986 resultados para sample complexity


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Indices of post awakening cortisol secretion (PACS), include the rise in cortisol(cortisol awakening response: CAR) and overall cortisol concentrations (e.g. area under the curve with reference to ground: AUCg) in the first 30—45 min. Both are commonly investigated in relation to psychosocial variables. Although sampling within the domestic setting is ecologically valid, participant non-adherence to the required timing protocol results in erroneous measurement of PACS and this may explain discrepancies in the literature linking these measures to trait well-being (TWB). We have previously shown that delays of little over 5 min(between awakening and the start of sampling) to result in erroneous CAR estimates. In this study, we report for the first time on the negative impact of sample timing inaccuracy (verified by electronic-monitoring) on the efficacy to detect significant relationships between PACS and TWB when measured in the domestic setting.Healthy females (N = 49, 20.5 ± 2.8 years) selected for differences in TWB collected saliva samples (S1—4) on 4 days at 0, 15, 30, 45 min post awakening, to determine PACS. Adherence to the sampling protocol was objectively monitored using a combination of electronic estimates of awakening (actigraphy) and sampling times (track caps).Relationships between PACS and TWB were found to depend on sample timing accuracy. Lower TWB was associated with higher post awakening cortisol AUCg in proportion to the mean sample timing accuracy (p < .005). There was no association between TWB and the CAR even taking into account sample timing accuracy. These results highlight the importance of careful electronic monitoring of participant adherence for measurement of PACS in the domestic setting. Mean sample timing inaccuracy, mainly associated with delays of >5 min between awakening and collection of sample 1 (median = 8 min delay), negatively impacts on the sensitivity of analysis to detect associations between PACS and TWB.

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This paper presents a low complexity high efficiency decimation filter which can be employed in EletroCardioGram (ECG) acquisition systems. The decimation filter with a decimation ratio of 128 works along with a third order sigma delta modulator. It is designed in four stages to reduce cost and power consumption. The work reported here provides an efficient approach for the decimation process for high resolution biomedical data conversion applications by employing low complexity two-path all-pass based decimation filters. The performance of the proposed decimation chain was validated by using the MIT-BIH arrhythmia database and comparative simulations were conducted with the state of the art.

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Motion compensated frame interpolation (MCFI) is one of the most efficient solutions to generate side information (SI) in the context of distributed video coding. However, it creates SI with rather significant motion compensated errors for some frame regions while rather small for some other regions depending on the video content. In this paper, a low complexity Infra mode selection algorithm is proposed to select the most 'critical' blocks in the WZ frame and help the decoder with some reliable data for those blocks. For each block, the novel coding mode selection algorithm estimates the encoding rate for the Intra based and WZ coding modes and determines the best coding mode while maintaining a low encoder complexity. The proposed solution is evaluated in terms of rate-distortion performance with improvements up to 1.2 dB regarding a WZ coding mode only solution.

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This paper describes a comparison of adaptations of the QuEChERS (quick, easy, cheap, effective, rugged and safe) approach for the determination of 14 organochlorine pesticide (OCP) residues in strawberry jam by concurrent use of gas chromatography (GC) coupled to electron capture detector (ECD) and GC tandem mass spectrometry (GC-MS/MS). Three versions were tested based on the original QuEChERS method. The results were good (overall average of 89% recoveries with 15% RSD) using the ultrasonic bath at five spiked levels. Performance characteristics, such as accuracy, precision, linear range, limits of detection (LOD) and quantification (LOQ), were determined for each pesticide. LOD ranged from 0.8 to 8.9 microg kg-1 ; LOQ was in the range of 2.5–29.8 microg kg- 1; and calibration curves were linear (r2>0.9970) in the whole range of the explored concentrations (5–100 microg kg- 1). The LODs of these pesticides were much lower than the maximum residue levels (MRLs) allowed in Europe for strawberries. The method was successfully applied to the quantification of OCP in commercially available jams. The OCPs were detected lower than the LOD.

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Dissertação de Mestrado em Ambiente, Saúde e Segurança.

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This paper studies the information content of the chromosomes of 24 species. In a first phase, a scheme inspired in dynamical system state space representation is developed. For each chromosome the state space dynamical evolution is shed into a two dimensional chart. The plots are then analyzed and characterized in the perspective of fractal dimension. This information is integrated in two measures of the species’ complexity addressing its average and variability. The results are in close accordance with phylogenetics pointing quantitative aspects of the species’ genomic complexity.

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Animal Cognition, V.6, pp. 259–267

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Relatório de Estágio apresentado à Escola Superior de Educação de Lisboa para obtenção de grau de mestre em Ensino do 1.º e 2.º Ciclo do Ensino Básico

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In the present longitudinal study, we investigated attachment quality in Portuguese mother–infant and in father–infant dyads, and evaluated whether attachment quality was related to parental sensitivity during parent–infant social interaction or to the amount of time each parent spent with the infant during play and in routine caregiving activities (e.g., feeding, bathing, play). The sample consisted of 82 healthy full-term infants (30 girls, 53 boys, 48 first born), and their mothers and fathers from mostly middle-class households. To assess parental sensitivity, mothers and fathers were independently observed during free play interactions with their infants when infants were 9 and 15 months old. The videotaped interactions were scored by masked coders using the Crittenden’s CARE-Index. When infants were 12 and 18 months old, mother–infant and father–infant dyads were videotaped during an adaptation of Ainsworth’s Strange Situation. Parents also described their level of involvement in infant caregiving activities using a Portuguese version of the McBride and Mills Parent Responsibility Scale. Mothers were rated as being more sensitive than fathers during parent–infant free play at both 9 and 15 months. There also was a higher prevalence of secure attachment in mother–infant versus father–infant dyads at both 12 and 18 months. Attachment security was predicted by the amount of time mothers and fathers were involved in caregiving and play with the infant, and with parents’ behavior during parent–infant free play.

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The total antioxidant capacity (TAC) of 28 flavoured water samples was assessed by ferric reducing antioxidant potential (FRAP), oxygen radical absorbance capacity (ORAC), trolox equivalent antioxidant capacity (TEAC) and total reactive antioxidant potential (TRAP) methods. It was observed that flavoured waters had higher antioxidant activity than the corresponding natural ones. The observed differences were attributed to flavours, juice and vitamins. Generally, higher TAC contents were obtained on lemon waters and lower values on guava and raspberry flavoured waters. Lower and higher TACs were obtained by TRAP and ORAC method, respectively. Statistical analysis suggested that vitamins and flavours increased the antioxidant content of the commercial waters.

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Carbamate compounds are an important group of cholinesterase inhibitors. There is a need for creating awareness regarding the risks of the inadequate carbamate use in the residential areas due to potential adverse human effects. Carbaryl is a commonly used pesticide worldwide. A simple, fast, and high throughput method was developed employing liquid chromatography with fluorescence detector to determine carbaryl residues in rat feces. The extraction was performed by using a rapid, easy, cheap, effective, reliable, and safe (QuEChERS) method, using acetonitrile as the extracting solvent. The parameters for the performance of the extraction method were optimized, such as ratio of mass of sample per volume of extraction solvent, QuEChERS content, and cleanup columns. Linear response was obtained for all calibration curves (solven and matrix-matched) over the established concentration range (5 500 mg/L) with a correlation coefficients higher than 0.999. The achieved recovery was 97.9% with relative standard deviation values of 1.1% (n D 4) at 167 mg/kg fortified concentration level and the limits of detection and quantification were 27.7 and 92.3 mg/kg respectively.

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Tese apresentada como requisito parcial para obtenção do grau de Doutor em Gestão de Informação

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The purpose of this study is to contribute to the changing innovation management literature by providing an overview of different innovation types and organizational complexity factors. Aiming at a better understanding of effective innovation management, innovation and complexity are related to the formulation of an innovation strategy and interaction between different innovation types is further explored. The chosen approach in this study is to review the existing literature on different innovation types and organizational complexity factors in order to design a survey which allows for statistical measurement of their interactions and relationships to innovation strategy formulation. The findings demonstrate interaction between individual innovation types. Additionally, organizational complexity factors and different innovation types are significantly related to innovation strategy formulation. In particular, more closed innovation and incremental innovation positively influence the likelihood of innovation strategy formulation. Organizational complexity factors have an overall negative influence on innovation strategy formulation. In order to define best practices for innovation management and to guide managerial decision making, organizations need to be aware of the co-existence of different innovation types and formulate an innovation strategy to more closely align their innovation objectives.

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Recently, unethical conduct in the workplace has been a focus of literature and media. Unethical pro-organizational behavior (UPB) refers to unethical conduct that employees engage in to benefit the organization. Given the complexity of UPB, there is an increasing need to understand how and under what conditions this attitude originates within organizations. Based on a sample of 167 employees and seven organizations, results support the moderated mediation model. An ethical leader increases employees’ organizational affective commitment which increases the likelihood to engage in UPB. However, the indirect relationship diminishes when employees feel authentic at work.

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Little is known about the opinions, beliefs and behavior of Swiss physicians regarding physical activity (PA) promotion in a primary care setting. A qualitative study was performed with semi-structured interviews. We purposively recruited and interviewed 16 physicians in the French speaking part of Switzerland. Their statements and ideas regarding the promotion of PA in a primary care setting were transcribed and synthesized from the tape recorded interviews. Les opinions, les représentations et les comportements des médecins suisses en matière de promotion de l'activité physique au cabinet médical restent largement méconnus en Suisse. Une étude qualitative a été réalisée au moyen d'entretiens semi-structurés. Nous avons intentionnellement recruté et interviewé 16 médecins en Suisse romande. Leurs opinions et attitudes concernant la promotion de l'activité physique au cabinet médical ont été transcrites et synthétisées à partir de l'enregistrement de ces entretiens.