Showing papers on "Literature survey published in 2008"

A survey of unresolved problems in life cycle assessment

Abstract: Life cycle assessment (LCA) stands as the pre-eminent tool for estimating environmental effects caused by products and processes from ‘cradle to grave’ or ‘cradle to cradle.’ It exists in multiple forms, claims a growing list of practitioners, and remains a focus of continuing research. Despite its popularity and codification by organizations such as the International Organization for Standards and the Society of Environmental Toxicology and Chemistry, life cycle assessment is a tool in need of improvement. Multiple authors have written about its individual problems, but a unified treatment of the subject is lacking. The following literature survey gathers and explains issues, problems and problematic decisions currently limiting LCA’s goal and scope definition and life cycle inventory phases. The review identifies 15 major problem areas and organizes them by the LCA phases in which each appears. This part of the review focuses on the first 7 of these problems occurring during the goal and scope definition and life cycle inventory phases. It is meant as a concise summary for practitioners interested in methodological limitations which might degrade the accuracy of their assessments. For new researchers, it provides an overview of pertinent problem areas toward which they might wish to direct their research efforts. Multiple problems occur in each of LCA’s four phases and reduce the accuracy of this tool. Considering problem severity and the adequacy of current solutions, six of the 15 discussed problems are of paramount importance. In LCA’s first two phases, functional unit definition, boundary selection, and allocation are critical problems requiring particular attention. Problems encountered during goal and scope definition arise from decisions about inclusion and exclusion while those in inventory analysis involve flows and transformations. Foundational decisions about the basis of comparison (functional unit), bounds of the study, and physical relationships between included processes largely dictate the representativeness and, therefore, the value of an LCA. It is for this reason that problems in functional unit definition, boundary selection, and allocation are the most critical examined in the first part of this review.

A Systematic Survey of Program Comprehension through Dynamic Analysis

Abstract: Preprint of paper published in: IEEE Transactions on Software Engineering, 35 (5), 2009; doi:10.1109/TSE.2009.28 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.

Chemistry, biology, and medicinal potential of narciclasine and its congeners.

Abstract: Ornamental flower growers know that placing a cut daffodil (a.k.a. narcissus) in a vase with other flowers has a negative effect on the quality of those flowers and significantly shortens their vase life. Furthermore, a common horticultural practice for the cultivation of narcissus flowers involves the introduction of cuts on the bulbs before immersing them into water. The mucilage that leaches out from the cuts is constantly removed by frequent changing of water and this leads to sprouting. These observations raise speculation that specific components in the mucilage of the narcissus bulbs may have powerful growth-inhibitory effects. Historical use of narcissus flowers, as well as at least thirty other plants of the Amaryllidaceae family, in folk medicine for the management of cancer1 speaks volumes to validate this conjecture. Indeed, powerful anticancer properties of Narcissus poeticus L. were already known to the Father of Medicine, Hippokrates of Kos (ca. B.C. 460–370), who recommended a pessary prepared from narcissus oil for the treatment of uterine tumors.2 His successors, the ancient Greek physicians Pedanius Dioscorides (ca. A.D. 40–90) and Soranus of Ephesus (A.D. 98–138) continued using this therapy in the first and second centuries A.D.3,4 In addition, the topical anticancer uses of extracts from this plant5,6 as well as from N. pseudonarcissus7–9 were recorded in the first century A.D. by the Roman natural philosopher Gaius Plinius Secundus, (A.D. 23–79), better known as Pliny the Elder.10 Even the Bible provides multiple references to the Mediterranean N. tazetta L., which has a long history of use against cancer.11 The applications of narcissus oil in cancer management continued in the middle ages in Chinese, North African, Central American and Arabian medicine.1,12 The uses of other genera of the Amaryllidaceae family were also common, e. g. Hymenocallis caribaea (L. emend Gawler) Herbert, utilized by early European medical practitioners for inflammatory tumors.13 More recently, the plants of the Amaryllidaceae have been under intense scrutiny for the presence of the specific metabolites responsible for the medicinal properties associated with this plant family. The study began in 1877 with the isolation of alkaloid lycorine from Narcissus pseudonarcissus14 and since then more than 100 alkaloids, exhibiting diverse biological activities, have been isolated from the Amaryllidaceae plants. Based on the present scientific evidence, it is likely that isocarbostyril constituents of the Amaryllidaceae, such as narciclasine, pancratistatin and their congeners, are the most important metabolites responsible for the therapeutic benefits of these plants in the folk medical treatment of cancer. Notably, N. poeticus L. used by the ancient Greek physicians, as was eluded before, is now known to contain some 0.12 g of narciclasine per kg of fresh bulbs.15 Continuing along this intriguing path, the focus of the present review is a comprehensive literature survey and discussion of the chemistry and biology of these compounds as specifically relevant to their potential use in medicine. The examination of the synthetic organic chemistry, more specifically the total synthesis efforts inspired by the challenging chemical structures of narciclasine, pancratistatin and their congeners, will be reduced to a minimum in view of the two very recent excellent reviews published on this subject.16,17

Nuclear receptor coregulators and human disease.

Abstract: Nuclear receptor (NR) coregulators (coactivators and corepressors) are essential elements in regulating nuclear receptor-mediated transcription. In a little more than a decade since their discovery, these proteins have been studied mechanistically and reveal that the regulation of transcription is a highly controlled and complex process. Because of their central role in regulating NR-mediated transcription and in coordinating intercompartmental metabolic processes, disruptions in coregulator biology can lead to pathological states. To date, the extent to which they are involved in human disease has not been widely appreciated. In a complete literature survey, we have identified nearly 300 distinct coregulators, revealing that a great variety of enzymatic and regulatory capabilities exist for NRs to regulate transcription and other cellular events. Here, we substantiate that coregulators are broadly implicated in human pathological states and will be of growing future interest in clinical medicine.

Single-Walled Carbon Nanotubes Can Induce Pulmonary Injury in Mouse Model

Abstract: Carbon nanotubes are a nanomaterial that is extensively used in industry. The potential health risk of chronic carbon nanotubes exposure has been raised as of great public concern. In the present study, we have demonstrated that intratracheal instillation of 0.5 mg of single-walled carbon nanotubes (SWCNT) into male ICR mice (8 weeks old) induced alveolar macrophage activation, various chronic inflammatory responses, and severe pulmonary granuloma formation. We then used Affymetrix microarrays to investigate the molecular effects on the macrophages when exposed to SWCNT. A biological pathway analysis, a literature survey, and experimental validation suggest that the uptake of SWCNT into the macrophages is able to activate various transcription factors such as nuclear factor κB (NF-κB) and activator protein 1 (AP-1), and this leads to oxidative stress, the release of proinflammatory cytokines, the recruitment of leukocytes, the induction of protective and antiapoptotic gene expression, and the activation o...

Can the West Save Africa

Abstract: In the new millennium, the Western aid effort towards Africa has surged due to writings 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 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 much 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, the response has been to try an even more ambitious effort. (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 "transformational" 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.

River current energy conversion systems : Progress, prospects and challenges

Abstract: River current energy conversion systems (RCECS) are electromechanical energy converters that convert kinetic energy of river water into other usable forms of energy. Over the last few decades, a number of reports on technical and economic feasibility of this technology have emerged. However, the potentials of this technology as an effective source of alternative energy have not yet been explored to a great extent. The underlying challenges of system design, operation and economics also lack proper understanding. In this article, starting with a definition of the RCECS, an overview of the technological advancements in the relevant field is provided. From a system engineering perspective, various merits and prospects of this technology along with pertinent challenges are discussed. The cross-disciplinary nature of approaching these challenges with an emphasis on the need for contributions from various technical and non-technical domains are also outlined in brief. This article may serve as a coherent literature survey or technology review that would provide better understanding of the subjacent issues and possibly rejuvenate research interest in this immensely potential field of energy engineering.

Biodegradation of organic pollutants by halophilic bacteria and archaea.

Abstract: Hypersaline environments are important for both surface extension and ecological significance. As all other ecosystems, they are impacted by pollution. However, little information is available on the biodegradation of organic pollutants by halophilic microorganisms in such environments. In addition, it is estimated that 5% of industrial effluents are saline and hypersaline. Conventional nonextremophilic microorganisms are unable to efficiently perform the removal of organic pollutants at high salt concentrations. Halophilic microorganisms are metabolically different and are adapted to extreme salinity; these microorganisms are good candidates for the bioremediation of hypersaline environments and treatment of saline effluents. This literature survey indicates that both the moderately halophilic bacteria and the extremely halophilic archaea have a broader catabolic versatility and capability than previously thought. A diversity of contaminating compounds is susceptible to be degraded by halotolerant and halophile bacteria. Nevertheless, significant research efforts are still necessary in order to estimate the true potential of these microorganisms to be applied in environmental processes and in the remediation of contaminated hypersaline ecosystems. This effort should be also focused on basic research to understand the overall degradation mechanism, to identify the enzymes involved in the degradation process and the metabolism regulation.

A survey of evaluation techniques used in augmented reality studies

Abstract: In this paper we report on an initial survey of user evaluation techniques used in Augmented Reality (AR) research. To identify all papers which include AR evaluations we reviewed research publications between the years 1993 and 2007 from online databases of selected scientific publishers. Starting with a total of 6071 publications we filtered the articles in several steps which resulted in 165 AR related publications with user evaluations. These publications were classified in two different ways: according to the evaluation type used following an earlier literature survey classification scheme; and according to the evaluation methods or approach used. We present the results of out literature survey, provide a comprehensive list of references of the selected publications, and discuss some possible research opportunities for future work. Keywords: Augmented Reality, user evaluation, evaluation methods. This work may not be copied or reproduced in whole or in part for any commercial purpose. Permission to copy in whole or in part without payment of fee is granted for non-profit educational and research purposes provided that all such whole or partial copies include the following: a notice that such copying is by permission of

A review on silt erosion in hydro turbines

Abstract: Erosive wear of hydro turbine runners is a complex phenomenon, which depends upon different parameters such as silt size, hardness and concentration, velocity of water, and base material properties. The efficiency of the turbine decreases with the increase in the erosive wear and final breakdown of hydro turbines. Various researchers have conducted experiments to study the effect of these parameters on erosive wear, but most of these experiments are on small-size samples in different types of test rigs to simulate the flow conditions in the turbine, but actual flow conditions and the phenomenon of erosive wear are too complex to simulate. In the present paper, studies undertaken in this field by several investigators have been discussed extensively. Based on literature survey various aspects related to silt erosion in hydro turbines, different causes for the declined performance and efficiency of the hydro turbines and suitable remedial measures suggested by various investigators have been discussed.

A review on benchmarking of supply chain performance measures

Abstract: Purpose – The purpose of this paper is to redress the imbalances in the past literature of supply chain benchmarking and enhance data envelopment analysis (DEA) modeling approach in supply chain benchmarking.Design/methodology/approach – The paper is sorted into sections: benchmarking, definitions, concepts and literature survey, supply chain benchmarking, problems in supply chain benchmarking, existing tools used in benchmarking, problems in existing tools and motivation of using DEA as a supply chain benchmarking tool. A range of recently published (1995‐2004) works is referred and aims to provide insights into possible new research focus in supply chain benchmarking.Findings – Provides information about new trends in supply chain benchmarking and what are the existing problems. Recognizes the lack of mathematical modeling tool in addressing this issue.Research limitations/implications – Supply chain benchmarking is gearing towards a holistic approach. DEA is deemed to be an appropriate benchmarking too...

Seeding the survey and analysis of research literature with text mining

Abstract: Text mining is a semi-automated process of extracting knowledge from a large amount of unstructured data. Given that the amount of unstructured data being generated and stored is increasing rapidly, the need for automated means to process it is also increasing. In this study, we present, discuss and evaluate the techniques used to perform text mining on collections of textual information. A case study is presented using text mining to identify clusters and trends of related research topics from three major journals in the management information systems field. Based on the findings of this case study, it is proposed that this type of analysis could potentially be valuable for researchers in any field.

Using Input‐Output Analysis to Measure the Environmental Pressure of Consumption at Different Spatial Levels

Abstract: Summary Input-output modeling is a useful tool for tracing environmental impacts of consumption. Because it includes impacts originating from production layers of infinite order (capturing the entire economy), input-output modeling is highly relevant for studies operating in a life-cycle context. In this article we show how the input-output approach can be used to enumerate the problem of sustainable consumption. Based on a literature survey including research done by the authors we present measures of the emissions of carbon dioxide at different spatial levels: nation, city, and household. Further, we take more environmental effects into account and introduce the concept of environmental efficiency by combining input-output modeling and data envelopment analysis. Finally, we discuss the policy relevance of the different measures. The article demonstrates that input-output modeling has a wide range of life-cycle oriented applications when combined with other data sources such as detailed trade statistics, foreign input-output and environmental statistics, and household expenditure data.

Interdependence in Comparative Politics: Substance, Theory, Empirics, Substance

Abstract: Interdependence is ubiquitous, and often central, across comparative politics. In comparative political economy, for example, globalization and rising capital mobility imply tax competition that suggests the fiscal policies of one country must depend crucially upon those of other countries with which it competes for capital. This paper shows this theoretically and, more generally, how any situation involving externalities from one unit's actions on others' implies interdependence. Positive/negative externalities induce negative/positive interdependence, which spurs competitive-races/free-riding, with corresponding early/late-mover advantages, and so strategic rush-to-act/delay-and-inaction. We show next how to model such interdependent processes empirically, that not doing so risks severe omitted-variable biases that erroneously favor domestic and exogenous-external accounts over interdependence but that doing so naively risks simultaneity biases with the opposite substantive implications. Then we discuss how to estimate properly specified interdependence models with spatial lags by maximum likelihood and, finally, how to interpret and present the resulting estimated spatio-temporally dynamic effects, response paths, and long-run steady-states, with their associated standard errors. We illustrate all this by replicating a noteworthy earlier, non-spatial, study of capital-tax competition. Web appendices contain further technical details, literature survey, data, statistical-software code, and spreadsheet templates for conducting all estimation and calculation procedures.

The Political Economy of Public Administration

Abstract: This literature survey distinguishes between public administration and economics, identifies some issues common to both fields and some reasons why public administration is not economics. Finally, it briefly surveys the contributions and limits of three bodies of economic literature that have in recent years profoundly influenced the study of public administration in America: public choice, modern corporate finance - and the contemporary macroeconomics it has inspired, and the new economics of organization.

Oleanolic acid and related derivatives as medicinally important compounds.

Abstract: Oleanolic acid has been isolated from chloroform extract of Olea ferruginea Royle after removal of organic bases and free acids. The literature survey revealed it to be biologically very important. In this review the biological significance of oleanolic acid and its derivatives has been discussed. The aim of this review is to update current knowledge on oleanolic acid and its natural and semisynthetic analogs, focussing on its cytotoxic, antitumer, antioxidant, anti-inflamatory, anti-HIV, acetyl cholinesterase, alpha-glucosidase, antimicrobial, hepatoprotective, anti-inflammatory, antipruritic, spasmolytic activity, anti-angiogenic, antiallergic, antiviral and immunomodulatory activities. We present in this review, for the first time, a compilation of the most relevant scientific papers and technical reports of the chemical, pre-clinical and clinical research on the properties of oleanolic acid and its derivatives.

The ecological significance of fructan in a contemporary flora

Abstract: Summary From an extensive literature survey and from analytical data of 130 species from the Sheffield flora, the physiological and molecular attributes, and occurrence of fructan are considered. The exceptionally high concentrations of fructan in many native species and its exclusive vacuolar location are noted. In view of the contention that fructan may function in low temperature tolerance, estimates are given of their maximum vacuolar concentration. For most species examined, this is unlikely to make a significant contribution to low temperature tolerance under the field conditions of the Sheffield flora. The association of high concentrations in the shoots of several species with high nuclear 2C DNA values is recorded. It is this correlation which may be of significance to several early-season growing species. By maintaining supplies of fructose and sucrose from vacuoles in tissue undergoing expansion at low temperatures (a feature associated with high DNA values), such species obviate the need for transport of carbohydrate over distance as in starch-storing species. By shortening supply lines at critical cold periods, fructan-rich species may have a considerable advantage over starch-storing, small-celled, transport-dependent species. However, such an advantage is not commonly exploited by the contemporary Sheffield flora. It is suggested that the ecological significance of fructan may best be seen in floras of the past or in contemporary floras undergoing more severe environmental stresses.

Orthopedic treatment outcomes in Class III malocclusion. A systematic review.

Abstract: Objective: To assess the scientific evidence on the effectiveness of early orthopedic treatment in Class III subjects. Materials and Methods: A literature survey was performed by applying the Medline database (Entrez PubMed). The survey covered the period from January 1966 to December 2005 and used the Medical Subject Headings (MeSH). The following study types that reported data on the effects of Class III treatment with orthopedic appliances (facial mask, chincup, FR-3) on intermaxillary sagittal and vertical relationships were included: randomized clinical trials (RCTs), and prospective and retrospective longitudinal controlled clinical trials (CCTs) with untreated Class III controls. Results: The search strategy resulted in 536 articles. After selection according to criteria for inclusion and exclusion, 19 articles qualified for the final review analysis. One RCT and 18 CCTs were retrieved. Conclusion: The quality standard of the retrieved investigations ranged from low (four studies) to mediu...

Secure neighborhood discovery: a fundamental element for mobile ad hoc networking

Abstract: Pervasive computing systems will likely be deployed in the near future, with the proliferation of wireless devices and the emergence of ad hoc networking as key enablers. Coping with mobility and the volatility of wireless communications in such systems is critical. Neighborhood discovery (ND) - the discovery of devices directly reachable for communication or in physical proximity - becomes a fundamental requirement and building block for various applications. However, the very nature of wireless mobile networks makes it easy to abuse ND and thereby compromise the overlying protocols and applications. Thus, providing methods to mitigate this vulnerability and secure ND is crucial. In this article we focus on this problem and provide definitions of neighborhood types and ND protocol properties, as well as a broad classification of attacks. Our ND literature survey reveals that securing ND is indeed a difficult and largely open problem. Moreover, given the severity of the problem, we advocate the need to formally model neighborhoods and analyze ND schemes.