881 |
Streaming Video over Unreliable and Bandwidth Limited NetworksAziz, Hussein January 2013 (has links)
The main objective of this thesis is to provide a smooth video playout on the mobile device over wireless networks. The parameters that specify the wireless channel include: bandwidth variation, frame losses, and outage time. These parameters may affect the quality of the video negatively, and the mobile users may notice sudden stops during the playout video, i.e., the picture is momentarily frozen, followed by a jump from one scene to a different one. This thesis focuses on eliminating frozen pictures and reducing the amount of video data that need to be transmitted. In order to eliminate frozen scenes on the mobile screen, we propose three different techniques. In the first technique, the video frames are split into sub-frames; these sub-frames are streamed over different channels. In the second technique the sub-frames will be “crossed” and sent together with other sub-frames that are from different positions in the streaming video sequence. If some sub-frames are lost during the transmission a reconstruction mechanism will be applied on the mobile device to recreate the missing sub-frames. In the third technique, we propose a Time Interleaving Robust Streaming (TIRS) technique to stream the video frames in different order. The benefit of that is to avoid losing a sequence of neighbouring frames. A missing frame from the streaming video will be reconstructed based on the surrounding frames on the mobile device. In order to reduce the amount of video data that are streamed over limited bandwidth channels, we propose two different techniques. These two techniques are based on identifying and extracting a high motion region of the video frames. We call this the Region Of Interest (ROI); the other parts of the video frames are called the non-Region Of Interest (non-ROI). The ROI is transmitted with high quality, whereas the non-ROI is interpolated from a number of references frames. In the first technique the ROI is a fixed size region; we considered four different types of ROI and three different scenarios. The scenarios are based on the position of the reference frames in the streaming frame sequence. In the second technique the ROI is identified based on the motion in the video frames, therefore the size, position, and shape of the ROI will be different from one video to another according to the video characteristic. The videos are coded using ffmpeg to study the effect of the proposed techniques on the encoding size. Subjective and objective metrics are used to measure the quality level of the reconstructed videos that are obtained from the proposed techniques. Mean Opinion Score (MOS) measurements are used as a subjective metric based on human opinions, while for objective metric the Structural Similarity (SSIM) index is used to compare the similarity between the original frames and the reconstructed frames.
|
882 |
Vliv tělesné kondice dojnic na hladinu ketolátek v krviBEŇASOVÁ, Veronika January 2019 (has links)
The aim of this diploma thesis is to evaluate the data about holstein dairy cow body condition at calving and to review its effect on ketones blood level and its relation to incidence of ketosis. The monitoring took place in a selected dairy farm from October 2017 to February 2019. Body condition of 280 cows was evaluated on the day of calving by assessing the body condition score (BCS) and later on 10 days in milk the blood level of B-hydroxybutyrate was measured. Furthermore, parity, body weight in calving day, body weight on 10 days in milk, content of milk fat and protein on 10 days in milk and milk yield on 10 days in milk were monitored. Average BCS of the herd was 3,7, the maximum measured BCS value was 5, the minimum was 2. Total incidence of ketosis on herd level was 21,07 % considering ketosis if BHB 1,0 mmol.l-1. 62,7 % of that was a subclinical form of ketosis while the remaining 37,3 % was the clinical form of ketosis. Correlation analysis of the relation between parity and level of BHB in blood showed positive correlation (r=0,15, p=0,00), when cows on higher lactation had higher level of blood BHB. Positive correlation between fat/protein ratio in milk and level of BHB in blood was evaluated by correlation analysis (r=0,31 , p=0,00). The BCS at calving and BHB level on 10 days in milk showed positive correlation (r=0,14 , p=0,02). As far as negative energy balance is taken into account, the positive correlation between BCS at calving and body weight loss was confirmed (r=0,17 , p=0,00). The fact that heavier cows and cows with higher BCS mobilise more body fat reserves was confirmed by positive correlation between the body weight at calving and the body weight loss (r=0,47, p=0,00) and between the body weight at calving and the fat/protein ratio in milk (r=0,27, p=0,00). Body weight at calving had provable positive impact on the milk yield (r=0,19, p=0,00).
|
883 |
Evaluación de escalas de riesgo como predictores de mortalidad en niños menores de cinco años con neumonía adquirida en la comunidad en el INSN entre los años 2013 – 2015, Lima PerúFernández Mormontoy, Jorge Arturo, Vargas Alvarado, Oscar Fernando 30 April 2019 (has links)
Antecedentes: La neumonía es una infección grave común en la infancia y principal causa de muerte en niños menores de 5 años. Se sabe poco sobre escalas que evalúen el riesgo de muerte por neumonía. Objetivos: Establecer qué escala tiene mejor desempeño como predictor de muerte por neumonía adquirida en la comunidad (NAC) en niños menores de cinco años. Métodos: Se realizo un estudio observacional, retrospectivo, analítico con un diseño de precisión diagnóstica en una cohorte de registros clínicos de pacientes con NAC entre 2013 y 2015 en las primeras 24 horas de ingreso al hospital. El desempeño de las tres escalas se evaluó comparando el área bajo la curva (ABC) como medida de capacidad discriminativa. Resultados: La escala PIRO modificada (Predisposition, Insult, Response and Organic dysfunction) tiene mayor capacidad discriminatoria con un ABC de 0,93 (IC del 95%: 0,89 a 0,96), siendo la mejor de las tres escalas evaluados. En segundo lugar, la escala RISC (Respiratory Index of Severity in Children) con ABC 0,83 (IC 95%: 0.79-0.87) y, finalmente, la escala PRESS (Pediatric Respiratory Severity Score) ABC 0.67 (IC 95% 0.61 - 0.74). Conclusión: Las escalas PIROm y RISC son buenos predictores de muerte en niños menores de 59 meses, basados en criterios clínicos, radiológicos y laboratoriales. La primera escala podría ser utilizada en centros de salud de mayor complejidad. La segunda escala netamente clínica podría ser utilizada en centros de atención primaria de salud. Se sugiere realizar más estudios en poblaciones con diversas características clínicas, demográficas y ambientales. / Background: Pneumonia is a common serious infection in childhood, being the major cause of death in children under 5 years. Little is kwon about clinical scales predicting risk of death owing to pneumonia Objectives: Establish which scale has better performance as a predictor of death due to community-acquired pneumonia (CAP) in children under five years. Methods: An observational, retrospective, analytical study with a diagnostic precision design was conducted in a cohort of clinical records of patients with CAP between 2013 and 2015 that were review in the first 24 hours of admission to the hospital. The performance of the three scales were evaluated by the comparison of the area under the curve (AUC) as a measure of discriminative capacity. Results: The PIRO modified scale (Predisposition, Insult, Response and Organic dysfunction) has greater discrimination capacity AUC of 0.93 (95% CI 0.89 - 0.96) being the best of the three evaluated. Secondly, the RISC scale (Respiratory Severity Index in children) with AUC 0.83 (95% CI: 0.79-0.87) and, finally, the PRESS scale (Pediatric Respiratory Severity Score) AUC 0.67 (95% CI 0.61 - 0.74). Conclusion: The PIROm and RISC scales are good predictors of death in children under 59 months, based on clinical, radiological and laboratory criteria. The first scale could be used in healthcare centers of higher complexity. The second scale purely clinical could be used in centers of primary health care attention. It is suggested to carry out more studies in diverse populations with different clinical, demographical and environmental characteristics. / Tesis
|
884 |
The performance of inverse probability of treatment weighting and propensity score matching for estimating marginal hazard ratiosNåtman, Jonatan January 2019 (has links)
Propensity score methods are increasingly being used to reduce the effect of measured confounders in observational research. In medicine, censored time-to-event data is common. Using Monte Carlo simulations, this thesis evaluates the performance of nearest neighbour matching (NNM) and inverse probability of treatment weighting (IPTW) in combination with Cox proportional hazards models for estimating marginal hazard ratios. Focus is on the performance for different sample sizes and censoring rates, aspects which have not been fully investigated in this context before. The results show that, in the absence of censoring, both methods can reduce bias substantially. IPTW consistently had better performance in terms of bias and MSE compared to NNM. For the smallest examined sample size with 60 subjects, the use of IPTW led to estimates with bias below 15 %. Since the data were generated using a conditional parametrisation, the estimation of univariate models violates the proportional hazards assumption. As a result, censoring the data led to an increase in bias.
|
885 |
Inseminação artificial em tempo fixo em vacas holandesas de alta produção / Timed artificial insemination in high producing holstein cowsSouza, Alexandre Henryli de 26 March 2008 (has links)
A presente tese foi dividida em 5 Experimentos. Os objetivos do Experimento 1 foram avaliar a utilização da gonadotrofina coriônica equina (eCG) e/ou do cipionato de estradiol (ECP) na dinâmica folicular e taxa de concepção de vacas holandesas submetidas a inseminação em tempo fixo (IATF). No D0, todos os animais (n = 782) receberam 2 mg de benzoato de estradiol (BE) e um dispositivo intravaginal de progesterona (CIDR). Oito dias depois, o CIDR foi retirado e todos os animais receberam PGF2?. Simultaneamente, os animais foram divididos em 4 grupos: G1) eCG + ECP no Dia 8; G2) eCG no Dia 8 + GnRH após 48h; G3) ECP no Dia 8; G4) GnRH após 48h. Amostras de sangue e exames utlra-sonográficos foram realizados frequentemente em um subgrupo de animais (n = 96). As análises estatísticas de todos os experimentos foram efetuadas com o proc GLIMMIX e proc MIXED do SAS. O uso de eCG e o escore de condição corporal (ECC) dos animais afetaram as concentrações circulantes de progesterona no diestro. Os animais do G2 apresentaram maior taxa de concepção que os do G4 (33,8% vs. 28,9%). Além disso, para animais de menor ECC, ficou evidente o benefício da aplicação de eCG (G2 = 44,4% vs. G4 = 6,1%). No Experimento 2 (n = 26), o objetivo foi comparar o efeito da administração da eCG no dia da remoção do CIDR em animais de menor (2,0-2,5) ou maior (3,0-3,5) ECC. Foram avaliadas algumas características do corpo lúteo (CL) como o volume e histologia, assim como as concentrações plasmáticas de progesterona no diestro. Independentemente da condição corporal dos animais, a eCG aumentou o volume do CL e a concentração plasmática de progesterona no diestro. O ECC afetou negativamente o volume e concentração de progesterona sérica no diestro. Não foi encontrado diferença na proporção de células grandes/pequenas, assim como no fluxo sanguíneo no CL entre os grupos experimentais. No Experimento 3, foi comparado a taxa de concepção em vacas de leite de alta produção (n = 388) após o uso do protocolo G2 do Experimento 1 (Capítulo I), com ou sem adição de ECP no momento da retirada do CIDR (novo ou usado). Não foi verificado efeito da adição do tratamento com ECP e nem do tipo do dispostivo na taxa de concepção. No Experimento 4 (n = 199), apesar no aumento verificado no diâmetro folicular no grupo tratado com GnRH 56h (17,8 mm) comparado com GnRH 48h (16,5 mm); e do atraso no momento da ovulação após a retirada do CIDR (GnRH 56h = 75,3h; GnRH 48h = 79,8h) não foi constatado qualquer diferença na concepção ao se atrasar a aplicação do GnRH de 48h para 56h em vacas inseminadas 16h depois do GnRH. No Experimento 5 (n = 185), a taxa de concepção não diferiu em animais que receberam o GnRH 48h ou 56h (momento da IATF) após a retirada do CIDR, indicando a possibilidade do emprego de um protocolo com apenas 3 manejos em vacas de leite de alta produção. / The current thesys has been divided in 5 Experiments. Objectives of Experiment 1 were to evaluate the effects of equine chorionic gonadotropin (eCG) and/or estradiol cypionate (ECP) on follicular dymanics and conception rate in Holstein cows receiving fixed timed artificial insemination (TAI). On D0, all cows (n = 782) received 2 mg of estradiol benzoate (EB) and one intravaginal progesterone device (CIDR). Eight days later, CIDR was removed and all animals were treated with PGF2?. Simultaneously, animals were divided in 4 groups: G1) eCG + ECP on Day 8; G2) eCG on Day 8 + GnRH 48h later; G3) ECP on Day 8; G4) GnRH 48h later. Blood samples and ultrasound exams were frequently performed in a subset of the animals (n = 96). All the statistical analyses for all experiments were performed with proc GLIMMIX and proc MIXED of SAS. Equine chorionic gonadotropin (eCG) treatment and body condition score (BCS) affected circulating progesterone in the diestrus. Cows in G2 had greater conception rates than cows in G4 (33,8% vs. 28,9%). In addition, in cows with lower BCS, eCG seems to be even more affective (G2 = 44,4% vs. G4 = 6,1%). In Experiment 2 (n = 26), the objective was to compare the effect of eCG the day of CIDR removal in animals with lower (2,0-2,5) or higher (3,0-3,5) BCS. Some variables such as corpus luteum (CL) volume, histology and circulating progesterone concentration in the diestrus were evaluated. Regardless of the body condition of the animals, eCG increased CL volume and circulating progesterone concentration in the diestrus. BCS negatively affected CL volume and circulating progesterone. There were no differences in large/small CL cell ratio, as well as CL blood flow between experimental groups. In Experiment 3, it was compared conception rate in dairy cows (n = 388) after using the same protocol G2 from Experiment 1 (Chapter I), with or without an ECP treatment at the time of CIDR (new or used) removal. Both ECP treatment and type of CIDR did not significantly affected conception rates. In Experiment 4 (n = 199), despite the fact that follicular diameter was increased in group GnRH 56h (17,8 mm) compared with GnRH 48h (16,5 mm); and of the delayed time of ovulation after CIDR removal (GnRH 56h = 75,3h; GnRH 48h = 79,8h), there were no differences in conception rates after delaying the GnRH treatment from 48h to 56h in cows inseminated 16h after GnRH. In Experiment 5 (n = 185), conception rate did not differ in animals that received GnRH 48h or 56h (at the time of TAI) after CIDR removal, indicating the possibility of using a protocol with only 3 handlings in high producing dairy cows.
|
886 |
Influência de diferentes sistemas de manejo sobre parâmetros comportamentais, produtivos e de qualidade de carne de bovinos confinados / Influence of different handling systems on the behavioural, productive and meat quality parameters of confined cattleNunes, Bruno César Prosdocimi 06 October 2009 (has links)
O presente estudo teve como objetivo investigar a influência de diferentes sistemas de manejo sobre a reatividade, parâmetros produtivos e de qualidade de carne e carcaça de bovinos confinados. Para isso, foram utilizados 50 novilhos Nelore, alocados em confinamento sob dois sistemas diferentes quanto ao manejo, o tradicionalmente empregado em fazendas (MT) e o baseado em princípios racionais de trabalho e na biologia dos bovinos, conhecido popularmente como manejo racional ou gentil (MR). Os animais de ambos os tratamentos receberam a mesma dieta e ficaram em confinamento por 126 dias (± 18 dias). Foram colhidas, durante os manejos de pesagem em brete, informações quanto ao ganho diário de peso (GDP) e reatividade (através do Escore de Comportamento Composto - ECC). Calculou-se, ao fim do confinamento, o ganho diário médio de peso (GDPtot). Durante o abate, foram colhidas informações quanto à reatividade dos bovinos no bloco de atordoamento (ECCabt). Durante a desossa, foram registradas informações quanto a coloração (L*, a* e b*) das amostras de Longissimus dorsi colhidas, três de cada animal, uma para cada tempo de maturação (0, 7 e 14 dias). Apos o período de maturação, procedeu-se com as análises de perdas de água por exsudação (PAE) e por cozimento (PAC), bem como de força de cisalhamento (MAC). Os resultados indicam que ocorreram influencias dos sistemas de manejo nas características PAE e MAC, com valores superiores e inferiores, respectivamente, em MR. Ocorreram influencias na interação tratamento e manejos ocorridos no GDP, com resultados superiores em MT. No parâmetro MAC ocorreu diferença significativa em relação aos dias de maturação, com diminuição ao longo do tempo de maturação, alem de diferenças nos tratamentos na carne nao maturada, com valores inferiores para MR. As características Contusões (totais, no dianteiro, na ponta de agulha e no traseiro), ECCabt, de coloração (L*, a* e b*) e de PAC não apresentaram diferenças significativas entre os tratamentos ou suas interações. Constatou-se melhor qualidade de carne de animais MR, porém com ganhos de peso ligeiramente inferiores aos do MT. A reatividade apresentou tendência de diminuição ao longo do confinamento, com valores ligeiramente inferiores para animais MR nos manejos de pesagem em brete e mais acentuados no momento do abate. / The present study investigated the influence of different handling systems on the reactivity, production parameters and quality of meat and carcass of confined cattle. The experiment used 50 Nellore steers placed in feedlots that received two different handling systems: the traditionally used in the Brazilian farms (MT) and the based on rational principles of work and in the biology of cattle, known as gentle handling (MR).Both treatments received the same diet and remained in confinement for 126 days (± 18 days). Were taken over the handling in squeeze chute, information about the daily weight gain (GDP) and reactivity (through the Composite Behaviour Score - ECC). At the end of the confinement, the average daily weight gain (GDPtot) was calculated. During the slaughter, was collected information of the reactivity of cattle in stunning pen (ECCabt). During the boning, were recorded information about the color (L *, a * b *) of Longissimus dorsi samples. Three samples from each animal was collected, one for each maturation period (0, 7 and 14 days). After the maturation period, that was preceded with the analysis of water loses by exudation (PAE) and by cooking (PAC) and the shear-force (MAC). The results indicate that there were influences of the handling systems features in PAC and MAC, with values higher and lower, respectively, in MR. Occurred influences in treatment and management occurred in GDP, with superior results in MT. In the MAC, parameter was significant difference for days to maturity, with a reduction over maturation time, and differences in treatment in the meat does not mature, with lower values for MR. The characteristics contusions, ECCabt, meat color (L *, a * b *) and PAC showed no significant differences between treatments or their interactions. It was better quality of meat from animals MR, but with gains weight slightly lower than that of MT. The reactivity, although not significantly different, tended to decrease during the confinement, with slightly lower values for MR in the management of animals weighing more pronounced in squeeze chute and at slaughter.
|
887 |
Parâmetros clínicos, hemogasométricos e radiográficos para avaliação respiratória de neonatos caninos nascidos em eutocia ou cesariana eletiva / Canine neonatal clinical, hemogasometric and radiographic assessment in eutocia or elective cesarean sectionSilva, Liege Cristina Garcia da 26 June 2008 (has links)
Estima-se que a mortalidade neonatal canina nas primeiras semanas de vida seja de 30%, em razão de diversas causas, dentre elas falhas de assistência neonatal. Em Medicina Humana, protocolos de assistência cardio-respiratória ao recém-nascido estão bem estabelecidos e são utilizados de rotina. Porém, os cuidados direcionados aos neonatos debilitados em Medicina Veterinária são, em geral, empíricos e passíveis de causar traumas e contusões. Deste modo, objetivou-se comparar o padrão do aparelho respiratório ao nascimento e a evolução durante a primeira hora de vida em neonatos nascidos em eutocia via vaginal ou cesariana eletiva; propor um protocolo de conduta para a avaliação do aparelho respiratório de neonatos nascidos em eutocia ou cesariana, por meio da auscultação cardio-torácica, do escore Apgar, hemogasometria, avaliação radiográfica pulmonar e da determinação do surfactante no líquido amniótico; relacionar o exame clínico geral com a avaliação específica do aparelho respiratório; estabelecer a análise de maior sensibilidade e especificidade na identificação de distúrbios respiratórios neonatais; quantificar os fosfolipídeos lecitina (L) e esfingomielina (E) no líquido amniótico; estabelecer a relação L/E, como indício de maturidade pulmonar. Utilizou-se 41 neonatos divididos em 2 grupos conforme a condição obstétrica: eutocia (1) ou cesariana eletiva (2). Foram avaliados o escore Apgar, temperatura corpórea e exame físico completo aos 0, 5 e 60 minutos pós-natal; hemogasometria venosa aos 0 e 60 minutos do nascimento e padrão radiográfico pulmonar ao nascimento. Houve significativo aumento dos valores de Apgar no decorrer da primeira hora de vida. Entretanto, o grupo 2 apresentou escore inferior ao nascimento e após 5 minutos. A temperatura corpórea neonatal apresentou significativa queda ao longo da primeira hora de vida, para ambos os grupos, com hipotermia após 5 e 60 minutos do nascimento. A auscultação pulmonar indicou irregularidade do padrão respiratório, presença de ruído respiratório de moderado a intenso e episódios de agonia respiratória, com evolução satisfatória ao longo da primeira hora de vida para ambos os grupos. Filhotes nascidos de cesariana apresentaram maior percentual de alterações radiográficas, com moderada a intensa opacificação pulmonar difusa, com pouca ou nenhuma definição da silhueta cardíaca e luz dos brônquios principais. Ao nascimento e após 1 hora, todos os neonatos apresentaram acidemia, sendo esta do tipo mista para o grupo 1 e do tipo respiratória para o grupo 2. Após 60 minutos houve parcial evolução do desequilíbrio ácido-básico em ambos os grupos. Não houve diferença estatística entre a relação L/E dos grupos 1 e 2 com valores de 7,29 (±3,55) e 5,89 (±4,87), respectivamente. Conclui-se que o padrão de análise do aparelho respiratório neonatal variou conforme a condição obstétrica; as variáveis de maior sensibilidade e especificidade para identificação de neonatos com distúrbios respiratórios ao nascimento foram auscultação torácica associada à avaliação hemogasométrica das variáveis pH e pCO2; os fosfolipídeos lecitina e esfingomielina presentes no líquido amniótico foram quantificados e a relação L/E estabelecida e indicou maturidade pulmonar independente da condição obstétrica. / Technical and scientific deficit related to veterinary neonatology is conspicuous. It is known that the canine mortality rate is up to 30% in the first weeks of life. In Human Medicine, neonatal cardio-respiratory assistance is well established and widely used. Thus, the objectives of the present study were to compare the respiratory system pattern at birth and its evolution during the first hour of life in puppies born through eutocia or cesarian section; to standardize neonatal respiratory system assessment under distinct obstetrics conditions; to correlate clinical general variables to the specific respiratory ones; to identify the most sensible and specific variables in order to attain neonatal respiratory diagnosis; to quantify the phospholipids lecithin (L) and sphingomielin (S) in amniotic fluid; to establish the L/S ratio and its correlation with lung maturity. Forty-one canine neonates were allocated into 2 groups according to the whelping condition: group 1 - eutocia and group 2 - elective cesarean section. The following assessments were performed at 0, 5 and 60 minutes after birth: Apgar score and rectal temperature. Venous hemogasometric evaluation was attained after birth and 1 hour later. Lung x-ray was performed between 0 and 5 minutes of life. Group 2 neonates showed lower vitality, with Apgar score significantly inferior at birth and after 5 minutes. Nevertheless, there was full satisfactory recovery at 5 minutes in both groups, with the Apgar score superior to 7. There was a significant reduction in rectal temperature with hypothermia at 5 and 60 minutes of birth in both groups. Respiratory pattern was irregular at lung auscultation, with mild to moderate sounds, but all neonates evolved properly among the first hour of life. Lung x-rays indicated relevant alterations in 17% of the puppies of group 1 and 30% of group 2. Cardiac silhouette and the main caudal bronchi were clearly visualized and the image of the thymus appeared like an enlarged domed volume in cranial mediastin, adjacent to the heart. The radiographic findings ranged from mild to moderate diffuse or restricted opacification of pulmonary parenchyma. Little or no definition of the cardiac silhouette, the main bronchi and the vagueness of the thymus were all findings consistent with pulmonary edema. All puppies presented acidemia at 0 and 60 minutes after birth, with partial recovery of the acid-base disorder in both groups during the first hour of life. L/S ratio was 7,29 (±3,55) for group 1 and 5,89 (±4,87) for group 2, with no statistical difference between them. In conclusion, obstetric condition influences neonatal respiratory pattern evaluation; lung auscultation associated with pH and pCO2 hemogasometric values, which were more sensible and specific to identify respiratory disorders at birth; lecithin and sphingomielin were quantified in the amniotic fluid; L/S ratio was established and indicated lung maturity regardless of the whelping condition.
|
888 |
Trauma and injury severity score: análise de novos ajustes no índice / Trauma and Injury Severity Score: analysis of new adjustments in the indexDomingues, Cristiane de Alencar 08 February 2013 (has links)
Introdução: O Trauma and Injury Severity Score (TRISS) é considerado padrão ouro na análise de probabilidade de sobrevida do doente traumatizado, apesar de suas limitações. Vários têm sido os esforços na tentativa de torná-lo mais acurado, tendo em vista seu importante papel nos Programas de Melhoria de Qualidade em Trauma. Objetivos: Propor três novos ajustes à equação do TRISS e comparar suas performances com o TRISS e o TRISS-like originais e com esses índices e o NTRISS com coeficientes ajustados à população do estudo; identificar se a técnica de imputação múltipla aumenta a acurácia das equações derivadas de bancos de dados com perdas e comparar o desempenho dos novos modelos quando derivados e aplicados em diferentes grupos de vítimas traumatizadas. Método: Trata-se de um estudo multicêntrico, retrospectivo, com vítimas de trauma internadas no Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC FMUSP) e no Centro de Trauma da Universidade da Califórnia San Diego Medical Center (UCSD MC), no período de 1º de janeiro de 2006 a 31 de dezembro de 2010. As informações dos doentes foram agrupadas em Bancos de Dados Derivação e Teste, sendo o primeiro utilizado para derivar as equações e o segundo para validar as equações geradas. Os coeficientes dos modelos foram estabelecidos pela análise de regressão logística. A curva Receiver Operating Characteristics (ROC) foi utilizada para avaliar a performance dos modelos e o algoritmo de DeLonge et al. para comparar as áreas sob as curvas (AUC). Resultados: A casuística foi composta de 2.416 doentes do HC FMUSP (São Paulo, Brasil) e 8.172 participantes do UCSD MC (San Diego, EUA). Os novos modelos propostos foram o NTRISS-like, que incluiu as variáveis Melhor Resposta Motora (MRM), Pressão Artéria Sistólica (PAS), New Injury Severity Score (NISS) e idade; o TRISS SpO2, com as variáveis Escala de Coma de Glasgow, PAS, saturação periférica de oxigênio (SpO2), Injury Severity Score, além da idade e o NTRISSlike SpO2 (MRM + PAS + SpO2 + NISS + idade). Todas as equações tiveram coeficientes ajustados para trauma contuso e penetrante. A técnica de imputação múltipla aplicada à derivação das equações não melhorou a acurácia dos modelos. Os modelos TRISS original, TRISS, TRISS-like e NTRISS com coeficientes ajustados e as novas propostas não apresentaram diferença estatisticamente significativa em sua performance. As novas equações ajustadas aos dados de São Paulo e as geradas com informações de San Diego apresentaram diferentes AUC ao serem aplicadas nos dois grupos de doentes dessas localidades. A acurácia sempre foi maior quando as equações foram aplicadas na população de San Diego. Conclusões: Os novos modelos apresentaram boa acurácia (cerca de 89,5%) e desempenho similar a outros ajustes do índice TRISS anteriormente publicados; portanto, podem ser utilizados nas avaliações de qualidade da assistência ao traumatizado. Os ajustes dos índices de probabilidade de sobrevida à realidade local de sua aplicação não melhoraram seu desempenho, resultado que reforça a incerteza sobre a necessidade desses ajustes, conforme o local de aplicação do índice. / Introduction: Trauma and Injury Severity Score (TRISS) is considered the \"gold standard\" in the analysis of survival probability of trauma patients, despite its limitations. There have been several efforts to make it more accurate because of its important role in Trauma Quality Improvement Programmes. Objectives: To propose three new adjustments to the TRISS equation and compare their performances with the TRISS and TRISS-like originals and these indices and NTRISS with coefficients adjusted to the study population; identify if the multiple imputation technique increases the accuracy of the equations derived from databases with missing; and to compare the performance of the new models when derivatives and applied to different groups of trauma patients. Methods: This is a multicenter, retrospective study with trauma victims admitted to the Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC FMUSP) and the Trauma Center at the University of California San Diego Medical Center (UCSD MC) for the period between January 1st, 2006 and December 31st, 2010. The information of patients were grouped into two different databases: derivation and testing; the first one served to derive the equations and the second was used to validate the equations generated. The model coefficients were established by logistic regression analysis. Receiver Operating Characteristic curve (ROC) was used to evaluate the performance of the models and De Long et al. algorithm to compare the areas under the curves (AUC). Results: The casuistic consisted of 2,416 patients from HC FMUSP (São Paulo, Brazil) and 8,172 participants from UCSD MC (San Diego, USA). The new models proposed were NTRISS-like which included the variables Best Motor Response (BMR), Systolic Blood Pressure (SBP), New Injury Severity Score (NISS) and age; TRISS SpO2 that included the variables Glasgow Coma Scale, SBP, saturation of peripheral oxygen (SpO2), Injury Severity Score and age; and NTRISS-like SpO2 (BMR + SBP + SpO2 + NISS + age). All equations had adjusted coefficients for blunt and penetrating trauma. The multiple imputation technique applied in the derivation of the equations did not improve the accuracy of the models. The original TRISS, and TRISS, TRISS-like and NTRISS with adjusted coefficients and the new proposals showed no statistically significant difference in performance. The new equations fitted to the São Paulo data and generated with information from San Diego showed different AUC when applied in the two patient groups in these localities. The accuracy was always higher when the equations were applied to the population of San Diego. Conclusions: The new models demonstrated good accuracy (about 89.5%) and similar performance to other TRISS adjustments previously published, and may be used in assessments of quality of care for traumatized. The survival probability scores adjustments to the local reality of its application did not improve its performance, a result that reinforces the uncertainty about the need for such adjustments, as the application site index.
|
889 |
Avaliação da fibrose miocárdica pela ressonância magnética cardíaca na estratificação prognóstica na miocardiopatia chagásica / Prognostic risk stratification in Chagas cardiomyopathy through myocardial fibrosis evaluation by cardiac magnetic resonanceSantos, Tiago Senra Garcia dos 15 May 2018 (has links)
Introdução: A miocardiopatia chagásica (MC) apresenta pior prognóstico que as etiologias isquêmica e não isquêmica de miocardiopatia, e acarreta alto custo. A fibrose miocárdica (FM) detectada pela Ressonância Magnética Cardíaca (RMC) mostrou-se um fator preditor independente de risco aumentado em diversas etiologias de insuficiência cardíaca. Na MC, a FM foi associada com marcadores conhecidos de pior prognóstico, como a disfunção ventricular esquerda e arritmia ventricular. Nossa hipótese é que a FM é um fator preditor independente de pior prognóstico na MC. Objetivos: Buscamos estabelecer o valor prognóstico da FM detectada pela RMC na predição de uma combinação de desfechos duros ou do desfecho secundário mortalidade por todas as causas. Adicionalmente, avaliamos se o valor prognóstico da FM é independente do Escore de Rassi. Métodos: Pacientes com MC foram incluídos retrospectivamente após a realização da RMC, que avaliou volumes e função cardíacos, além de quantificar a FM. Dados clínicos, de imagem e seguimento foram registrados, e o desfecho primário foi a combinação de mortalidade por todas as causas, transplante cardíaco, terapia antitaquicardia ou choque apropriado pelo cardiodesfibrilador implantável e morte súbita cardíaca abortada; o desfecho secundário foi mortalidade por todas as causas. Resultados: Foram incluídos no estudo130 pacientes, a maioria de mulher (53,9%), com idade média de 53,6±11,5 anos. A maioria dos pacientes (68,4%) não tinha sintomas de insuficiência cardíaca, apesar da dilatação ventricular esquerda (54%) e alterações da contratilidade (65,9%) serem comuns. A RMC mostrou dilatação do ventrículo esquerdo (volume diastólico final indexado médio de 118,6±50,5ml/m²) e disfunção sistólica (fração de ejeção média de 43,2±16,3%) e a FM foi identificada em 76,1%, massa média de 15,2±16,5g. Ao longo do seguimento médio de 6,8 anos, 58 (44,6%) pacientes atingiram o desfecho combinado e 45 (34,6%) faleceram. A MF associou-se ao desfecho primário como variável contínua (Razão de risco (RR) ajustada 1,031 (Intervalo de Confiança (IC) 95% 1,013-1,049; p=0.001) e nos pacientes com FM extensa ( >= 12,3g) (RR ajustado 2,107 (IC 95% 1,111-3,994I; p=0,022)) de forma independente ao Escore de Rassi. A FM expressa como variável contínua também se associou à morte por todas as causas (RRajustado1,028 (IC 95% 1,005-1,051; p=0,017)) de forma independente do Escore de Rassi, exceto quando analisada como variável categórica. Conclusões: A fibrose miocárdica é um preditor independente de pior prognóstico na miocardiopatia chagásica. Nossos dados apoiam o uso da RMC para estratificar melhor o risco nessa população e, possivelmente, guiar o tratamento / Background: Chagas cardiomyopathy (CC) portends worse prognosis than ischemic and other non-ischemic cardiomyopathies and carries a high economic burden. Myocardial fibrosis (MF) detected by cardiac magnetic resonance (CMR) has been demonstrated as an independent predictor of increased risk in several etiologies of heart failure. In CC, MF has been associated with know risk factors of poor outcome, such as left ventricular dysfunction and ventricular arrhythmia. We hypothesized that MF is an independent predictor of worse prognosis in CC. Objectives: we sought to determine the prognostic value of MF detected by CMR in predicting a combined endpoint of hard events or the secondary outcome of all-cause mortality. In addition, we evaluated if the prognostic value of MF is independent of the Rassi risk score. Methods: patients with CC were retrospectively followed after CMR evaluation of cardiac volumes, function and MF quantification. Clinical, imaging and follow-up data were recorded and the primary outcome was a combination of all-cause mortality, heart transplantation, anti-tachycardia pacing or appropriate shock from an implantable cardiac defibrillator and aborted sudden cardiac death; the secondary outcome was all-cause death. Results: 130 patients were included in the study, with a majority of females (53.9%) and a mean age of 53.6±11.5 years. Most patients (68.4%) had no symptoms of heart failure, even though left ventricular dilatation (54%) and wall-motion abnormalities (65.9%) were common. On CMR, left ventricular dilatation (mean end-diastolic volume index 118.6±50.5ml/m²) and dysfunction (mean ejection fraction 43.2±16.3%) were observed and MF was found in 76.1%, with a mean mass of 15.2±16.5g. Over a mean follow-up of > 6.2 years, 58 (44.6%) patients reached the combined endpoint and 45 (34.6%) patients died. Myocardial fibrosis mass was associated with the primary outcome both as continuous variable (adjusted HR 1.031 (1.013-1.049 95% CI; p=0.001) and in patients with extensive MF ( >= 12.3g) (adjusted HR 2.107 (1.111-3.994 95% CI; p=0.022), independently from the Rassi Score. Myocardial fibrosis mass expressed as a continuous variable was also associated with all-cause death (adjusted HR 1.028 (1.005-1.051 95% CI; p=0.017) independently from the Rassi Score, but not when analyzed as a categorical variable. Conclusions: Myocardial fibrosis is an independent predictor of adverse outcome in Chagas cardiomyopathy. Our data support the use of CMR in better stratifying risk in this population and possibly guiding therapy
|
890 |
Evaluating the User Experience of Microsoft HoloLens and Mobile Device Using an Augmented Reality ApplicationPola, Sai Vijay January 2019 (has links)
Context: In recent years, everyone is completely relying on using computers and smartphones in our daily activities. Augmented Reality will superimpose virtual and computer-generated information on top of the real world. Volvo Construction Equipment (VCE) team is planning to use Augmented Reality applications on a real construction site to track the details of the vehicles without going to the laboratory. An Augmented reality application is developed for Microsoft HoloLensand Mobile device and the user experience is evaluated. This research has been conducted at PDRL-BTH, in collaboration with VCE. Objectives: In this research, the key attributes are collected, which should be displayed in both the devices and compare the user experience using the user satisfaction score. Furthermore, this research involves exploring and evaluating the difference in the user experience between both the devices. Methods: In this study first an interview is carried out with the design engineers of the VCE team. Some open-ended questions were asked to the VCE team. The information required from the VCE team is collected and documented and further an experiment on the user experience has been conducted to calculate the User Satisfaction Score between the Microsoft HoloLens and Mobile device. After the experiment, the significant difference has been measured using statistical techniques among the two devices. To measure the size of the difference Cohen’s D effect size is used. Results: The significant difference between the User Satisfaction Score of the two devices has been done using T-test. The results state that the significant value is less than 0.05 and hence the null hypothesis is rejected. The measurable difference states that Microsoft HoloLens has a better user interface than the Mobile device with respect to the user satisfaction Score. Conclusions: After obtaining the results and analyzing the data, we conclude that there is a significant difference in the user experience of Microsoft HoloLens when compared to Mobile device. We also conclude that Microsoft HoloLens has better user experience when compared to the Mobile device.
|
Page generated in 0.0601 seconds