375 research outputs found

    Modeling toothpaste brand choice: An empirical comparison of artificial neural networks and multinomial probit model

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    Copyright @ 2010 Atlantis PressThe purpose of this study is to compare the performances of Artificial Neural Networks (ANN) and Multinomial Probit (MNP) approaches in modeling the choice decision within fast moving consumer goods sector. To do this, based on 2597 toothpaste purchases of a panel sample of 404 households, choice models are built and their performances are compared on the 861 purchases of a test sample of 135 households. Results show that ANN's predictions are better while MNP is useful in providing marketing insight

    The effect of vascular graft and human umbilical cord blood-derived CD34+ stem cell on peripheral nerve healing

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    AIM: There are many trials concerning peripheral nerve damage causes and treatment options. Unfortunately, nerve damage is still a major problem regarding health, social and economic issues. On this study, we used vascular graft and human cord blood derived stem cells to find an alternative treatment solution to this problem. MATERIAL AND METHODS: We used 21 female Wistar rats on our study. They were anesthetized with ketamine and we studied right hind limbs. On Group 1, we did a full layer cut on the right sciatic nerve. On Group 2, we did a full layer cut on the right sciatic nerve, and we covered synthetic vascular graft on cut area. On Group 3, we did a full layer cut on right sciatic nerve, and we covered the area with stem cell applied vascular graft. RESULTS: At the end of postoperative 8. weeks, we performed EMG on the rats. When we compared healthy and degenerated areas as a result of EMG, we found significant amplitude differences between the groups on healthy areas whereas there was no significant difference on degenerated areas between the groups. Then we re-opened the operated area again to reveal the sciatic nerve cut area, and we performed electron microscope evaluation. On the stem cell group, we observed that both the axon and the myelin sheet prevented degeneration. CONCLUSION: This study is a first on using synthetic vascular graft and cord blood derived CD34+ cells in peripheral nerve degeneration. On the tissues that were examined with electron microscope, we observed that CD34+ cells prevented both axonal and myelin sheath degeneration. Nerve tissue showed similar results to the control group, and the damage was minimal. © 2018 Ali Yilmaz, Abdullah Topcu, Cagdas Erdogan, Levent Sinan Bir, Barbaros Sahin, Gulcin Abban, Erdal Coskun, Ayca Ozkul

    Synthesis of minimum-cost shields for multi-agent systems

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    In this paper, we propose a general approach to derive runtime enforcement implementations for multiagent systems, called shields, from temporal logical specifications. Each agent of the multi-agent system is monitored, and if needed corrected, by the shield, such that a global specification is always satisfied. The different ways of how a shield can interfere with each agent in the system in case of an error introduces the need for quantitative objectives. This work is the first to discuss the shield synthesis problem with quantitative objectives. We provide several cost functions that are utilized in the multi-agent setting and provide methods for the synthesis of cost-optimal shields and fair shields, under the given assumptions on the multi-agent system. We demonstrate the applicability of our approach via a detailed case study on UAV mission planning for warehouse logistics and simulating the shielded multi-agent system on ROS/Gazebo

    Psychometric validation of the Turkish nine-item Internet Gaming Disorder Scale–Short Form (IGDS9-SF)

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    The main aims of the current study were to test the factor structure, reliability and validity of the nine-item Internet Gaming Disorder Scale-Short Form (IGDS9- SF), a standardized measure to assess symptoms and prevalence of Internet Gaming Disorder (IGD). In the present study participants were assessed with the IGDS9-SF, nine-item Internet Gaming Disorder Scale (IGDS) and the Young's Internet Addiction Test-Short Form (YIAT-SF). Confirmatory factor analyses demonstrated that the factor structure (i.e., the dimensional structure) of the IGDS9-SF was satisfactory. The scale was also reliable (i.e., internally consistent with a Cronbach's alpha of 0.89) and showed adequate convergent and criterion-related validity, as indicated by statistically significant positive correlations between average time daily spent playing games during last year, IGDS and YIAT-SF scores. By applying the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) threshold for diagnosing IGD (e.g., endorsing at least five criteria), it was found that the prevalence of disordered gamers ranged from 0.96% (whole sample) to 2.57% (e-sports players). These findings support the Turkish version of the IGDS9-SF as a valid and reliable tool for determining the extent of IGD-related problems among young adults and for the purposes of early IGD diagnosis in clinical settings and similar research

    Feasibility study of installation of solar panels on a high power HF antenna land

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    In HF broadcasting, the transmitters are typically very powerful. In the case of Turkish Radio and Television (TRT), total transmission average power may reach up to 5 MW. Therefore, it is natural to utilize solar panels as a means of alternative/backup energy for the continuous transmission of RF signal satisfying the requirement of broadcasting. In the TRT HF broadcasting array field, two areas are designated as the candidate areas for solar panel installation. In these areas, electric fields are simulated, measured, and compared. Simulations are done using the Numerical Electromagnetic Code (4nec2). The suitability of the regions for the solar panel installation are evaluated based on the ICNIRP human exposure limits. In addition, 4nec2 simulations are used to see the effect of metal frames of solar panels on the radiation patterns of the short-wave antenna arrays in the two solar panel candidate areas of TRT HF broadcasting station. Simulation results show that metal frames do not seem to have a significant effect on the radiation patterns of the short-wave antenna arrays. © 2016 Wiley Periodicals, Inc

    Caregiving in multiple sclerosis and quality of life: a meta-synthesis of qualitative research

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    Objective: The lack of adequate conceptualisation and operationalisation of quality of life (QoL) limits the ability to have a consistent body of evidence to improve QoL research and practice in informal caregiving for people with multiple sclerosis (MS). Thus, we conducted a meta-synthesis of qualitative research to improve the conceptual understanding of the experiences of MS carers and to identify factors that affect carers' QoL. Design: Systematic searches of five electronic databases yielded 17 qualitative studies which were synthesised using the principles of meta-ethnography. Results: The synthesis resulted in nine inter-linking themes: Changes and losses; challenges revolving around MS; caregiving demands; burden of care; future concerns; external stressors; experiences of support; strategies used in managing the caregiving role; and motivating factors. Our findings suggest that MS carers can have both positive and negative experiences which may bring challenges and rewards to the carers. Conclusion: We present a proposed QoL model for MS caregiving which can be used to inform the development of interventions for MS carers to improve their QoL. However, further empirical research is needed to examine the utility of this model and to explore the concept of QoL in MS carers in more detail

    Home-based pre-surgical psychological intervention for knee osteoarthritis (HAPPiKNEES): a feasibility randomized controlled trial

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    Objective: To determine the feasibility of conducting a trial of a pre-surgical psychological intervention on pain, function, and mood in people with knee osteoarthritis listed for total knee arthroplasty. Design: Multi-centre, mixed-methods feasibility randomized controlled trial of intervention plus usual care versus usual care. Setting: Participants’ homes or hospital. Participants: Patients with knee osteoarthritis listed for total knee arthroplasty and score >7 on either subscales of Hospital Anxiety and Depression Scale. Intervention: Up-to 10 sessions of psychological intervention (based on cognitive behavioural therapy). Main measures: Feasibility outcomes (recruitment and retention rates, acceptability of trial procedures and intervention, completion of outcome measures), and standardized questionnaires assessing pain, function, and mood at baseline, and four and six months post-randomisation. Results: Of 222 people screened, 81 did not meet inclusion criteria, 64 did not wish to participate, 26 were excluded for other reasons, and 51 were randomized. A total of 30 completed 4-months outcomes and 25 completed 6-month outcomes. Modal number of intervention sessions completed was three (range 2–8). At six-month follow-up, mood, pain, and physical function scores were consistent with clinically important benefits from intervention, with effect sizes ranging from small (d = 0.005) to moderate (d = 0.74), and significant differences in physical function between intervention and usual care groups (d = 1.16). Feedback interviews suggested that participants understood the rationale for the study, found the information provided adequate, the measures comprehensive, and the intervention acceptable. Conclusion: A definitive trial is feasible, with a total sample size of 444 people. Pain is a suitable primary outcome, but best assessed 6 and 12 months post-surgery

    Multiplicity: an organizing principle for cancers and somatic mutations

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    <p>Abstract</p> <p>Background</p> <p>With the advent of whole-genome analysis for profiling tumor tissue, a pressing need has emerged for principled methods of organizing the large amounts of resulting genomic information. We propose the concept of multiplicity measures on cancer and gene networks to organize the information in a clinically meaningful manner. Multiplicity applied in this context extends Fearon and Vogelstein's multi-hit genetic model of colorectal carcinoma across multiple cancers.</p> <p>Methods</p> <p>Using the Catalogue of Somatic Mutations in Cancer (COSMIC), we construct networks of interacting cancers and genes. Multiplicity is calculated by evaluating the number of cancers and genes linked by the measurement of a somatic mutation. The Kamada-Kawai algorithm is used to find a two-dimensional minimum energy solution with multiplicity as an input similarity measure. Cancers and genes are positioned in two dimensions according to this similarity. A third dimension is added to the network by assigning a maximal multiplicity to each cancer or gene. Hierarchical clustering within this three-dimensional network is used to identify similar clusters in somatic mutation patterns across cancer types.</p> <p>Results</p> <p>The clustering of genes in a three-dimensional network reveals a similarity in acquired mutations across different cancer types. Surprisingly, the clusters separate known causal mutations. The multiplicity clustering technique identifies a set of causal genes with an area under the ROC curve of 0.84 versus 0.57 when clustering on gene mutation rate alone. The cluster multiplicity value and number of causal genes are positively correlated via Spearman's Rank Order correlation (<it>r<sub>s</sub></it>(8) = 0.894, Spearman's <it>t </it>= 17.48, <it>p </it>< 0.05). A clustering analysis of cancer types segregates different types of cancer. All blood tumors cluster together, and the cluster multiplicity values differ significantly (Kruskal-Wallis, <it>H </it>= 16.98, <it>df </it>= 2, <it>p </it>< 0.05).</p> <p>Conclusion</p> <p>We demonstrate the principle of multiplicity for organizing somatic mutations and cancers in clinically relevant clusters. These clusters of cancers and mutations provide representations that identify segregations of cancer and genes driving cancer progression.</p

    The nation in context: how intergroup relations shape the discursive construction of identity continuity and discontinuity

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    The perceived collective continuity (PCC) of a national identity serves as a crucial source of stability and self‐esteem for group members. Recent work has explored the consequences of perceived continuity when the meaning of a nation’s past is seen in a negative light, and the challenges this brings for the negotiation of a positive identity in the present, signalling the potential value of perceived discontinuity The current paper extends this literature by examining the role of intergroup relations in the construction of both collective continuities and discontinuities. Through analysing the discursive management of national identity in nine focus groups in a post‐conflict context (Serbia, N = 67), we reveal how the tensions between continuity and discontinuity are embedded within a broader discussion of the nation’s relationship with relevant national outgroups across its history. The findings contribute to theoretical knowledge on the interlinking of national identity and PCC by illustrating the ways in which intergroup relations of the past shape the extent to which continuity is seen as desirable or undesirable. We argue that despite the psychological merits of collective continuity, discontinuity can become attractive and useful when there is limited space to challenge how a nation’s history is remembered and the valence given to the past. The paper concludes by offering an account of how social and political contexts can influence the nature, functions, and valence of PCC within national identities
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