evidence Integrating the Data, Building Claims Reasoning Patterns Stage 3: Analyzing, Building the Argument of Discovery Complex Reasoning Divergent Reasoning Comparative Reasoning Building the Discovery Argument: An Example Mapping the Argument of Discovery Analyzing the Argument Tips Summary Checklist 6. The Literature Critique: Interpreting the Research The Literature Critique Implicative Reasoning: The Literature Critique The Two Arguments Argument Patterns Backing Fallacies The Case Is Everything Tips Summary Checklist 7. Writing the Review: Write, Audit, Edit The Writing Process: An Overview Writing to Understand: An Overview Exploratory Writing: Creating Writing Readiness Exploratory Writing: The Literature Review Outlining: An Overview Some Common Outlining Mistakes Outlining the Literature Review The Introduction to the Literature Review The Body of the Literature Review The Background of the Study The Thesis Argument The Summation of the Literature Review Auditing and Editing the Outline Tips on Writing Drafts The Preliminary Draft: An Overview The Preliminary Draft: The Write Tips on Writing the Early Drafts Style Manuals and Author's Guides Preliminary Draft: The Audit Preliminary Draft: The Edit Writing to Be Understood The First Draft The First Draft Audit: The Outside Review The Second and Third Drafts: Polishing the Work The Second Draft and Beyond: Writing the Polished Work The Polished Draft Audit: The Referred Review The Final Tip Summary References Index

Journal ArticleDOI
TL;DR: This work provides a review of significant contributions in the literature on multiway models, algorithms as well as their applications in diverse disciplines including chemometrics, neuroscience, social network analysis, text mining and computer vision.
Abstract: Two-way arrays or matrices are often not enough to represent all the information in the data and standard two-way analysis techniques commonly applied on matrices may fail to find the underlying structures in multi-modal datasets. Multiway data analysis has recently become popular as an exploratory analysis tool in discovering the structures in higher-order datasets, where data have more than two modes. We provide a review of significant contributions in the literature on multiway models, algorithms as well as their applications in diverse disciplines including chemometrics, neuroscience, social network analysis, text mining and computer vision.

Journal ArticleDOI
TL;DR: In this paper, the authors present a review of the highlights that have been achieved during the recent years worldwide and the state-of-the-art for most important efforts in the field of desalination by renewable energies, with emphasis on technologies and economics.
Abstract: Energy is an essential ingredient of socio-economic development and economic growth. Renewable energy provides a variable and environmental friendly option and national energy security at a time when decreasing global reserves of fossil fuels threatens the long-term sustainability of global economy. The integration of renewable resources in desalination and water purification is becoming increasingly attractive. This is justified by the fact that areas of fresh water shortages have plenty of solar energy and these technologies have low operating and maintenance costs. In this paper an attempt has been made to present a review, in brief, work of the highlights that have been achieved during the recent years worldwide and the state-of-the-art for most important efforts in the field of desalination by renewable energies, with emphasis on technologies and economics. The review also includes water sources, demand, availability of potable water and purification methods. The classification of distillation units has been done on the basis of literature survey till today. A comparative study between different renewable energy technologies powered desalination systems as well as economics have been done. The real problem in these technologies is the optimum economic design and evaluation of the combined plants in order to be economically viable for remote or arid regions. Wind energy technology is cheaper than the conventional ones, and used extensively around the world. The slow implementation of renewable energy projects especially in the developing countries are mostly due to the governments subsides of conventional fuels products and electricity. The economic analyses carried out so far have not been able to provide a strong basis for comparing economic viability of each desalination technology. The economic performances expressed in terms of cost of water production have been based on different system capacity, system energy source, system component, and water source. These differences make it difficult, if not impossible, to assess the economic performance of a particular technology and compare it with others. Reverse osmosis is becoming the technology of choice with continued advances being made to reduce the total energy consumption and lower the cost of water produced.

Journal ArticleDOI
TL;DR: A brief summary of the role of biomass in heavy metal removal from aqueous solutions can be found in this paper, where the authors discuss the equilibria and kinetic aspects of biosorption.

Journal ArticleDOI
TL;DR: In this paper, a review of research contributions on forest management and planning using multi-criteria decision making (MCDM) based on an exhaustive literature survey is provided, focusing on the application aspects highlighting theoretical underpinnings and controversies.

Journal ArticleDOI
TL;DR: A systematic literature survey aimed at the identification and structuring of research on program comprehension through dynamic analysis is reported on, which offers insight in what constitutes the main contributions of the field and supports the task of identifying gaps and opportunities.
Abstract: Program comprehension is an important activity in software maintenance, as software must be sufficiently understood before it can be properly modified. The study of a program's execution, known as dynamic analysis, has become a common technique in this respect and has received substantial attention from the research community, particularly over the last decade. These efforts have resulted in a large research body of which currently there exists no comprehensive overview. This paper reports on a systematic literature survey aimed at the identification and structuring of research on program comprehension through dynamic analysis. From a research body consisting of 4,795 articles published in 14 relevant venues between July 1999 and June 2008 and the references therein, we have systematically selected 176 articles and characterized them in terms of four main facets: activity, target, method, and evaluation. The resulting overview offers insight in what constitutes the main contributions of the field, supports the task of identifying gaps and opportunities, and has motivated our discussion of several important research directions that merit additional consideration in the near future.

Journal ArticleDOI
TL;DR: In this article, the authors present a survey of the major analytical models for adhesively bonded joints, especially for single lap joints, and a comparative study is made in terms of time requirements and failure prediction for various cases.

Proceedings ArticleDOI
07 Mar 2009
TL;DR: Two methods are described and demonstrated: one for detecting (causal analysis) and one for avoiding (setup randomization) measurement bias, which demonstrate that measurement bias is significant and commonplace in computer system evaluation.
Abstract: This paper presents a surprising result: changing a seemingly innocuous aspect of an experimental setup can cause a systems researcher to draw wrong conclusions from an experiment. What appears to be an innocuous aspect in the experimental setup may in fact introduce a significant bias in an evaluation. This phenomenon is called measurement bias in the natural and social sciences.Our results demonstrate that measurement bias is significant and commonplace in computer system evaluation. By significant we mean that measurement bias can lead to a performance analysis that either over-states an effect or even yields an incorrect conclusion. By commonplace we mean that measurement bias occurs in all architectures that we tried (Pentium 4, Core 2, and m5 O3CPU), both compilers that we tried (gcc and Intel's C compiler), and most of the SPEC CPU2006 C programs. Thus, we cannot ignore measurement bias. Nevertheless, in a literature survey of 133 recent papers from ASPLOS, PACT, PLDI, and CGO, we determined that none of the papers with experimental results adequately consider measurement bias.Inspired by similar problems and their solutions in other sciences, we describe and demonstrate two methods, one for detecting (causal analysis) and one for avoiding (setup randomization) measurement bias.

Journal ArticleDOI
TL;DR: Local bond average (LBA) as mentioned in this paper has been proposed to compare the measurable quantities of a specimen to the identities of its representative bonds and the energetic responses of these bonds (bond nature, order, length and strength) to external stimuli, such as changes in temperatures and coordination environments.

Journal ArticleDOI
TL;DR: These guidelines can serve to facilitate the design of future multi-centre clinical trials of stereotactic radiotherapy in other patient groups and aid a more uniform implementation of this technique outside clinical trials.
Abstract: A phase III multi-centre randomised trial (ROSEL) has been initiated to establish the role of stereotactic radiotherapy in patients with operable stage IA lung cancer. Due to rapid changes in radiotherapy technology and evolving techniques for image-guided delivery, guidelines had to be developed in order to ensure uniformity in implementation of stereotactic radiotherapy in this multi-centre study. A Quality Assurance Working Party was formed by radiation oncologists and clinical physicists from both academic as well as non-academic hospitals that had already implemented stereotactic radiotherapy for lung cancer. A literature survey was conducted and consensus meetings were held in which both the knowledge from the literature and clinical experience were pooled. In addition, a planning study was performed in 26 stage I patients, of which 22 were stage 1A, in order to develop and evaluate the planning guidelines. Plans were optimised according to parameters adopted from RTOG trials using both an algorithm with a simple homogeneity correction (Type A) and a more advanced algorithm (Type B). Dose conformity requirements were then formulated based on these results. Based on current literature and expert experience, guidelines were formulated for this phase III study of stereotactic radiotherapy versus surgery. These guidelines can serve to facilitate the design of future multi-centre clinical trials of stereotactic radiotherapy in other patient groups and aid a more uniform implementation of this technique outside clinical trials.

01 Jan 2009
TL;DR: A survey of the development of algorithms for enforcing nonnegativity constraints in scientific computation is given, with special emphasis on such constraints in least squares computations in numerical linear algebra and in nonlinear optimization.
Abstract: A survey of the development of algorithms for enforcing nonnegativity constraints in scientific computation is given. Special emphasis is placed on such constraints in least squares computations in numerical linear algebra and in nonlinear optimization. Techniques involving nonnegative low-rank matrix and tensor factorizations are also emphasized. Details are provided for some important classical and modern applications in science and engineering. For completeness, this report also includes an effort toward a literature survey of the various algorithms and applications of nonnegativity constraints in numerical analysis.

Journal ArticleDOI
TL;DR: Although the survey reveals many insights and opportunities, five major areas for future study became apparent: activity interactions, global process improvements, process models as an organizing structure for knowledge management, modeling in cases of uncertainty and ambiguity, and determining the optimum amount of process prescription and structure for an innovative project.
Abstract: Given the crucial role of process modeling in product development (PD) project management research and practice, and the variety of models proposed in the literature, a survey of the PD process modeling literature is timely and valuable. In this work, we focus on the activity network-based process models that support PD project management and present a comprehensive survey of the literature published in the last decade. To organize our survey, we use a framework based on the purposes of PD process models: project visualization, project planning, project control, and project development. For each purpose, we provide an overview of the relevant models, highlight their key assumptions and findings, synthesize key insights, and illuminate avenues for further research. Although the survey reveals many insights and opportunities, five major areas for future study became apparent: activity interactions, global process improvements, process models as an organizing structure for knowledge management, modeling in cases of uncertainty and ambiguity, and determining the optimum amount of process prescription and structure for an innovative project.

Journal ArticleDOI
01 Mar 2009-Urology
TL;DR: It is concluded that spermatozoal dysfunction in varicocele patients could be multifactorial, and oxidative stress-induced injury appears to be one of the main causes.

Journal ArticleDOI
TL;DR: In the new millennium, the Western aid effort toward Africa has surged due to writ- ings by well-known economists, a celebrity mass advocacy campaign, and decisions by Western leaders to make Africa a major foreign policy priority as discussed by the authors.
Abstract: In the new millennium, the Western aid effort toward Africa has surged due to writ- ings by well-known economists, a celebrity mass advocacy campaign, and decisions by Western leaders to make Africa a major foreign policy priority. This survey contrasts the predominant "transformational" approach (West comprehensively saves Africa) to occasional swings to a "marginal" approach (West takes one small step at a time to help individual Africans). Evaluation of "one step at a time" initiatives is generally easier than that of transformational ones either through controlled experiments (although these have been oversold) or simple case studies where it is easier to attribute outcomes to actions. We see two themes emerge from the literature survey: (1) escalation—as each successive Western transformational effort has yielded disappointing results (as judged at least by stylized facts, since again the econometrics are shaky), the response has been to try an even more ambitious effort and (2) the cycle of ideas—rather than a progressive testing and discarding of failed ideas, we see a cycle in aid ideas in many areas in Africa, with ideas going out of fashion only to come back again later after some lapse long enough to forget the previous disappointing experience. Both escalation and cyclicality of ideas are symptomatic of the lack of learning that seems to be characteristic of the "transfor- mational" approach. In contrast, the "marginal" approach has had some successes in improving the well-being of individual Africans, such as the dramatic fall in mortality.

Journal ArticleDOI
TL;DR: The finding of HPVG alone cannot be an indication for emergency exploration, and an evidence-based algorithm is developed to guide the clinician in management of patients with HPVG.
Abstract: Objective To review the use of computed tomography (CT) and radiography in managing hepatic portal venous gas (HPVG) at a university-affiliated tertiary care center and in the literature. Hepatic portal venous gas is frequently associated with acute mesenteric ischemia, accounting for most of the HPVG-associated mortality. While early studies were necessarily dependent on plain abdominal radiography, modern high-resolution CT has revealed a host of benign conditions in which HPVG has been reported that do not require emergent surgery. Data Sources Patient records from our institution over the last 10 years and relevant studies from BioMed Central, CENTRAL, PubMed, and PubMed Central. In addition, references cited in selected works were also used as source data. Study Selection Patient records were selected if the CT or radiograph findings matched the term hepatic portal venous gas . Studies were selected based on the search terms hepatic portal venous gas or portal venous gas . Data Extraction Quantitative and qualitative data were quoted directly from cited work. Data Synthesis Early studies of HPVG were based on plain abdominal radiography and a literature survey in 1978 found an associated mortality rate of 75%, primarily due to ischemic bowel disease. Modern abdominal CT has resulted in the detection of HPVG in more benign conditions, and a second literature survey in 2001 found a total mortality of only 39%. While the pathophysiology of HPVG is, as yet, unclear, changing abdominal imaging technology has altered the significance of this radiologic finding. Hepatic portal venous gas therefore predicts high risk of mortality (>50%) if detected by plain radiography or by CT in a patient with additional evidence of necrotic bowel. If detected by CT in patients after surgical or endoscopic manipulation, the clinician is advised that there is no evidence of increased risk. If HPVG is detected by CT in patients with active peptic ulcer disease, intestinal obstruction and/or dilatation, or mucosal diseases such as Crohn disease or ulcerative colitis, caution is warranted, as risk of death may approach 20% to 30%. Conclusion The finding of HPVG alone cannot be an indication for emergency exploration, and we have developed an evidence-based algorithm to guide the clinician in management of patients with HPVG.

Journal ArticleDOI
TL;DR: Overall, the large-scale analyses of karyotype features within a well-supported phylogenetic framework enabled the most likely patterns of chromosome evolution in Liliaceae to be reconstructed, highlighting diverse modes of kARYotype evolution, even within this comparatively small monocot family.

Journal ArticleDOI
TL;DR: The ICF has already made a major impact on the way in which data concerning disability are conceptualized, collected and processed but there is a clear need for a classification of personal factors to allow for complete reporting on the experience of disability.
Abstract: Background: in 2001 the w orld Health Organization adopted the International Classification of Functioning, Disability and Health (ICF) and it has since been utilized extensively. Aim: A literature survey was undertaken to document reported use of the ICF, with regard to type of use, aims and implementation issues. Methods: A convenience sample of 243 papers was analysed. Results: There were few papers from developing countries, with USA and German authors responsible for almost 50% of the papers. The papers were published in 105 journals covering varying disciplines, health conditions and sectors. Problems included missing or overlapping codes, and codes that were inadequately granular. The Activity/Participation Category qualifiers presented users with the most challenges, and non-standard use of the qualifiers was often reported. The need for a category classifying Personal Factors was identified. Conclusion: The ICF has already made a major impact on the way in which data concerning disability are conceptualized, collected and processed. Utilization in developing countries must be encouraged. The addition and clarification of certain codes should be considered by the w orld Health Organization. There is a clear need for a classification of per sonal factors to allow for complete reporting on the experience of disability.

Journal ArticleDOI
TL;DR: In this article, the authors analyzed the connection between information and communications technologies and economic growth, and found that there appears to be a positive economic impact from expanded broadband deployment and adoption.