Effect of carbohydrate supplementation on walking performance in peripheral arterial disease: A preliminary physiologic study

Objective: In this preliminary study we tested the effect of short-term carbohydrate supplementation on carbohydrate oxidation and walking performance in peripheral arterial disease. Methods: Eleven patients with peripheral arterial disease and intermittent claudication and 8 healthy control subjects completed several weeks of baseline exercise testing, then were given supplementation for 3 days with a carbohydrate solution and placebo. Maximal walking time was assessed with a graded treadmill test. Carbohydrate oxidation during a submaximal phase of this test was measured with indirect calorimetry. At the end of baseline testing a biopsy specimen was taken from the gastrocnemius muscle, and the active fraction of pyruvate dehydrogenase complex activity was determined. Results: Carbohydrate supplementation resulted in a significant increase in body weight and carbohydrate oxidation during exercise in patients with intermittent claudication and control subjects. Maximal walking time decreased by 3% in control subjects, whereas it increased by 6% in patients with intermittent claudication (group X treatment interaction, P < .05). There was a wide range of performance responses to carbohydrate supplementation among patients with claudication (-3%-37%). This effect was greater in poorer performers, and was negatively correlated (P < .05) with muscle pyruvate dehydrogenase complex activity. Conclusion: Preliminary data suggest that carbohydrate oxidation during exercise might contribute to exercise intolerance in more dysfunctional patients with intermittent claudication and that carbohydrate supplementation might be an effective therapeutic intervention in these patients.

The development of hard real-time systems using a formal approach

Hard real-time systems are a class of computer control systems that must react to demands of their environment by providing `correct' and timely responses. Since these systems are increasingly being used in systems with safety implications, it is crucial that they are designed and developed to operate in a correct manner. This thesis is concerned with developing formal techniques that allow the specification, verification and design of hard real-time systems. Formal techniques for hard real-time systems must be capable of capturing the system's functional and performance requirements, and previous work has proposed a number of techniques which range from the mathematically intensive to those with some mathematical content. This thesis develops formal techniques that contain both an informal and a formal component because it is considered that the informality provides ease of understanding and the formality allows precise specification and verification. Specifically, the combination of Petri nets and temporal logic is considered for the specification and verification of hard real-time systems. Approaches that combine Petri nets and temporal logic by allowing a consistent translation between each formalism are examined. Previously, such techniques have been applied to the formal analysis of concurrent systems. This thesis adapts these techniques for use in the modelling, design and formal analysis of hard real-time systems. The techniques are applied to the problem of specifying a controller for a high-speed manufacturing system. It is shown that they can be used to prove liveness and safety properties, including qualitative aspects of system performance. The problem of verifying quantitative real-time properties is addressed by developing a further technique which combines the formalisms of timed Petri nets and real-time temporal logic. A unifying feature of these techniques is the common temporal description of the Petri net. A common problem with Petri net based techniques is the complexity problems associated with generating the reachability graph. This thesis addresses this problem by using concurrency sets to generate a partial reachability graph pertaining to a particular state. These sets also allows each state to be checked for the presence of inconsistencies and hazards. The problem of designing a controller for the high-speed manufacturing system is also considered. The approach adopted mvolves the use of a model-based controller: This type of controller uses the Petri net models developed, thus preservIng the properties already proven of the controller. It. also contains a model of the physical system which is synchronised to the real application to provide timely responses. The various way of forming the synchronization between these processes is considered and the resulting nets are analysed using concurrency sets.

The effect of nutritional supplementation on visual function

The aim of this research was to determine the effect of a lutein-based nutritional supplemented on measures of visual function in normal and ARMD-affected eyes. Thirty participants were recruited to the ARMD cohort (aged between 55 and 82 years, mean ± SD: 69.2 ± 7.8) and 46 were recruited into the normal cohort (aged between 22 and 73 years, mean ± SD: 50.0 ± 15.9). Outcome measures were distance (DVA) and near (NVA) visual acuity, contrast sensitivity (CS), photostress recovery time measured with the Eger Macular Stressometer (EMS), central visual function assessed with the Macular Mapping test (MMT), and fundus photography. Reliability studies were carried out for the EMS and the MMT. A change of 14 s is required to indicate a clinically significant change in EMS time, and a change of 14 MMT points is required to indicate a clinically significant change in MMT score. Sample sizes were sufficient for the trial to have 80% power to detect a significant clinical effect at the 5% significance level for all outcome measures in the normal cohort, and for CS in the ARMD cohort. The study demonstrated that a nutritional supplement containing 6mg lutein, 750 mg vitamin A, 250 mg vitamin C, 34 mg vitamin E, 10 mg zinc, and 0.5 mg copper had no effect on the outcome measures over nine or 18 months in normal or ARMD affected participants. The finding that nine months of antioxidant supplementation, in this case, has no significant effect on CS in ARMD-affected participants adds to the literature, and contrasts with previous RCTs, the AREDS and the LAST. This project has added to the debate about the use of nutritional supplementation prior to the onset of ARMD.

Impact of just-in-time on job content, employee attitudes and well-being:a longitudinal study

Just-in-time (JIT) production systems are increasingly being seen as a vital way for manufacturing organizations to enhance their competitiveness. A number of commentators have suggested that this will simplify jobs and reduce employee well-being. This paper presents a conceptual framework for interpreting the effects of JIT and reports findings from a study of the impact of JIT on the content of workers'jobs and on job satisfaction and psychological strain. The introduction of JIT led to a reduction in control over work timing, an increase in production pressure, and a drop in job satisfaction. Contrary to claims in the literature, no changes were found in control over work methods, other aspects of cognitive demands and skill use, and in psychological strain. The study shows that JIT can be implemented without radical changes in job content or adverse impact in terms of employee strain, and the implications of these findings are discussed.

A randomised controlled trial investigating the effect of nutritional supplementation on visual function in normal, and age-related macular disease affected eyes:design and methodology [ISRCTN78467674]

Background: Age-related macular disease is the leading cause of blind registration in the developed world. One aetiological hypothesis involves oxidation, and the intrinsic vulnerability of the retina to damage via this process. This has prompted interest in the role of antioxidants, particularly the carotenoids lutein and zeaxanthin, in the prevention and treatment of this eye disease. Methods: The aim of this randomised controlled trial is to determine the effect of a nutritional supplement containing lutein, vitamins A, C and E, zinc, and copper on measures of visual function in people with and without age-related macular disease. Outcome measures are distance and near visual acuity, contrast sensitivity, colour vision, macular visual field, glare recovery, and fundus photography. Randomisation is achieved via a random number generator, and masking achieved by third party coding of the active and placebo containers. Data collection will take place at nine and 18 months, and statistical analysis will employ Student's t test. Discussion: A paucity of treatment modalities for age-related macular disease has prompted research into the development of prevention strategies. A positive effect on normals may be indicative of a role of nutritional supplementation in preventing or delaying onset of the condition. An observed benefit in the age-related macular disease group may indicate a potential role of supplementation in prevention of progression, or even a degree reversal of the visual effects caused by this condition.

Determining the number of nodes for wireless sensor networks

The number of nodes has large impact on the performance, lifetime and cost of wireless sensor network (WSN). It is difficult to determine, because it depends on many factors, such as the network protocols, the collaborative signal processing (CSP) algorithms, etc. A mathematical model is proposed in this paper to calculate the number based on the required working time. It can be used in the general situation by treating these factors as the parameters of energy consumption. © 2004 IEEE.

(Table 6) Number of specimens of Polymastiidae and Suberitidae spp. found in ANDEEP I and II stations, POLARSTERN cruises ANT-XIX/4 and ANT-XXII/3

The Antarctic deep-water fauna of Polymastiidae and Suberitidae is revised using recently collected material from the Weddell Sea. The former family appeared to be more abundant and diverse than the latter family in the studied area. Seven species within five polymastiid genera and three species within three suberitid genera are described. Relatively high sponge abundance at two stations deeper than 4700 m was mainly constituted by a polymastiid species Radiella ant- arctica sp. nov. Previously, representatives of Radiella have never been found in the Antarctic. An eurybathic species, Polymastia invaginata , well known from the Antarctic and subantarctic, appeared to be especially abundant at less than 1000 m depth. Another eurybathic polymastiid species, Tentorium cf. semisuberites , known for its bipolar distribution, was the third abundant species at the depths between 1000-2600 m, with the highest density found at the deeper stations. Tentorium papillatum , endemic of the Southern Hemisphere, was registered only at a depth of about 1000 m. Other spe- cies studied were less abundant. Astrotylus astrotylus , the representative of the endemic Antarctic genus, was found exclusively deeper than 4500 m, often together with R. antarctica . Acanthopolymastia acanthoxa , the endemic deep- water Antarctic species, was registered at 3000 m. The discovery of suberitid Aaptos robustus sp. nov. at about 2300 m is the first signalization of Aaptos in the Antarctic and at such a considerable depth. The finding of Suberites topsenti deeper than 4700 m is also remarkable. In general the results achieved confirm the high degree of geographical ende- mism of the Antarctic deep-water sponge fauna and the eurybathic distribution of many Antarctic sponge species.

(Table 2) Collection sites and number of specimens of Usnea subgenus Neuropogon species

Usnea species of the Neuropogon group are amongst the most widespread and abundant macrolichens in Antarctic regions. Four principal species, U. antarctica, U. aurantiaco-atra, U. sphacelata and U. subantarctica, have been described on morphological grounds. However, identification to species level is often difficult and atypical morphologies frequently arise. Over 400 specimens were collected on the Antarctic Peninsula and Falkland Islands. Both morphological and molecular characters (ITS and RPB1) were used to compare samples to clarify taxonomic relationships. Morphological characteristics used included presence of apothecia, apothecial rays, soredia, papillae, fibrils, pigmentation and the diameter of the central axis as a proportion of branch diameter. Results revealed a very close relationship between U. antarctica and U. aurantiaco-atra, suggesting that they might constitute a species pair or be conspecific. Usnea sphacelata was comprised of at least two genetically distinct groups with no clear differences in morphology. One group included the first reported fertile specimen of this species. Usnea subantarctica was phylogenetically distinct from the other main Antarctic Usnea species, but clustered with U. trachycarpa. Genetic variation was evident within all species although there was no clear correlation between geographic origin and genetic relatedness. Phylogenetic analyses indicated that species circumscription in the Neuropogon group needs revision, with the principal species being non-monophyletic. None of the morphological characters, or groups of characters, used in this study proved to be completely unambiguous markers for a single species. However, axis thickness was supported as being informative for the identification of monophyletic lineages within the group.

Leader's reflections on knowledge, knowing and not knowing: an analysis of change over time

One commonality across the leadership and knowledge related literature is the apparent neglect of the leaders own knowledge. This thesis sought to address this issue through conducting exploratory research into the content of leader’s personal knowledge and the process of knowing it. The empirical inquiry adopted a longitudinal approach, with interviews conducted at two separate time periods with an extended time-interval between each. The findings from this research contrast with images of leadership which suggest leaders are in control of what they know, that they own their own knowledge. The picture that emerges is one of individuals struggling to keep abreast of the knowledge required to deal with the dynamics and uncertainties of organisational life. Much knowledge is tacit, provisional and perishable and the related process of knowing more organic, evolutionary and informal than any structured or orchestrated approach. The collective nature of knowing is a central feature, with these leaders embedded in networks of uncontrollable relationships. In view of the indeterminate nature of knowing, the boundary between what is known and what one needs to know is both amorphous and ephemeral, and the likelihood of knowledge-absences is escalated. A significant finding in this regard is the identification of two critical points where not-knowing is most likely (entry and exit from role) and the differing implications of each. Overtime the knowledge that is legitimised or prioritised is significantly altered as these leaders replace the dogmas that were previously held in high esteem with the lessons from their own experience. This experience brings increased self-knowledge and a deeper appreciation of the values and morals instilled in their early lives. In view of the above findings, this study makes theoretical contribution to a number of core literatures: authentic leadership, role transition and knowledge-absences. In terms of leadership development, the findings point to the necessity to prepare leaders for the challenges they will encounter at the pivotal stages of the leadership role.

Berry size and seed number of V. myrtillus and E. hermaphroditum according to treatment, and environmental parameters 1991-2009 at Abisko Research Station

This study investigated the effects of long-term-enhanced UV-B, and combined UV-B with elevated CO2 on dwarf shrub berry characteristics in a sub-arctic heath community. Germination of Vaccinium myrtillus was enhanced in seeds produced at elevated UV-B, but seed numbers and berry size were unaffected. Elevated UV-B and CO2 stimulated the abundance of V. myrtillus berries, whilst UV-B alone stimulated the berry abundance of V. vitis-idaea and Empetrum hermaphroditum. Enhanced UV-B reduced concentrations of several polyphenolics in V. myrtillus berries, whilst elevated CO2 increased quercetin glycosides in V. myrtillus, and syringetin glycosides and anthocyanins in E. hermaphroditum berries. UV-B x CO2 interactions were found for total anthocyanins, delphinidin-3-hexoside and peonidin-3-pentosidein in V. myrtillus berries but not E. hermaphroditum. Results suggest positive impacts of UV-B on the germination of V. myrtillus and species-specific impacts of UV-B x elevated CO2 on berry abundance and quality. The findings have relevance and implications for human and animal consumers plus seed dispersal and seedling establishment.

Probabilistic approach of water residence time and connectivity using Markov Chains with application to tidal embayments

Markov Chain analysis was recently proposed to assess the time scales and preferential pathways into biological or physical networks by computing residence time, first passage time, rates of transfer between nodes and number of passages in a node. We propose to adapt an algorithm already published for simple systems to physical systems described with a high resolution hydrodynamic model. The method is applied to bays and estuaries on the Eastern Coast of Canada for their interest in shellfish aquaculture. Current velocities have been computed by using a 2 dimensional grid of elements and circulation patterns were summarized by averaging Eulerian flows between adjacent elements. Flows and volumes allow computing probabilities of transition between elements and to assess the average time needed by virtual particles to move from one element to another, the rate of transfer between two elements, and the average residence time of each system. We also combined transfer rates and times to assess the main pathways of virtual particles released in farmed areas and the potential influence of farmed areas on other areas. We suggest that Markov chain is complementary to other sets of ecological indicators proposed to analyse the interactions between farmed areas - e.g. depletion index, carrying capacity assessment. Markov Chain has several advantages with respect to the estimation of connectivity between pair of sites. It makes possible to estimate transfer rates and times at once in a very quick and efficient way, without the need to perform long term simulations of particle or tracer concentration.