An investigation of key determinants of customer loyalty : evidence from Ghana’s mobile telecommunication industry

In a fiercely competitive business environment such as the mobile network services setting, it is a marketplace reality that the ability of firms to attract and retain customers ultimately determines their growth and survival prospects. This study, therefore, investigates how customer satisfaction, perceived service quality, perceived value, corporate image and switching cost determine customer loyalty in the mobile network services setting of Ghana. A total of 140 respondents completed an online survey via emails and social media platforms in Ghana. The results of the empirical study reveal that customer satisfaction had the greatest impact on loyalty. Service quality and perceived value are both directly and indirectly related to loyalty through satisfaction. The results also show that corporate image is a direct antecedent of customer loyalty. The role of image as a key factor in mobile network services marketing is thus confirmed. However, the influence of switching costs on customer loyalty was not corroborated in this study. We suggest that managers should emphasize service quality and perceived value as core elements for building satisfaction and loyalty. In regard to Mobile Number Portability (MNP) intentions, the study found that there were as many customers who were likely to port their numbers as there were those who might not. Notwithstanding, those with porting intent were fairly larger. Some customers also reported indecisiveness with MNP. As such, brand managers should design unique marketing strategies aimed at each of these consumer groups

A method to increase reproducibility in adult ventricular myocyte sizing and flow cytometry: Avoiding cell size bias in single cell preparations.

RATIONALE:Flow cytometry (FCM) of ventricular myocytes (VMs) is an emerging technology in adult cardiac research that is challenged by the wide variety of VM shapes and sizes. Cellular variability and cytometer flow cell size can affect cytometer performance. These two factors of variance limit assay validity and reproducibility across laboratories. Washing and filtering of ventricular cells in suspension are routinely done to prevent cell clumping and minimize data variability without the appropriate standardization. We hypothesize that washing and filtering arbitrarily biases towards sampling smaller VMs than what actually exist in the adult heart. OBJECTIVE:To determine the impact of washing and filtering on adult ventricular cells for cell sizing and FCM. METHODS AND RESULTS:Left ventricular cardiac cells in single-cell suspension were harvested from New Zealand White rabbits and fixed prior to analysis. Each ventricular sample was aliquoted before washing or filtering through a 40, 70, 100 or 200μm mesh. The outcomes of the study are VM volume by Coulter Multisizer and light-scatter signatures by FCM. Data are presented as mean±SD. Myocyte volumes without washing or filtering (NF) served as the "gold standard" within the sample and ranged from 11,017 to 46,926μm3. Filtering each animal sample through a 200μm mesh caused no variation in the post-filtration volume (1.01+0.01 fold vs. NF, n = 4 rabbits, p = 0.999) with an intra-assay coefficient of variation (%CV) of <5% for all 4 samples. Filtering each sample through a 40, 70 or 100μm mesh invariably reduced the post-filtration volume by 41±10%, 9.0±0.8% and 8.8±0.8% respectively (n = 4 rabbits, p<0.0001), and increased the %CV (18% to 1.3%). The high light-scatter signature by FCM, a simple parameter for the identification of ventricular myocytes, was measured after washing and filtering. Washing discarded VMs and filtering cells through a 40 or 100μm mesh reduced larger VM by 46% or 11% respectively (n = 6 from 2 rabbits, p<0.001). CONCLUSION:Washing and filtering VM suspensions through meshes 100μm or less biases myocyte volumes to smaller sizes, excludes larger cells, and increases VM variability. These findings indicate that validity and reproducibility across laboratories can be compromised unless cell preparation is standardized. We propose no wash prior to fixation and a 200μm mesh for filtrations to provide a reproducible standard for VM studies using FCM

3D Computation of reactive moulding processes

International audienceElectrical equipment for medium and high voltage is manufactured using reactive moulding process. During mould filling, air bubbles or weld-lines can appear which may be a huge problem for electrical insulation devices. Moreover, the use of thermoset materials induces delamination due to the resin's shrinkage. Product development delays can be reduced using numerical tools to simulate part forming process. In this paper, we present a three dimensional finite element analysis of the filling and curing stages of reactive moulding process. During the first stage, flow computation takes into account heat transfer and the curing reaction according to appropriate models. In the curing phase, the evolution of the degree of cure is coupled with an evolution model of the glass transition temperature. Taking in account his coupling phenomenon permits the computation of a more realistic curing kinetic and modelling of the slowdown at vitrification. The thermal field prediction is then more accurate. To validate this approach, experiments were performed. A comparison with computational results shows a good agreement in filling and temperature evolution inside the cavity

Desempenho de crianças do ensino fundamental na solução de problemas aritméticos

Performance of children of the elementary school in arithmetics problems solving This study compared the performance of students of the first year of the elementary school (groups 1F and 1IN) and students of the second year of elementary school (groups 2F and 2IN), tested at the beginning (IN) or at the end of the school year (F), in mathematical problems solving. Thirty eight participants divided into 4 groups were submitted to the same procedure, that consisted in mathematical problems oral presentation. After each answer the participants were asked about form of solution. Data was analysed related to the amount of correct answers and the strategies employed. Correct answers and the use of writing were more frequent in Group 2F and less frequent in Group 1IN. Groups 2F and 1F showed a more frequent use of algorithms. Results also show a better performance of Group 1F related to Group 2IN, suggesting that the history of recent frequency to school favours the performance of the participants.Este estudo buscou comparar o desempenho de alunos da primeira série do ensino fundamental (Grupos 1F e 1IN) e alunos da segunda série do ensino fundamental (Grupos 2F e 2IN), testados no início (IN) ou final do ano letivo (F), na solução de problemas matemáticos. Trinta e oito alunos divididos em 4 grupos foram submetidos ao mesmo procedimento, que consistia da apresentação oral de problemas matemáticos. Após cada resposta, o aluno era questionado sobre a forma de solução. Os dados foram analisados quanto ao índice de acertos e às estratégias empregadas. Os acertos e o uso da escrita foram maiores no Grupo 2F e menores no Grupo 1IN. Os grupos 2F e 1F apresentaram uso mais freqüente de algoritmos. Os resultados também indicam melhor desempenho do Grupo 1F em relação ao Grupo 2IN, sugerindo que a história de freqüência recente à escola favorece o desempenho dos alunos

Economic efficiency when prices are not fixed:disentangling quantity and price efficiency

This paper proposes an approach to compute cost efficiency in contexts where units can adjust input quantities and to some degree prices so that through their joint determination they can minimise the aggregate cost of the outputs they secure. The model developed is based on the data envelopment analysis (DEA) framework and can accommodate situations where the degree of influence over prices ranges from minimal to considerable. When units cannot influence prices at all the model proposed reduces to the standard cost efficiency DEA model for the case where prices are taken as exogenous. In addition to the cost efficiency model, we introduce an additive decomposition of potential cost savings into a quantity and a price component, based on Bennet indicators

Avaliação das propriedades físico-químicas e biológicas de um cimento endodôntico a base de silicato de cálcio ¿ MTA Fillapex

Orientador: Alexandre Augusto ZaiaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O cimento endodôntico obturador MTA Fillapex® foi criado numa tentativa de aliar as propriedades físico-químicas e a capacidade seladora dos cimentos resinosos às excelentes propriedades biológicas do agregado trióxido mineral (MTA). Entretanto, ainda existe uma escassez de trabalhos na literatura avaliando as suas características físico-químicas e biológicas. Dessa forma, os objetivos deste estudo foram: 1) avaliar propriedades físico-químicas (radiopacidade, escoamento e pH) e biológicas (citotoxicidade) do cimento endodôntico MTA Fillapex e comparar com o cimento AH Plus, 2) realizar um acompanhamento em longo prazo do efeito citotóxico em fibroblastos 3T3 de diferentes cimentos endodônticos contemporâneos, e 3) avaliarem a partir de um ensaio multiparamétrico em longo prazo os efeitos citotóxicos do MTA Fillapex e do AH Plus em uma cultura primária de osteoblastos humanos. Os resultados do estudo mostraram que embora o AH Plus tenha apresentado radiopacidade estatisticamente maior que o MTA Fillapex (P0.05). No entanto, uma semana após sua manipulação o AH Plus se tornou não citotóxico em todos os parâmetros avaliados. Por outro lado, o MTA Fillapex permaneceu citotóxico durante todo o período experimental, mostrando diferenças estatisticamente significantes quando comparados com o AH Plus (P0.05). After one week AH Plus become noncytotoxic, on all three parameters evaluated. Conversely, MTA Fillapex remained cytotoxic over the entire experimental period, showing significantly differences when compared to AH Plus (P<0.05). Within the employed methodology and according to the results can be concluded that although MTA Fillapex showed suitable physicochemical properties for use in endodontic therapy, it appeared highly cytotoxic in the different tested conditionsDoutoradoEndodontiaDoutor em Clínica Odontológic

A PORTABLE AND INEXPENSIVE DO-IT-YOURSELF TEMPERATURE SENSOR

Nowadays it is important to have commercial solutions to be used in teaching and research laboratories for the needs. We can have different equipment according to the necessary parameters of control being related to the influence of parameters internal or external to the laboratory practice. However they can't be straightforward to use, their costs can be considerable.  In this context, the do-it-yourself approach is an interesting alternative. In this paper we report the construction of a temperature sensor made by students. Based on a probe taken from a deactivated equipment, the sensor development and validation encompassed its design and building up, the establishment of a connection to a personal computer via USB, the setup of computer-controlled processes, which included remote control, graphical and numerical displaying and signal acquisition, and finally its testing. Tests were performed in water containers with different temperatures, namely boiling, room and ice. The obtained results are comparable to those from a commercial thermometer. This student experiment project allowed not only to contact different disciplines such as chemistry, electronics, and programming but also to gain competencies that can be used outside the class context. We proved it is possible to build tailor-made electronic devices capable of providing useful measurements to chemical purposes old equipment in an inexpensive and trustworthy way

Design of double-walled carbon nanotubes for biomedical applications

Double-walled carbon nanotubes (DWNTs) prepared by catalytic chemical vapour deposition were functionalized in such a way that they were optimally designed as a nano-vector for the delivery of small interfering RNA (siRNA), which is of great interest for biomedical research and drug development. DWNTs were initially oxidized and coated with a polypeptide (Poly(Lys:Phe)), which was then conjugated to thiol-modified siRNA using a heterobifunctional cross-linker. The obtained oxDWNT–siRNA was characterized by Raman spectroscopy inside and outside a biological environment (mammalian cells). Uptake of the custom designed nanotubes was not associated with detectable biochemical perturbations in cultured cells, but transfection of cells with DWNTs loaded with siRNA targeting the green fluorescent protein (GFP) gene, serving as a model system, as well as with therapeutic siRNA targeting the survivin gene, led to a significant gene silencing effect, and in the latter case a resulting apoptotic effect in cancer cells