84 research outputs found
Understanding Daily Travel Patterns of Subway Users â An Example from the Beijing Subway
The daily travel patterns (DTPs) present short-term and timely characteristics of the usersâ travel behaviour, and they are helpful for subway planners to better understand the travel choices and regularity of subway users (SUs) in details. While several well-known subway travel patterns have been detected, such as commuting modes and shopping modes, specific features of many patterns are still confused or omitted. Now, based on the automatic fare collection (AFC) system, a data-mining procedure to recognize DTPs of all SUs has become possible and effective. In this study, DTPs are identified by the station sequences (SSs), which are modelled from smart card transaction data of the AFC system. The data-mining procedure is applied to a large weekly sample from the Beijing Subway to understand DTPs. The results show that more than 93% SUs of the Beijing Subway travel in 7 DTPs, which are remarkably stable in share and distribution. Different DTPs have their own unique characteristics in terms of time distribution, activity duration and repeatability, which provide a wealth of information to calibrate different types of users and characterize their travel patterns.</p
Efficient Sequence Transduction by Jointly Predicting Tokens and Durations
This paper introduces a novel Token-and-Duration Transducer (TDT)
architecture for sequence-to-sequence tasks. TDT extends conventional
RNN-Transducer architectures by jointly predicting both a token and its
duration, i.e. the number of input frames covered by the emitted token. This is
achieved by using a joint network with two outputs which are independently
normalized to generate distributions over tokens and durations. During
inference, TDT models can skip input frames guided by the predicted duration
output, which makes them significantly faster than conventional Transducers
which process the encoder output frame by frame. TDT models achieve both better
accuracy and significantly faster inference than conventional Transducers on
different sequence transduction tasks. TDT models for Speech Recognition
achieve better accuracy and up to 2.82X faster inference than RNN-Transducers.
TDT models for Speech Translation achieve an absolute gain of over 1 BLEU on
the MUST-C test compared with conventional Transducers, and its inference is
2.27X faster. In Speech Intent Classification and Slot Filling tasks, TDT
models improve the intent accuracy up to over 1% (absolute) over conventional
Transducers, while running up to 1.28X faster
Deep Reinforcement Learning for Flipper Control of Tracked Robots
The autonomous control of flippers plays an important role in enhancing the
intelligent operation of tracked robots within complex environments. While
existing methods mainly rely on hand-crafted control models, in this paper, we
introduce a novel approach that leverages deep reinforcement learning (DRL)
techniques for autonomous flipper control in complex terrains. Specifically, we
propose a new DRL network named AT-D3QN, which ensures safe and smooth flipper
control for tracked robots. It comprises two modules, a feature extraction and
fusion module for extracting and integrating robot and environment state
features, and a deep Q-Learning control generation module for incorporating
expert knowledge to obtain a smooth and efficient control strategy. To train
the network, a novel reward function is proposed, considering both learning
efficiency and passing smoothness. A simulation environment is constructed
using the Pymunk physics engine for training. We then directly apply the
trained model to a more realistic Gazebo simulation for quantitative analysis.
The consistently high performance of the proposed approach validates its
superiority over manual teleoperation
Quercus texana âJin Fen Shi Jiaâ: A New Colored Landscape Tree
Quercus L. is an important tree of the family Fagaceae, and widely distributed in Asia, Africa, Europe, and the Americas (Jiang et al. 2019). There are âź500 species, which can be generally divided into two subgenera and eight sections (ChassĂŠ 2018). The section Lobatae is naturally distributed in North America, Central America, and Colombia in South America. There are reports of breeding horticultural cultivars from tree species of this section in Europe and the United States. These cultivars include different leaf colors and tree shapes, such as Quercus coccinea âSplendensâ, Quercus palustris Pacific Brilliance⢠âPWJR08â (bright red leaves in autumn), Quercus texana âNew Madridâ (red leaves in spring), Quercus rubra âAureaâ (yellow leaves in spring), Q. texana HighpointÂŽ âQNFTAâ, Q. palustris Green PillarÂŽ âPringreenâ and Quercus phellos HightowerÂŽ âQPSTAâ (have narrow crown and are densely branched), and Q. palustris âGreen Dwarfâ (low tree-shape) (Iqbal et al. 2017; Lancaster 1977; Russell et al. 2021; Torres-Miranda et al. 2011). Q. texana, also known as Nuttallâs oak, is a medium-sized deciduous tree with rapid growth, strong adaptability, and high ornamental value (Costello et al. 2011). It belongs to the section Lobatae, which are native to the Mississippi River Basin in the southeastern United States (BarrĂłn et al. 2017; Manos et al. 1999; Sargent 1918). The trunk of Q. texana is upright with a tower-shaped crown. The leaves of Q. texana are simple, with lobed and toothed margins, broad and rounded lobes, and leaf length of 10 to 15 cm. The leaves are green and give dense shade in summer, and then turn bright red or reddish-brown in autumn; the leaves remain until late in the year on the twigs. Q. texana is commonly used for landscaping purposes and timber production, fuel wood, firewood, and charcoal. The species is known for its straight grain, resistance to fungal decay, and overall durability, making it a desirable species for industrial applications such as flooring, paneling, and furniture (Wang et al. 2022).
This species is often chosen for landscape applications because of its adaptable nature, rapid growth rate, and beautiful foliage. In recent years, researchers have been working to produce improved cultivars of Q. texana, and various new cultivars have been created with enhanced characteristics such as greater biotic and abiotic resistance, improved growth rate, and desirable foliage shapes and colors.
In China, some institutes have conducted systematic research since the 1990s on the introduction and cultivation of Q. texana. After screening, we selected some cultivars and provenances with good growth and strong adaptability (Chen et al. 2013). Now there are five cultivars of Q. texana authorized by the National Forestry and Grassland Administration (China): cultivars Yan Yu (red leaves in autumn), Long Xiang No. 7 and Long Xiang No. 10 (yellow leaves in spring), and Long Xiang No. 3 and Long Xiang No. 8 (red leaves in spring). The new cultivars possess excellent ornamental features and provide more options in landscape applications
Radioprotective Effect of Grape Seed Proanthocyanidins In Vitro and In Vivo
We have demonstrated that grape seed proanthocyanidins (GSPs) could effectively scavenge hydroxyl radical (â˘OH) in a dose-dependent manner. Since most of the ionizing radiation- (IR-) induced injuries were caused by â˘OH, this study was to investigate whether GSPs would mitigate IR-induced injuries in vitro and in vivo. We demonstrated that GSPs could significantly reduce IR-induced DNA strand breaks (DSBs) and apoptosis of human lymphocyte AHH-1 cells. This study also showed that GSPs could protect white blood cells (WBC) from IR-induced injuries, speed up the weight of mice back, and decrease plasma malondialdehyde (MDA), thus improving the survival rates of mice after ionizing radiation. It is suggested that GSPs have a potential as an effective and safe radioprotective agent
Understanding the Eastward Shift and Intensification of the ENSO Teleconnection Over South Pacific and Antarctica Under Greenhouse Warming
The PacificâSouth America (PSA) teleconnection pattern triggered by the El NiĂąo/Southern Oscillation (ENSO) is suggested to be moving eastward and intensifying under global warming. However, the underlying mechanism is not completely understood. Previous studies have proposed that the movement of the PSA teleconnection pattern is attributable to the eastward shift of the tropical Pacific ENSO-driven rainfall anomalies in response to the projected El NiĂąo-like sea surface temperature (SST) warming pattern. In this study, we found that with uniform warming, models will also simulate an eastward movement of the PSA teleconnection pattern, without the impact of the uneven SST warming pattern. Further investigation reveals that future changes in the climatology of the atmospheric circulation, particularly the movement of the exit region of the subtropical jet stream, can also contribute to the eastward shift of the PSA teleconnection pattern by modifying the conversion of mean kinetic energy to eddy kinetic energy
Genome sequencing and analysis of the paclitaxelproducing endophytic fungus \u3cem\u3ePenicillium aurantiogriseum\u3c/em\u3e NRRL 62431
Background
Paclitaxel (Taxolâ˘) is an important anticancer drug with a unique mode of action. The biosynthesis of paclitaxel had been considered restricted to the Taxus species until it was discovered in Taxomyces andreanae, an endophytic fungus of T. brevifolia. Subsequently, paclitaxel was found in hazel (Corylus avellana L.) and in several other endophytic fungi. The distribution of paclitaxel in plants and endophytic fungi and the reported sequence homology of key genes in paclitaxel biosynthesis between plant and fungi species raises the question about whether the origin of this pathway in these two physically associated groups could have been facilitated by horizontal gene transfer.
Results
The ability of the endophytic fungus of hazel Penicillium aurantiogriseum NRRL 62431 to independently synthesize paclitaxel was established by liquid chromatography-mass spectrometry and proton nuclear magnetic resonance. The genome of Penicillium aurantiogriseum NRRL 62431 was sequenced and gene candidates that may be involved in paclitaxel biosynthesis were identified by comparison with the 13 known paclitaxel biosynthetic genes in Taxus. We found that paclitaxel biosynthetic gene candidates in P. aurantiogriseum NRRL 62431 have evolved independently and that horizontal gene transfer between this endophytic fungus and its plant host is unlikely.
Conclusions
Our findings shed new light on how paclitaxel-producing endophytic fungi synthesize paclitaxel, and will facilitate metabolic engineering for the industrial production of paclitaxel from fungi
A Novel Recombinant Peste des Petits Ruminants-Canine Adenovirus Vaccine Elicits Long-Lasting Neutralizing Antibody Response against PPR in Goats
BACKGROUND: Peste des petits ruminants (PPR) is a highly contagious infectious disease of goats, sheep and small wild ruminant species with high morbidity and mortality rates. The Peste des petits ruminants virus (PPRV) expresses a hemagglutinin (H) glycoprotein on its outer envelope that is crucial for viral attachment to host cells and represents a key antigen for inducing the host immune response. METHODOLOGY/PRINCIPAL FINDINGS: To determine whether H can be exploited to generate an effective PPRV vaccine, a replication-competent recombinant canine adenovirus type-2 (CAV-2) expressing the H gene of PPRV (China/Tibet strain) was constructed by the in vitro ligation method. The H expression cassette, including the human cytomegalovirus (hCMV) promoter/enhancer and the BGH early mRNA polyadenylation signal, was inserted into the SspI site of the E3 region, which is not essential for proliferation of CAV-2. Infectious recombinant rCAV-2-PPRV-H virus was generated in transfected MDCK cells and used to immunize goats. All vaccinated animals produced antibodies upon primary injection that were effective in neutralizing PPRV in vitro. Higher antibody titer was obtained following booster inoculation, and the antibody was detectable in goats for at least seven months. No serious recombinant virus-related adverse effect was observed in immunized animals and no adenovirus could be isolated from the urine or feces of vaccinated animals. Results showed that the recombinant virus was safe and could stimulate a long-lasting immune response in goats. CONCLUSIONS/SIGNIFICANCE: This strategy not only provides an effective PPR vaccine candidate for goats but may be a valuable mean by which to differentiate infected from vaccinated animals (the so-called DIVA approach)
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