927 resultados para Na retention


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The objective of this study was to resolve how a privately owned health club can retain their existing customers. It was also resolved why there is a need for customer retention in general, and what the constructs leading to retention are. In addition, the relationship between customer satisfaction and customer retention was studied and discussed.

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The cuticle covers the aerial parts of land plants, where it serves many important functions, including water retention. Here, a recessive cuticle mutant, eceriferum-ym (cer-ym), of Hordeum vulgare L. (barley) showed abnormally glossy spikes, sheaths, and leaves. The cer-ym mutant plant detached from its root system was hypersensitive to desiccation treatment compared with wild type plants, and detached leaves of mutant lost 41.8% of their initial weight after 1 h of dehydration under laboratory conditions, while that of the wild type plants lost only 7.1%. Stomata function was not affected by the mutation, but the mutant leaves showed increased cuticular permeability to water, suggesting a defective leaf cuticle, which was confirmed by toluidine blue staining. The mutant leaves showed a substantial reduction in the amounts of the major cutin monomers and a slight increase in the main wax component, suggesting that the enhanced cuticle permeability was a consequence of cutin deficiency. cer-ym was mapped within a 0.8 cM interval between EST marker AK370363 and AK251484, a pericentromeric region on chromosome 4H. The results indicate that the desiccation sensitivity of cer-ym is caused by a defect in leaf cutin, and that cer-ym is located in a chromosome 4H pericentromeric region.

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The objective of this masters thesis was to examine the effect of customer orientation on customer satisfaction and how customer satisfaction and customer retention contribute to firm profitability. Beside customer orientation, also other antecedents of customer satisfaction, i.e. service quality, flexibility, trust and commitment, were investigated as control variables. Literature review revealed several research gaps concerning research of the key concepts. These research calls were also answered. The empirical study focused on one case company, a telecommunication expert. The data for the empirical part was collected with web-based questionnaire from case companys business customers in January-February 2008. Sample (N=95) produced 59 answers, thus the response rate of the survey was 62,1%. The data was analyzed by using statistical analysis program, SPSS. As a conclusion, the results indicate that customer orientation do not affect customer satisfaction directly, but through service quality, flexibility and trust. Moreover, customer satisfaction has positive impacts on commitment and intentions to stay as a customer in the future, but not on profitability. In the present study, only past purchase behavior, measured with customer database measure, is positively related to firm profitability.

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Whole-genome duplication (WGD) is usually followed by gene loss and karyotype repatterning. Despite evidence of new adaptive traits associated with WGD, the underpinnings and evolutionary significance of such genome fractionation remain elusive. Here, we use Buckler mustard (Biscutella laevigata) to infer processes that have driven the retention of duplicated genes after recurrent WGDs. In addition to the β- and α-WGD events shared by all Brassicaceae, cytogenetic and transcriptome analyses revealed two younger WGD events that occurred at times of environmental changes in the clade of Buckler mustard (Biscutelleae): a mesopolyploidy event from the late Miocene that was followed by considerable karyotype reshuffling and chromosome number reduction and a neopolyploidy event during the Pleistocene. Although a considerable number of the older duplicates presented signatures of retention under positive selection, the majority of retained duplicates arising from the younger mesopolyploidy WGD event matched predictions of the gene balance hypothesis and showed evidence of strong purifying selection as well as enrichment in gene categories responding to abiotic stressors. Retention of large stretches of chromosomes for both genomic copies supported the hypothesis that cycles of WGD and biased fractionation shaped the genome of this stress-tolerant polypolyloid, promoting the adaptive recruitment of stress-responding genes in the face of environmental challenges.

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OBJECTIVES: The aim of this study was to quantify loss to follow-up (LTFU) in HIV care after delivery and to identify risk factors for LTFU, and implications for HIV disease progression and subsequent pregnancies. METHODS: We used data on pregnancies within the Swiss HIV Cohort Study from 1996 to 2011. A delayed clinical visit was defined as >&#8201;180 days and LTFU as no visit for >&#8201;365 days after delivery. Logistic regression analysis was used to identify risk factors for LTFU. RESULTS: A total of 695 pregnancies in 580 women were included in the study, of which 115 (17%) were subsequent pregnancies. Median maternal age was 32 years (IQR 28-36 years) and 104 (15%) women reported any history of injecting drug use (IDU). Overall, 233 of 695 (34%) women had a delayed visit in the year after delivery and 84 (12%) women were lost to follow-up. Being lost to follow-up was significantly associated with a history of IDU [adjusted odds ratio (aOR) 2.79; 95% confidence interval (CI) 1.32-5.88; P&#8201;=&#8201;0.007] and not achieving an undetectable HIV viral load (VL) at delivery (aOR 2.42; 95% CI 1.21-4.85; P&#8201;=&#8201;0.017) after adjusting for maternal age, ethnicity and being on antiretroviral therapy (ART) at conception. Forty-three of 84 (55%) women returned to care after LTFU. Half of them (20 of 41) with available CD4 had a CD4 count <&#8201;350&#8201;cells/&#956;L and 15% (six of 41) a CD4 count <&#8201;200&#8201;cells/&#956;L at their return. CONCLUSIONS: A history of IDU and detectable HIV VL at delivery were associated with LTFU. Effective strategies are warranted to retain women in care beyond pregnancy and to avoid CD4 cell count decline. ART continuation should be advised especially if a subsequent pregnancy is planned.

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Tutkielma ksittelee kieliopillisen suvun silymist myhisess muinaisenglannissa (<i>Late Old English</i>) ja varhaiskeskienglannissa (<i>Early Middle English</i>). Tutkielman tavoitteena on ptell, kuinka kieliopillinen suku silyy kolmessa muinaisenglannin/varhaiskeskienglannin aikakautta edustavassa tekstiss. Lhdeaineisto on valittu edustamaan aikaa (1150-1225), jolloin kieliopillisen suvun on sanottu kadonneen englannin kielest. Lhdeaineisto mys edustaa kahta eri tekstilajia, ja tarjoaa siten aineistoa niiden vliseen vertailuun. Aineistosta on analysoitu nominien ptteit, demonstratiivipronomineja sek anaforisia persoonapronomineja, joissa substantiivien kieliopillinen suku nkyy. Osa anaforisista viittauksista on selitettviss personifikaatiolla, jolloin elottomiin objekteihin tai ksitteisiin on liitetty inhimillistvi piirteit. Tutkimuksen perusteella kieliopillinen suku silyy viel joissakin muodoissa 1200- luvulle saakka. Merkittv on aineistossa esiintyv runsas vaihtelu ja pyhimyselmnkertojen ja lketieteellisen tekstin vliset erot.

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The objective of this masters thesis was to develop a model for mobile subscription acquisition cost, SAC, and mobile subscription retention cost, SRC, by applying activity-based cost accounting principles. The thesis was conducted as a case study for a telecommunication company operating on the Finnish telecommunication market. In addition to activity-based cost accounting there were other theories studied and applied in order to establish a theory framework for this thesis. The concepts of acquisition and retention were explored in a broader context with the concepts of customer satisfaction, loyalty and profitability and eventually customer relationship management to understand the background and meaning of the theme of this thesis. The utilization of SAC and SRC information is discussed through the theories of decision making and activity-based management. Also, the present state and future needs of SAC and SRC information usage at the case company as well as the functions of the company were examined by interviewing some members of the company personnel. With the help of these theories and methods it was aimed at finding out both the theory-based and practical factors which affect the structure of the model. During the thesis study it was confirmed that the existing SAC and SRC model of the case company should be used as the basis in developing the activity-based model. As a result the indirect costs of the old model were transformed into activities and the direct costs were continued to be allocated directly to acquisition of new subscriptions and retention of old subscriptions. The refined model will enable managing the subscription acquisition, retention and the related costs better through the activity information. During the interviews it was found out that the SAC and SRC information is also used in performance measurement and operational and strategic planning. SAC and SRC are not fully absorbed costs and it was concluded that the model serves best as a source of indicative cost information. This thesis does not include calculating costs. Instead, the refined model together with both the theory-based and interview findings concerning the utilization of the information produced by the model will serve as a framework for the possible future development aiming at completing the model.

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The objective of this study is to resolve how customer retention is managed in Finnish health and fitness clubs, and how is this comparable with the theoretical aspects of customer retention. It is also discussed how the process leading to customer retention is handled, and what the essential elements of customer retention and loyalty are specifically in the health and fitness club industry. In addition, it is discussed to what extent do health and fitness club companies implement the elements of customer retention in their businesses. Finally, there is discussion about the relationship and priority between the behavioral and attitudinal methods of creating retention in the companies. The data was collected by interviewing the management of six health and fitness clubs from different geographical regions in Finland. Results indicated that the most important constructs concerning customer retention were switching barriers, pricing strategy, competitive aspect, corporate image, service quality, employee retention, and customer satisfaction. In addition, the implementation of customer retention was found to vary between different sized companies and companies from different geographical locations. Moreover, it was discovered that the companies put more effort in constructs that are considered to create customer loyalty instead of retention.

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In the literature survey retention mechanisms, factors effecting retention and microparticles were studied. Also commercial microparticle retention systems and means to measure retention were studied. Optical retention measurement with RPA and Lasentec FBRM was studied. The experimental part contains study of different cationic polyacrylamides, anionic silica, bentonite and new generation micropolymer. In these studies the dosage, dosing order and dosing history were changing factors. The experimental work was done with RPA-apparatus with which, the retention process can be followed in real time. In testing was found that silica yielded better retention, when dosed nontraditionally before the polymer. Also silica was very dependant on the polymer dosage. With bentonite good colloidal retention was achieved with relatively low doses. Unlike silica bentonite was not dependant on polymer dosage. The relation of bentonite and polymer dosage is more defining when high retention is wanted. With 3-component systems using bentonite very high retention was achieved. With silica no improvement in retention was found in 3-component systems compared to dual component systems.

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Nanofiltration performance was studied with effluents from the pulp and paper industry and with model substances. The effect of filtration conditions and membrane properties on nanofiltration flux, retention, and fouling was investigated. Generally, the aim was to determine the parameters that influence nanofiltration efficiency and study how to carry out nanofiltration without fouling by controlling these parameters. The retentions of the nanofiltration membranes studied were considerably higher than those of tight ultrafiltration membranes, and the permeate fluxes obtained were approximately the same as those of tight ultrafiltration membranes. Generally, about 80% retentions of total carbon and conductivity were obtained during the nanofiltration experiments. Depending on the membrane and the filtration conditions, the retentions of monovalent ions (chloride) were between 80 and 95% in the nanofiltrations. An increase in pH improved retentions considerably and also the flux to some degree. An increase in pressure improved retention, whereas an increase in temperature decreased retention if the membrane retained the solute by the solution diffusion mechanism. In this study, more open membranes fouled more than tighter membranes due to higher concentration polarization and plugging of the membrane material. More irreversible fouling was measured for hydrophobic membranes. Electrostatic repulsion between the membrane and the components in the solution reduced fouling but did not completely prevent it with the hydrophobic membranes. Nanofiltration could be carried out without fouling, at least with the laboratory scale apparatus used here when the flux was below the critical flux. Model substances had a strong form of the critical flux, but the effluents had only a weak form of the critical flux. With the effluents, some fouling always occurred immediately when the filtration was started. However, if the flux was below the critical flux, further fouling was not observed. The flow velocity and pH were probably the most important parameters, along with the membrane properties, that influenced the critical flux. Precleaning of the membranes had only a small effect on the critical flux and retentions, but it improved the permeability of the membranes significantly.

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Based on a specially created mass spectral database utilizing 23 tetradecenyl and 22 hexadecenyl acetate standards along with Kvats retention indices obtained on a very polar stationary phase [poly (biscyanopropyl siloxane)] (SP 2340), (Z)-9-hexadecenyl acetate, (Z)-11-hexadecenyl acetate and (E)-8-hexadecenyl acetate were identified in active pheromone extracts of Elasmopalpus lignosellus. This identification was more efficient than our previous study using gas chromatography/mass spectrometry with a dimethyl disulfide derivative where we could only identify the first two acetates. The acetate composition of the pheromone gland differed from region to region in Brazil and from that from the Tifton (GA, USA) population, suggesting polymorphism or a different sub-species.

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The aim of this work is the production and characterization of plasma polymerized acetaldehyde thin films. These films show highly polar species, are hydrophilic, organophilic and easily adsorb organic reactants with CO radicals but only allow permeation of reactants with OH radicals. The good step coverage of films deposited on aluminum trenches is useful for sensor development. Films deposited on hydrophobic substrates may result in a discontinued layer, which allows the use of preconcentration in sample pretreatment. Deposition on microchannels showed the possibility of chromatographic columns and/or retention system production to selectively detect or remove organic compounds from gas flows.

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Genetic algorithm and multiple linear regression (GA-MLR), partial least square (GA-PLS), kernel PLS (GA-KPLS) and Levenberg-Marquardt artificial neural network (L-M ANN) techniques were used to investigate the correlation between retention index (RI) and descriptors for 116 diverse compounds in essential oils of six Stachys species. The correlation coefficient LGO-CV (Q) between experimental and predicted RI for test set by GA-MLR, GA-PLS, GA-KPLS and L-M ANN was 0.886, 0.912, 0.937 and 0.964, respectively. This is the first research on the QSRR of the essential oil compounds against the RI using the GA-KPLS and L-M ANN.

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Genetic algorithm and partial least square (GA-PLS) and kernel PLS (GA-KPLS) techniques were used to investigate the correlation between retention indices (RI) and descriptors for 117 diverse compounds in essential oils from 5 Pimpinella species gathered from central Turkey which were obtained by gas chromatography and gas chromatography-mass spectrometry. The square correlation coefficient leave-group-out cross validation (LGO-CV) (Q) between experimental and predicted RI for training set by GA-PLS and GA-KPLS was 0.940 and 0.963, respectively. This indicates that GA-KPLS can be used as an alternative modeling tool for quantitative structure-retention relationship (QSRR) studies.