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Rich History (rich + history)

Distribution by Scientific Domains

Medical Sciences	42%

Selected Abstracts

Construction of Exact Simultaneous Confidence Bands for a Simple Linear Regression Model

INTERNATIONAL STATISTICAL REVIEW, Issue 1 2008
Wei Liu
Summary A simultaneous confidence band provides a variety of inferences on the unknown components of a regression model. There are several recent papers using confidence bands for various inferential purposes; see for example, Sun et al. (1999), Spurrier (1999), Al-Saidy et al. (2003), Liu et al. (2004), Bhargava & Spurrier (2004), Piegorsch et al. (2005) and Liu et al. (2007). Construction of simultaneous confidence bands for a simple linear regression model has a rich history, going back to the work of Working & Hotelling (1929). The purpose of this article is to consolidate the disparate modern literature on simultaneous confidence bands in linear regression, and to provide expressions for the construction of exact 1 ,, level simultaneous confidence bands for a simple linear regression model of either one-sided or two-sided form. We center attention on the three most recognized shapes: hyperbolic, two-segment, and three-segment (which is also referred to as a trapezoidal shape and includes a constant-width band as a special case). Some of these expressions have already appeared in the statistics literature, and some are newly derived in this article. The derivations typically involve a standard bivariate t random vector and its polar coordinate transformation. Résumé Un intervalle de confiance simultanée fournit une variété d'inférences sur les composantes inconnues d'un modéle de régression. Plusieurs articles récents utilisent des intervalles de confiance dans des buts variés; voir par exemple Sun, Raz et Faraway (1999), Spurrier (1999), Al-Saidy et al. (2003), Liu, Jamshidian et Zhang (2004), Bhargava et Spurrier (2004), Piegorsch et al. (2005), Liu et al. (2007). La construction d'intervalles de confiance simultanés pour un simple modéle de régression linéaire a une histoire riche, qui remonte aux travaux de Working et hotelling (1929). L'objet de cet article est de consolider la littérature moderne disparate sur les intervalles de confiance simultanés dans la régression linéaire, de fournir des expressions pour la construction d'intervalles de confiance simultanés de niveau exact 1 ,, pour un modéle de régression linéaire simple ou pour des formes unilatérales ou bilatérales. Nous concentrons notre attention sur les trois formes les plus reconnues: hyperbolique, à deux segments et à trois segments (qui est aussi appelée forme trapézoïdale et inclut un intervalle de largeur constante comme cas spécial). Certaines de ces expressions sont déjà apparues dans la littérature statistique, d'autres sont nouvellement introduites dans cet article. Les dérivations comprennent typiquement un vecteur aléatoire standard bivarié t et sa transformation en coordonnées polaires. [source]

How you count counts: the importance of methods research in applied ecology

JOURNAL OF APPLIED ECOLOGY, Issue 5 2008
Chris S. Elphick
Summary 1Methods papers play a crucial role in advancing applied ecology. Counting organisms, in particular, has a rich history of methods development with many key advances both in field sampling and the treatment of resulting data. 2Most counts, however, have associated errors due to portions of the population of interest being unavailable for detection (e.g. target population not fully sampled; individuals present but not detectable), detection mistakes (e.g. detectable individuals missed; non-existent individuals recorded), or erroneous counts (e.g. large groups miscounted; individuals misidentified). 3Developments in field methods focus on reducing biases in the actual counts. Simultaneously, statisticians have developed many methods for improving inference by quantifying and correcting for biases retrospectively. Prominent examples of methods used to account for detection errors include distance sampling and multiple-observer methods. 4Simulations, in which population characteristics are set by the investigator, provide an efficient means of testing methods. With good estimates of sampling biases, computer simulations can be used to evaluate how much a given counting problem affects estimates of parameters such as population size and decline, thereby allowing applied ecologists to test the efficacy of sampling designs. Combined with cost estimates for each field method, such models would allow the cost-effectiveness of alternative protocols to be assessed. 5Synthesis and applications. Major advances are likely to come from research that looks for systematic patterns, across studies, in the effects of different types of bias and assumption violation on the ecological conclusions drawn. Specifically, determining how often, and under what circumstances, errors contribute to poor management and policy would greatly enhance future application of ecological knowledge. [source]

Conceptualising spirituality and religion for healthcare

JOURNAL OF CLINICAL NURSING, Issue 21 2008
Barbara Pesut
Aims., To discuss some of the challenges of conceptualising spirituality and religion for healthcare practice. Background., With the growing interest in spirituality in healthcare, has come the inevitable task of trying to conceptualise spirituality, a daunting task given the amorphous nature of spirituality, the changing understandings of spirituality among individuals and the diverse globalised society within which this task is taking place. Spirituality's relationship to religion is a particularly challenging point of debate. Design., Critical review. Conclusions., Three social and historical conditions , located in the context of Western thought , have contributed to current conceptualisations of spirituality and religion: the diminishment of the social authority of religion as a result of the Enlightenment focus on reason, the rise of a postmodern spirituality emphasising spiritual experience and current tensions over the ideological and political roles of religion in society. The trend to minimise the social influence of religion is a particular Western bias that seems to ignore the global megatrend of the resurgence of religion. Current conceptualisations are critiqued on the following grounds: that they tend to be ungrounded from a rich history of theological and philosophical thought, that a particular form of elitist spirituality is emerging and that the individualistic emphasis in recent conceptualisations of spirituality diminishes the potential for societal critique and transformation while opening the door for economic and political self interest. Relevance to clinical practice., Constructing adequate conceptualisations of spirituality and religion for clinical practice entails grounding them in the wealth of centuries of philosophical and theological thinking, ensuring that they represent the diverse society that nursing serves and anchoring them within a moral view of practice. [source]

WICKED WATER PROBLEMS: SOCIOLOGY AND LOCAL WATER ORGANIZATIONS IN ADDRESSING WATER RESOURCES POLICY,

JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 3 2000
David M. Freeman
ABSTRACT: Water policy problems are wicked, not in an ethically deplorable sense, but in the sense that they present us with especially difficult challenges of becoming more effective in our interdisciplinary collaboration, of integrating two very different types of knowledge, of working across several socio-political units of analysis simultaneously, and of better organizing water as a common property resource. Sociology, as a discipline, does not have a particularly rich history of successful interdisciplinary collaboration on water resources research and teaching, but it potentially has a most useful contribution to make by focusing on the analysis of local common property resource organizations that operate in the interface between individual resource users and State-Federal entities. These organizations (e.g., water user associations, mutual companies, irrigation districts, acequias, conservancy districts) have been the orphans of water policy discourse but their operations are critical to undertaking more effective 21st century social analysis, research work, and action programs. Sociologists who work to better comprehend the operations of, and constraints upon, these organizations build a sociology that can better collaborate with other water-related disciplines in addressing the challenges posed by the wickedness of our water problems. [source]

Regulation of Blood Flow in the Microcirculation

MICROCIRCULATION, Issue 1 2005
STEVEN S. SEGAL
ABSTRACT The regulation of blood flow has rich history of investigation and is exemplified in exercising skeletal muscle by a concerted interaction between striated muscle fibers and their microvascular supply. This review considers blood flow control in light of the regulation of capillary perfusion by and among terminal arterioles, the distribution of blood flow in arteriolar networks according to metabolic and hemodynamic feedback from active muscle fibers, and the balance between peak muscle blood flow and arterial blood pressure by sympathetic nerve activity. As metabolic demand increases, the locus of regulating oxygen delivery to muscle fibers "ascends" from terminal arterioles, through intermediate distributing arterioles, and into the proximal arterioles and feed arteries, which govern total flow into a muscle. At multiple levels, venules are positioned to provide feedback to nearby arterioles regarding the metabolic state of the tissue through the convection and production of vasodilator stimuli. Electrical signals initiated on smooth muscle and endothelial cells can travel rapidly for millimeters through cell-to-cell conduction via gap junction channels, rapidly coordinating vasodilator responses that govern the distribution and magnitude of blood flow to active muscle fibers. Sympathetic constriction of proximal arterioles and feed arteries can restrict functional hyperemia while dilation prevails in distal arterioles to promote oxygen extraction. With vasomotor tone reflecting myogenic contraction of smooth muscle cells modulated by flow-induced vasodilator production by endothelium, the initiation of functional vasodilation and its modulation by shear stress and sympathetic innervation dictate how and where blood flow is distributed in microvascular networks. A remarkable ensemble of signaling pathways underlie the integration of smooth muscle and endothelial cell function in microvascular networks. These pathways are being defined with new insight as novel approaches are applied to understanding the cellular and molecular mechanisms of blood flow control. [source]

JUDAISM AND NATURAL LAW

THE HEYTHROP JOURNAL, Issue 6 2009
JONATHAN JACOBS
The question of the relation between Judaism and natural law is important both for scholars and for reflective persons with an interest in the grounds of Jewish moral thought. There is a rich history of natural law theorizing that has had considerable influence, and there has been a revival of natural law theorizing in the contemporary period. The topic of the present discussion is of more than historical interest; it is a live question of real, current relevance. [source]

The taming of the shrew or corneal transplantation: past, present and future

ACTA OPHTHALMOLOGICA, Issue 2008
U PLEYER
Keratoplasty has definitely its paradoxes. It has been the first successful transplantation in man and is with approx. 100. 000 grafts/year easily the most frequent allograft in human medicine. At the same time it is still the least understood form of transplantation in respect to its biology. It is both, the most successfull as well as probably the most underestimated procedure regarding its risks in clinical transplantation. Indeed, the common assumtion, that corneal transplantation is a safe procedure with good prognosis may have hindered more intensive effort of research in this field. This lecture aims to highlight significant milestones in the rich history of corneal transplantation, and to pay tribute to the many inspired and dedicated individuals involved in the development of keratoplasty. There are still limitations to corneal transplantation, and corneal allograft rejection still poses the greatest challenge to the modern corneal surgeon. Therefore, particular emphasis will be paid to recent efforts and developments to overcome this challenge. [source]