Human Pose Estimation from Monocular Images : a Comprehensive Survey

Human pose estimation refers to the estimation of the location of body parts and how they are connected in an image. Human pose estimation from monocular images has wide applications (e.g., image indexing). Several surveys on human pose estimation can be found in the literature, but they focus on a certain category; for example, model-based approaches or human motion analysis, etc. As far as we know, an overall review of this problem domain has yet to be provided. Furthermore, recent advancements based on deep learning have brought novel algorithms for this problem. In this paper, a comprehensive survey of human pose estimation from monocular images is carried out including milestone works and recent advancements. Based on one standard pipeline for the solution of computer vision problems, this survey splits the problema into several modules: feature extraction and description, human body models, and modelin methods. Problem modeling methods are approached based on two means of categorization in this survey. One way to categorize includes top-down and bottom-up methods, and another way includes generative and discriminative methods. Considering the fact that one direct application of human pose estimation is to provide initialization for automatic video surveillance, there are additional sections for motion-related methods in all modules: motion features, motion models, and motion-based methods. Finally, the paper also collects 26 publicly available data sets for validation and provides error measurement methods that are frequently used

Ambient volatile organic compounds in a suburban site between Beijing and Tianjin : Concentration levels, source apportionment and health risk assessment

Volatile organic compounds (VOCs) have vital implications for secondary pollutants, atmospheric oxidation and human health. Ambient VOCs were investigated using an online system, gas chromatography-mass spectrometry/flame ionization detector (GC-MS/FID), at a suburban site in Xianghe in the North China Plain from 6 November 2017 to 29 January 2018. Positive matrix factorization (PMF) receptor model was applied to identify the major VOC contributing sources. Four-step health risk assessment method was used to estimate risks of all risk-posing VOC species. A total of 101 VOCs were quantified, and the mean concentration of total VOCs was 61.04 +/- 65.18 ppbv. The VOCs were dominated by alkanes (38.76%), followed by alkenes, aromatics, halocarbons, OVOCs, acetylene and acetonitrile. The results of PMF revealed that vehicle exhaust, industrial emissions, liquefied petroleum gas & natural gas, solvent utilization and secondary and long-lived species contributed 31.0%, 26.4%, 18.6%, 13.6% and 10.4%, respectively, to the total VOCs. Pollutant-specific and source-specific non-carcinogenic and carcinogenic risk estimates were conducted, which showed that acrolein and vehicle exhaust had evident noncarcinogenic risks of 4.9 and 0.9, respectively. The carcinogenic risks of specific species (1,3-butadiene, acetaldehyde, benzene, chloroformand 1,2-dichloroethane) and identified sources were above the United States Environmental Protection Agency (USEPA) acceptable level (1.0 x 10(-6)) but below the tolerable risk level (1.0 x 10(-4)). Vehicle exhaust was the largest contributor (56.2%) to noncarcinogenic risk, but solvent utilization (32.6%) to carcinogenic risk. Moreover, with the evolution of pollution levels, almost all VOC species, contributions of alkenes, aromatics, solvent utilization and vehicle exhaust, and pollutant-specific and source-specific risks increased continuously and noticeably. Collectively, our findings unraveled the importance of alkenes, aromatics, solvent utilization and vehicle exhaust in the evolution of pollution levels. Future studies should consider targeting these VOC groups and sources when focusing on effective reduction strategies and assessing public health risks. (c) 2019 Elsevier B.V. All rights reserved.Peer reviewe

Mechanismen des Wachstums und strukturelle Eigenschaften von Di-indenoperylene auf Metall, dielektrischen und organischen Oberflächen

The aim of this dissertation was to study the organic-inorganic (organic semiconductors with metals or dielectric materials) and organic-organic (organic hetero-structures) interfaces in variable architecture design for organic electronic devices. For this purpose, we performed complementary techniques such as atomic force microscopy (AFM), scanning tunneling microscopy (STM), scanning electron microscopy (SEM), as well as in-situ and ex-situ X-ray diffraction (XRD). The planar molecules n-type F16CuPc, PTCDI-C8 combined with p-type H16CuPc, pentacene, DIP are chosen as model systems of organic semiconductors. Al2O3(11-20), Cu(100) single crystal and SiO2 are used as substrates for organic molecular epitaxy. The study of DIP grown on SiO2 is devoted to understand the growth process of organic semiconductors on dielectric materials. We disclose that DIP films grown on SiO2 undergo a morphological transition from layer-by-layer (LBL) growth to rapid roughening with increasing film thickness over a large temperature range. In the LBL growth regime, we studied carefully the 2D islands size distribution, shape and their lateral correlation to gain insight into self-affine, scaling and fractal properties of the 2D islands. The onset of the growth mode transition is layer and temperature dependent, from D~3 ML at RT, ~4 ML at 90 °C to ~5 ML at 120 °C. In the rapid roughening regime, increasing substrate temperature leads to a lower growth exponent value, namely, ~0.84 at RT, ~0.80 at 90 °C, and ~0.77 at 120 °C. For the structural aspect, in spite of amorphous character of the SiO2 surface, the first DIP layer is under a compressive strain of ~ 3-4 % along b lattice vector, ~ 0.8 % strain along a lattice vector initially. The spacing between different DIP thin film layers decreases rapidly from initial 18 Å to 16.73 Å. The transition in morphology is coincident with the transition in structure. We use thin DIP films grown on copper single crystal are a model system to study the growth of organic molecules on metal surfaces. The structure of the thin films is investigated by STM. The growth of the DIP submonolayer is observed in real time at room temperature, 240 K and 150 K. The results show clearly that different substrate temperature leads to different cluster mobility. In addition, the first monolayer of DIP is commensurate to the substrates forming chiral domains. The molecular substrate interaction leads to ordered 2D structure and further to the epitaxial growth of the monolayer. The 2D domains of the monolayer are metastable, annealing results in a better ordering of the molecules. Organic-organic hetero-structures bear great interest as building blocks for future organic electronics and optoelectronics, for instance, OLEDs or photovoltaic cells. Structure and morphology are of crucial importance for high-performance devices. We studied a few hetero-structures, DIP-H16CuPc, F16CuPc-H16CuPc and PTCDI-pentacene by means of in-situ XRD and AFM, therefore a throughout understanding of the correlation between the structural ordering, growth mode and film thickness, which is essential for producing controllable architectures. In the end, we extend our study to the growth of nano- or micro- sized organic structures for advanced organic electronics. One dimensional organic F16CuPc nanowires and nanotubes were grown via OMBE by performing Au nanoparticles patterned SiO2 substrates. The large microsize organic DIP single crystals were synthesized by functionalizing the SiO2 surfaces with self assembled monolayers.Das Ziel dieser Dissertation war die Untersuchung der Eigenschaften von organisch-anorganischen (z.B. organischen Halbleitern mit Metallen oder dielektrischem SiO2) und organisch-organischen (z.B. organische Halbleitern mit organischen Halbleitern) Grenzflächen in verschiedenem Architektur design für organisch elektronische Geräte. Zu diesem Zweck haben wir ergänzende Techniken benutzt; dazu gehören Rasterkraftmikroskopie (AFM), Rastertunnelmikroskopie (STM), Rasterelektronenmikroskopie (SEM), so-wie in-situ und ex-situ Röntgenstreuung (XRD). Die planaren Moleküle n-Type F16CuPc, PTCDI-C8 kombiniert mit p-Type H16CuPc, Pentacene, DIP werden als Modellsysteme für organische Halbleiter ausgewählt. Al2O3(11-20), Cu(100) Einkristalle und SiO2 werden als Substrate für die organische Molekularstrahlepitaxie verwendet. Um das Wachstum der organischen Halbleiter auf dielektrischen Materialien zu verstehen, werden DIP Dünnschichten auf SiO2 untersucht. Die morphologischen Übergange der DIP Dünnschichten von einem Lagen Wachstumsmodus zu einem schnellen Aufrauungsmodus werden über einen großen Temperaturbereich beobachtet. Im Regime des Lagenwachstung Bereich werden die Größeverteilung und Gestalt, so-wie laterale Korrelation der zweidimensionalen Inseln sorgfältig untersucht um ihre Selbstaffinität, ihre Skalierung und ihre fraktalen Eigenschaften aufzudecken. Der Anfang des Übergangs vom Lagewachstum zum 3D Insel-Wachstumsmodus ist temperatur- und lage-abhängig, bei RT ~ 3 ML, bei 90 °C ~ 4 ML und bei 120 °C ~ 5 ML. Im Regime der schnellen Aufrauung führt die Erhöhung der Substrattemperatur zu einer Verschiebung des Skalenexponenten zu niedrigeren Werten, nämlich von 0.84 bei RT ~ 0.80 bei 90 °C und ~ 0.77 bei 120 °C. Unter dem strukturellen Aspekt bildet die erste DIP Monolage eine dichtere Schicht, trotz des amorphen Charakters der SiO2 Oberfläche. Die erste DIP-Schicht wird unter Einfluss des Substrates entlang des Gitter-Vektors b auf 96%-97% komprimiert (bezogen auf die relaxierte Struktur von dünnen Filmen), während sie entlang des Gitter Vektors a auf nur 99.2% komprimiert wird. Der Abstand zwischen verschiedenen Monolagen von DIP-Filmen ändert sich rapide von ~ 18 Å auf 16.73 Å. Der Übergang in die Morphologie von Lagenwachstum zur schnellen Aufrauung ist gleichzeitig mit einer Strukturänderung verbunden. Dünne DIP Schichten auf Kupfereinkristallen stellen ein ideales Modellsystem für organische Moleküle auf metallischen Oberflächen dar. Die Struktur der Schichten wurde mittels STM untersucht. Das Wachstum der Submonolagen von DIP auf Cu(100) wurde bei Raumtemperatur, 240 K und 150 K in Echtzeit beobachtet. Messungen an Submonolagen von DIP zeigen eindeutig, dass die Clustermobilität ein Merkmal für verschiedene Substrattemperaturen ist. Zudem wächst die erste Monolage DIP kommensurabel auf dem Metallsubstrat in chiralen Domänen. Die Molekül-Substrat-Wechselwirkungen führen zu der beobachteten 2D-Anordnung und des weiteren zum einem epitaktischen Wachstum der Monolagen. Die 2D-Domänen der Monolagen sind metastabil, d.h. eine bessere Anordnung der Moleküle ist nach dem Ausheizen zu sehen. Organisch-organische Heteroschichten sind für zukünftige elektronische und opto-elektronische Bauteile von großem Interesse, z.B. für OLEDs oder für photovoltaische Zellen. Struktur und Morphologie von Heteroschichten haben große Bedeutung für die High-Performance solcher Geräte. Die Heterostrukturen, DIP-H16CuPc, F16CuPc-H16CuPc und PTCDI-Pentacene werden mittels in-situ XRD und AFM untersucht, um ein vollständiges Verständnis der Zusammenhänge zwischen der struktural Anordnung, Wachstumsmodus und Schichtdicke zu erlangen, die für die Herstellung der beherrschbaren Architekturen unerlässlich ist. Schließlich werden das Wachstum von Nanoß und Mikrometer großen organischen Strukturen untersucht. Einerseits werden eindimensionale organische F16CuPc Nanodrähte und Nanoröhren wurden mittels OMBE auf mit Au Nanopartikel bedeckten SiO2-Substraten aufgewachsen. Andererseits werden organische DIP-Einkristalle im Mikrometerbereich große auf SiO2 synthetisiert, deren Substrat zuvor mit Hilfe von SAMs funktionalisiert wurde

Actin reorganization in hippocampal neurons may play a role in early learning and memory impairment after propofol anesthesia in rats

Objectives To observe changes in actin and dendritic spines in the hippocampus after propofol anesthesia, and to evaluate the role of these changes in subsequent learning impairment in both young (3-month-old) and aged (20-month-old) male rats. Methods The shuttle box test was used to evaluate learning from 1, 3, 7, or 14 days after anesthesia. Both F-actin content and dendritic spines in the hippocampal CA1 region were observed using immunofluorescent staining and western blot assays. Results The latency of the escape response was significantly prolonged until 7 days after anesthesia in the aged rats, and their learning curves were shifted. Dendritic spines were also decreased in the aged rats within 7 days after anesthesia, and F-actin content was significantly increased until 14 days after anesthesia. Conclusions Learning was inhibited after propofol anesthesia, especially in aged rats. The over-polymerization of actin and subsequent reorganization of dendritic spines in the hippocampus may be responsible for this learning impairment. Our findings suggest that synaptic plasticity may be an underlying mechanism of perioperative neurocognitive disorders

Roles of c-Fos, EGR-1, PKA, and PKC in cognitive dysfunction in rats after propofol anesthesia

This study aimed to investigate possible changes in the spatial memory of rats and the expression or activity of EGR-1, c-Fos, PKA, and PKC after propofol anesthesia. Thirty-six Sprague-Dawley rats aged 20 months and 36 Sprague-Dawley rats aged three months were each randomly divided into three groups: the control group, the Morris Water Maze (MWM) group, and the propofol group. In the propofol groups of both young and aged rats, the rats were anesthetized by propofol for two or four hours and then performed the MWM test two days or two weeks after anesthesia to assess cognitive function. EGR-1, c-Fos, PKA, and PKC expressions in the rat hippocampus were determined via immunohistochemistry. For the older rats, the escape latency in the P4h/2d group was significantly prolonged (P < 0.05), and the learning curve was right-shifted in the P4h/2w group (P < 0.05). The expression levels of EGR-1, c-Fos, PKA, and PKC in the MWM groups were significantly higher than those in the control groups (P < 0.05). In the P4h/2d group of aged rats, the expression levels of both PKA and PKC were decreased compared with those of the MWM groups. The decreased expression of both protein kinases may be responsible for the observed impairment after propofol anesthesia

The Effects of Floods on the Incidence of Bacillary Dysentery in Baise (Guangxi Province, China) from 2004 to 2012

Research shows potential effects of floods on intestinal infections. Baise, a city in Guangxi Province (China) had experienced several floods between 2004 and 2012 due to heavy and constant precipitation. This study aimed to examine the relationship between floods and the incidence of bacillary dysentery in Baise. A mixed generalized additive model and Spearman correlation were applied to analyze the relationship between monthly incidence of bacillary dysentery and 14 flood events with two severity levels. Data collected from 2004 to 2010 were utilized to estimate the parameters, whereas data from 2011 to 2012 were used to validate the model. There were in total 9255 cases of bacillary dysentery included in our analyses. According to the mixed generalized additive model, the relative risks (RR) of moderate and severe floods on the incidence of bacillary dysentery were 1.40 (95% confidence interval (CI): 1.16–1.69) and 1.78 (95% CI: 1.61–1.97), respectively. The regression analysis also indicated that the flood duration was negatively associated with the incidence of bacillary dysentery (with RR: 0.57, 95% CI: 0.40–0.86). Therfore, this research suggests that floods exert a significant part in enhancing the risk of bacillary dysentery in Baise. Moreover, severe floods have a higher proportional contribution to the incidence of bacillary dysentery than moderate floods. In addition, short-term floods may contribute more to the incidence of bacillary dysentery than a long-term flood. The findings from this research will provide more evidence to reduce health risks related to floods

Research on application of high performance alkali-free liquid accelerator in shotcrete support

At present, sprayed concrete has problems such as low strength, large rebound amount, and high dust concentration. Developed a new type of alkali-free liquid accelerator, which can effectively improve the performance of shotcrete. The alkali-free liquid accelerator is mainly composed of aluminum sulfate, active aluminum hydroxide, alcohol amine, amide, and stabilizer. Through laboratory tests and field tests, when the alkali-free liquid accelerator admixture is 5% to 7%, the initial setting time is within 5 minutes, and the final setting time is within 10 minutes. The strength of shotcrete reaches 12.8MPa in one day, and the compressive strength ratio of 28d is more than 95.3%, and the rebound amount is within 10%. Compared with ordinary alkali-free liquid accelerator and alkaline liquid accelerator, the strength of sprayed concrete mixed with the alkali-free liquid accelerator is greatly improved, which is more conducive to the support of the sprayed layer, reduced rebound and dust, effectively improve the construction environment and increase construction efficiency

Speciation of chromium in chromium yeast

High-performance liquid chromatography was used to separate Cr(III) and Cr(VI) in samples with detection by inductively coupled plasma mass spectrometry(ICP-MS). The separation was achieved on a weak anion exchange column. The mobile phase was pH 7.0 ammonium nitrate solution. The redox reaction between Cr(III) and Cr(VI) was avoided during separation and determination. This separation method could be used to separate the samples with large concentration differences between Cr(III) and Cr(VI). The alkaline digestion was used to extract chromium in solid sample, which had no effect on the retention time and the peak area of the Cr(VI). However, the conversion of Cr(VI) from Cr(III) was observed during alkaline digestion, which displayed positive relation with the ratio of Cr(III) and Cr(VI) in samples. Both Cr(III) and Cr(VI) contents of chromium yeasts cultured in media with different chromium additions were determined. The spike recoveries of Cr(VI) for chromium yeasts were in the range of 95-108 %

Deletion of intragenic tandem repeats in unit C of FLO1 of Saccharomyces cerevisiae increases the conformational stability of flocculin under acidic and alkaline conditions.

Flocculation is an attractive property for Saccaromyces cerevisiae, which plays important roles in fermentation industry and environmental remediation. The process of flocculation is mediated by a family of cell surface flocculins. As one member of flocculins, Flo1 is characterized by four families of repeats (designated as repeat units A, B, C and D) in the central domain. It is generally accepted that variation of repeat unit A in length in Flo1 influences the degree of flocculation or specificity for sugar recognization. However, no reports were observed for other repeat units. Here, we compared the flocculation ability and its sensitivity to environmental factors between yeast strain YSF1 carrying the intact FLO1 gene and yeast strains carrying the derived forms of FLO1 with partial or complete deletion of repeats in unit C. No obvious differences in flocculation ability and specificity of carbohydrate recognition were observed among these yeast strains, which indicates the truncated flocculins can stride across the cell wall and cluster the N-terminal domain on the surface of yeast cells as the intact Flo1 thereby improving intercellular binding. However, yeast strains with the truncated flocculins required more mannose to inhibit completely the flocculation, displayed broad tolerance of flocculation to pH fluctuation, and the fewer the repeats in unit C, the stronger adaptability of flocculation to pH change, which was not relevant to the position of deletion. This suggests that more stable active conformation is obtained for flocculin by deletion the repeat unit C in the central domain of Flo1, which was validated further by the higher hydrophobicity on the surface of cells of YSF1c with complete deletion of unit C under neutral and alkaline conditions and the stabilization of GFP conformation by fusion with flocculin with complete deletion of unit C in the central domain