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Fundamental Nature (fundamental + nature)
Selected AbstractsDopamine Transporter in vitro Binding and in vivo Imaging in the BrainBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 6 2001Kim A. Bergström Recent findings indicate that dopamine reuptake is more like a highly regulated than a constitutive determinant of dopamine clearance. Positron emission tomography (PET) and single-photon emission tomography (SPET) offer unique methods to study dopamine transporter function. Results from in vivo PET and SPET studies correspond well with in vitro studies performed on post mortem human brain tissue. Considering some of the variances between in vitro and in vivo receptor binding phenomena it may be that the role of a compound to alter binding to monoamine uptake sites in vitro does not indicate its potential to affect monoamine transporters after administration in vivo. This discrepancy may be better understood taking into account recent studies indicating the possibility of a rapid regulation of transporter function and surface expression. Furthermore, the dopamine transporter is a fruitful target for CNS drug discovery. Fundamental nature of drug actions in vivo may be studied using demonstrated in vitro and in vivo imaging methods. [source] Auditor Quality and the Accuracy of Management Earnings Forecasts,CONTEMPORARY ACCOUNTING RESEARCH, Issue 4 2000PETER M. CLARKSON Abstract In this study, we appeal to insights and results from Davidson and Neu 1993 and McConomy 1998 to motivate empirical analyses designed to gain a better understanding of the relationship between auditor quality and forecast accuracy. We extend and refine Davidson and Neu's analysis of this relationship by introducing additional controls for business risk and by considering data from two distinct time periods: one in which the audit firm's responsibility respecting the earnings forecast was to provide review-level assurance, and one in which its responsibility was to provide audit-level assurance. Our sample data consist of Toronto Stock Exchange (TSE) initial public offerings (IPOs). The earnings forecast we consider is the one-year-ahead management earnings forecast included in the IPO offering prospectus. The results suggest that after the additional controls for business risk are introduced, the relationship between forecast accuracy and auditor quality for the review-level assurance period is no longer significant. The results also indicate that the shift in regimes alters the fundamental nature of the relationship. Using data from the audit-level assurance regime, we find a negative and significant relationship between forecast accuracy and auditor quality (i.e., we find Big 6 auditors to be associated with smaller absolute forecast errors than non-Big 6 auditors), and further, that the difference in the relationship between the two regimes is statistically significant. [source] A CRITICAL LOOK AT PAP ADEQUECY: ARE OUR CRITERIA SATISFACTORY?CYTOPATHOLOGY, Issue 2006D.R. Bolick Liquid based Pap (LBP) specimen adequacy is a highly documented, yet poorly understood cornerstone of our GYN cytology practice. Each day, as cytology professionals, we make adequacy assessments and seldom wonder how the criteria we use were established. Are the criteria appropriate? Are they safe? What is the scientific data that support them? Were they clinically and statistically tested or refined to achieve optimal patient care? In this presentation, we will take a fresh look at what we know about Pap specimen adequacy and challenge some of the core assumptions of our daily practice. LBP tests have a consistent, well-defined surface area for screening, facilitating the quantitative estimates of slide cellularity. This provides an unprecedented opportunity to establish reproducible adequacy standards that can be subjected to scientific scrutiny and rigorous statistical analysis. Capitalizing on this opportunity, the TBS2001 took the landmark step to define specimen adequacy quantitatively, and set the threshold for a satisfactory LBP at greater than 5,000 well visualized squamous epithelial cells. To date, few published studies have attempted to evaluate the validity or receiver operator characteristics for this threshold, define an optimal threshold for clinical utility or assess risks of detection failure in ,satisfactory' but relatively hypocellular Pap specimens. Five years of cumulative adequacy and cellularity data of prospectively collected Pap samples from the author's laboratory will be presented, which will serve as a foundation for a discussion on ,Pap failure'. A relationship between cellularity and detection of HSIL will be presented. Risk levels for Pap failure will be presented for Pap samples of different cellularities. The effect of different cellularity criterion on unsatisfactory Pap rates and Pap failure rates will be demonstrated. Results from this data set raise serious questions as to the safety of current TBS2001 adequacy guidelines and suggest that the risk of Pap failure in specimens with 5,000 to 20 000 squamous cells on the slide is significantly higher than those assumed by the current criteria. TBS2001 designated all LBP to have the same adequacy criterion. Up to this point, it has been assumed that ThinPrep, SurePath, or any other LBP would be sufficiently similar that they should have the same adequacy criteria. Data for squamous cellularity and other performance characteristics of ThinPrep and SurePath from the author's laboratory will be compared. Intriguing data involving the recently approved MonoPrep Pap Test will be reviewed. MonoPrep clinical trial data show the unexpected finding of a strong correlation between abundance of endocervical component and the detection of high-grade lesions, provoking an inquiry of a potential new role for a quantitative assessment of the transition zone component. The current science of LBP adequacy criteria is underdeveloped and does not appear to be founded on statistically valid methods. This condition calls us forward as a body of practitioners and scientists to rigorously explore, clarify and define the fundamental nature of cytology adequacy. As we forge this emerging science, we will improve diagnostic performance, guide the development of future technologies, and better serve the patients who give us their trust. Reference:, Birdsong GG: Pap smear adequacy: Is our understanding satisfactory? Diagn Cytopathol. 2001 Feb; 24(2): 79,81. [source] Monomeric and polymeric anionic gemini surfactants and mixed surfactant systems in micellar electrokinetic chromatography.ELECTROPHORESIS, Issue 2 2005Part II: Characterization of chemical selectivity using two linear solvation energy relationship models Abstract Sodium di(undecenyl) tartarate monomer (SDUT), a vesicle-forming amphiphilic compound possessing two hydrophilic carboxylate headgroups and two hydrophobic undecenyl chains, was prepared and polymerized to form a polymeric vesicle (i.e., poly-SDUT). The anionic surfactants of SDUT and poly-SDUT (carboxylate head group) and sodium dodecyl sulfate, SDS (sulfate head groups) as well as mixed surfactant systems (SDS/SDUT, SDS/poly-SDUT, and SDUT/poly-SDUT) were applied as pseudostationary phases in micellar electrokinetic chromatography (MEKC). Two linear solvation energy relationship (LSER) models, i.e., solvatochromic and solvation parameter models, were successfully applied to investigate the effect of the type and composition of pseudostationary phases on the retention mechanism and selectivity in MEKC. The solvatochromic and solvation parameter models were used to help understand the fundamental nature of the solute-pseudostationary phase interactions and to characterize the properties of the pseudostationary phases (e.g., solute size and hydrogen bond-accepting ability for all pseudostationary phases). The solute types were found to have a significant effect on the LSER system coefficients and on the predicted retention factors. Although both LSER models provide the same information, the solvation parameter model is found to provide much better results both statistically and chemically than the solvatochromic model. [source] Time domain characteristics of hoof-ground interaction at the onset of stance phaseEQUINE VETERINARY JOURNAL, Issue 7 2006J. F. BURN Summary Reasons for performing study: Little is known about the interaction of the hoof with the ground at the onset of stance phase although is it widely believed that high power collisions are involved in the aetiopathology of several conditions causing lameness. Objectives: To answer 3 questions regarding the fundamental nature of hoof-ground collision: (1) is the collision process deterministic for ground surfaces that present a consistent mechanical interface (2) do collision forces act on the hoof in a small or large range of directions and (3) Is the hoof decelerated to near-zero velocity by the initial deceleration peak following ground contact? Methods: Hoof acceleration during the onset of stance phase was recorded using biaxial accelerometry for horses trotting on a tarmac surface and on a sand surface. Characteristics of the collision process were identified both from vector plots and time series representations of hoof acceleration, velocity and displacement. Results: The response of the hoof to collision with smooth tarmac was predominantly deterministic and consistent with the response of a spring-damper system following shock excitation. The response to collision with sand was predominantly random. The deceleration peak following ground contact did not decelerate the hoof to near-zero velocity on tarmac but appeared to on sand. On both surfaces, collision forces acted on the hoof in a wide range of directions. Conclusions: The study suggests the presence of stiff, visco-elastic structures within the foot that may act as shock absorbers isolating the limb from large collision forces. Potential relevance: The study indicates objectives for future in vivo and in vitro research into the shock absorbing mechanism within the equine foot; and the effects of shoe type and track surface properties on the collision forces experienced during locomotion. Studies of this nature should help to establish a link between musculoskeletal injury, hoof function and hoof-ground interaction if, indeed, one exists. [source] The New Sovereignty in International Relations,INTERNATIONAL STUDIES REVIEW, Issue 3 2003David A. Lake The academic study of sovereignty is undergoing a mini-renaissance. Stimulated by criticisms of classical conceptions of sovereignty in systemic theories of politics, scholars returned to sovereignty as a topic of inquiry in the late 1980s and early 1990s. Their studies are finally bearing fruit. This essay focuses on the new conceptions of sovereignty that are emerging and (1) discusses the fundamental nature of sovereignty, (2) reviews the classical perspective on sovereignty, (3) surveys new constructivist alternatives to this classical view, (4) examines important new work on the problematic nature of sovereignty, (5) identifies continua of hierarchic relationships that make sense of the various forms of mixed or restricted sovereignty that we observe in world politics, and (6) argues why it is important to study alternative, hierarchic relationships in international relations. The principal themes throughout are that sovereignty is far more problematic than recognized in the classical model, that important elements of hierarchy exist in the global system, and that both our theories and practice of international politics would be improved by explicitly incorporating variations in hierarchy. [source] Is EMDR an exposure therapy?JOURNAL OF CLINICAL PSYCHOLOGY, Issue 1 2002A review of trauma protocols This article presents the well established theoretical base and clinical practice of exposure therapy for trauma. Necessary requirements for positive treatment results and contraindicated procedures are reviewed. EMDR is contrasted with these requirements and procedures. By the definitions and clinical practice of exposure therapy, the classification of EMDR poses some problems. As seen from the exposure therapy paradigm, its lack of physiological habituation and use of spontaneous association should result in negligible or negative effects rather than the well researched positive outcomes. Possible reasons for the effectiveness of EMDR are discussed, ranging from the fundamental nature of trauma reactions to the nonexposure mechanisms utilized in information processing models. © 2002 John Wiley & Sons, Inc. J Clin Psychol 58: 43,59, 2002. [source] Where Does Personality Have Its Influence?JOURNAL OF PERSONALITY, Issue 6 2008A Supermatrix of Consistency Concepts ABSTRACT An understanding of the nature of personality depends on clear conceptions of consistency. Researchers have applied the term consistency in ambiguous and inconsistent ways over the last half century, which has led to a great deal of confusion and debate over the existence of personality. This article seeks to reframe and extend conceptions of consistency and thus proposes three important ways consistency concepts differ from each other. The first way consistency concepts differ from each other is in the competing determinant of behavior that the consistency is across: time, situation content, or behavior content. The second way consistency concepts differ from each other is in the definition of behavior enactment: single enactment, aggregate enactment, contingent enactment, or patterned enactment. When these two dimensions are crossed with a third dimension,definition of similarity (absolute, relative-position, or ipsative),they create a supermatrix of 36 consistency concepts. Empirical support for each of these 36 consistency concepts, or its failure, has uniquely different implications for the fundamental nature of personality. This supermatrix can serve as a guide for future research aimed at discovering the nature of personality. [source] On the cosmological distance and redshift between any two objectsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2000J. Liske We discuss the problem of how to calculate the distance between two cosmological objects given their redshifts and angular separation on the sky. Although of a fundamental nature, this problem and its solution seem to lack a detailed description in the literature. We present a new variant of its solution and quantitatively assess the most commonly used approximation. [source] Community lifestyle of Candida in mixed biofilms: a mini reviewMYCOSES, Issue 6 2009Z. M. Thein Summary Candida is the most common human fungal pathogen that causes a variety of afflictions from superficial mucosal infections to deep mycoses. Biofilm formation is a major virulence factor of Candida, and more than 300 articles have been published on Candida biofilms over the past two decades. However, most of these data are on monospecies biofilms of Candida, and information on mixed-species Candida biofilms or bacteria,Candida combinations is still scarce. Yet, in nature, the yeast exist in a mixed milieu either in the oral cavity or in other habitats with a multitude of bacteria colonising mucosal surfaces within a shared community. This mini review describes the current knowledge on candidal,candidal or bacterial,candidal interactions in mixed-species biofilms. The underlying mechanisms of these interactions appear to depend on several factors relating to biofilm development, such as species and strains of organisms, nutritional factors, aerobiosis and related environmental factors. Although the fundamental nature of these interactions appears to be commensalism and antagonism, the emerging evidence based on novel molecular, proteomic and imaging tools indicates these biological mechanisms to be far more complex than hitherto recognised. Demystifying the mechanisms underlying the growth and development of mixed-species communities involving Candida will undoubtedly yield useful data for the effective management of microbial infections in general. [source] Probing Noncovalent Interactions in Biomolecular Crystals with Terahertz SpectroscopyCHEMPHYSCHEM, Issue 4 2008Thomas Kleine-Ostmann Dr. Unique insights: The complexities of intermolecular interactions within biomolecular crystals (see figure, solid state thymine) are studied using a combination of spectroscopic and quantum-chemical techniques. Insights into the fundamental nature of the various low-frequency peaks is achieved and intra- vs intermolecular modes are distinguished. [source] | |||||||||||||