Dynamic modeling of web purchase behavior and e-mailing impact by Petri net

In this article, the authors introduce Petri nets to model the dynamics of web site visits and purchase behaviors in the case of wish list systems. They describe web site activities and their transition with probability distributions and model the sequential impact of influential factors through links that better explain web purchase behavior dynamics. The basic model, which analyzes site connections and purchases to explain visit and purchase behavior, performs better than a classical negative binomial regression model. To demonstrate its flexibility, the authors extend the wish list Petri net model to measure the impact of e-mailing intervals on visit frequency and purchase.internet; wish list; e-mail; Petri net; dynamic model

Intertester agreement and validity of identifying lumbar pain provocative movement patterns using active and passive accessory movement tests

Objective: The purpose of this study was to evaluate the interexaminer agreement and validity of active and passive pain provocation tests in the lumbar spine. Methods: Two blinded raters examined 36 participants, 18 of whom were asymptomatic and 18 reported subacute nonspecific low back pain (LBP). Two types of pain provocation tests were performed: (1) physiological movements in single (flexion/extension) and, when necessary, combined planes and (2) passive accessory intervertebral movement tests of each lumbar vertebra in prone with the lumbar spine in neutral, flexion, and extension position .Results: The interobserver agreement in both groups was good to excellent for the identification of flexion (κ =0.87-1) or extension (κ =0.65-0.74) as the most painful pattern of spinal movement. In healthy participants, 0% was identified as having a flexion provocative pattern and 8.8% were identified as having an extension provocative pattern. In the LBP group, 20% were identified as having flexion provocative pattern vs 60% with an extension provocative pattern. The average interexaminer agreement for passive accessory intervertebral movement tests in both groups was moderate to excellent (κ =0.42-0.83). The examiners showed good sensitivity (0.67-0.87) and specificity (0.82-0.85) to distinguish participants with LBP using this combined examination procedure. Conclusion: The use of a combination of pain provocative tests was found to have acceptable interexaminer reliability and good validity in identifying the main pain provocative movement pattern and the lumbar segmental level of involvement. These pain provocation tests were able to distinguish participants with LBP from asymptomatic participants and may help clinicians in directing manual therapy treatment

Development and validation of a questionnaire assessing volitional competencies to enhance the performance of physical activities in chronic low back pain patients

BACKGROUND: Motivation has long been emphasized as the most important determinant of action. However, there is a substantial gap between people's goals and their attainment. Patients may be motivated and yet unable to take action if their volitional competencies are insufficient. One of the important tasks of volition is goal-maintenance. Research has stressed the importance of a volitional tool, the implementation intentions. Implementation intentions indicate where, when, and how the action leading to the goal will be performed. Forming implementation intentions favours the execution of goal-directed efforts, and reinforces the relationship between intentions and behaviours. Results from various studies clearly suggest that volitional competencies and implementation intentions could play a role in low back pain (LBP) patients. However, there is at present no questionnaire allowing assessing the capacity of implementation intentions of physical activities in LBP patients. METHODS/DESIGN: This study will develop such a questionnaire, using a 3-step approach. A first qualitative step to build categories and generate items; 30 patients suffering chronic LBP will be invited to participate in semi-structured interviews; verbatim and derived items will then be submitted to a panel of experts, using a Delphi method; a second quantitative step to examine the properties of items, and determine the factorial structure of the questionnaire; 100 patients suffering chronic LBP will be recruited to respond to this phase; and third, preliminary psychometric analyses (item-scale correlations, construct validity, reliability); 180 chronic LBP patients will be recruited for this phase of the study. The relationships between implementation intentions and variables affecting physical activity on chronic LBP patients, i.e. pain, physical capacities, fear-avoidance beliefs, kinesiophobia, work status, and level of physical activity will be considered. DISCUSSION: Developing a questionnaire to assess implementation intentions would allow investigating the role of these intentions in the transition from acute to chronic LBP. The results of this study should contribute to the understanding of the psychological processes at stake in the development of chronic LBP, and in particular to the identification of factors eventually favouring patients' participation in and adherence to active physical treatments

Lombalgies juvéniles: quelle attitude en 2010?

The first part of this article reviews the evolution of diagnostic issues regarding low back pain (LBP) in children and adolescents in recent years. The attitude recommended in the literature has been adapted to current epidemiological data showing that non specific LBP is largely prevalent in these age groups, much like in adult populations. Thus, it seems reasonable to avoid an overly aggressive therapeutic attitude, especially in the adolescent population. The second part of the article is devoted to non specific LBP and summarizes recent studies. These data show that the impact of LBP on the quality of life in children and adolescents is very low, with the exception, however, of a small subgroup of adolescents suffering generalized pain in conjunction with LBP

What affects creative performance in idea co-creation : competitive cooperative or coopetitive climate ?

Companies develop co-creation platforms to collect innovative ideas generated by consumers. The idea competition model is traditionally used to organise such collective action and has been widely implemented by companies. In parallel, the development of collaborative platforms and social networks have led to the appearance of co-creation platforms based on a cooperation model with community features. In addition to these two classical models, a third model, a combination of competition and cooperation — the coopetition model — has emerged. Although there is growing interest in this model, no study to date has compared its performance to the other two models. Our research objective is to investigate and compare how these three models affect creative performance in terms of idea quantity and quality. We thus conducted an experiment with 177 students to generate ideas that were submitted to an established company. The results show that the coopetition model generates more ideas and more creative ideas than the other two models. We also offer insights on how a consumer co-creation platform should be designed to achieve better creative performance

Non-specific low back pain

Non-specific low back pain has become a major public health problem worldwide. The lifetime prevalence of low back pain is reported to be as high as 84%, and the prevalence of chronic low back pain is about 23%, with 11-12% of the population being disabled by low back pain. Mechanical factors, such as lifting and carrying, probably do not have a major pathogenic role, but genetic constitution is important. History taking and clinical examination are included in most diagnostic guidelines, but the use of clinical imaging for diagnosis should be restricted. The mechanism of action of many treatments is unclear, and effect sizes of most treatments are low. Both patient preferences and clinical evidence should be taken into account for pain management, but generally self-management, with appropriate support, is recommended and surgery and overtreatment should be avoided

No kidding: low back pain and type of container influence adolescents' perception of load heaviness

The relationship between low back pain (LBP) and the lifting/carrying of loads is still a matter of great discussion. In teenagers, the weight of the school bag has been considered to play a pathogenic role in LBP but the relationship between the actual weight of the school bag and LBP symptoms does not seem to be a straightforward one. Numerous factors have been identified that influence the perception of weight. This study aimed to evaluate the influence of low back pain and the type of container on the perception of load heaviness by healthy teenagers

Assessing the association between low back pain, quality of life, and life events as reported by schoolchildren in a population-based study

Low back pain (LBP) is prevalent in teenagers but not necessarily detrimental to their quality of life (QoL). This population-based study evaluated a global QoL score and the association between LBP and life events and/or health problems affecting QoL. Schoolchildren were investigated in Fribourg-Switzerland and Barcelona-Spain. In addition to the KIDSCREEN, a health-related QoL questionnaire, two Numerical Rating Scales were used to assess QoL in general, and the influence of LBP on QoL. Open questions explored life events and health problems affecting QoL; responses were submitted to content analysis. Adolescents were stratified: Pain-free, Other pain (OP), isolated LBP (IsoLBP), LBP + other pains (LBP + OP), and LBP + whole-body pain (LBP + WBP). Between-group comparisons were performed using Chi-squared tests and ANOVA. Linear regression analysis was performed to assess between-group differences in the impact of LBP on QoL. Schoolchildren (1,470) (mean age = 15.05 years, 52.6% = boys) completed the questionnaire. LBP lasting >1 day in the last month was reported by 39.8% (N = 560): of them, 242 (43.2%) reported IsoLBP, 268 (47.9%) LBP + OP, and 50 (9.1%) LBP + WBP. QoL was lower in LBP + WBP (mean = 6.44 vs. LBP + OP = 7.8; IsoLBP = 7.6, OP = 7.96, Pain-free = 8.1; p 30% of this group identifying life events and/or health problems vs. 10-12% in PFree or IsoLBP groups (p < 0.001). IsoLBP affected QoL marginally (mean = 2.4 ± 2.2) compared to LBP + WBP (mean = 4.9 ± 2.4) (p < 0.001). LBP affected QoL marginally. These results stress the distinction between disease and common life experience. They also indicate the potential value of global QoL assessments in clinical settings

Low back pain in adolescents: is quality of life poorer in those seeking medical attention?

Paired case-control study

Study of the information delivery by general practitioners and rheumatologists to patients with acute low back pain.

Providing information to patients regarding appropriate management of LBP is a crucial component of primary care and treatment of low back pain (LBP). Limited knowledge is available, however, about the information delivered by physicians to patients with low back pain. Hence, this study aimed at evaluating (1) the self-reported practices of French physicians concerning information about patients with acute LBP (2) the consistency of these practices with the COST B13 guidelines, and (3) the effects of the delivery of a leaflet summarizing the COST B13 recommendations on the management of patient information, using the following study design: 528 French physicians [319 general practitioners (GP) and 209 rheumatologists (RH)] were asked to provide demographic information, responses to a Fear Avoidance Beliefs questionnaire adapted for physicians and responses to a questionnaire investigating the consistency of their practice with the COST B13 guidelines. Half of the participants (163 GP and 105 RH) were randomized to receive a summary of the COST B13 guidelines concerning information delivery to patient with low back pain and half (156 GP and 104 RH) were not given this information. The mean age of physicians was 52.1 +/- 7.6 years, 25.2% were females, 75% work in private practice, 63.1% reported to treat 10-50 patients with LBP per month and 18.2% <10 per month. The majority of the physicians (71.0%) reported personal LBP episode (7.1% with a duration superior to 3 months). Among the 18.4% (97) of the physicians that knew the COST B13 guidelines, 85.6% (83/97) reported that they totally or partially applied these recommendations in their practice. The average work (0-24) and physical activity (0-24) FABQ scores were 21.2 +/- 8.4 and 10.1 +/- 6.0, respectively. The consistency scores (11 questions scored 0 to 6, total score was standardized from 0 to 100) were significantly higher in the RH group (75.6 +/- 11.6) than in GP group (67.2 +/- 12.6; p < 0.001). The delivery of a summary of the COST B13 guidelines significantly improved the consistency score (p = 0.018). However, a multivariate analysis indicated that only GP consistency was improved by recommendations' delivery.The results indicated that GP were less consistent with the European COST B13 guidelines on the information of patients with acute LBP than RH. Interestingly, delivery of a summary of these guidelines to GP improved their consistency score, but not that of the RH. This suggests that GP information campaign can modify the message that they deliver to LBP, and subsequently could change patient's beliefs on LBP