E-commerce: continuous growth or leveling out?

This paper challenges the basis of highly optimistic predictions for growth e.g. [2][3] and, a number of barriers to business to consumer e-commerce are discussed. In a corporate age when 'the customer is king' [14], it is questioned whether Internet shopping really is what consumers 'want' or 'need'. The discussion provides a socio-technical exposition underlying this optimism and counters it by a prudent and realistic model for progress in the area of e-commerce. As a result, we suggest that in the near future e-commerce may mature as a steadily growing niche market, an alternative way to shop, rather than the way. We suggest that the Internet will probably evolve as an all-embracing communication and information tool, rather than the 'shopping mall' of the future. A discussion on the future of business to customer e-commerce is presented

Investigation

of antnet routing algorithm by employing multiple ant colonies for packet switched networks to overcome the stagnation proble

The Antnet Routing Algorithm- A Modified Version

Abstract – Antnet is an agent based routing algorithm that is influenced from the unsophisticated and individual ant’s emergent behaviour. Ants (software agents) are used in antnet to collect information and to update the probabilistic distance vector routing table entries. Modified antnet algorithm has been introduced, which improve the throughput and average delay. Results shows that by detecting and dropping 0.5 % of packets routed through the non-optimal routes the average delay per packet decreased and network throughput can be increased. The effect of the traffic fluctuations has been limited with the boundaries introduced in this paper and the number of ants in the network has been limited with the current throughput of the network at any given time. I

Meta-analysis of randomized controlled trials of atrial fibrillation ablation with pulmonary vein isolation versus without

Objectives This meta-analysis examined the ability of pulmonary vein isolation (PVI) to prevent atrial fibrillation in randomized controlled trials (RCTs) in which the patients not receiving PVI nevertheless underwent a procedure. Background PVI is a commonly used procedure for the treatment of atrial fibrillation (AF), and its efficacy has usually been judged against therapy with anti-arrhythmic drugs in open-label trials. There have been several RCTs of AF ablation in which both arms received an ablation, but the difference between the treatment arms was inclusion or omission of PVI. These trials of an ablation strategy with PVI versus an ablation strategy without PVI may provide a more rigorous method for evaluating the efficacy of PVI. Methods Medline and Cochrane databases were searched for RCTs comparing ablation including PVI with ablation excluding PVI. The primary efficacy endpoint was freedom from atrial fibrillation (AF) and atrial tachycardia at 12 months. A random-effects meta-analysis was performed using the restricted maximum likelihood estimator. Results Overall, 6 studies (610 patients) met inclusion criteria. AF recurrence was significantly lower with an ablation including PVI than an ablation without PVI (RR: 0.54; 95% confidence interval [CI]: 0.33 to 0.89; p 1⁄4 0.0147; I2 1⁄4 79.7%). Neither the type of AF (p 1⁄4 0.48) nor the type of non-PVI ablation (p 1⁄4 0.21) was a significant moderator of the effect size. In 3 trials the non-PVI ablation procedure was performed in both arms, whereas PVI was performed in only 1 arm. In these studies, AF recurrence was significantly lower when PVI was included (RR: 0.32; 95% CI: 0.14 to 0.73; p 1⁄4 0.007, I2 78% Conclusion In RCTs where both arms received an ablation, and therefore an expectation amongst patients and doctors of benefit, being randomized to PVI had a striking effect, reducing AF recurrence by a half

Efficacy of pulmonary vein isolation in preventing atrial fibrillation: meta-analysis of randomized controlled trials with an invasive control procedure

Introduction Pulmonary vein isolation (PVI) is a commonly used element in treatment of atrial fibrillation (AF) but has never been tested in an intentionally placebo (sham) controlled trial. Nevertheless there have been several randomized controlled trials (RCTs) in which both arms receive an ablation procedure but the only difference between treatment arms is inclusion or omission of PVI. As long as both doctor and patient have reason to believe that the procedures in both arms are effective, such RCTs could be an effective proxy for placebo controlled trials. Methods Medline and Cochrane databases were searched for RCTs comparing catheter ablation including PVI with left atrial ablation excluding PVI. The primary efficacy endpoint was freedom from AF/atrial tachycardia at 6 months. A random-effects meta-analysis was performed using the restricted maximum likelihood (REML) estimator. Results Overall, seven studies (909 patients) met inclusion criteria. Across the 7 trials, mean age was 57.3, 70.2% of participants were male. In four trials (352 patients) the non-PVI ablation procedure was performed in both arms, while PVI was performed in only one arm. The non-PVI ablation procedures were complex fractionated atrial electrogram ablation (2 studies), ganglionated plexi ablation (1 study) and focal impulse and rotor modulation (1 study). In these, AF recurrence was significantly lower when PVI was included (RR 0.48, 95% CI 0.26-0.90, I2 64.4%)In an analysis of all 7 studies, AF recurrence was significantly lower in ablation with an ablation strategy including PVI compared to one without PVI (Figure 1, RR 0.67, 95% CI 0.53-0.85, p = 0.001, I2 0%). Neither type of AF (persistent vs. paroxysmal, p=0.43) nor type of non-PVI ablation (p=0.35) were significant moderators of the effect size. A sensitivity analysis omitting each study in turn showed similar results to the primary analysis. In particular exclusion of the retracted OASIS trial showed results similar to the primary analysis. Conclusion PVI significantly reduces AF recurrence against a procedural control. A true placebo controlled trial of PVI versus placebo PVI (and no other procedure) might show an even larger efficacy because there would be no background efficacy in the control arm. It remains unknown how these convincing reductions in electrically documented AF would relate to symptom regression, since the correspondence between arrhythmia and symptoms is imperfect. A placebo (sham) controlled RCT would be the ideal method of testing this