Areas Of Ambiguity Research Articles

The dilemma of left ventricular outflow tract obstruction and sudden death in hypertrophic cardiomyopathy: do patients with gradients really deserve prophylactic defibrillators?

Hypertrophic cardiomyopathy (HCM) is the most common genetic heart disease, as well as the most frequent cause of sudden cardiac death in young people including competitive athletes.1 The devastating consequence of sudden death has, in fact, been central to our perception of the natural history of HCM for almost 50 years, as its initial contemporary description by Teare in 1958.1 Now that HCM has assumed an important place in the implantable cardioverter-defibrillator (ICD) era,2 the issue of risk stratification and sudden death prevention has become a major clinical consideration and central to the management of these patients, adding enormously to the complexity of the disease. Indeed, the ICD was initially promoted specifically for HCM in 20002, and subsequently thousands of young patients have been afforded this potentially life-saving therapy. The efficacy of the ICD in HCM, for both secondary and primary prevention, is now well established.2,3 Despite this encouraging development, a mismatch persists between the power of ICD technology to recognize and successfully abort potentially lethal ventricular tachyarrhythmias, and our ability to prospectively identify, with precision, each individual patient who may benefit from a prophylactically implanted device. Indeed, in a heterogeneous disease with a low cardiac event rate such as HCM, decisions regarding sudden death prevention are frequently encumbered by risk profiles of individual patients which fall into uncertain grey areas of ambiguity between high and low risk. At this point, six major risk factors for sudden death have been proposed in HCM, including prior cardiac arrest for which there is general agreement regarding the role of secondary prevention ICDs.1,2,4,5 The five traditional risk markers for primary prevention include: (1) sudden death due to HCM in one or more relatives; (2) massive left ventricular (LV) … ** Corresponding author. Tel: +1 612 863 3996; fax: +1 612 863 3875. E-mail address : hcm.maron{at}mhif.org

Letters to the Editor

Back to table of contents Previous article Next article Letters to the EditorFull AccessLetters to the EditorELEANOR STEIN M.D., F.R.C.P.(C.),ELEANOR STEIN M.D., F.R.C.P.(C.)Search for more papers by this author,Published Online:1 Apr 2006https://doi.org/10.1176/ajp.2006.163.4.747AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail To the Editor:I applaud Dr. Mayou et al. for questioning the validity of the diagnosis of somatoform disorders. It has never been a clinically useful classification. I question, however, the suggestion that 25%–50% of the patients seen by primary and secondary care physicians with somatic symptoms that are unexplained by a general medical condition should be classified on axis III of DSM. DSM is, after all, a psychiatric classification. Should these tens of millions of patients be assumed to have a psychiatric disorder because we cannot clearly define their complaints?The authors stated that patients fitting the descriptors “somatoform disorder,” “functional somatic syndrome,” and “medically unexplained symptoms” (used interchangeably in the article) “lie in an ambiguous area of medical thinking somewhere between medicine and psychiatry” (p. 847). This statement is unproven. It assumes the following:That patients with symptoms that are not diagnosable with current medical technology are psychologically different from those with a clear diagnosisThat patients who are not diagnosable with current paradigms should be classified with DSM (a psychiatric classification)That current paradigms are complete and unflawed and thus patients not fitting these paradigms must be in the psychosomatic gray zoneI remember my confusion during medical school psychiatry training when told that some psychoses were “functional” and some were “organic.” I could not understand how behavior, feelings, and thoughts could be so affected without some measurable change in cellular or subcellular function. Did our crude technology, unable to discern pathology, mean that it did not exist? Now that we have the tools (computerized tomography, functional magnetic resonance imaging, positron emission spectroscopy, single photon emission computed tomography, receptor binding ligands), we can measure changes in people with psychoses, and the organic/functional polarity has moved to the background. If one studies medical history, one will note that as diagnostic technology improves, fewer and fewer disorders are categorized as “psychosomatic” or “functional.” DSM has aided in this progress by defining disorders more precisely (e.g., schizophrenic versus bipolar psychosis) so that homogeneous groups can be studied. Consider a study designed to include the huge heterogeneous group encompassed by the term “medically unexplained symptoms.” What would be the chance of any clear finding? What organ would be studied? This mixing of diverse patients is a recipe to avoid finding anything clinically useful.The central hypothesis of the article by Dr. Mayou et al. that the understanding and classification of somatoform disorders should be changed is valid. But the suggested solution of classifying one-quarter to one-half of all medical attenders as having a somatoform disorder (or any of its synonyms) is faulty. I would suggest instead to narrow the rubric of “somatoform disorders” to include only the few severely dysfunctional patients in whom acknowledging feelings is too painful and whose physical symptoms can be shown to result in lieu of direct emotional expression. For the majority of patients with “somatic symptoms unexplained by a general medical condition,” we should continue to refine the medical categories that are already in use until there is solid evidence to suggest a better alternative.Calgary, Alta., Canada FiguresReferencesCited byDetailsCited byNone Volume 163Issue 4 April, 2006Pages 747-747THE AMERICAN JOURNAL OF PSYCHIATRY April 2006 Volume 163 Number 4 Metrics PDF download History Published online 1 April 2006 Published in print 1 April 2006

Aerodynamic ground effect: a case study of the integration of CFD and experiments

Ground effect aerodynamics, although a subject of much interest to automotive, aircraft and naval architecture designers, is still an area of some uncertainty due to the problematic nature of experimental (and sometimes numerical) simulation. An integrated study, making use of both experimental (Particle Imaging Velocimetry) and numerical techniques (Computational Fluid Dynamics finite volume solver), is used to demonstrate the effect and importance of the common assumptions and simulation issues. For certain important ground effect situations, it becomes clear that a numerical simulation is the only feasible option; however, a careful and systematic study of similar experiments is vital to gain the confidence required in the numerical solution. Only when this confidence has been gained, can the numerical simulation confidently be used for prediction of the experimentally unfeasible, but important, situation. Three ambiguous areas of ground effect aerodynamics are identified, and a combination of numerical and experimental results presented.

Molecular and morphological supertree of stony corals (Anthozoa: Scleractinia) using matrix representation parsimony

The supertree algorithm matrix representation with parsimony was used to combine existing hypotheses of coral relationships and provide the most comprehensive species-level estimate of scleractinian phylogeny, comprised of 353 species (27% of extant species), 141 genera (63%) and 23 families (92%) from all seven suborders. The resulting supertree offers a guide for future studies in coral systematics by highlighting regions of concordance and conflict in existing source phylogenies. It should also prove useful in formal comparative studies of character evolution. Phylogenetic effort within Scleractinia has been taxonomically uneven, with a third of studies focussing on the Acroporidae or its most diverse genera. Sampling has also been geographically non-uniform, as tropical, reef-forming taxa have been considered twice as often as non-reef species. The supertree indicated that source trees concur on numerous aspects of coral relationships, such as the division between robust versus complex corals and the distant relationship between families in Archaeocoeniina. The supertree also supported the existence of a large, taxonomically diverse and monophyletic group of corals with many Atlantic representatives having exsert corallites. Another large, unanticipated clade consisted entirely of solitary deep-water species from three families. Important areas of ambiguity include the relationship of Astrocoeniidae to Pocilloporidae and the relative positions of several, mostly deep-water genera of Caryophylliidae. Conservative grafting of species at the base of congeneric groups with uncontroversial monophyletic status resulted in a more comprehensive, though less resolved tree of 1016 taxa.

Management Mistakes in Healthcare: Identification, Correction and Prevention

Management Mistakes in Healthcare: Identification, Correction and Prevention

Stranger in a strange land: twenty years of living and writing in Catalonia

This article is a subjective account of the various problems involved in moving to a nationally ambiguous area such as Catalonia; and a discussion of the function of autobiographical writing for authors living abroad.

Research, audit, practice development and service evaluation: implications for research and clinical governance

AbstractThe importance of ensuring a high level of scientific and ethical standards in health and social care research underpins the Department of Health's framework for research governance (DOH, 2001). This paper presents our current thinking regarding some areas of ambiguity. The explanations offered are open to challenge and we see the paper as a contribution to the debates surrounding these different activities rather than providing a template for making decisions about what constitutes research, audit, practice development and service evaluation. However, we also hope that the paper will provide some practical guidance in undertaking these activities. Copyright © 2005 Whurr Publishers Ltd.

Understanding Why Carers' Assessments Do Not Always Take Place

Recent pronouncements from both government and carers' organisations have expressed disappointment at the low numbers of carers' assessments being undertaken by social care practitioners. The reasons offered for this are varied. They commonly tend to emphasise issues of bureaucratic incompetence, for example the failure by Social Services Departments to provide information to carers about their rights, or else highlighting practitioner attitudes that are out of step with current thinking, for example wanting to retain decision-making power and not involving carers. Scarcity of resources is a theme that permeates most explanations. While these explanations certainly have some validity, this paper argues that for many practitioners, the very nature of the relationship with carers is a problematic one, containing several interrelated areas of confusion, ambiguity and tension that often go unacknowledged—particularly by policy makers, politicians and senior managers whose ideas about carers are often based on idealisations of what a carer is. Carers have become reified. This paper discusses some of the major concerns and argues that the tensions, ambiguities and confusion experienced help explain the less than full engagement by some practitioners with the carers' agenda as promoted by carers' organisations and government policy.

A Theoretical Model of Musical Memorization.

The purpose of this article is to describe a model of how music is memorized for performances. The process of memorization appears to comprise three stages: preview, practice, and over-learning. Previous experience and enculturation also are very important in informing the memorization process. Hach stage is subdivided. The preview stage is divided into notational overview, aural overview, and performance overview. The practice stage is divided into notational practice and conscious memorization. The over-learning stage is divided into re-learning, automatization, and maintenance rehearsal. For the purposes of this model, the four most commonly discussed memorization strategies (aural, visual, kinesthetic, and analytical) are divided and grouped into sensory learning styles (consisting of aural, visual, and kinesthetic memories), and an analytical learning style (discussed separately). Four processing strategies also are discussed: holistic, serial, additive, and segmented. The amount of time and effort expended during each stage is a matter of individual preferences, performance goals, task difficulty, training, and ability. Furthermore, the stages and the subdivisions are flexible and not necessarily sequential, nor indeed compulsory, for all performers. A picture of how music is memorized for performance is emerging from 100 years of research and introspection. For more than a century (one of the earliest discussions of musical memory is Shinn, 1898), performers have attempted to understand the process of memorization by attempting to understand themselves, that is, investigating memorization by reflecting on their own individual practice. Pedagogues not only have sought to understand, but also to describe the process and identify successful memorization strategics for use by their students. Early researchers (e.g., Rubin-Rabson, 1937, 1939, 194Oa, 194Ob, 194 Ia, 194 Ib, 194 Ic, 1941d,& 1947) primarily were concerned with finding the most effective memorization strategies, though later researchers (e.g., Chaffin IGruson, 1988;Hallam, 1997;Miklaszewski, 1989& 1995) generally adopted a descriptive, rather than experimental approach, using interview and case study data to understand the memorization process. Despite the long history, investigations into musical memory have been sporadic and unsystematic. Though sharing common experiences, musicians lack common terminology with which to discuss the process of memorization and experimental researchers have been unable to shed light on the process. The process remains a mystery to many, thus leading to ineffective or inefficient memorization strategies, superstitious behavior, and additional performance anxiety. The purpose of this article is to clarify the process of memorization by synthesizing knowledge scattered throughout the literature. Relevant information will be organized into a working model, which also will serve to highlight areas of ignorance or ambiguity for future researchers to explore. The mode] is preliminary in that it is expected to change and grow as researchers continue to clarify the complex process of musical memorization. Memorization Model Overview The process of memorization appears to comprise three stages: preview, practice, and over-learning (see Figure 1). These stages appear consistent with those proposed by Wicinski ( 1950, in Miklaszewski, 1989): getting to know the music, hard work on technical problems, and fusion of ideas and technical skills. Imreh and Chaffin's model includes more detail, especially concerning the transitional stages of scouting it out section by section, gray stage,putting it together, polishing, and maintenance (Chaffin, Imreh, & Crawford, 2002.) The current model also includes a preliminary stage of enculturation and experience that might affect the memorization of music. Each stage is subdivided: The preview stage is divided into notational overview, aural overview, and performance overview; the practice stage is divided into notational practice and conscious memorization; and the overlearning stage is divided into re-learning, automatization and maintenance rehearsal. …

Outcome Management of Intellectual Assets

47 Intellectual assets have become new business assets for the corporate management. Created through intellectual activities, they are separated from the asset holders (inventors, authors) and organizations (companies, departmental sections), after which they are utilized under a given rule to realize their potential values. The traditional bisection algorithm of physical and financial assets is rapidly losing ground to this revolutionary movement. The current diversified source for corporate growth and the ambiguity of the scope of core businesses have contributed to the raised expectations towards this new asset. Intellectual assets will fulfill their role as business assets if they produce mid — and long — term outcomes, promote corporate activities, and stabilize the company’s territorial reign. In this paper, I shall propose the theoretical models of intellectual assets from the viewpoint of outcome management, bearing their properties in mind. To begin with, I would like to answer the question of what an intellectual asset is. If one wishes to categorize this asset he/she may start by defining it from the core reaching out to the more ambiguous outer areas.

Learning Styles: An overview of theories, models, and measures

Although its origins have been traced back much further, research in the area of learning style has been active for—at a conservative estimate—around four decades. During that period the intensity of activity has varied, with recent years seeing a particularly marked upturn in the number of researchers working in the area. Also of note is the variety of disciplines from which the research is emerging. Increasingly, research in the area of learning style is being conducted in domains outside psychology—the discipline from which many of the central concepts and theories originate. These domains include medical and health care training, management, industry, vocational training and a vast range of settings and levels in the field of education. It is of little wonder that applications of these concepts are so wide ranging given the centrality of learning—and how best to do it—to almost every aspect of life. As a consequence of the quantity of research, the diversity of the disciplines and domains in which the research is conducted, and the varied aims of the research, the topic has become fragmented and disparate. This is almost certainly how it must appear to practitioners and researchers new to the area, with its complexities and convolutions difficult to comprehend and assimilate. As such, it is perhaps timely to present an account of the central themes and issues surrounding learning style and to consider the instruments available for the measurement of style. This paper aims to provide such an account, attempting to clarify common areas of ambiguity and in particular issues surrounding measurement and appropriate instruments. It aims to bring together necessary components of the area in such a way as to allow for a broader appreciation of learning style and to inform regarding possible tools for measurement. It is anticipated that such an account will promote research in the field by presenting it as more accessible and by developing a greater appreciation for the area across disciplines and in researchers and practitioners new to the area.

Expression of p16INK4A in Pap Smears Containing Atypical Glandular Cells from the Uterine Cervix

To verify one of the diagnostic dilemmas concerning atypical glandular cells (AGC) by immunocytochemical detection of p16INK4A (p16) applied to routine Pap smears with correlation of follow-up biopsies for improvement of cytologic diagnoses. The study included 36 Pap smears in AGC diagnostic categories, all of which were correlated histologically. The cytologic diagnoses of AGC were further classified according to the 2001 Bethesda System. All Pap smears were decolorized and immunostained with the primary anti-p16 antibody, clone E6H4. Immunoreactivity for p16 was correlated with histologic sections in a semiblind fashion. Of the 36 smears containing AGC, 22 (61%) were reclassified as general AGC and 14 (39%) as AGC--favor neoplasia. Follow-up biopsies revealed that 15 (42%) cervixes had no obvious abnormalities and that 21 (58%) cases had different cervical lesions. More than half the cases (19/36, 53%) of follow-up biopsies concerning AGC-containing smears represented significant lesions. There was a much higher proportion of significant lesions (13/14, 93%) in AGC--favor neoplasia than those (6/22, 27%) in general AGC cases. Fifteen of 36 (36%) AGC-containing cases were actually squamous abnormalities on follow-up biopsies. p16 Immunocytochemical stain was reactive in 22 (61%) of 36 smears, either weakly/sporadically (2 cases, 6%) or strongly positively (20 cases, 55%). Conversely, 14 (39%) of the smears were negative for p16 and displayed predominantly reactive changes. However, there was 1 case of high grade squamous intraepithelial lesion showing negative immunostaining for p16. From the view-point of clinical significance, this analysis was highly sensitive (sensitivity, 95%) and specific (specificity, 88%) and had favorable positive (90%) and negative (94%) predictive values. On the basis of both morphologic and immunostaining patterns, there was a clear association between strong p16 immunostaining of atypical cells in smears and the presence of significant lesions in the cervix except in 1 patient. Similarly, there was a clear association between lack of p16 expression and absence of cervical lesions. p16 Immunocytochemical stain can be applied successfully to conventional Pap smears and may serve as a useful biomarker in diagnoses of AGC-containing smears. This may offer a more objective parameter to help clarify this ambiguous area of gynecologic cytopathology.

Diaspora in the Reading of Jewish History, Identity, and Difference

In recent years, classical historians have sought to explore the interplay of a wide variety of peoples and civilizations in the ancient Mediterranean. This method seeks not to erase the power exercised both culturally and politically by the Greeks and Romans but to shed greater light on the areas of contradiction and ambiguity that accompanied their hegemonic expressions; that is, to examine more closely not only attempts at domination but also the shifting strategies and consequences produced at the site of contact among Greeks, Romans, and others. While such paradigmatic shifts have resulted in numerous regional studies of the ancient Mediterranean, the case of the ancient Jews, who cannot be accounted for within any single region, has invited perhaps more heated debate than any other. For an evaluation of the lives of the majority of Jews in antiquity necessitates coming to terms with the complex and lengthy experience of diaspora. The stakes attached to such historical investigations are considerable. Given that, for many Jews, the diaspora begun in antiquity was concluded only with the foundation of the state of Israel in 1948, studies of the ancient diaspora are poised to interrogate some of the very foundations of modern Jewish identity, as well as contemporary claims of Jewish territorial rights and nationhood.

The Interaction between Primary Teachers' Perceptions of ICT and Their Pedagogy

The paper presents a study which focuses on the interaction between primary teachers' perceptions of Information and Communication Technology (ICT) and their pedagogy. Their perceptions of ICT are explored in terms of their reported understandings of the nature and purpose of ICT in primary schools. A qualitative, case study approach was used to investigate the perceptions and pedagogy of a small group of teachers working within one school, Carberry Junior School in England. The study was carried out during an eighteen month period of significant change in primary schools responding to the UK Government's National Grid for Learning initiative and its impact on models of access to ICT resources and expectations in teaching and pupil achievement. The paper highlights the teachers' perceptions of ICT as a social and cultural phenomenon, as an ambiguous area constructed as a discrete subject, curriculum resource and higher-order capability, and as a ‘new’ field in primary schools.

Expression of p16 INK4A in Papanicolaou smears containing atypical squamous cells of undetermined significance from the uterine cervix

Objective This study aimed to verify one of the major diagnostic dilemmas in routine Papanicolaou (Pap) smears. Atypical squamous cells of undetermined significance (ASCUS) were tested immunocytochemically for p16 INK4A (p16), and results were correlated with follow-up biopsies for more accurate diagnoses. Methods The study included 66 Pap smears of ASCUS diagnostic categories, all of which were correlated histologically. The cytological diagnoses of ASCUS were further classified cytologically according to the 2001 Bethesda System, as “atypical squamous cells of undetermined significance (ASC-US)” or “atypical squamous cells which cannot exclude HSIL (ASC-H).” All Pap smears were decolorized and immunostained with the primary anti-p16 antibody, clone E6H4. Immunoreactivity for p16 was correlated with histological sections (which were also immunostained for comparison) in a semiblind fashion. Results Of the 66 smears containing ASCUS, 47 (71%) were reclassified as ASC-US and 19 (29%) as ASC-H. Follow-up biopsies revealed that 21 (32%) cervices had no obvious abnormalities but only reactive changes. A significant proportion of histological diagnoses were CIN1/LSIL (24 cases, 36%), CIN2 or 3/HSIL (17 cases, 26%), squamous cell carcinoma (two cases, 3%), or AIS/adenocarcinoma (two cases, 3%). The p16 immunocytochemical stain was reactive in 40 (60.6%) of 66 smears: either weakly/sporadically (18 cases, 45%) or strongly positive (22 cases, 55%). Conversely, 26 (39.4%) of the smears were negative for p16 and displayed predominantly reactive changes. However, five cases of LSIL and one of HSIL were negative for p16. From the results of p16 immunoreactivity of atypical cells for detection of biopsy-proved significant lesions (HSIL or higher), this analysis was highly sensitive (sensitivity, 95%) and specific (specificity, 96%) and had favorable positive (91%) and negative (98%) predictive values. Conclusion On the basis of both morphological and immunostaining patterns, there is a clear association between strong p16 immunostaining of atypical cells in the smears and the presence of significant lesions in the cervix, except in two patients. Similarly, there is a clear association between the lack of p16 expression and the absence of cervical lesions. The p16 immunocytochemical stain can be applied successfully to conventional Pap smears and may serve as a useful biomarker in ASCUS-containing smear diagnoses. This may offer a more objective parameter to help clarify this ambiguous area in gynecological cytopathology.

What we don't understand about teaching for understanding: Questions from science education

Like any other complex agenda of reform, the notion of teaching for understanding contains areas of uncertainty and ambiguity. This paper uses an hermeneutic research cycle to identify some uncertainties in understanding of teaching for understanding. These areas of uncertainty are discussed in relation to the literature and vignettes from three interpretive case studies of science teaching. Three questions are considered: Is teaching for understanding a method or an outcome of teaching? Does specialist language interfere with understanding, or construct it? What kind of understanding does teaching with analogies promote? It concludes with a discussion of four issues: the difficulties faced by teachers in teaching for understanding, the wider context of school science, the nature of teacher change, and the need for elaborated examples of successful teaching for understanding.

The involvement of service users in the assessment of Diploma in Social Work students on practice placements

The government, local authorities and academic institutions in the United Kingdom all positively support the involvement of service users in social work practice and education. Based upon research undertaken for a Master's dissertation, this article argues for such an inclusive approach. The author works for the Training and Development Services of an English Social and Caring Services department, which delivers a Diploma in Social Work course in collaboration with the local university college. This course began to incorporate service users' views in the assessment of students on practice placements in the mid-1990s. This was a helpful development, although areas of ambiguity and difficulty became apparent, as did a lack of clarity and consistency in the implementation of the process. A qualitative survey of the views of practice teachers was conducted by means of semi-structured interviews, which focussed on the main principles, issues and practical implications of service user involvement in the assessment of DipSW students. The article offers a summary of the findings of the survey, and a critical discussion of the main issues and difficulties that emerged. Some recommendations are made for the course that the author is associated with, although they would probably apply to most DipSW courses in the United Kingdom. The author is male, white and British.

Current Management of Scaphoid Fractures: Twenty Questions Answered

In an article a decade ago, Nicholas Barton posed twenty key questions about the management of scaphoid fractures. Here, experts from Europe, America, Australia and Japan respond to the questions, rephrased by Izge Gunal and Ismail Calli. The text resembles a panel discussion, with Barton the moderator and Gunal and Calli the scribes. The question—discussion—comment format covers diagnosis, imaging, treatment and complications. Each section is well illustrated with diagrams and images. Barton tries to emphasize the points of agreement and to explain the not infrequent disagreement between contributors. The division by questions means that readers can readily focus on aspects that relate most to their practice. However, anyone seeking prescriptive answers will be disappointed: the information on diagnostic and treatment options is presented in a mixture of research outcomes and anecdote. The book is certainly useful in revealing areas of ambiguity that could be clarified by further research; there are, of course, many more than twenty questions to be answered. The style and format will have its fans, but some readers might prefer less emphasis on personal views and a more scientific write-up.

Mechanism of gravi-sensing and -transduction in gravitropism of higher plants

In higher plants, some organs such as roots, hypocotyls, and stems, can sense the direction of gravity to regulate their orientation. Gravitropic response is composed of four steps; 1. gravity sensing and conversion of physical stimuli to biochemical signals, 2. intracellular signal transduction in gravity sensing cells, 3. signal transmitting to responding tissues, 4. differential growth of organs. Here we focus on the former two steps. Recent studies using modern technique have gradually unveiled early events and mechanism of gravitropic response. Genetic approach provided evidences that strongly support the classical theory for gravity sensing (step 1). Computational analysis suggested the existence of another gravity sensing mechanism in roots. Spatial and temporal ion imaging in living organs in real time provided information on step 2. In addition, reverse genetic approach suggested asymmetrical intracellular distribution of auxin transporter [correction of transpoter] is a possible link between step 2 and 3. However, molecular basis of the signaling mechanism remains unknown. We believe extensive molecular genetic approach combined with recent techniques cited here shed the light to this ambiguous area of research.

Two Centuries of Central Water Management in the Netherlands

For two centuries the Rijkswaterstaat has been responsible for public works in the Netherlands. Founded in 1798, this national government agency, which now numbers twelve thousand employees, has left its mark on the country. The river landscape has been completely re-created. Deep-sea inlets and large inland saltwater lakes such as the Zuider Zee have been cut off from the sea, reducing the country's coastline by about 2,800 kilometers (from 3,400 to 650). More than 350,000 hectares of land have been reclaimed. The Rijkswaterstaat has also been involved in infrastructure development. At present there are in the Netherlands 3,000 kilometers of railway lines, around 4,000 kilometers of navigable waterways, 18,000 kilo meters of cycle paths, and more than 100,000 kilometers of asphalt roads. Numerous structural works, as they are known in civil engineering parl ance, dominate the Dutch landscape: weirs, locks, storm surge barriers, bridges, viaducts, cloverleafs, tunnels, overpasses, and the like. Such struc tures have taken the place of other features?church spires, windmills, pol lard willows, poplars?that once dotted the horizon. The Rijkswaterstaat cannot claim full credit or responsibility for all these structures. Many other actors influence public works and infrastruc ture. Water boards, for instance, are responsible for local water control and for maintaining water quality. The Rijkswaterstaat operates in a complex environment. It has to deal with the various administrative bodies (the state, provinces, municipalities, and water boards) responsible for similar types of public works and infrastructure. It inhabits an ambiguous area between government and private enterprise, since many tasks can be car ried out by private companies. Furthermore, the agency sees itself as a civil service organization confronted by numerous political parties and social