Subjects: Materials Science >> Materials Science (General) submitted time 2024-05-27
Abstract： Manufacturing hydrogels with identical electrochemical properties are typically riddled with unresolved inquiries and challenges. Here, we utilized ultra-light graphene flakes to trace the influence of convection phenomena during reactions on hydrogels’ formation and structural non-uniformity, elucidating its mechanisms. Furthermore, we confirmed that an external electric field induced the orientation of functional groups of hydrogels along the direction of this field, revealing the mechanism of its influence on the structural non-uniformity and electrochemical properties of hydrogels. Additionally, we discovered that ion diffusion was Stumbling-to-Fetters by the functional groups on the polymer chains within the hydrogel, unveiling this mechanism and developing the Virginia Creeper (VC) model for hydrogels. We demonstrated the scalability and application of the VC model. Furthermore, we proposed a molecular-ion diffusion and current decay equation to describe the electrochemical properties of hydrogels. As an application of the VC model, we developed a bionic cardiovascular system and proved its potential to seamlessly interface with living organisms and generate bio-like bioelectricity. Our findings provide novel insights into triboelectricity and guidance for producing hydrogels with identical electrochemical properties, and offer a new pathway for bioelectric generation and the design of new hydrogel devices.
Peer Review Status:
Awaiting Review
Subjects: Medicine, Pharmacy >> Preventive Medicine and Hygienics submitted time 2024-05-27 Cooperative journals: 《中国全科医学》
Abstract： Acute ischemic stroke（AIS）is characterized by high rates of disability，mortality，and recurrence，posing a significant burden on patients and society. In the era of big data，predictive models are increasingly used in patient diagnosis，treatment decisions，prognosis management，and healthcare resource allocation，highlighting their growing importance. Machine learning methods have become a crucial tool for predicting the prognosis of AIS patients and have been widely applied. This review explores recent advancements in the study of AIS prognosis prediction，focusing on machine learning methods. It discusses current issues and challenges faced by machine learning models，aiming to provide new insights and references for methods of early assessment and prediction of prognosis outcomes in AIS patients.
Subjects: Medicine, Pharmacy >> Preventive Medicine and Hygienics submitted time 2024-05-27 Cooperative journals: 《中国全科医学》
Abstract： Background Previous studies have found that inter-arm blood pressure difference（IAD）and mild cognitive impairment（MCI）are both associated with cardiovascular risk factors，but it is unclear whether there is an association between IAD and MCI. Objective To explore the relationship between IAD and MCI in rural elderly persons and to provide a scientific basis for clarifying the mechanisms of cognitive decline in elderly persons. Methods From July to August 2019，the rural elderly residents aged 60 years and older were selected using the multi-stage cluster sampling method from 5 townships in 2 counties（districts）of Guizhou Province，and questionnaire surveys，general physical examinations，cognitive function assessments，and bilateral arm blood pressure measurements were carried out among them. Cognitive function was evaluated using the Mini-Mental State Examination（MMSE） scale，and activities of daily living were assessed using the Activities of Daily Living（ADL） scale. Spearman rank correlation analysis and binary logistic regression model were used to investigate the association between IAD and MCI in the elderly persons. Results A total of 1 795 questionnaires were distributed，and data from 1 088 participants were finally included in the study by excluding subjects with incomplete information on the questionnaires，those who did not undergo blood pressure measurements，and those who did not undergo blood tests. Among the 1 088 rural elderly residents，138 patients（12.68%）with MCI，99 patients（9.10%）with systolic inter-arm blood pressure difference（sIAD） ≥ 10 mmHg，and 80 patients（7.35%）with diastolic inter-arm blood pressure difference（dIAD） ≥ 10 mmHg were detected. Individuals with IAD ≥ 10 mmHg had a higher prevalence of MCI and lower MMSE scores，orientation scores，language scores，and delayed recall scores compared to those with IAD <10 mmHg （P<0.05）. The results of correlation analysis showed that the sIAD was significantly negatively associated with the total MMSE score （rs=-0.094），orientation score （rs=-0.082），verbal ability score （rs=-0.065） and delayed recall score （rs=-0.104）；and the dIAD was significantly negatively associated with the total MMSE score （rs=-0.080），orientation score （rs=-0.094），and attentional calculation score （rs=-0.063）（all P<0.05）. Multivariate logistic regression analysis showed that the risk of MCI increased by 8.80% for each 1 mmHg increase in sIAD （OR=1.088，95%CI=1.046-1.131；P<0.001）；sIAD ≥ 10 mmHg （OR=2.169，95%CI=1.262-3.728；P<0.05） and dIAD ≥ 10 mmHg （OR=1.926，95%CI=1.047-3.542；P<0.05） were the influencing factors for the occurrence of MCI in the elderly. Conclusion The prevalence of MCI in rural elderly was 12.68%，and their elevated IAD was associated with an increased risk of MCI. And the risk of MCI was higher in elderly with IAD ≥ 10 mmHg than in those with IAD <10 mmHg.
Subjects: Medicine, Pharmacy >> Preventive Medicine and Hygienics submitted time 2024-05-27 Cooperative journals: 《中国全科医学》
Abstract： Background Although the number of case reports on pulmonary infarction（PI）secondary to pulmonary embolism（PE）is increasing in recent years，its misdiagnosis remains common，mainly as pneumonia. In patients with intermediate and high-risk pulmonary embolism，delays in diagnosis and timely treatment would lead to poor prognosis. Objective By analyzing the pneumonia-misdiagnosed cases of patients with PI，we summarized their clinical characteristics and related risk factors，and constructed a multivariate joint model to improve the accurate diagnosis rate at early stage. Methods This retrospective study included the hospitalized patients with pulmonary embolism at the First Affiliated Hospital of USTC from January 2017 to December 2023. In the group of pneumonia-misdiagnosed patients with intermediate to high-risk PI，we analyzed the clinical characteristics and compared the differences between the misdiagnosed groups and control group. Furthermore，using a multivariate logistic regression analysis，we explored the independent predictive factors of the delayed diagnosis，analyze the predictive value of various indicators for the misdiagnosis by ROC curves，and compared the AUC values using Delong test. Results Among 101 cases of PI patients，70 of them were misdiagnosed as pneumonia. Comparing with the control group，the characteristics of misdiagnosed patients were old age，higher incidences of fever and chest pain with unlikely presence of dyspnea. From 2017 to 2023，the misdiagnosis rate gradually decreased in percentages of 100.0%，83.3%，74.1%，71.4%，63.2%，66.7%，and 50.0%，respectively. Based on the results of multivariate logistic regression analysis，the characteristics of over sixty-years-old age（OR=18.271，95%CI=4.373-76.339，P<0.001），fever（OR=16.073，95%CI=3.510-73.786，P<0.001），chest pain（OR=6.660，95%CI=1.571-28.233，P=0.010）and non-dyspnea（OR=9.027，95%CI=2.049-30.249，P=0.003）were independent predictive factors for the misdiagnosis. Therefore，a multivariate joint model was constructed as the following equation：Y=-6.624+0.095×A（factor of age）+2.510×F（factor of fever）+2.683×N（factor of non-dyspnea chest pain）. The model indicated the PI misdiagnosis parameters as AUC under the curve（OR=0.880，95%CI=0.802-0.959，P<0.001），best cutoff value（0.854），sensitivity（0.871）and specificity（0.806）. Therefore，the predictive values are superior to single-factor indicators of age（Z=2.771，P=0.006），fever（Z=4.653，P<0.001）and non dyspnea chest pain（Z=4.014，P<0.001）. Conclusion Although the misdiagnosis rate of pulmonary infarction has decreased in recent years. Clinicians should keep alert to the differential diagnosis of pulmonary infarction and pneumonia in elderly PE patients with symptoms of fever and non-dyspnea chest pain.
Subjects: Medicine, Pharmacy >> Preventive Medicine and Hygienics submitted time 2024-05-27 Cooperative journals: 《中国全科医学》
Abstract： Background In patient involvement，patients are transforming from mere recipients to collaborators in medical services by integrating their experiences and needs throughout the entire healthcare process into medical practice. This aims to enhance the effectiveness，efficiency，and quality of healthcare services. However，the implementation of proven patient#2;centered strategies for patient involvement in the quality improvement among chronic obstructive pulmonary disease（COPD）in our country remains to be explored.Objective This scoping review systematically reviews and analyzes the existing strategies for patient involvement among patients with COPD to provide a reference for implementation that in China.Methods Employing the scoping review guidelines of Joanna Briggs Institute in Australia as the methodological framework，the relevant studies on patient involvement among patient with COPD were searched by computer on PubMed，Embase，Cochrane Library，CNKI，Wanfang Database，China Biology Medicine disc. A thematic analysis was methodically applied to distill and synthesize findings. Results A total of 37 articles were included in this review. The categorization of patient involvement was divided into three types：direct involvement in medical care，organizational-level，and clinical research. Based on the intensity of involvement，categories were further classified into three levels：consultation，engagement，and collaborative leadership. A nine-category matrix of patient involvement behaviors was constructed through intensity and type. The implementation of COPD patient engagement was primarily reflected in five categories encompassing eight behaviors，including：integration in direct medical care（patients expressing their preferences and wishes regarding treatment plans）；consultation at the organizational management level（assessing patient treatment experiences and organizing discussions around patients' concerns）；as well as involvement in clinical research，including consultation（listening to patient needs）and engagement（expressing preferences and wishes for interventions，involved in the development of assessment tools，and in discussions about research design and implementation）. Assessing patient treatment experiences（10 articles，27.03%）and expressing patient preferences and wishes regarding interventions（10 articles，27.03%）were the two most frequently implemented behaviors of patient involvement in COPD. Conclusion There are numerous measures for patient involvement in the improvement of medical quality，but there is still limited practice in the field of COPD. Very few studies have assessed the impact of patient involvement on clinical outcomes and quality of life，indicating that the practice of patient involvement in China requires further exploration.
Subjects: Medicine, Pharmacy >> Preventive Medicine and Hygienics submitted time 2024-05-27 Cooperative journals: 《中国全科医学》
Abstract： Background Hypertension is a common chronic disease that seriously endangers the health of the population. The primary-care doctors are the main force in the management of hypertension. However，the doctor-induced therapeutic of inertia greatly affects the achievement of primary-care hypertension control. Objective The aim of this study is to investigate the current status of therapeutic inertia among primary healthcare providers in the diagnosis and treatment process of hypertension，and analyze the causes of therapeutic inertia，providing a reference basis for improving hypertension control rates in China. Methods A simple random sampling method was used to distribute questionnaires to primary healthcare providers in 32 primary healthcare institutions in Tianjin from July to August 2023. The therapeutic inertia in the diagnosis and treatment process of hypertension was evaluated from three dimensions: knowledge mastery of hypertension diagnosis and treatment，“soft reasons”and “overestimation of treatment efficacy” as well as “medical insurance policies.” Binary logistic regression analysis was employed to explore the influencing factors of therapeutic inertia.Results A total of 407 questionnaires were distributed in this study，and 386 valid questionnaires were collected，yielding an effective response rate of 97.96%. (1) The average score for primary healthcare providers' knowledge of hypertension diagnosis and treatment was 6 (0.5)，with a scoring rate of 61.19% (5.50/9.00). The total score for therapeutic inertia in hypertension management was 48 (7.0)，with a scoring rate of 56.55% (45.24/80.00). (2) The scores for the “soft reasons” dimension，“overestimation of treatment efficacy” dimension，and “medical insurance policies” dimension were 26 (4.8)，10 (2.0)，and 6 (2.5) respectively，with scoring rates of 51.97% (25.89/50.00)，65.42% (9.81/15.00)，and 44.64% (6.96/15.00) respectively. When comparing the average scores of the three dimensions of therapeutic inertia，the “medical insurance policies” dimension had the lowest score compared to the other two groups (P<0.05). Multivariate analysis showed that male gender，rural areas，lower mastery of hypertension diagnosis and treatment knowledge，and a weekly patient volume of less than 10 hypertensive individuals were associated with a higher tendency towards therapeutic inertia among primary healthcare providers (P<0.05). Conclusion therapeutic inertia is prevalent among primary healthcare providers in the diagnosis and treatment process of hypertension. Low levels of hypertension treatment cognition，overestimation of treatment efficacy，and “soft reasons” are the primary factors contributing to therapeutic inertia among primary healthcare providers. It is recommended to strengthen education on therapeutic inertia in hypertension，conduct diversified training on diagnostic and management knowledge，and promote clinical informatization and artificial intelligence decision-making systems to effectively improve the therapeutic inertia of primary healthcare providers in hypertension management.
Subjects: Medicine, Pharmacy >> Preventive Medicine and Hygienics submitted time 2024-05-27 Cooperative journals: 《中国全科医学》
Abstract： Background Diabetes mellitus is difficult to cure and has a long process . The level of self-care is crucial for determining the regression and health outcomes of patients with diabetes. A comprehensive and theory-based tool is urgently needed to assess the level of self-care of diabetes. In this way，the self-care of patients with diabetes can be kept up to date and accurate nursing care can be carried out. Objective To examine the psychometric properties of the Chinese version of Self-care of Diabetes Inventory（SCODI），and provide a scientifically validated assessment tool for the self-care of Chinese patients with diabetes. Methods The Brislin Translation Model was used for translation and cultural adaptation of the English version of the SCODI into Chinese. A total of 261 adult patients with diabetes were enrolled using a consecutive sampling method at the First Affiliated Hospital and the Affiliated Sir Run Run Hospital of Nanjing Medical University from December 2022 to June 2023. Data were collected using a self-developed general information questionnaire and the Chinese version of SCODI. Exploratory factor analysis was used to assess the structural validity. Cronbach's α，split-half reliability and composite reliability were used to describe the reliability. Glycosylated hemoglobin was used as a criterion to assess the criterion-related validity. Spearman's rank correlation analysis was used to examinate the correlation between the Chinese version of SCODI score and glycosylated hemoglobin. Results The Chinses version of SCODI contained 4 dimensions and 40 items：self-care maintenance score（75.94±13.15），self-care monitoring score（70.65±18.71），self-care management score（69.16±18.24），and self-care confidence score（85.41±13.63）. In the self-care maintenance dimension，4 factors were identified：complication screening behaviors，exercise behaviors，hygienic care behaviors and diet-medication behaviors. The self-care monitoring dimension had 2 factors：physical monitoring and symptom identification. The self-care management dimension included 2 factors：autonomous behaviors and counseling behaviors. Two factors were extracted from the self-care confidence dimension：monitoring and managing confidence，health maintenance confidence. The Cronbach's α，split-half reliability and composite reliability values for the total scale were 0.915，0.836 and 0.912，respectively. The Cronbach's α for the four dimensions were 0.709-0.908. A significantly negative correlation was observed between each subscale and glycosylated hemoglobin（rs=-0.160，-0.300，-0.177，-0.192；P<0.001），serving as a criterion. Conclusion Based on the middle-range theory of self care of chronic illness，the Chinese version of SCODI exhibits strong psychometric properties，making it a valid and reliable instrument for evaluating self-care of Chinese patients with diabetes.
Subjects: Management Science >> Other Disciplines of Management Science submitted time 2024-05-26
Abstract： The misuse and abuse of NHST (null hypothesis significance test) and p value are quite serious in scientific research. NHST is a hybrid of Fisher’s significance test and N-P hypothesis test. But how is it mingled and how is it reflected in the calculation steps? Where are the logical flaws in NHST and p value calculations? There are no detailed and simple answers to these questions. Expounding, analyzing and comparing the steps of Fisher’s significance test, N-P hypothesis test and NHST clearly, combined with a typical example for the logical defect analysis of NHST and p-value calculations, can provide some inspiration for the empirical researchers who are not deeply involved in the field of statistics.
Peer Review Status:Awaiting Review
Subjects: Psychology >> Applied Psychology Subjects: Psychology >> Social Psychology submitted time 2024-05-26
Abstract： Orderly display, from our urban planning to the layout of goods in shops, is widely used in our nearby environment. Researches have shown that the need for order is one of the basic human needs and people prefer objects under orderly display. Our study enriched this line of work by exploring the association between display order and product attribution and providing evidence that disorder can be beneficial. Specifically, natural attribution (vs. artificial product) is associated with disorder (vs. order). Furthermore, for natural product (vs. artificial product), consumers prefer them in disorderly display (vs. orderly display). Based on the associative learning mechanism, 4 studies were conducted to examine how display order and product attribute match together and influences consumers’ product preference. Also, the mediating role of fluency perception and moderating role of valence cue were examined.
Study 1 (N = 34, 18 men) intended to explore the matching relationship between product attribution and display order with the method of Implicit Association Test. Participants were instructed to sort a series of stimuli into two categories(natural or artificial) as quickly as possible. Study 2 (N = 280, 105 men) aimed to test the match effect of product attribution and display order in explicit level using within-subjects design. After showing the interpretation of both constructs’ definition, participants were asked to match natural (vs. artificial) product to orderly or disorderly display. Study 3 (N = 200, 75 men) used between-subjects design to further investigate the effect of product attribution and display order on consumer preference, and the mediation role of processing fluency, with product content remain the same, i.e., mango. Participants were shown one picture and asked to indicate their preference and processing fluency. Study 4 (N = 240, 98 men) investigated the boundary effect of valence cue. The participants were asked to evaluate the valence of all categories of product attribution and display order as priming method. Then participants were shown two pictures of natural or artificial product in disorderly and orderly display. In the end, they indicate their liking and processing fluency of pictures.
The main results of this study are as follows: (1) natural attribution (vs. artificial product) is associated with disorder (vs. order) in both implicit and explicit level; (2) for natural (vs. artificial) product, consumers have higher preference for product in disorderly (vs. orderly) display; (3) product attribution and display order influences consumers’ product preferences through the mediation role of processing fluency; (4) valence cue moderate consumers’ preference for natural products in different display order.
This research identify and explore a previously unidentified lay theory, the natural (vs. artificial) = disorder (order) intuition. Moreover, based on dual-process of associative learning, we further explore the contradictory naïve theory of our proposal. And this research contributes to the literature of natural product and product display. It provides managers with guidelines on arrangement of display order for product with different attribution when organizing shelf display or designing advertisement.
Subjects: Biology >> Biochemistry submitted time 2024-05-25
Abstract： Drug addiction is a serious chronic relapsing brain disease, and methamphetamine dependence has a complex course and is difficult to treat, causing a serious public health burden. In this study, we compared and analyzed the urine proteome of methamphetamine-using patients (patients who stopped using methamphetamine within 24 hours), methamphetamine-withdrawing patients (patients who stopped using drugs for more than 3 months and entered rehabilitation treatment), healthy individuals. The urine proteome of methamphetamine-addicted patients (including patients who were using methamphetamine and methamphetamine-withdrawing patients) was significantly different from that of healthy individuals, and some differential proteins and their enriched biological functions showed that they were associated with addiction or neurotoxicity of methamphetamine and may be potential intervention targets for drug addiction. Patients who withdrew methamphetamine for more than 3 months were still difficult to return to normal levels and may be used to reveal the reasons for the high rate of methamphetamine relapse. In this study, a method of studying addictive drugs from the perspective of urine proteomics was established, which proved that urine proteome can reflect the effects of methamphetamine abuse on the body relatively systematically and comprehensively, and has the potential to provide clues for the study and practice of clinical addictive diseases.
Peer Review Status:Awaiting Review
Subjects: Biology >> Biochemistry submitted time 2024-05-25
Abstract： Taking compound nutrient supplements is a common means of health management. No studies have investigated the overall effects of complex nutrient supplements on healthy individuals from the perspective of the urine proteome. In this study, we compared and analyzed the urine proteome of healthy individuals after taking compound nutrient supplements for 2 weeks, 4 weeks and before taking them, and found that the urine proteome changed more significantly after taking compound nutrient supplements for 2 weeks, and the differential proteins and their enriched pathways may be associated with nutrient supplementation, such as erythropoietin receptor (fold change of 449.5 after taking compound nutrient supplements for 2 weeks). The results of this study provide new clues about the health effects of complex nutrient supplements from the perspective of the urine proteome and help to optimize guidelines and recommendations for the use of complex nutrient supplements.
Peer Review Status:Awaiting Review
Subjects: Biology >> Molecular Biology submitted time 2024-05-24
Abstract： Differential and even opposing functions of two major antioxidant transcription factors Nrf1 and Nrf2 (encoded by Nfe2l1 and Nfe2l2, respectively) are determined by distinctions in their tempospatial positioning, topological repartitioning, proteolytic processing, and biochemical modification, as well as in their shared evolutionary origin. As a matter of fact, the allelopathic potentials of Nrf1 and Nrf2 (both resembling two entangled ‘Yin-Yang’ quanta that comply with a dialectic law of the unity of opposites) are fulfilled to coordinately control redox physiological homeostasis so as to be maintained within the presetting thresholds. By putative exponential curves of redox stress and intrinsic anti-redox capability, there is inferable to exist a set point at approaching zero with the ‘Golden Mean’ for the healthy survival (i.e., dubbed the ‘zero theory’). A bulk of the hitherto accumulating evidence demonstrates that the set point of redox homeostasis is dictated selectively by multi-hierarchical threshold settings, in which the living fossil-like Nrf1 acts as a robust indispensable determinon, whereas Nrf2 serves as a versatile chameleon-like master regulon, in governing the redox homeodynamic ranges. This is attributable to the facts that Nrf2 has exerted certain ‘double-edged sword’ effects on life process, whereas Nrf1 executes its essential physiobiological functions, along with unique pathophysiological phenotypes, by integrating its ‘three-in-one’ roles elicited as a specific triplet of direct sensor, transducer and effector within multi-hierarchical stress responsive signaling to redox metabolism and target gene reprogramming. Here, we also critically reviewed redox regulation of physio-pathological functions from the eco-evo-devo perspectives, through those coding rules (redox code, stress-coping code, and topogenetic code). The evolving concepts on stress and redox stress were also further revisited by scientific principles of physics and chemistry, apart from two novel concepts of ‘oncoprotists’ and ‘reverse central dogma’ being introduced in this interdisciplinary and synthetic review.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2024-05-24 Cooperative journals: 《Research in Astronomy and Astrophysics》
Xiaoyu Luo, Sheng Zheng, Zhibo Jiang, Zhiwei Chen, Yao Huang, Shuguang Zeng, Xiangyun Zeng, Rui Zhang, Chen Long, Guangrong Zhou et al.
Sheng Zheng
Zhibo Jiang
Zhiwei Chen
Yao Huang
Shuguang Zeng
Xiangyun Zeng
Rui Zhang
Chen Long
Guangrong Zhou
Jinbo Hu
Abstract： In this study, we present a catalog of molecular clumps extracted from 13CO (J = 1 − 0) emission data of the Milky Way Imaging Scroll Painting (MWISP) project. The data covers the inner Milky Way within the longitude range 10° ≤ l ≤ 20° and the latitude strip of . The workflow for the extraction of clumps, namely Facet-SS-3D-Clump, consists of two parts: the identification of clump candidates and their verification. First, Facet-SS-3D-Clump employs FacetClumps to identify clump candidates. Subsequently, high-confidence clumps are obtained by cross-matching with the clumps detected by other algorithms, such as dendrogram. Second, these high-confidence clumps are used as prior knowledge to train a semi-supervised deep clustering approach, SS-3D-Clump, which is applied to verify clump candidates detected by FacetClumps, providing confidence levels for the molecular clumps. Finally, the catalog comprising 18,757 molecular clumps was obtained using Facet-SS-3D-Clump, and the catalog is 90% complete above 37 K km s−1. We observe a significant deviation of the mean Galactic latitude for clumps within ∣b∣ ≤ 2° from the midplane, with . We found that 82.3% of the dust clumps correspond to 13CO clumps by matching with Herschel infrared dust clumps. In the future, Facet-SS-3D-Clump will be applied to detect 13CO clumps in the entire MWISP data.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-05-24 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： Cassiopeia A (Cas A) is a well-known candidate for studying cosmic-ray acceleration, in which compact features of various scales have attracted much attention. Based on observations by the Very Large Array of Cas A at 6 cm and 21 cm, we measure the spectral index distribution of various scale components using the observation of the 1998 epoch. We decompose its total density image into nine scale components, and map the temperature spectral index distribution of each component, which ranges from −2.48 ± 0.01 to −2.91 ± 0.05. We find that the spectral indices increase from the small scale to large scale components. A damped post-shock magnetic field model with a strength larger than ∼200 μG and a damping length scale less than ∼10% of the remnant radius can account for the spectral index variation naturally.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-05-24 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： Temporary capture efficiency is studied in the framework of the circular restricted three-body problem in two steps. First, a non-uniform distribution of test particles around the secondary’s orbit is obtained by fully accounting the secondary’s gravitational influence. Second, the capture efficiency is computed based on the non-uniform distribution. Several factors influencing the result are discussed. By studying the capture efficiency in the circular restricted three-body problem of different mass ratios, a power-law relation between the capture efficiency (p) and the mass ratio (μ) is established, which is given by p ≈ 0.27 × μ0.53, within the range of 3.0035 ×10−6 ≤ μ ≤ 3.0034 × 10−5. Taking the Sun–Earth system as an example, the influence from the orbit eccentricity of the secondary on the non-uniform distribution and the capture efficiency is studied. Our studies find that the secondary’s orbit eccentricity has a negative influence on the capture efficiency.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-05-24 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： The distribution of the LSBGs is bimodal in the g − r color, indicating the two distinct populations of the blue (g − r < 0.60) and red (g − r > 0.60) LSBGs. The blue LSBGs appear spiral, disk or irregular while the red LSBGs are spheroidal or elliptical and spatially clustered. This trend shows that the color has a strong correlation with galaxy morphology for LSBGs. In the spatial distribution, the blue LSBGs are more uniformly distributed while the red ones are highly clustered, indicating that red LSBGs preferentially populate a denser environment than the blue LSBGs. Besides, both populations have a consistent distribution of ellipticity (median ), half-light radius (median reff ∼ 4”) and Sérsic index (median n = 1), implying the dominance of the full sample by the round and disk galaxies. This sample has definitely extended the studies of LSBGs to a regime of lower surface brightness, fainter magnitude and broader other properties than the previously Sloan Digital Sky Survey-based samples.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-05-24 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： Open clusters (OCs) are common in the Milky Way, but most of them remain undiscovered. There are numerous techniques, including some machine-learning algorithms, available for the exploration of OCs. However, each method has its limitations and therefore, different approaches to discovering OCs hold significant values. We develop a comprehensive approach method to automatically explore the data space and identify potential OC candidates with relatively reliable membership determination. This approach combines the techniques of Hierarchical Density-Based Spatial Clustering of Applications with Noise, Gaussian mixture model, and a novel cluster member identification technique, color excess constraint. The new method exhibits efficiency in detecting OCs while ensuring precise determination of cluster memberships. Because the main feature of this technique is to add an extra constraint (EC) for the members of cluster candidates using the homogeneity of color excess, compared to typical blind search codes, it is called Blind Search-Extra Constraint (BSEC) method. It is successfully applied to the Gaia Data Release 3, and 83 new OCs are found, whose color–magnitude diagrams (CMDs) are fitted well to the isochrones. In addition, this study reports 621 new OC candidates with discernible main sequence or red giant branch. It is shown that BSEC technique can discard some false negatives of previous works, which takes about three percentage of known clusters. It shows that as an EC, the color excess (or two-color) constraint is useful for removing fake cluster member stars from the clusters that are identified from the positions and proper motions of stars, and getting more precise CMDs, when differential reddening of member stars of a cluster is not large (e.g., ΔE(GBP − GRP) < 0.5 mag). It makes the CMDs of 15% clusters clearer (in particular for the region near turnoff) and therefore is helpful for CMD and stellar population studies. Our result suggests that the color excess constraint is more appropriate for clusters with small differential reddening, such as globular clusters or older OCs, and clusters that the distances of member stars cannot be determined accurately.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-05-24 Cooperative journals: 《Research in Astronomy and Astrophysics》
Hao Li, Qing Zhao, Long Shao, Tao Liu, Chenzhou Cui and Yunfei Xu
Hao Li
Qing Zhao
Long Shao
Tao Liu
Chenzhou Cui
Yunfei Xu
Abstract： Nowadays, astronomy has entered the era of Time-Domain Astronomy, and the study of the time-varying light curves of various types of objects is of great significance in revealing the physical properties and evolutionary history of celestial bodies. The Ground-based Wide Angle Cameras telescope, on which this paper is based, has observed more than 10 million light curves, and the detection of anomalies in the light curves can be used to rapidly detect transient rare phenomena such as microgravity lensing events from the massive data. However, the traditional statistically based anomaly detection methods cannot realize the fast processing of massive data. In this paper, we propose a Discrete Wavelet (DW)-Gate Recurrent Unit-Attention (GRU-Attention) light curve warning model. Wavelet transform has good effect on data noise reduction processing and feature extraction, which can provide richer and more stable input features for a neural network, and the neural network can provide more flexible and powerful output model for wavelet transform. Comparison experiments show an average improvement of 61% compared to the previous pure long-short-term memory unit (LSTM) model, and an average improvement of 53.5% compared to the previous GRU model. The efficiency and accuracy of anomaly detection in previous paper work are not good enough, the method proposed in this paper possesses higher efficiency and accuracy, which incorporates the Attention mechanism to find out the key parts of the light curve that determine the anomalies. These parts are assigned higher weights, and in the actual anomaly detection, the star is detected with 83.35% anomalies on average, and the DW-GRU-Attention model is compared with the DW-LSTM model, and the detection result f1 is improved by 5.75% on average, while having less training time, thus providing valuable information and guidance for astronomical observation and research.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-05-24 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： In this work, we consider a conventional test of gravitational wave (GW) propagation which is based on the phenomenological parameterized dispersion relation to describe potential departures from General Relativity (GR) along the propagation of GWs. But different from tests conventionally performed previously, we vary multiple deformation coefficients simultaneously and employ the principal component analysis (PCA) method to remedy the strong degeneracy among deformation coefficients and obtain informative posteriors. The dominant PCA components can be better measured and constrained, and thus are expected to be more sensitive to potential departures from the waveform model. Using this method we analyze ten selected events and get the result that the combined posteriors of the dominant PCA parameters are consistent with GR within 99.7% credible intervals. The standard deviation of the first dominant PCA parameter is three times smaller than that of the original dispersion parameter of the leading order. However, the multi-parameter test with PCA is more sensitive to not only potential deviations from GR but also systematic errors of waveform models. The difference in results obtained by using different waveform templates hints that the demands of waveform accuracy are higher to perform the multi-parameter test with PCA. Whereas, it cannot be strictly proven that the deviation is indeed and only induced by systematic errors. It requires more thorough research in the future to exclude other possible reasons in parameter estimation and data processing.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-05-24 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： Based on the collected multiwavelength data, namely in the radio (NVSS, FIRST, RATAN-600), IR (WISE), optical (Pan-STARRS), UV (GALEX), and X-ray (ROSAT, Swift-XRT) ranges, we have performed a cluster analysis for the blazars of the Roma-BZCAT catalog. Using two machine learning methods, namely a combination of PCA with k-means clustering and Kohonen’s self-organizing maps (SOMs), we have constructed an independent classification of the blazars (five classes) and compared the classes with the known Roma-BZCAT classification (FSRQs, BL Lacs, galaxy-dominated BL Lacs, and blazars of an uncertain type) as well as with the high synchrotron peaked (HSP) blazars from the 3HSP catalog and blazars from the TeVCat catalog. The obtained groups demonstrate concordance with the BL Lac/FSRQ classification along with a continuous character of the change in the properties. The group of HSP blazars stands out against the overall distribution. We examine the characteristics of the five groups and demonstrate distinctions in their spectral energy distribution shapes. The effectiveness of the clustering technique for objective analysis of multiparametric arrays of experimental data is demonstrated.
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