Simulation of ‘stationary’ SAP and SEP phenomena by 2-dimensional potential field modelling

In order to model the distribution of potentials in the hand due to antidromic SAP propagation and in the body due to afferent conduction of the median nerve volley, 2-dimensional matrices of the appropriate shape were constructed, each containing a ‘generator’ consisting of up to 3 ‘source’ and 3 ‘sink’ points. The value of the field potential at other sites was calculated using a finite difference method.It was shown that the potential gradient is virtually zero in matrix zones which are separated from the region containing the generator by a constriction in the boundary of the conductor. Points on the far side of the constriction remain virtually equipotential, at a level determined by the potential at the junction. This is naturally influened by the proximity of the generator, so that as the generator approaches the constriction a potential difference will develop between points on the far side, irrespective of their distance from the junction, and other remote parts of the matrix. In the context of human SAPs and SEPs, such factors may be of paramount importance in the generation of so-called ‘stationary’ or ‘far-field’ potentials.With additional postulates concerning the manner in which the SAP is attenuated by the termination of axons as it propagates through the hand, and the course taken by the median nerve volley between the arm and the neck, it was possible to model the majority of stationary SAP phenomena described by Kimura et al. (1984), and also the distribution and latency of the P9 SEP component following median nerve stimulation.     

‘Ins’ and ‘outs’ of triple therapy

Chronic oral anticoagulant treatment is obligatory in patients (class I) with mechanical heart valves and in patients with atrial fibrillation with CHADS2 score >1. When these patients undergo percutaneous coronary intervention with placement of a stent, there is also an indication for treatment with aspirin and clopidogrel. Unfortunately, triple therapy is known to increase the bleeding risk. For this group of patients, the bottom line is to find the ideal therapy in patients with indications for both chronic anticoagulation therapy and percutaneous intervention to prevent thromboembolic complications such as stent thrombosis without increasing the risk of bleeding. (Neth Heart J 2010;18:444-50.)     

Special Issue on‘‘Metagenomics of Marine Environments’’

<正>We are pleased to announce a special issue on‘‘Metagenomics of Marine Environments’’of the journal Genomics,ProteomicsBioinformatics(GPB),aiming to provide a platform for high-quality papers focusing on the topic and we invite submissions for this special issue(to be published in the fall of 2015).With most microbes being difficult or impossible to culture     

Structural and Narrative Reconstruction of Rural Residents’ Representations of ‘Nature’, ‘Wildlife’, and ‘Landscape’

The objective of this paper is the structural and narrative reconstruction of representations of ‘nature’, ‘wildlife’ and ‘landscape’, held by rural residents of the Dadia Forest Reserve. Data collection involved in-depth interviews. Employing a social representations’ approach, we recovered representational elements that are expected in the case of rural belief systems, such as negative dispositions towards wolves and foxes, as well as elements of an urban adherence, such as nature’s independence. Representational elements refer to visual aspects of the countryside, which seem compatible with the figurative nucleus of the rural idyll. Concerning ‘wildlife’, residents focused on vultures, which comprise the main tourist attraction of the reserve. Scientific knowledge adds to the complexity of the narrative schema, which corresponds to the representation of ‘wildlife’. Interviewees perceived the rural landscape as an interface between the natural and the human-conditioned environment. Our study shows that interviewees make no reference to environmental conservation or quality of life issues, as it could be expected according to relatively wide definitions of the term ‘environmentalism’. Environmental messages reinforced by ecotourism development seem to be recalled primarily in terms of their compatibility with the perceived economic benefit of local people. Despite ecotourism development, representational elements that diverge from a tourist version of ‘nature’, ‘wildlife’ and ‘landscape’ were not pronounced within rural belief-systems. Further interventions within the study area are needed, in order to address a variety of topics under the environmental conservation discourse and raise the environmental awareness of rural residents.     

Simulation of Association Curves and ‘Scatchard’ Plots of Binding Reactions where Ligand and Receptor are Degraded or Internalized

Abstract

Frequently during the course of binding to a receptor, ligand is degraded. In some preparations receptor is degraded. And with isolated cell preparations, ligand and/or receptor are internalized. Here we present a mathematical model for the combined binding and other reactions which gives useful information about the behaviour of such systems. The set of differential equations is solved numerically to simulate association curves and the resulting values of bound and free ligand are used to construct Scatchard plots. Where non-ideal conditions exist, the Scatchard plots are generally curvilinear. Dependence of this curvilinearity on time of measurement of free and bound ligand, on degradation and internalization of ligand and on degradation and internalization of receptor is shown. Equilibrium constants derived from the Scatchard plots are generally incorrect but the derived receptor concentration is often correct. The simulations lead to possibilities for distinction among the several side reactions in ligand-receptor binding systems.     

Simulation of Association Curves and ‘Scatchard’ Plots of Binding Reactions Where Ligand and Receptor are Degraded or Internalized

Abstract

Frequently during the course of binding to a receptor, ligand is degraded. In some preparations receptor is degraded. And with isolated cell preparations, ligand and/or receptor may be internalized. Here we present a mathematical model in which the binding and other reactions are combined. The resulting set of differential equations is solved numerically to simulate association curves and the resulting values of bound and free ligand are used to construct Scatchard plots. Where non-ideal conditions exist, the Scatchard plots are generally curvilinear. Dependence of this curvilinearity - on time of measurement of free and bound ligand, on degradation and internalization of ligand, and on degradation and internalization of receptor - is shown. Equilibrium constants derived from the Scatchard plots are generally incorrect but the derived receptor concentration is often correct. The simulations suggest experimental possibilities for distinction among the several side reactions in ligand-receptor binding systems.     

Making sense of ‘mixture’: states and the classification of ‘mixed’ people

Caribbean diaspora intellectuals have contributed significantly to African-American political struggles over the years, despite arguments by some African-American intellectuals about what they discern as West Indian negativism, extremism, and divisiveness in American political life. This essay examines the legacy of a representative sample of diasporic Caribbean intellectuals since the time of the Harlem Renaissance in the 1920s and culminating in the 1970s, notably, Garvey, members of the African Blood Brotherhood [ABB], C.L.R. James, and Walter Rodney, to demonstrate the phenomenal ideological vision, organizational capability, and political activism they have brought into fostering solidarity with African Americans in the struggle for fundamental change. The focus here is on their respective contributions to the debate on the relationship between class and race in America and the black diaspora generally, which has helped to shape the form, and orient the direction of African-American and Caribbean diasporic struggles for the better part of the twentieth century.     

Kinetics of degradation of ‘short-’ and ‘long-lived’ proteins in cultured mammalian cells

Two distinct classes of protein referred to as short- and long-lived (Poole and Wibo, 1973) were found in pulse-chased HeLa S-3 and BHK 21/C13 cells. From experiments with pulse times ranging from 1 min to 20 h, a clear inverse correlation emerged between the pulse length and the percentage of protein which was hydrolysed intracellularly in the first h of chase. Using a 5 min pulse labelling with ³H-leucine, cells were either harvested immediately or after a 2 h chase. Approximately 35% of the label incorporated by cells was lost in a 2h chase; however, electrophoretic separation of cytosol and residual cytoplasmic fractions revealed no significant alteration in their protein profiles. The technique of selectively labelling ‘short’ and ‘long-lived’ proteins, which implies qualitative differences between them, is more readily interpreted as an artificial polarisation of a declining statistical probability curve of proteolysis with time which is similar for all nascent proteins.     

The ‘curse’ of Westermarck 1

This article consists of a critical application of recent theory of nationalism to the unusual case of Mauritius. It is a poly‐ethnic and poly‐religious society whose inhabitants neither share a mythical distant past nor consider themselves culturally identical, but where nation‐building has nevertheless been moderately successful since the late 1960s. Through an examination of the processes of institutional and cultural nation‐building in the island, it is argued that the current Eurocentric view of the nation (notably as a culturally homogeneous imagined community) must be modified to fit cases like this one. Thus, the value of nationalism and nationhood as comparative concepts is questioned.     

Automated analysis of neuromuscular ‘jitter’

This paper describes an interactive program for real time analysis of the neuromuscular jitter. Two implementations, using different hardware for data acquisition, reflect the modular design and flexibility of the software. Details on the time windows are given as well as the available commands. The program features: (1) immediate feedback of acquired data; (2) optional manual editing of data; (3) simple, yet flexible commands; (4) several plot options of raw or analysed data; (5) database interface.     

The spectre of ‘spurious’ correlations

Summary Ecologists often standardize data through the use of ratios and indices. Such measures are employed generally to remove a size effect induced by some relatively uniteresting variable. The implications of using the resultant data in correlation and regression analyses are poorly recognized. We show that ratios and indices often provide surprising and spurious results due to their unusual properties. As a solution, we advocate the use of randomization tests to evaluate hypotheses confounded by spurious correlations. In addition, we emphasize that identifying the appropriate null correlation is of utmost importance when statistically evaluating ratios, although this issue is frequently ignored.     

Poetic transformations of yolmo ‘sadness’

One way in which Yolmo Sherpa of Helambu, Nepal, come to terms with loss is to sing of it. The paper seeks to show how one Yolmo song of sadness works to express, evoke and assuage sentiments of funerary grief. Yet to best explore the transformative poetics of the song, we must trace its semantic links to other songs and situations, and so develop a contextual understanding of the experiential contours of Yolmo sadness, the local ethos of emotional avoidance and restraint, and the sociopolitical nature of emotional distress in the Helambu valley. The findings of this analysis lead the author to argue, in contrast with recent ethnographies which treat discourses on emotions as rhetorical strategies rather than as reflections of personal or communal experience, that we need an integrative approach which focuses on the relationship between language and experience, politics and felt emotion.     

Implementation of a ‘standard’ LIMS

This article is an extract of a presentation given at the LIMS conference in the Hague June 4, 1997 [S.M. Fransen et al., Presentation given at the conference LIMS 97, June 4 1997 in the Hague.]. It describes the project steps for the LIMS project in the Danish company Novo Nordisk, with focus on vendor evaluation, validation and implementation of a ‘Standard’ LIMS software. The main project steps are described and experiences gained are discussed.