Pedestrian Crossing Action Recognition and Trajectory Prediction with 3D Human Keypoints

Accurate understanding and prediction of human behaviors are critical prerequisites for autonomous vehicles, especially in highly dynamic and interactive scenarios such as intersections in dense urban areas. In this work, we aim at identifying crossing pedestrians and predicting their future trajectories. To achieve these goals, we not only need the context information of road geometry and other traffic participants but also need fine-grained information of the human pose, motion and activity, which can be inferred from human keypoints. In this paper, we propose a novel multi-task learning framework for pedestrian crossing action recognition and trajectory prediction, which utilizes 3D human keypoints extracted from raw sensor data to capture rich information on human pose and activity. Moreover, we propose to apply two auxiliary tasks and contrastive learning to enable auxiliary supervisions to improve the learned keypoints representation, which further enhances the performance of major tasks. We validate our approach on a large-scale in-house dataset, as well as a public benchmark dataset, and show that our approach achieves state-of-the-art performance on a wide range of evaluation metrics. The effectiveness of each model component is validated in a detailed ablation study.Comment: ICRA 202

Pushing the Limits of Machine Design: Automated CPU Design with AI

Design activity -- constructing an artifact description satisfying given goals and constraints -- distinguishes humanity from other animals and traditional machines, and endowing machines with design abilities at the human level or beyond has been a long-term pursuit. Though machines have already demonstrated their abilities in designing new materials, proteins, and computer programs with advanced artificial intelligence (AI) techniques, the search space for designing such objects is relatively small, and thus, "Can machines design like humans?" remains an open question. To explore the boundary of machine design, here we present a new AI approach to automatically design a central processing unit (CPU), the brain of a computer, and one of the world's most intricate devices humanity have ever designed. This approach generates the circuit logic, which is represented by a graph structure called Binary Speculation Diagram (BSD), of the CPU design from only external input-output observations instead of formal program code. During the generation of BSD, Monte Carlo-based expansion and the distance of Boolean functions are used to guarantee accuracy and efficiency, respectively. By efficiently exploring a search space of unprecedented size 10^{10^{540}}, which is the largest one of all machine-designed objects to our best knowledge, and thus pushing the limits of machine design, our approach generates an industrial-scale RISC-V CPU within only 5 hours. The taped-out CPU successfully runs the Linux operating system and performs comparably against the human-designed Intel 80486SX CPU. In addition to learning the world's first CPU only from input-output observations, which may reform the semiconductor industry by significantly reducing the design cycle, our approach even autonomously discovers human knowledge of the von Neumann architecture.Comment: 28 page

High prevalence of Rickettsia spp. in ticks from wild hedgehogs rather than domestic bovine in Jiangsu province, Eastern China

BackgroundSpotted fever group Rickettsia (SFGR), containing various pathogenic Rickettsia spp., poses remarkable negative influences to public health by causing various severe or mild diseases. Information regarding prevalence of SFGR in ticks in Jiangsu province, Eastern China, is still limited and needs urgent investigations.MethodsHedgehog- and bovine-attached ticks were collected from Jiangsu province, Eastern China. DNA of individual ticks was extracted for nested polymerase chain reaction amplifications targeting gltA, 16S ribosomal RNA (rrs), ompA, ompB, and sca4 genes following with sequencing. SFGR-specific IgG antibodies in sera of local donators were evaluated using ELISA.ResultsOverall, 144 (83.2%) of the 173 ticks from hedgehogs and 2 (1.2%) of the 168 ticks from bovine were positive for one of the three identified Rickettsia spp., with significant difference between the two groups (P = 3.6e-52). Candidatus Rickettsia principis (9; 5.2%) and R. heilongjiangensis (135; 78.0%) were detected in Haemaphysalis flava rather than in H. longicornis ticks from hedgehogs. R. heilongjiangensis (1; 0.6%) and Candidatus R. jingxinensis (or Candidatus R. longicornii) (1; 0.6%) were identified in H. longicornis and Rhipicephalus microplus ticks from bovine, respectively. Phylogenetic analysis indicated Candidatus R. jingxinensis belonged to R. japonica subgroup, whereas Candidatus R. principis belonged to a novel subgroup. Higher serological prevalence of spotted fever and SFGR-specific IgG antibody level in humans were observed around the investigated area than in urban areas, without significant difference.ConclusionCandidatus R. principis and Candidatus R. jingxinensis were identified in Jiangsu province, Eastern China, and fully genetically characterized for the first time. The higher prevalence of SFGR in hedgehog-attached ticks as well as the higher SFGR-specific IgG antibody level and seropositive rate in humans around the investigated area suggested that more attention should be paid to SFGR. This pathogen is usually transmitted or harbored by wild animals and ticks. This study provides important epidemiological data for both physicians and public health officers in developing early prevention and control strategies against potential Rickettsia infections and in the preparation of suitable testing and treatment needs for rickettsiosis in the endemic areas

Characteristics and Relationships between Species Diversity and Productivity of Different Grassland Types in the Burqin Forest Region of the Altai Mountains

The Altai Mountain is located at the intersection of cold and arid regions. Climate change and overgrazing directly affect the growth of the grassland ecosystem in this region. This study took the grassland community in the Burqin forest area of the Altai Mountains as an example to analyze the species diversity and productivity of different grassland types based on 50 sampling plots. The relationship between species diversity and the productivity of grassland types at different altitudes was also discussed. The results showed that: (1) In the Burqin forest area, the desert steppe was dominated by Gramineae, Compositae, and Leguminosae. Montane steppe and mountain meadows were dominated by Umbelliferae, Gramineae, and Liliaceae. Gramineae, Ranunculaceae, and Liliaceae were the dominant families in both montane meadows steppe and alpine steppe but occurred in varying proportions. (2) The variation in plant numbers at the family–species level was characterized as montane steppe > alpine meadow > montane meadow steppe > desert steppe > mountain meadows. (3) The similarity in species composition among communities of different grassland types was low. In DS and MM, the number of grasslands and species played a decisive role in determining the biomass. The biomass of MS and AM was determined using the Simpson and Shannon–Wiener indices, and the number of dominant species determined the biomass. The number of grasslands and species did not have a significant impact on the biomass of MMS, which may be due to human factors such as grazing. (4) The dominant species in the grassland at an altitude of 1200–1400 m is prominent. The number of individuals in the dominant species was large and evenly distributed. Margalef peaked at an altitude of 1600–1800 m, but the number of individuals was small, resulting in low biomass and diversity in this range. Most plants survive at an altitude of 2000–2200 m; therefore, in grassland protection and planning management, it is important to consider the specific situation of plant growth under different habitats at different altitudes and make reasonable protection decisions based on local conditions to maintain species diversity and sustainable development of grassland ecosystems. This study provides basic data to support the theoretical basis for the protection and sustainable utilization of grassland resources and the restoration of degraded grasslands in the study region

Beam position measurement system at HIRFL-CSRm

Beam position measurement system can not only provide the beam position monitoring, but also be used for global orbit correction to reduce beam loss risk and maximize acceptance. The Beam Position Monitors (BPM) are installed along the synchrotron to acquire beam position with the front-end electronics and data acquisition system (DAQ). To realize high precision orbit measurement in the main heavy ion synchrotron and cooling storage ring of heavy-ion research facility in Lanzhou (HIRFL-CSRm), a series of alignment and calibration work has been implemented on the BPM and its DAQ system. This paper analyzed the tests performed in the laboratory as well as with beam based on the developed algorithms and hardware. Several filtering algorithms were designed and implemented on the acquired BPM raw data, then the beam position and resolution were calculated and analyzed. The results show that the position precision was significantly improved from more than 100 μm to about 50 μm by implementing the new designed filtering algorithm. According to the analyzation of the measurement results and upcoming physical requirements, further upgrade scheme for the BPM DAQ system of CSRm based on field programmable gate array (FPGA) technology was proposed and discussed

β-Lactam Antibiotics Enhance the Pathogenicity of Methicillin-Resistant Staphylococcus aureus via SarA-Controlled Lipoprotein-Like Cluster Expression

β-Lactam antibiotics are widely applied to treat infectious diseases. However, certain poor disease outcomes caused by β-lactams remain poorly understood. In this study, we have identified a cluster of lipoprotein-like genes (lpl, sa2275–sa2273) that is upregulated in the major clinically prevalent MRSA clones in response to subinhibitory concentrations of β-lactam induction. The major highlight of this work is that β-lactams stimulate the expression of SarA, which directly binds to the lpl cluster promoter region and upregulates lpl expression in MRSA. Deletion of lpl significantly decreases proinflammatory cytokine levels in vitro and in vivo. The β-lactam-induced Lpls enhance host inflammatory responses by triggering the Toll-like-receptor-2-mediated expressions of interleukin-6 and tumor necrosis factor alpha. The β-lactam-induced Lpls are important virulence factors that enhance MRSA pathogenicity. These data elucidate that subinhibitory concentrations of β-lactams can exacerbate the outcomes of MRSA infection through induction of lpl controlled by the global regulator SarA.Methicillin-resistant Staphylococcus aureus (MRSA) resists nearly all β-lactam antibiotics that have a bactericidal activity. However, whether the empirically used β-lactams enhance MRSA pathogenicity in vivo remains unclear. In this study, we showed that a cluster of lipoprotein-like genes (lpl, sa2275 to sa2273 [sa2275–sa2273]) was upregulated in MRSA in response to subinhibitory concentrations of β-lactam induction. The increasing expression of lpl by β-lactams was directly controlled by the global regulator SarA. The β-lactam-induced Lpls stimulated the production of interleukin-6 and tumor necrosis factor alpha in RAW 264.7 macrophages. The lpl deletion mutants (N315Δlpl and USA300Δlpl) decreased the proinflammatory cytokine levels in vitro and in vivo. Purified lipidated SA2275-his proteins could trigger a Toll-like-receptor-2 (TLR2)-dependent immune response in primary mouse bone marrow-derived macrophages and C57BL/6 mice. The bacterial loads of N315Δlpl in the mouse kidney were lower than those of the wild-type N315. The β-lactam-treated MRSA exacerbated cutaneous infections in both BALB/c and C57BL/6 mice, presenting increased lesion size; destroyed skin structure; and easily promoted abscess formation compared with those of the untreated MRSA. However, the size of abscesses caused by the β-lactam-treated N315 was negligibly different from those caused by the untreated N315Δlpl in C57BL/6 TLR2−/− mice. Our findings suggest that β-lactams must be used carefully because they might aggravate the outcome of MRSA infection compared to inaction in treatment

Composite Hydrogel Modified by IGF-1C Domain Improves Stem Cell Therapy for Limb Ischemia

Stem cell treatment for critical limb ischemia yields a limited therapeutic effect due to cell loss and dysfunction caused by local ischemic environment. Biomimetic scaffolds emerge as ideal cell delivery vehicles for regulating cell fate via mimicking the components of stem cell niche. Herein, we prepared a bioactive hydrogel by mixing chitosan and hyaluronic acid that is immobilized with C domain peptide of insulin-like growth factor 1 (IGF-1C) and examined whether this hydrogel could augment stem cell survival and therapeutic potential. Our results showed that IGF-1C-modified hydrogel increased in vitro viability and proangiogenic activity of adipose-derived stromal cells (ADSCs). Moreover, cotransplantation of hydrogel and ADSCs into ischemic hind limbs of mice effectively ameliorated blood perfusion and muscle regeneration, leading to superior limb salvage. These therapeutic effects can be ascribed to improved ADSC retention, angiopoientin-1 secretion, and neovascularization, as well as reduced inflammatory cell infiltration. Additionally, hydrogel enhanced antifibrotic activity of ADSCs, as evidenced by decreased collagen accumulation at late stage. Together, our findings indicate that composite hydrogel modified by IGF-1C could promote survival and proangiogenic capacity of ADSCs and thereby represents a feasible option for cell-based treatment for critical limb ischemia