4 resultados para Multivariate unit root tests

em Universidade Federal do Rio Grande do Norte(UFRN)


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Image compress consists in represent by small amount of data, without loss a visual quality. Data compression is important when large images are used, for example satellite image. Full color digital images typically use 24 bits to specify the color of each pixel of the Images with 8 bits for each of the primary components, red, green and blue (RGB). Compress an image with three or more bands (multispectral) is fundamental to reduce the transmission time, process time and record time. Because many applications need images, that compression image data is important: medical image, satellite image, sensor etc. In this work a new compression color images method is proposed. This method is based in measure of information of each band. This technique is called by Self-Adaptive Compression (S.A.C.) and each band of image is compressed with a different threshold, for preserve information with better result. SAC do a large compression in large redundancy bands, that is, lower information and soft compression to bands with bigger amount of information. Two image transforms are used in this technique: Discrete Cosine Transform (DCT) and Principal Component Analysis (PCA). Primary step is convert data to new bands without relationship, with PCA. Later Apply DCT in each band. Data Loss is doing when a threshold discarding any coefficients. This threshold is calculated with two elements: PCA result and a parameter user. Parameters user define a compression tax. The system produce three different thresholds, one to each band of image, that is proportional of amount information. For image reconstruction is realized DCT and PCA inverse. SAC was compared with JPEG (Joint Photographic Experts Group) standard and YIQ compression and better results are obtain, in MSE (Mean Square Root). Tests shown that SAC has better quality in hard compressions. With two advantages: (a) like is adaptive is sensible to image type, that is, presents good results to divers images kinds (synthetic, landscapes, people etc., and, (b) it need only one parameters user, that is, just letter human intervention is required

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In this work, the quantitative analysis of glucose, triglycerides and cholesterol (total and HDL) in both rat and human blood plasma was performed without any kind of pretreatment of samples, by using near infrared spectroscopy (NIR) combined with multivariate methods. For this purpose, different techniques and algorithms used to pre-process data, to select variables and to build multivariate regression models were compared between each other, such as partial least squares regression (PLS), non linear regression by artificial neural networks, interval partial least squares regression (iPLS), genetic algorithm (GA), successive projections algorithm (SPA), amongst others. Related to the determinations of rat blood plasma samples, the variables selection algorithms showed satisfactory results both for the correlation coefficients (R²) and for the values of root mean square error of prediction (RMSEP) for the three analytes, especially for triglycerides and cholesterol-HDL. The RMSEP values for glucose, triglycerides and cholesterol-HDL obtained through the best PLS model were 6.08, 16.07 e 2.03 mg dL-1, respectively. In the other case, for the determinations in human blood plasma, the predictions obtained by the PLS models provided unsatisfactory results with non linear tendency and presence of bias. Then, the ANN regression was applied as an alternative to PLS, considering its ability of modeling data from non linear systems. The root mean square error of monitoring (RMSEM) for glucose, triglycerides and total cholesterol, for the best ANN models, were 13.20, 10.31 e 12.35 mg dL-1, respectively. Statistical tests (F and t) suggest that NIR spectroscopy combined with multivariate regression methods (PLS and ANN) are capable to quantify the analytes (glucose, triglycerides and cholesterol) even when they are present in highly complex biological fluids, such as blood plasma

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It has been shown that the development of peri-implant mucositis is associated with biofilm accumulation. It is believed that the therapeutic approaches used in periodontal disease may have a positive effect in the cases of peri-implant disease. The aim of this study was to evaluate the effectiveness of non-surgical treatment of peri-implant mucositis, with or without the use of chlorhexidine 0,12% in subjects rehabilitated with osseointegrated implants. Thus, patients were randomly divided into test group (chlorhexidine surgical therapy) and control (non-surgical treatment). This therapy consisted of an adaptation of the (Full Mouth scalling and Root Planing) nonoperative protocol FMSRP, but without the use of ultrasound. The visible plaque index (VPI), gingival bleeding index (GBI), probing depth (PD), bleeding on probing (BOP) and keratinized mucosa clinical parameters were evaluated at baseline and at different times after treatment. The data were not normally distributed and the implant was considered the sampling unit. Data were analyzed using Fri edman and Wilcoxon chi-square (=5%), tests using the Statistical Package for Social Sciences 17.0 (SPSS). Thus, 119 implants were evaluated, 61 in the test group and 58 in the control group. The results showed statistically significant differences for the variables: average BTI implants in both groups (p<0,001), mean ISG implants both in the test group (p<0,001), and control (p= 0,006) of implants; PS for the test group (p< 0,001) and control (p = 0,015) and SS (p<0,001) in the two treatment groups. However, there was no statistically significant difference when the groups were compared. The PS and SS variables showed no statistically significant difference in any of independent interest to the study (age, sex, smoking, treatment group, keratinized mucosa at different times, peri-implant biotype, average VPI implants and GBI). Thus, it can be concluded that both the mechanical treatment isolated as its association with chlorhexidine mouthwash 0.12% can be used for the treatment of peri-implant mucositis. Moreover, the condition of oral h ygiene has improved between baseline and six months and the depth and bleeding on probing decreased after three and six months

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The growth of the elderly population is a global phenomenon and, in Brazil, this transformation is happening in a very rapid rhythm. With the current population aging, this emerging age group will need more health care and attention. One of the characteristics of the population aging is the progressive accumulation of disabilities, which makes it more vulnerable to falls. This study was developed with the purpose of knowing the episode falls in the scope of an elderly population treated at a Family Health Unit. It is a research with cross-sectional nature, and its sample was composed by 121 elderly. The research was approved by the Ethics Committee of HUOL, with Opinion nº 816.022. We applied a questionnaire to the participants, and the results were statistically analyzed by using Chi-square test and Fisher’s exact test to verify the association between variables. In order to perform a multivariate analysis, we used the method of the Binomial Logistic Regression. For both tests, we accepted significance p<0,05 and CI of 95%. The results prove that the majority belongs to the female gender (76,9%); the age group of elderly reaches 88,4% and 11,6% is over-aged; regarding the marital status, 35,3% are married and 29,4% widowed; 92,1% with family income between one and two minimum wages; and 91,8% live with their partners and/or children. Regarding the frequency of falls, we found that 61,2% of the surveyed elderly suffered one or more falls in 2014. As associated factors, it became clear that 73,8% were due to extrinsic factors, 6,4% to intrinsic factors and 21,4% to both factors. As a consequence of the fall, we found that 89,2% have fear of falling again, 37,3% showed anxiety and 13,3% had their ambulation affected. Concerning the exposure to the risk factors, the most prevalent places were: street/avenue (31,0%), pavement (19,0%), living room (14,3%) and courtyard/backyard (10,7%). The study has proven a statistically significant association among female gender (p=0,001), rubble/objects in the backyard (p=0,015) and furniture that may cause accidents (p=0,005). It was evident among the elderly people surveyed, 72.7% receive little information about falls, being a risk factor for falls. We conclude that there is a high frequency of falls in the surveyed elderly, thereby constituting a worrisome data because this event in the elderly population is a serious matter, which raises the need to ensure them a safe environment in their homes and, above all, outside them. The information provided by the Family Health Strategy team are important to avoid these occurrences, which reinforces the need for developing health education activities together with the population as a way to prevent and reduce the occurrence of falls, thereby improving the quality of life of elderly.