155 research outputs found
Examining scholars' activity on a Chinese blogging and academic social network site
This study analyzes scholars' activity on a popular academic blogging and social network site (SNS) in China, ScienceNet. We collected blogs, comments, recommendations, likes, and user profile information and analyzed how different groups of users differ in their patterns of activity with others in different disciplines, professional ranks, and universities. Results indicate that: 1) scholars in management and mathematics are active in recommending and commenting other users; 2) scholars from well-known universities and research institutes often receive more comments and recommendations than those from other universities; 3) scholars with higher professional ranks are more active, and are more likely to receive comments and recommendations from others. These findings suggest different usage of academic SNS among scholars of different disciplines, ranks, and universities
Exploring Browsing Behavior of Product Information in an M-commerce Application: a Transaction Log Analysis
This research aims to describe the information browsing and merchandise purchasing behaviors of the users in an M-commerce application. Data used in this research comes from the transaction logs of 290 heavy users in March 2015. We established the mapping between the request parameters in the log and the user information behavior to future analyze the pattern of user behavior. People are most concerned about the details of items, and actively share their favorite items and shops to others. The times of view is power-law distribution. We also find that the items which are viewed 9 times and are included in the submitted order are most likely to be bought. There is a positive correlation between the purchase of items and the numbers of browsing and sharing behaviors
Avatar Knowledge Distillation: Self-ensemble Teacher Paradigm with Uncertainty
Knowledge distillation is an effective paradigm for boosting the performance
of pocket-size model, especially when multiple teacher models are available,
the student would break the upper limit again. However, it is not economical to
train diverse teacher models for the disposable distillation. In this paper, we
introduce a new concept dubbed Avatars for distillation, which are the
inference ensemble models derived from the teacher. Concretely, (1) For each
iteration of distillation training, various Avatars are generated by a
perturbation transformation. We validate that Avatars own higher upper limit of
working capacity and teaching ability, aiding the student model in learning
diverse and receptive knowledge perspectives from the teacher model. (2) During
the distillation, we propose an uncertainty-aware factor from the variance of
statistical differences between the vanilla teacher and Avatars, to adjust
Avatars' contribution on knowledge transfer adaptively. Avatar Knowledge
Distillation AKD is fundamentally different from existing methods and refines
with the innovative view of unequal training. Comprehensive experiments
demonstrate the effectiveness of our Avatars mechanism, which polishes up the
state-of-the-art distillation methods for dense prediction without more extra
computational cost. The AKD brings at most 0.7 AP gains on COCO 2017 for Object
Detection and 1.83 mIoU gains on Cityscapes for Semantic Segmentation,
respectively.Comment: Accepted by ACM MM 202
DAMO-YOLO : A Report on Real-Time Object Detection Design
In this report, we present a fast and accurate object detection method dubbed
DAMO-YOLO, which achieves higher performance than the state-of-the-art YOLO
series. DAMO-YOLO is extended from YOLO with some new technologies, including
Neural Architecture Search (NAS), efficient Reparameterized Generalized-FPN
(RepGFPN), a lightweight head with AlignedOTA label assignment, and
distillation enhancement. In particular, we use MAE-NAS, a method guided by the
principle of maximum entropy, to search our detection backbone under the
constraints of low latency and high performance, producing ResNet/CSP-like
structures with spatial pyramid pooling and focus modules. In the design of
necks and heads, we follow the rule of ``large neck, small head''.We import
Generalized-FPN with accelerated queen-fusion to build the detector neck and
upgrade its CSPNet with efficient layer aggregation networks (ELAN) and
reparameterization. Then we investigate how detector head size affects
detection performance and find that a heavy neck with only one task projection
layer would yield better results.In addition, AlignedOTA is proposed to solve
the misalignment problem in label assignment. And a distillation schema is
introduced to improve performance to a higher level. Based on these new techs,
we build a suite of models at various scales to meet the needs of different
scenarios. For general industry requirements, we propose DAMO-YOLO-T/S/M/L.
They can achieve 43.6/47.7/50.2/51.9 mAPs on COCO with the latency of
2.78/3.83/5.62/7.95 ms on T4 GPUs respectively. Additionally, for edge devices
with limited computing power, we have also proposed DAMO-YOLO-Ns/Nm/Nl
lightweight models. They can achieve 32.3/38.2/40.5 mAPs on COCO with the
latency of 4.08/5.05/6.69 ms on X86-CPU. Our proposed general and lightweight
models have outperformed other YOLO series models in their respective
application scenarios.Comment: Project Website: https://github.com/tinyvision/damo-yol
Vascular Endothelial Cells Produce Soluble Factors That Mediate the Recovery of Human Hematopoietic Stem Cells after Radiation Injury
AbstractThe risk of terrorism with nuclear or radiologic weapons is considered to be high over the coming decade. Ionizing radiation can cause a spectrum of hematologic toxicities, from mild myelosuppression to myeloablation and death. However, the potential regenerative capacity of human hematopoietic stem cells (HSCs) after radiation injury has not been well characterized. In this study, we sought to characterize the effects of ionizing radiation on human HSCs and to determine whether signals from vascular endothelial cells could promote the repair of irradiated HSCs. Exposure of human bone marrow CD34+ cells to 400 cGy caused a precipitous decline in hematopoietic progenitor cell content and primitive cells capable of repopulating nonobese diabetic/severe combined immunodeficient mice (SCID-repopulating cells), which was not retrievable via treatment with cytokines. Conversely, culture of 400 cGy–irradiated bone marrow CD34+ cells with endothelial cells under noncontact conditions supported the differential recovery of both viable progenitor cells and primitive SCID-repopulating cells. These data illustrate that vascular endothelial cells produce soluble factors that promote the repair and functional recovery of HSCs after radiation injury and suggest that novel factors with radiotherapeutic potential can be identified within this milieu
Low-Cost ZnO:YAG-Based Metal-Insulator-Semiconductor White Light-Emitting Diodes with Various Insulators
ZnO:YAG-based metal-insulator-semiconductor (MIS) diodes with various insulators were synthesized on an indium tin oxide (ITO) glass by ultrasonic spray pyrolysis. SiO2 and MnZnO (MZO) were separately used as insulators. X-ray diffraction revealed the crystalline structure of the ZnO:YAG film. The photoluminescence (PL) properties of the ZnO:YAG film were studied and the color of photoluminescence was found to be almost white. The electrical properties of the diodes with different insulators and thicknesses were compared. The diode with the SiO2 insulator had a lower threshold voltage, smaller leakage current, and a higher series resistance than that with the MZO insulator layer
Hydrogen Sulfide Protects against Chemical Hypoxia-Induced Injury by Inhibiting ROS-Activated ERK1/2 and p38MAPK Signaling Pathways in PC12 Cells
Hydrogen sulfide (H2S) has been proposed as a novel neuromodulator and neuroprotective agent. Cobalt chloride (CoCl2) is a well-known hypoxia mimetic agent. We have demonstrated that H2S protects against CoCl2-induced injuries in PC12 cells. However, whether the members of mitogen-activated protein kinases (MAPK), in particular, extracellular signal-regulated kinase1/2(ERK1/2) and p38MAPK are involved in the neuroprotection of H2S against chemical hypoxia-induced injuries of PC12 cells is not understood. We observed that CoCl2 induced expression of transcriptional factor hypoxia-inducible factor-1 alpha (HIF-1α), decreased cystathionine-β synthase (CBS, a synthase of H2S) expression, and increased generation of reactive oxygen species (ROS), leading to injuries of the cells, evidenced by decrease in cell viability, dissipation of mitochondrial membrane potential (MMP) , caspase-3 activation and apoptosis, which were attenuated by pretreatment with NaHS (a donor of H2S) or N-acetyl-L cystein (NAC), a ROS scavenger. CoCl2 rapidly activated ERK1/2, p38MAPK and C-Jun N-terminal kinase (JNK). Inhibition of ERK1/2 or p38MAPK or JNK with kinase inhibitors (U0126 or SB203580 or SP600125, respectively) or genetic silencing of ERK1/2 or p38MAPK by RNAi (Si-ERK1/2 or Si-p38MAPK) significantly prevented CoCl2-induced injuries. Pretreatment with NaHS or NAC inhibited not only CoCl2-induced ROS production, but also phosphorylation of ERK1/2 and p38MAPK. Thus, we demonstrated that a concurrent activation of ERK1/2, p38MAPK and JNK participates in CoCl2-induced injuries and that H2S protects PC12 cells against chemical hypoxia-induced injuries by inhibition of ROS-activated ERK1/2 and p38MAPK pathways. Our results suggest that inhibitors of ERK1/2, p38MAPK and JNK or antioxidants may be useful for preventing and treating hypoxia-induced neuronal injury
Role of 18
Background. Positron emission tomography/computed tomography (PET/CT) is recommended for colorectal cancer (CRC) patients with suspected malignant pulmonary lesions. This study aims to systematically discuss the 18F-FDG-PET/CT diagnosis of solitary pulmonary lesions that are strongly suspected to be malignant in CRC patients who have previously undergone curative therapy. Methods. This retrospective study involved 49 consecutive CRC patients who had previously undergone curative therapy and then underwent PET/CT for the investigation of solitary pulmonary lesions that were strongly suspected to be malignant. Results. Pathological examination confirmed the presence of pulmonary metastases (29 patients, 59.2%), primary lung cancer (15 patients, 30.6%), and benign pulmonary disease (5 patients, 10.2%). Small lung lesions, advanced pathological stage, adjuvant chemotherapy after CRC surgery, solitary pulmonary lesions with lower border irregularity, higher carcinoembryonic antigen level, and the lack of concomitant mediastinal lymph node metastasis were more likely to be associated with pulmonary metastasis than with primary lung cancer. None of these factors was independently significant in the multivariate analysis. Conclusion. Clinicopathological characteristics help to differentiate metastasis and primary lung cancer to some extent during the diagnosis of solitary pulmonary lesions suspected to be malignant in this group of patients. This may provide valuable information to clinicians
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