Combined active and semi-supervised learning using particle walking temporal dynamicscombined active and semi-supervised learning using particle walking temporal dynamics

Both Semi-Supervised Leaning and Active Learning are techniques used when unlabeled data is abundant, but the process of labeling them is expensive and/or time consuming. In this paper, those two machine learning techniques are combined into a single nature-inspired method. It features particles walking on a network built from the data set, using a unique random-greedy rule to select neighbors to visit. The particles, which have both competitive and cooperative behavior, are created on the network as the result of label queries. They may be created as the algorithm executes and only nodes affected by the new particles have to be updated. Therefore, it saves execution time compared to traditional active learning frameworks, in which the learning algorithm has to be executed several times. The data items to be queried are select based on information extracted from the nodes and particles temporal dynamics. Two different rules for queries are explored in this paper, one of them is based on querying by uncertainty approaches and the other is based on data and labeled nodes distribution. Each of them may perform better than the other according to some data sets peculiarities. Experimental results on some real-world data sets are provided, and the proposed method outperforms the semi-supervised learning method, from which it is derived, in all of them.

Preliminary in vitro and ex vivo evaluation of afzelin, kaempferitrin and pterogynoside action over free radicals and reactive oxygen species

Biological activities of flavonoids have been extensively reviewed in literature. The biochemical profile of afzelin, kaempferitrin, and pterogynoside acting on reactive oxygen species was investigated in this paper. The flavonoids were able to act as scavengers of the superoxide anion, hypochlorous acid and taurine chloramine. Although flavonoids are naturally occurring substances in plants which antioxidant activities have been widely advertised as beneficial, afzelin, kaempferitrin, and pterogynoside were able to promote cytotoxic effect. In red blood cells this toxicity was enhanced, depending on flavonoids concentration, in the presence of hypochlorous acid, but reduced in the presence of 2,20 -azo-bis(2-amidinopropane) free radical. These flavonoids had also promoted the death of neutrophils, which was exacerbated when the oxidative burst was initiated by phorbol miristate acetate. Therefore, despite their well-known scavenging action toward free radicals and oxidants, these compounds could be very harmful to living organisms through their action over erythrocytes and neutrophils.

Effects of time exposure and low power sonochemical treatment on ZnO mesostructures

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Histopathology of the pulp of primary molars with active and arrested dentinal caries

The purpose of this study was to compare the histological appearance of the pulp of human primary molars with active and arrested lesions. The sample consisted of 36 primary molars (18 with active lesions and 18 with arrested lesions) extracted from 35 children between 5 to 9 years of age. The histological diagnosis was classified in normal pulp, transitional stage, partial pulpitis, total pulpitis and total necrosis, and then subdivided in three subgroups: treatable, untreatable and questionable. Results showed that normal pulp or transitional stage (treatable category) was diagnosed in 50% of teeth with arrested lesions, compared to 11.1% of teeth with active lesions. Partial pulpitis (questionable category) was present in 38.8% with arrested lesions compared to 22.2% with active lesions. Total pulpitis and total necrosis (untreatable category) was diagnosed in 11.2% with arrested lesions compared to 66.7% with active lesions. The observed frequencies of histological categories between both groups were statistically significant (P < 0.05). Histologically, pulp reaction under active and arrested lesions in primary molars revealed the formation of a basophilic calcio-traumatic line at the junction of the primary and reparative dentin, formation of reparative dentin and a regular odontoblastic layer in 60% of the cases. Results indicated that the type of lesion (active or arrested) is a good indicator of the histological status of the pulp.

Longitudinal effects of physical activity on self-efficacy and cognitive processing of active and sedentary elderly women

Previous studies support that regular physical activity in aging contributes as a protective factor against cognitive decline and improves mood states. However, there is a lack of longitudinal studies in this area. Objective: To observe possible changes in cognition related with physical activity. METHODS: This study reassessed, after one-year period, 31 elderly women divided into two groups, sedentary versus active, using behavioral scales and cognitive tests. RESULTS: The active group exhibited significantly enhanced performance in general cognitive function, particularly on tasks of episodic memory and praxis, and also on the mood states scale compared to the sedentary group. The active women also reported higher self-efficacy. CONCLUSION: Long-term physical activity promoted improvement on quality of life in the elderly women.

Comparison of active and passive forces of the pelvic floor muscles in women with and without stress urinary incontinence

Background: The reduction of the pelvic floor muscles (PFM) strength is a major cause of stress urinary incontinence (SUI). Objective: To compare active and passive forces, and vaginal cavity aperture in continent and stress urinary incontinent women. Method: The study included a total of thirty-two women, sixteen continent women (group 1 - G1) and sixteen women with SUI (group 2 - G2). To evaluate PFM passive and active forces in anteroposterior (sagittal plane) and left-right directions (frontal plane) a stainless steel specular dynamometer was used. Results: The anteroposterior active strength for the continent women (mean +/- standard deviation) (0.3 +/- 0.2 N) was greater compared to the values found in the evaluation of incontinent women (0.1 +/- 0.1 N). The left-right active strength (G1=0.43 +/- 0.1 N; G2=0.40 +/- 0.1 N), the passive force (G1=1.1 +/- 0.2 N; G2=1.1 +/- 0.3 N) and the vaginal cavity aperture (G1=21 +/- 3 mm; G2=24 +/- 4 mm) did not differ between groups 1 and 2. Conclusion: The function evaluation of PFM showed that women with SUI had a lower anteroposterior active strength compared to continent women.

Effects of active and passive lacebacks on antero-posterior position of maxillary first molars and central incisors

The purpose of this study was to compare the effects of active and passive lacebacks on antero-posterior position of maxillary first molars and central incisors during leveling phase. Twenty-three subjects with Class I and Class II malocclusion were treated with first premolars extraction using preadjusted appliances (MBT 0.022-inch brackets). The leveling phase was performed with stainless steel archwires only. The sample was divided into 2 groups: 14 subjects received active lacebacks (Group 1) and 9 subjects received passive lacebacks (Group 2). Lacebacks were made from 0.008-inch ligature wire. Lateral cephalometric radiographs were taken pre- and post-leveling phase. Student's t-test was applied to determine the differences between pre- and post-leveling mean values and to determine the mean differences between groups. In Group I, the first molars showed a significant mesial movement, whereas no change was observed in Group 2. In both groups, maxillary central incisor crowns moved to lingual side. In conclusion, active laceback produced anchorage loss of maxillary first molars whereas passive laceback did not affect the position of these teeth. Active and passive lacebacks were effective in preventing central incisor proclination.

A new snowfall detection algorithm for high latitude regions based on a combination of active and passive sensors

Precipitation retrieval over high latitudes, particularly snowfall retrieval over ice and snow, using satellite-based passive microwave spectrometers, is currently an unsolved problem. The challenge results from the large variability of microwave emissivity spectra for snow and ice surfaces, which can mimic, to some degree, the spectral characteristics of snowfall. This work focuses on the investigation of a new snowfall detection algorithm specific for high latitude regions, based on a combination of active and passive sensors able to discriminate between snowing and non snowing areas. The space-borne Cloud Profiling Radar (on CloudSat), the Advanced Microwave Sensor units A and B (on NOAA-16) and the infrared spectrometer MODIS (on AQUA) have been co-located for 365 days, from October 1st 2006 to September 30th, 2007. CloudSat products have been used as truth to calibrate and validate all the proposed algorithms. The methodological approach followed can be summarised into two different steps. In a first step, an empirical search for a threshold, aimed at discriminating the case of no snow, was performed, following Kongoli et al. [2003]. This single-channel approach has not produced appropriate results, a more statistically sound approach was attempted. Two different techniques, which allow to compute the probability above and below a Brightness Temperature (BT) threshold, have been used on the available data. The first technique is based upon a Logistic Distribution to represent the probability of Snow given the predictors. The second technique, defined Bayesian Multivariate Binary Predictor (BMBP), is a fully Bayesian technique not requiring any hypothesis on the shape of the probabilistic model (such as for instance the Logistic), which only requires the estimation of the BT thresholds. The results obtained show that both methods proposed are able to discriminate snowing and non snowing condition over the Polar regions with a probability of correct detection larger than 0.5, highlighting the importance of a multispectral approach.

Analysis and Implementation of Multiphase-Multilevel Inverter for Open-Winding Loads

Research work carried out in focusing a novel multiphase-multilevel ac motor drive system much suitable for low-voltage high-current power applications. In specific, six-phase asymmetrical induction motor with open-end stator winding configuration, fed from four standard two-level three-phase voltage source inverters (VSIs). Proposed synchronous reference frame control algorithm shares the total dc source power among the 4 VSIs in each switching cycle with three degree of freedom. Precisely, first degree of freedom concerns with the current sharing between two three-phase stator windings. Based on modified multilevel space vector pulse width modulation shares the voltage between each single VSIs of two three-phase stator windings with second and third degree of freedom, having proper multilevel output waveforms. Complete model of whole ac motor drive based on three-phase space vector decomposition approach was developed in PLECS - numerical simulation software working in MATLAB environment. Proposed synchronous reference control algorithm was framed in MATLAB with modified multilevel space vector pulse width modulator. The effectiveness of the entire ac motor drives system was tested. Simulation results are given in detail to show symmetrical and asymmetrical, power sharing conditions. Furthermore, the three degree of freedom are exploited to investigate fault tolerant capabilities in post-fault conditions. Complete set of simulation results are provided when one, two and three VSIs are faulty. Hardware prototype model of quad-inverter was implemented with two passive three-phase open-winding loads using two TMS320F2812 DSP controllers. Developed McBSP (multi-channel buffered serial port) communication algorithm able to control the four VSIs for PWM communication and synchronization. Open-loop control scheme based on inverse three-phase decomposition approach was developed to control entire quad-inverter configuration and tested with balanced and unbalanced operating conditions with simplified PWM techniques. Both simulation and experimental results are always in good agreement with theoretical developments.

Global scale investigation of cirrus clouds properties using active and passive sensors

A year of satellite-borne lidar CALIOP data is analyzed and statistics on occurrence and distribution of bulk properties of cirri are provided. The relationship between environmental and cloud physical parameters and the shape of the backscatter profile (BSP) is investigated. It is found that CALIOP BSP is mainly affected by cloud geometrical thickness while only minor impacts can be attributed to other quantities such as optical depth or temperature. To fit mean BSPs as functions of geometrical thickness and position within the cloud layer, polynomial functions are provided. It is demonstrated that, under realistic hypotheses, the mean BSP is linearly proportional to the IWC profile. The IWC parameterization is included into the RT-RET retrieval algorithm, that is exploited to analyze infrared radiance measurements in presence of cirrus clouds during the ECOWAR field campaign. Retrieved microphysical and optical properties of the observed cloud are used as input parameters in a forward RT simulation run over the 100-1100 cm-1 spectral interval and compared with interferometric data to test the ability of the current single scattering properties database of ice crystal to reproduce realistic optical features. Finally a global scale investigation of cirrus clouds is performed by developing a collocation algorithm that exploits satellite data from multiple sensors (AIRS, CALIOP, MODIS). The resulting data set is utilized to test a new infrared hyperspectral retrieval algorithm. Retrieval products are compared to data and in particular the cloud top height (CTH) product is considered for this purpose. A better agreement of the retrieval with the CALIOP CTH than MODIS is found, even if some cases of underestimation and overestimation are observed.

Reliability and discriminatory power of methods for dental plaque quantification

This in situ study evaluated the discriminatory power and reliability of methods of dental plaque quantification and the relationship between visual indices (VI) and fluorescence camera (FC) to detect plaque.

Childhood cancer and nuclear power plants in Switzerland: a census-based cohort study

Background Previous studies on childhood cancer and nuclear power plants (NPPs) produced conflicting results. We used a cohort approach to examine whether residence near NPPs was associated with leukaemia or any childhood cancer in Switzerland. Methods We computed person-years at risk for children aged 0–15 years born in Switzerland from 1985 to 2009, based on the Swiss censuses 1990 and 2000 and identified cancer cases from the Swiss Childhood Cancer Registry. We geo-coded place of residence at birth and calculated incidence rate ratios (IRRs) with 95% confidence intervals (CIs) comparing the risk of cancer in children born <5 km, 5–10 km and 10–15 km from the nearest NPP with children born >15 km away, using Poisson regression models. Results We included 2925 children diagnosed with cancer during 21 117 524 person-years of follow-up; 953 (32.6%) had leukaemia. Eight and 12 children diagnosed with leukaemia at ages 0–4 and 0–15 years, and 18 and 31 children diagnosed with any cancer were born <5 km from a NPP. Compared with children born >15 km away, the IRRs (95% CI) for leukaemia in 0–4 and 0–15 year olds were 1.20 (0.60–2.41) and 1.05 (0.60–1.86), respectively. For any cancer, corresponding IRRs were 0.97 (0.61–1.54) and 0.89 (0.63–1.27). There was no evidence of a dose–response relationship with distance (P > 0.30). Results were similar for residence at diagnosis and at birth, and when adjusted for potential confounders. Results from sensitivity analyses were consistent with main results. Conclusions This nationwide cohort study found little evidence of an association between residence near NPPs and the risk of leukaemia or any childhood cancer.

Probing The Active And Allosteric Binding Sites Of Soybean Lipoxygenase-1

Soybean lipoxygenase-1 is a model for lipoxygenase activity. While the mechanism of oxygenation is understood, the substrate binding mechanism has not yet been elucidated. Two putative binding mechanisms are the ¿head-first¿ and ¿tail-first¿ models, in which the carboxy-terminus or the methyl terminus of the fatty acid substrate is inserted into the active site while the remainder of the molecule protrudes from the surface, respectively. Previous work has demonstrated that derivatization of fatty acid substrates with D-tryptophan increases active site affinity. It has also been shown that while polyunsaturated fatty acids are the natural substrates of lipoxygenases, monounsaturated fatty acids can be oxygenated at a much slower rate. Starting with a monounsaturated fatty acid, oleic acid, as a platform, the molecule N-oleoyl-D-tryptophan (ODT) was synthesized with the anticipation of it being a potent competitive substrate-analogue inhibitor that could be used to discern the substrate binding mechanism. Inhibition kinetics demonstrated that this molecule functions as a partially competitive inhibitor, through an unknown mechanism. The implication behind partially competitive inhibition is that substrate and inhibitor molecules can bind simultaneously to the enzyme, which alludes to the presence of an allosteric binding domain. To investigate the possibility of an inhibitor binding site on the non-catalytic subunit, limited proteolysis was used to cleave the subunits apart which should have eliminated inhibition. Interestingly, it was observed that at high substrate concentrations the inhibitor was completely ineffective, but at low substrate concentrations the inhibitor maintained its standard efficacy. A satisfactory explanation for these results has not yet been determined.

Concordance Probability and Discriminatory Power in Proportional Hazards Regression

The concordance probability is used to evaluate the discriminatory power and the predictive accuracy of nonlinear statistical models. We derive an analytic expression for the concordance probability in the Cox proportional hazards model. The proposed estimator is a function of the regression parameters and the covariate distribution only and does not use the observed event and censoring times. For this reason it is asymptotically unbiased, unlike Harrell's c-index based on informative pairs. The asymptotic distribution of the concordance probability estimate is derived using U-statistic theory and the methodology is applied to a predictive model in lung cancer.