Pulse transit time changes observed with different limb positions

Pulse transit time (PTT) is a non-invasive measure of arterial compliance. It can be used to assess instantaneous blood pressure (BP) changes in continual cardiovascular measurement such as during overnight respiratory sleep studies. In these studies, periodic changes in limb position can occur randomly. However, little is known about their possible effects on PTT monitored on the various limbs. The objective of this study was to evaluate PTT differences on all four limbs during two positional changes (lowering and raising of a limb). Ten healthy adults (seven male) with a mean age of 27.0 years were recruited in this study. The results showed that the limb that underwent a positional change had significant (p < 0.05) local PTT differences when compared to its nominal baseline value, whereas PTT changes in the other remaining limbs were insignificant (p > 0.05). The mean PTT value measured from a vertically-raised limb increased by 42.7 ms, while it decreased by 28.1 ms with a half-lowered limb. The PTT differences observed during positional change can be contributed to by the complex interactions between hydrostatic pressure changes, autonomic and local autoregulation experienced in these limbs. Hence the findings herein suggest that PTT is able to reflect local circulatory responses despite changes in the position of other limbs. This can be useful in prolonged clinical observations where limb movements are expected.

Postural activity of the abdominal muscles varies between regions of these muscles and between body positions

The abdominal muscles have an important role in control and movement of the lumbar spine and pelvis. Given there is new evidence of morphological and functional differences between distinct anatomical regions of the abdominal muscles, this study investigated whether there are regional differences in postural activity of these muscles and whether recruitment varies between different body positions. Eleven subjects with no history of low back pain that affected function or for which they sought treatment participated in the study. Electromyographic (EMG) activity of the upper, middle and lower regions of transversus abdominis (TrA), the middle and lower regions of obliquus internus abdominis (OI) and the middle region of obliquus externus abdominis (OE) was recorded using intramuscular electrodes. All subjects performed rapid, unilateral shoulder flexion in standing and six subjects also moved their upper limb in sitting. There were regional differences in the postural responses of TrA with limb movement. Notably, the onset of EMG of the upper region was later than that of the lower and middle regions. There were no differences in the EMG onsets of lower and middle TrA or OI. The postural responses of the abdominal muscles were also found to differ between body positions, with recruitment delayed in sitting compared to standing. This study showed that there is regional differentiation in TrA activity with challenges to postural control and that body position influences the postural responses of the abdominal muscles. These results may reflect variation in the contribution of abdominal muscle regions to stability of the trunk. (c) 2004 Elsevier B.V. All rights reserved.

GONOME: measuring correlations between GO terms and genomic positions

Background: Current methods to find significantly under- and over-represented gene ontology (GO) terms in a set of genes consider the genes as equally probable balls in a bag, as may be appropriate for transcripts in micro-array data. However, due to the varying length of genes and intergenic regions, that approach is inappropriate for deciding if any GO terms are correlated with a set of genomic positions. Results: We present an algorithm - GONOME - that can determine which GO terms are significantly associated with a set of genomic positions given a genome annotated with (at least) the starts and ends of genes. We show that certain GO terms may appear to be significantly associated with a set of randomly chosen positions in the human genome if gene lengths are not considered, and that these same terms have been reported as significantly over-represented in a number of recent papers. This apparent over-representation disappears when gene lengths are considered, as GONOME does. For example, we show that, when gene length is taken into account, the term development is not significantly enriched in genes associated with human CpG islands, in contradiction to a previous report. We further demonstrate the efficacy of GONOME by showing that occurrences of the proteosome-associated control element (PACE) upstream activating sequence in the S. cerevisiae genome associate significantly to appropriate GO terms. An extension of this approach yields a whole-genome motif discovery algorithm that allows identification of many other promoter sequences linked to different types of genes, including a large group of previously unknown motifs significantly associated with the terms 'translation' and 'translational elongation'. Conclusion: GONOME is an algorithm that correctly extracts over-represented GO terms from a set of genomic positions. By explicitly considering gene size, GONOME avoids a systematic bias toward GO terms linked to large genes. Inappropriate use of existing algorithms that do not take gene size into account has led to erroneous or suspect conclusions. Reciprocally GONOME may be used to identify new features in genomes that are significantly associated with particular categories of genes.

The role of resources in achieving target competitive positions

Competitive positioning has become an essential component of modern marketing management. For a firm to target effective positions for its products and services, it needs to decide on the market segment (where it will compete) as well as the differential advantage it will emphasise (how it will compete). Until recently, empirical research on positioning has received little attention, while substantial insight has been gained with respect to the concept of competitive positioning. Furthermore, Hooley, Moller and Broderick have highlighted the lack of empirical studies relative to theoretical ones related to positioning in general and to the relationship between positioning and the different components of each competitive positioning that a firm might choose. This study focuses on product competitive positioning in over-the-counter (OTC) pharmaceuticals in the British market. It was found that certain resources underpin specific competitive positions.

The resource underpinnings of competitive positions

Competitive positioning is central to market-focussed management, comprising the choice of target market the firm will operate in, and how it will compete in that market. Positioning decisions are complex and require the firm to find a profitable match between market requirements and firm ability to satisfy them. Equally important, however, is the longer term sustainability of any position created in the market place. Drawing on theory from the strategic management and marketing domains the authors argue that the competitive position achieved is a key marketing resource with the potential to generate sustainable competitive advantage. The paper examines alternative competitive positions, the marketing resources necessary to underpin them, and how they are defended against competitor imitation or encroachment. Some positions are found to be inherently more defensible than others.

Information systems management positions - a market perspective

Information systems (IS) managers have become key senior executives for organising the IT resources for delivering support to businesses. Understanding characteristics of IS managers’ employment positions is hence an increasingly important topic in computer personnel research. An investigation in Singapore that included a job advertisement analysis, surveys and case studies was thus conducted to investigate such aspects. This article presents the findings of the job advertisement analysis concerning what kinds of IS managers the market is seeking and what are the basic conditions for such management positions. The literature in this area asserts that job advertisements represent firms’ wishes and the nature of the conditions required of different IS personnel. The results of this analysis therefore reflect a collective market perspective about the changing IS managerial workplace. The results of the analysis benefit both firms and IS employees in formulating personnel development plans and actions, and raise issues for further research.