Number of results to display per page
Search Results
1172. A comparative study of HMMs and DBNs applied to Facial Action Units Recognition
- Creator:
- Popa, M. C., Rothkrantz , L. J. M., Datcu , D., Wiggers, P., Braspenning , R., and Shan, C.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Hidden Markov Models, Dynamic Bayesian Networks, Facial Action Units Recognition, and Facial Action Coding System
- Language:
- English
- Description:
- From a theoretical point of view, Hidden Markov Models (HMMs) and Dynamic Bayesian Networks (DBNs) are similar, still in practice they pose different challenges and perform in a different manner. In this study we present a comparative analysis of the two spatial-temporal classification methods: HMMs and DBNs applied to the Facial Action Units (AUs) recognition problem. The Facial Action Coding System (FACS) developed by Ekman and Friesen decomposes the face into 46 AUs, each AU being related to the contraction of one or more specific facial muscles. FACS proved its applicability to facial behavior modeling, enabling the recognition of an extensive palette of facial expressions. Even though a lot has been published on this theme, it is still difficult to draw a conclusion regarding the best methodology to follow, as there is no common basis for comparison and sometimes no argument is given why a certain classification method was chosen. Therefore, our main contributions reside in discussing and comparing the relative performance of the two proposed classifiers (HMMs vs. DBNs) and also of different Region of Interest (ROI) selections proposed by us and different optical flow estimation methods. We can consider our automatic system towards AUs classification an important step in the facial expression recognition process, given that even one emotion can be expressed in different ways, fact that suggests the complexity of the analyzed problem. The experiments were performed on the Cohn-Kanade database and showed that under the same conditions regarding initialization, labeling, and sampling, both classification methods produced similar results, achieving the same recognition rate of 89% for the classification of facial AUs. Still, by enabling non-fixed sampling and using HTK, HMMs rendered a better performance of 93% suggesting that they are better suited for the special task of AUs recognition.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1173. A comparative study of Ligophorus uruguayense and L. saladensis (Monogenea: Ancyrocephalidae) from Mugil liza (Teleostei: Mugilidae) in southern Brazil
- Creator:
- Marchiori, Natalia C, Pariselle, Antoine, Pereira, Joaber, Agnèse, Jean-François, Durand, Jean-Dominique, and Vanhove, Maarten P.M
- Format:
- electronic, počítač, and online zdroj
- Type:
- model:article and TEXT
- Subject:
- morfologie (biologie), parazitické organismy, morphology (biology), parasitic organisms, molecular systematics, mullet, taxonomy, 2, and 59
- Language:
- English
- Description:
- Representatives of Ligophorus Euzet et Suriano, 1977 were found on the gills of Mugil liza Valenciennes caught in southern Brazil. They were identified as Ligophorus uruguayense Failla Siquier et Ostrowski de Núñez, 2009 and Ligophorus saladensis Marcotegui et Martorelli, 2009, even though specific identification proved to be difficult due to inconsistencies in some diagnostic features reported for these two species. Therefore, a combined morphological and molecular approach was used to critically review the validity of these species, by means of phase contrast and confocal fluorescence microscopical examination of sclerotised hard parts, and assessing the genetic divergence between L. saladensis, L. uruguayense and their congeners using rDNA sequences. The main morphological differences between the two species relate to the shape of the accessory piece of the penis and the median process of the ventral bar. The accessory piece in L. uruguayense is shorter than in L. saladensis, has a cylindrical, convex upper lobe and straight lower lobe (vs with the distal tip of the lower lobe turning away from the upper lobe in the latter species). The ventral bar has a V-shaped anterior median part in L. uruguayense (vs U-shaped in L. saladensis). The two species are suggested to be part of a species complex together with L. mediterraneus Sarabeev, Balbuena et Euzet, 2005. We recommend to generalise such comparative assessment of species of Ligophorus for a reliable picture of the diversity and diversification mechanisms within the genus, and to make full use of its potential as an additional marker for mullet taxonomy and systematics., Natalia C. Marchiori, Antoine Pariselle, Joaber Pereira Jr., Jean-François Agnèse, Jean-Dominique Durand, Maarten P.M. Vanhove., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1174. A comparative study of reactive hyperemia in human forearm skin and muscle
- Creator:
- Addor, G., Delachaux, A., Dischl, B., Hayoz, D., Liauder, L., Waeber, B., and Feihl, Francois
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, patologická fyziologie, ischemie, physiology, pathological physiology, ischemia, vasodilation, laser Doppler, strain gauge plethysmography, surrogate endpoint, acetylsalicylate, 14, and 612
- Language:
- English
- Description:
- Reactive hyperemia (RH) in forearm muscle or skin microcirculation has been considered as a surrogate endpoint in clinical studies of cardiovascular disea e. We evaluated two potential confounders that might limit such use of RH, namely laterality of measurement and intake of non-steroidal anti-inflammatory drugs (NSAIDS). Twenty-three young non-smoking healthy adults were enrolled. In Experiment 1 (n=16), the RH elicited by 3 min of ischemia was recorded in the muscle (strain gauge plethysmography, hand excluded) and skin (laser Doppler imaging) of both forearms. In Experiment 2 (n=7), RH was determined in the dominant forearm only, one hour following oral acetylsalicylic acid (1 g) or placebo. In Experiment 1, peak RH was identical in both forearms, and so were the corresponding durations of responses. RH lasted significantly less in muscle than in skin (p=0.003), a hitherto unrecognized fact. In the skin, acetylsalicylate reduced duration (43 vs. 57.4 s for placebo, p=0.03), without affecting the peak response. In muscle, duration tended to decrease with acetylsalicylate (21.4 vs. 26.0 s with placebo, p=0.06) and the peak increase in blood flow was blunted (27.2 vs. 32.4 ml/min/100 ml tissue with placebo, p=0.003). We conclude that, when using RH as a surrogate endpoint in studies of cardiovascular disease, a confounding by laterality of measurement need not be feared, but NSAIDS may have an influence, although perhaps not on the peak response in the skin., G. Addor, A. Delachaux, B. Dischl, D. Hayoz, L. Liaudet, B. Waeber, F. Feihl., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1175. A comparative study of the abdominal trichobothria of Trichophora, with emphasis on Lygaeoidea (Hemiptera: Heteroptera)
- Creator:
- Gao, Cuiqing, Rédei, Dávid, Shi, Xueqin, Cai, Bo, Liang, Ke, Gao, Shuo, and Bu, Wenjun
- Type:
- article, model:article, and TEXT
- Subject:
- Heteroptera, Hemiptera, Trichophora, Lygaeoidea, abdominal trichobothria, morphology, and systematics
- Language:
- English
- Description:
- Members of the clade Trichophora (Hemiptera: Heteroptera: Pentatomomorpha) have trichobothria on their abdominal sterna. There is no comparative study of the fine structure of abdominal trichobothria in the group and until now the trichobothria of their immatures were virtually unknown. The fine structure of the abdominal trichobothrial complex (= the trichobothrium and its associated structures) of adults of 98 species belonging to 25 families in 5 superfamilies and larvae of 7 species belonging to 7 families in 2 superfamilies of Trichophora were examined using scanning electron microscopy. This study indicates that the fine structure of the abdominal trichobothria is very variable and useful for determining evolutionary lineages within the clade. Six types of bothria, three of trichomes and three of microtrichia are recognized and their evolutionary transformations discussed. Changes in the size of trichomes, and density and size of the microtrichia during the postembryonic development of selected species are discussed.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1176. A comparative study of the utilization of ether- and ester-linked phospholipid-containing liposomes by J774.E1 macrophage cell-line infected with Leishmania mexicana mexicana amastigotes
- Creator:
- Hrčková, G., Shah, A., Hart, D.T., and Halton, D.W.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Leishmania m. mexicana, ester-, ether-linked phosphatydilcholine, igands (native LDL, acetylated LDL), and liposome uptake
- Language:
- English
- Description:
- The macrophage cell-line J774.E1 and Leishmania m. mexicana infection was used to investigate the uptake of liposomes, which differed in their bulk phospholipid: ester- or ether-analogue of phosphatydilcholine (PC). The receptor-mediated uptake of both species of liposomes, containing native or acetylated LDL as ligands was also evaluated. Uninfected and infected J774.E1 cell-line accumulated more ester- and ether-liposomes alone than mixed type (50:50, ester/ether). The utilization was significantly enhanced when both types of liposomes contained native LDL. The highest uptake was recorded for liposomes bearing acetylated LDL by infected J774.E1 cells. Accumulation of ester- and ether-liposomes with the same ligand was not markedly affected by different chemical nature of PC. Finally, ether-liposomes alone possessed certain activity against Leishmania m. mexicana amastigotes. The results presented here demonstrated the usefulness of ether-liposomes with specific ligands in site-specific delivery of antileishmanial compounds in vitro.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1177. A comparative study of two methodologies for binary datasets analysis
- Creator:
- Frolov, Alexander, Húsek , Dušan, Polyakov , Pavel Y., and Řezanková, Hana
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Dimension reduction, statistics, data mining, Boolean factor analysis, Boolean matrix factorization, information gain, likelihood-maximization, and bars problem
- Language:
- English
- Description:
- Studied are differences of two approaches targeted to reveal latent variables in binary data. These approaches assume that the observed high dimensional data are driven by a small number of hidden binary sources combined due to Boolean superposition. The first approach is the Boolean matrix factorization (BMF) and the second one is the Boolean factor analysis (BFA). The two BMF methods are used for comparison. First is the M8 method from the BMDP statistical software package and the second one is the method suggested by Belohlavek \& Vychodil. These two are compared to BFA, especially with the Expectation-maximization Boolean Factor Analysis we had developed earlier has, however, been extended with a binarization step developed here. The well-known bars problem and the mushroom dataset are used for revealing the methods' peculiarities. In particular, the reconstruction ability of the computed factors and the information gain as the measure of dimension reduction was under scrutiny. It was shown that BFA slightly loses to BMF in performance when noise-free signals are analyzed. Conversely, BMF loses considerably to BFA when input signals are noisy.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1178. A comparison of aggression and impulsivity between smokers and non-smokers
- Creator:
- Zaidi, Uzma
- Format:
- electronic, electronic resource, remote, and elektronický zdroj
- Type:
- model:article, article, Text, srovnávací studie, and TEXT
- Subject:
- kouření--epidemiologie--psychologie--škodlivé účinky, agrese--psychologie, impulzivní chování, poruchy vyvolané užíváním tabáku--psychologie, průzkumy a dotazníky, studenti, dospělí, lidé, and mužské pohlaví
- Language:
- English
- Description:
- The study aimed to investigate the role of aggression and impulsivity in smoking among male adult students. It was hypothesized that there would be significant difference between smokers and non- smokers on the traits of aggression and impulsivity. The sample of two hundred male adult students was selected from different universities of Islamabad. Two subscales of Impulsiveness and Aggression were administered to measure the personality traits of aggression and impulsivity. Descriptive statistics and t-test was calculated for analysis of data. Results showed that there is significant differences in aggression and impulsivity between smokers and non-smokers. The result can be helpful for psychologist and other professionals to plan public health therapeutic and social reengineering interventions for youth., Uzma Zaidi, and Literatura
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1179. A comparison of capture-mark-recapture and camera-based mark-resight to estimate abundance of Alpine marmot (Marmota marmota)
- Creator:
- Forti, Alessandro, Partel, Piergiovanni, Orsingher, Michel J., Volcan, Gilberto, Dorigatti, Enrico, Pedrotti, Luca, and Corlatti, Luca
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- Bowden estimator, camera traps, Marmota, and population size
- Language:
- English
- Description:
- Obtaining reliable estimates of population abundance is of utmost importance for wildlife research and management. To this aim, camera-traps are increasingly used, as this method has the advantage of being noninvasive and allows for continuous monitoring. Camera traps can be used to estimate abundance in combination with traditional capture-recapture techniques, as well as with estimators that do not require marked individuals. Here, we investigated the use of camera-based mark-recapture methods applied to an Alpine marmot (Marmota marmota) population in the Paneveggio-Pale di San Martino Natural Park (eastern Italian Alps). We compared abundance estimates derived from a traditional capture-mark-recapture (CMR) framework and camera trap mark-resight (CTMR) over three consecutive years. CMR models estimated a population size of n = 19 individuals (95% CI = 18-27), n = 15 (14-22) and n = 24 (22-32) in 2019, 2020 and 2021 respectively. CTMR returned an estimated population size of n = 24 (95% CI = 18-30), n = 20 (17-24) and n = 22 (21-24) for the same years. The difference between the estimate of these two methods was significant only in 2020, with CMR returning a lower estimate than CTMR (95% CI = –9.4-–0.6). This difference was not significant for 2019 (95% CI = –10.9-0.9) and 2021 (95% CI = –1.8-5.9). Based on our results, the use of CTMR techniques is promising in the estimation of absolute population size of marmots, and the estimator was slightly more precise than CMR. Further studies are needed to evaluate the effectiveness of CTMR with reduced capture effort.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1180. A comparison of different rubber dam systems on a dental simulator
- Creator:
- Kapitán, Martin, Šustová, Zdeňka, Koberová Ivančaková, Romana, and Suchánek, Jakub
- Format:
- print, text, and regular print
- Type:
- model:article, article, Text, srovnávací studie, časopisecké články, práce podpořená grantem, and TEXT
- Subject:
- design vybavení, lidé, testování materiálů, biologické modely, and gumové blány
- Language:
- English
- Description:
- The purpose of this study was to test the hypothesis that more recently developed rubber dam systems (OptraDam ® Plus and OptiDam™) are faster and easier to handle, and that the quality of isolation is not decreased. The rubber dam systems were applied in standard conditions on a dental simulator in several model clinical situations. The time of preparation, application and removal were measured and the quality of isolation was evaluated. The median time of rubber dam placement was 51 s (Q1 = 38 s; Q3 = 79 s). The shortest median time of application was with OptiDam™ (42 s), followed by a conventional rubber dam (53 s), and finally the longest was with OptraDam® Plus (58 s). The median volume of fluid remaining in the isolated space after 5 minutes was 9.5 mL (Q1 = 8 mL; Q3 = 10 mL). The largest median volume of remaining water was with OptiDam™ (10 mL), followed by a conventional rubber dam (9.5 mL) and the least with OptraDam® Plus (8.5 mL). The afore-stated hypothesis about the advantages of modern rubber dam isolation systems was accepted for OptiDam™, but rejected for OptraDam® Plus. The results could contribute to decision-making concerning the choice of rubber dam system. and Martin Kapitán, Zdeňka Šustová, Romana Ivančaková, Jakub Suchánek
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public