226 research outputs found
3D Model-free Visual Localization System from Essential Matrix under Local Planar Motion
Visual localization plays a critical role in the functionality of low-cost
autonomous mobile robots. Current state-of-the-art approaches for achieving
accurate visual localization are 3D scene-specific, requiring additional
computational and storage resources to construct a 3D scene model when facing a
new environment. An alternative approach of directly using a database of 2D
images for visual localization offers more flexibility. However, such methods
currently suffer from limited localization accuracy. In this paper, we propose
an accurate and robust multiple checking-based 3D model-free visual
localization system to address the aforementioned issues. To ensure high
accuracy, our focus is on estimating the pose of a query image relative to the
retrieved database images using 2D-2D feature matches. Theoretically, by
incorporating the local planar motion constraint into both the estimation of
the essential matrix and the triangulation stages, we reduce the minimum
required feature matches for absolute pose estimation, thereby enhancing the
robustness of outlier rejection. Additionally, we introduce a multiple-checking
mechanism to ensure the correctness of the solution throughout the solving
process. For validation, qualitative and quantitative experiments are performed
on both simulation and two real-world datasets and the experimental results
demonstrate a significant enhancement in both accuracy and robustness afforded
by the proposed 3D model-free visual localization system
Genetic insights into gut microbiota and risk of prostatitis: a Mendelian randomization study
BackgroundThe dysbiosis of gut microbiota (GM) is considered a contributing factor to prostatitis, yet the causality remains incompletely understood.MethodsThe genome-wide association study (GWAS) data for GM and prostatitis were sourced from MiBioGen and FinnGen R10, respectively. In the two-sample Mendelian randomization (MR) analysis, inverse variance weighting (IVW), MR-Egger, weighted median, simple mode, weighted mode, and maximum likelihood (ML) methods were utilized to investigate the causal relationship between GM and prostatitis. A series of sensitivity analysis were conducted to confirm the robustness of the main results obtained from the MR analysis.ResultsAccording to the IVW results, genus Sutterella (OR: 1.37, 95% CI: 1.09–1.71, p = 0.006) and genus Holdemania (OR: 1.21, 95% CI: 1.02–1.43, p = 0.028) were associated with an increased risk of prostatitis. The phylum Verrucomicrobia (OR: 0.76, 95% CI: 0.58–0.98, p = 0.033) and genus Parasutterella (OR: 0.84, 95% CI: 0.70–1.00, p = 0.045) exhibited a negative association with prostatitis, indicating a potential protective effect. Sensitivity analysis showed that these results were not affected by heterogeneity and horizontal pleiotropy. Furthermore, the majority of statistical methods yielded results consistent with those of the IVW analysis.ConclusionsIn this study, we identified two GM taxon that might be protective against prostatitis and two GM taxon that could increase the risk of developing prostatitis. These findings could potentially provide a valuable theoretical basis for the future development of preventive and therapeutic strategies for prostatitis
Flexible impulse response of the multi-bar linkage with heavy load
It is based on the advantages of virtual prototyping technology, the dynamics mathematic model was established for the large mechanism by applying multi body dynamics theory. In order to adapt the users to special request of the strip width size, appeared the continuous casting and continuous rolling technology, and greatly reduce the width types of continuous casting. The components of the equipments are often considered the rigid body. The precision is not high premise in the process of work, usually the parts works as elastic under the high speed and the heavy load, neglects various components the elastic function will cause the result error, even will be wrong. Studied analysis dynamic characteristic of the adjustment width machine, and analyzed the component in detail for the rigid body or the elastic. The results provide the theoretically support to work out adjustment the width potentialities and strength analysis of the key parts
Evaluating the suitability of marginal land for a perennial energy crop on the Loess Plateau of China
Abstract With a large marginal land area, the Loess Plateau in China holds great potential for biomass production and environmental improvement. Identifying suitable locations for biomass production on marginal land is important for decision‐makers from the viewpoint of land‐use planning. However, there is limited information on the suitability of marginal land within the Loess Plateau for biomass production. Therefore, this study aims to evaluate the suitability of the promising perennial energy crop switchgrass (Panicum virgatum L.) on marginal land across the Loess Plateau. A fuzzy logical model was developed and validated based on field trials on the Loess Plateau and applied to the marginal land of this region, owing to its ability of dealing with the continuous nature of soil, landscape variations, and uncertainties of the input data. This study identified that approximately 12.8–20.8 Mha of the Loess Plateau as available marginal land, of which 2.8–4.7 Mha is theoretically suitable for switchgrass cultivation. These parts of the total marginal land are mainly distributed in northeast and southwest of the Loess Plateau. The potential yield of switchgrass ranges between 44 and 77 Tg. This study showed that switchgrass can grow on a large proportion of the marginal land of the Loess Plateau and therefore offers great potential for biomass provision. The spatial suitability maps produced in this study provide information to farmers and policymakers to enable a more sustainable development of biomass production on the Loess Plateau. In addition, the fuzzy‐theory‐based model developed in this study provided a good framework for evaluating the suitability of marginal land
Laser in Glaucoma and Ocular Hypertension Trial (LIGHT) in China - A Randomized Controlled Trial: Design and Baseline Characteristics
PURPOSE: To describe the baseline characteristics of a trial to evaluate whether selective laser trabeculoplasty (SLT), as a first-line treatment, provides superior economic and health-related quality of life outcomes to medical treatment in China. DESIGN: The LiGHT China trial is an unmasked, single-center, pragmatic, randomized controlled trial. METHODS: A total of 771 previously undiagnosed patients with primary open angle glaucoma (POAG, 622 patients) or ocular hypertension (OHT, 149 patients) at Zhongshan Ophthalmic Center were recruited from March 2015 to January 2019. Subjects were randomized to SLT-1st (followed by medication then surgery when required) or Medicine-1st (medication followed by surgery when required). The primary outcome was health-related quality of life (HRQL). The secondary outcomes were clinical outcomes, cost, cost-effectiveness, Glaucoma Utility Index, Glaucoma Symptom Scale, visual function, and safety. RESULTS: The mean age of POAG patients was 49.8 years and 38.8 years for OHT. The median intraocular pressure was 20 mm Hg for the 1,105 POAG eyes and 24 mm Hg for the 271 OHT eyes. POAG eyes had thinner central cornea thickness (CCT, 536 µm) than OHT eyes (545 µm). Median mean deviation of the visual field in POAG eyes was -4.2 dB. Median refractive error was -1.5 D for OHT eyes and -1.25 D for POAG eyes. There was no difference between POAG and OHT patients on baseline scores of GUI, GSS and VF-14. The difference between OHT and POAG on the EQ-5D-5L was 0.024. CONCLUSIONS: Compared with participants in the LiGHT UK trial, participants in this trial were younger, more myopic and had more severe visual field defects
Data processing system of continuous temperature measurement for liquid steel
Six different methods of accurate measurement of the temperature of liquid steel in real time are analyzed. Using a comparison and analysis, a fast and accurate mathematical model is obtained.Проведен анализ шести различных методов точного измерения температуры жидкой
стали в реальном времени. С помощью сравнения и анализа результатов получена быстрая
и точная математическая модель.Проведено аналіз шести різних методів точного вимірювання температури рідкої сталі в
реальному часі. . За допомогою порівняння і аналізу результатів отримана швидка і точна
математична модель
Monounsaturated and polyunsaturated fatty acids concerning prediabetes and type 2 diabetes mellitus risk among participants in the National Health and Nutrition Examination Surveys (NHANES) from 2005 to March 2020
ObjectiveUnsaturated fatty acids (UFA) may be related to glycometabolism. While associations between UFA intake (especially their subtype) and prediabetes or type 2 diabetes mellitus (T2DM) need to be further studied. In this study, we aimed to evaluate the potential relation of UFA with prediabetes and T2DM.MethodsA total of 16,290 adults aged older than 18 years from the National Health and Nutrition Examination Survey (NHANES) from 2005 to March 2020 were included in the present analysis. Dietary intake was assessed by two day, 24-hour dietary recalls and daily intake of total monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA); four specific fatty acids of MUFA and seven specific fatty acids of PUFA were calculated. Prediabetes and T2DM were diagnosed by fasting glucose, glycohemoglobin, and self-reported medication or insulin. Rao–Scott modified chi-square tests, the Taylor series linearization method, and multivariable logistic regression analyses were applied to analyze the associations of dietary MUFA and PUFA intake with diabetes risk.ResultsOf the participants, 44.34% had prediabetes and 13.16% had T2DM patients. From multivariate analysis, we found that intake of MUFA, PUFA, and some subtypes was negatively associated with the risk of prediabetes and T2DM in Americans. Compared with adults in the lowest tertile, those in the highest MUFA (PUFA) tertile had an approximately 50% (49%) and 69% (68%) lower risk of prediabetes and T2DM, respectively. Moreover, the effects of the subtypes of MUFA and PUFA on prediabetes and T2DM were different. Higher intakes of MFA 18:1, MFA 20:1, PFA 18:2, and PFA 18:3 and higher tertile intakes of MFA 16:1 and PFA 20:4 were related to a lower risk of prediabetes and T2DM. Similarly, the effects of MUFA, PUFA, and subtype on prediabetes and T2DM varied among different age groups, being weakened along with age.ConclusionOur study suggested that total MUFA and PUFA intake might be essential in preventing prediabetes and T2DM, especially in Americans. However, this protective effect may decrease with age. Moreover, the effects of the specific UFA on prediabetes and T2DM need further consideration
Active control of magnetoresistance of organic spin valves using ferroelectricity
Organic spintronic devices have been appealing because of the long spin life
time of the charge carriers in the organic materials and their low cost,
flexibility and chemical diversity. In previous studies, the control of
resistance of organic spin valves is generally achieved by the alignment of the
magnetization directions of the two ferromagnetic electrodes, generating
magnetoresistance.1 Here we employ a new knob to tune the resistance of organic
spin valves by adding a thin ferroelectric interfacial layer between the
ferromagnetic electrode and the organic spacer. We show that the resistance can
be controlled by not only the spin alignment of the two ferromagnetic
electrodes, but also by the electric polarization of the interfacial
ferroelectric layer: the MR of the spin valve depends strongly on the history
of the bias voltage which is correlated with the polarization of the
ferroelectric layer; the MR even changes sign when the electric polarization of
the ferroelectric layer is reversed. This new tunability can be understood in
terms of the change of relative energy level alignment between ferromagnetic
electrode and the organic spacer caused by the electric dipole moment of the
ferroelectric layer. These findings enable active control of resistance using
both electric and magnetic fields, opening up possibility for multi-state
organic spin valves and shed light on the mechanism of the spin transport in
organic spin valves
Uterine rupture disguised by urinary retention following a second trimester induced abortion: a case report
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