Satellite antenna phase center offsets (PCOs) is an important error source in global navigation satellite system (GNSS). With GNSS observations in a global network, the PCOs estimation strategy ...generally uses a dual-frequency (DF) ionospheric-free (IF) combination as the observation model. This model cannot derive the PCO values at each frequency, which results in the PCOs of the third frequency being unavailable for GPS satellites in the igs14.atx product. In this contribution, the PCOs estimation method of the third frequency based on uncombined (UC) precise orbit determination (POD) model is developed. The PCOs of the first- and second frequencies are fixed to the known values while PCOs of the third frequency are regarded as estimated parameters. This method is tested on the PCO estimation of GPS L5 frequency by using 110 ground stations throughout the entire year of 2018. The averaged standard deviations of L5 PCOs over one year are derived, with x-, y-, and z-offsets being 0.2, 0.2, and 1.6 cm, respectively. The corresponding difference values of the derived weighing averaged PCOs compared to the values of the igs14.atx product are 0.2, 0.1, and 9.9 cm. The POD experiment is processed to validate the derived PCOs of L5 over a period of 50 days. Results show that the accuracy of orbits, clocks and station positions is slightly improved after using estimated PCOs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
ObjectiveTo evaluate the efficiency of county public hospitals in Shandong Province following China’s new medical reform and compare the efficiency of hospitals with different bed sizes for improving ...efficiency.Design and settingThis was a cross-sectional study on the efficiency and size of 68 county public hospitals in China in 2017.Outcome measuresData envelopment analysis was used to calculate the efficiency scores of hospitals and to analyse the slack values of inefficient hospitals. The actual number of open beds, doctors, nurses and total expenditure were selected as inputs, and the total number of annual visits, discharges and total income were selected as outputs. The Kruskal-Wallis H test was employed to compare the efficiency of hospitals with different bed sizes. The χ2 test was used to compare the returns to scale (RTS) of hospitals with different bed sizes.ResultsTwenty (29.41%) hospitals were efficient. There were 27 hospitals with increasing returns to scale, 23 hospitals with constant returns to scale and 18 hospitals with decreasing returns to scale (DRS). The differences in technical efficiency (p=0.248, p>0.05) and pure technical efficiency (p=0.073, p>0.05) were not statistically significant. However, the differences in scale efficiency (p=0.047, p<0.05) and RTS (p<0.001) were statistically significant. Hospitals with DRS began to appear at 885 beds. All sample hospitals with more than 1100 beds were already saturated and some hospitals even had a negative scale effect.ConclusionsThe government and hospital managers should strictly control the bed size in hospitals and make hospitals resume operating in the interests of public welfare. Interventions that rationally allocate health resources and improve the efficiency of medical workers are conducive to solving redundant inputs and insufficient outputs.
This paper presents a case-based reasoning (CBR) method in combination with ontology theory to carry out decision making for assembly sequence planning (ASP). Due to the ontology unifying various ...kinds of assembly sequence-related knowledge from different sources, the CBR approach enables a unified structured representation of previous cases and target cases to achieve integration and sharing of knowledge. Based on the similarity measure of classes and properties in ontology theory, the similarity calculation between target ASP case and previous ASP cases is carried out by considering the connection type, motion-transmission type, and location-support type, and a similarity-based previous cases retrieval algorithm is proposed. The combination of ontology and CBR enables flexible and high-quality assembly sequence decisions under various conditions; the ontology-based rule-based reasoning (RBR) method is also adopted as a supplement to CBR in the assembly sequence construction process. Additionally, a reducer case is used to validate the effectiveness of the proposed method.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract The efficiency of decision‐making in public organizations is a key area of interest for public administration scholars. Drawing on upper echelons theory, this study examines how top ...managers' empowering leadership affects decision‐making speed and comprehensiveness in public organizations. Through a three‐wave questionnaire survey involving 1149 TMT members from 133 public organizations in China, we tested the proposed theoretical model and hypotheses. Our findings reveal that top manager empowering leadership positively and indirectly influences decision‐making speed and comprehensiveness in public organizations, and through its effects on TMT behavioral integration. Furthermore, TMT work style similarity and TMT cognitive diversity can enhance and weaken the mediating relationships, respectively. Chinese Abstract 如何进行高质高效的战略决策是公共管理学者关注的重要话题。然而，从高层视角探讨公共组织有效决策过程的影响因素研究仍极度匮乏。基于高层梯队理论，本研究对来自中国教育部门高层管理团队的调查问卷进行数据分析，探讨了最高领导者授权型领导对公共组织决策速度和全面性的影响机制。结果表明，最高领导者授权型领导通过高管团队行动整合的中介作用对公共组织决策速度和全面性具有积极的间接影响，高管团队的工作方式相似性和认知多样性分别作为边界条件增强和削弱了上述中介关系。本研究为公共部门高层梯队理论与战略领导力研究做出了重要贡献。
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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has been shown to aid in the prevention, alleviation, and treatment of inflammatory bowel disease (IBD), but the progression and mechanisms are largely unstudied, partly because of a ...lack of appropriate models.
human gut models must accurately recreate oxygen concentration gradients consistent with those
to mimic gene expression, metabolism, and host-microbiome interactions. A non-equipment-intensive and inexpensive method for constructing the gut-on-a-chip with physiological oxygen concentration gradients remains challenging. Here, we propose a simple strategy using numerical simulations in a dual-channel gut-on-a-chip to guide chip design and achieve controllable oxygen gradients. By varying the size of microchannels, blocking the oxygen penetration of the polydimethylsiloxane layer at a given location, and controlling the flow of hypoxic/aerobic media, this strategy creates steep gradients across the intestinal epithelium. IBD symptoms were induced on the chip by tumor necrosis factor-α and lipopolysaccharide treatment.
has been validated to contribute to the stability of the intestinal epithelial barrier, including preventing epithelial barrier disruption and promoting the repair of damaged intestinal epithelial cell monolayers. These effects may be associated with the co-localization of
and ZO-1. This simple but robust approach for designing microfluidic devices is applicable to various organs-on-chips in which fluid dynamics and concentration profiles between different media must be considered. With the customized chip, the integration of activated
provides an initial step toward developing a multi-factorial IBD platform. The approach could be scaled up for disease modeling, high-throughput drug screening and personalized medicine.
Abdominal aortic aneurysm (AAA) is a fatal vascular disease with insidious symptoms. However, the mechanism behind its development remains unclear. The transient receptor potential vanilloid (TRPV) ...family has crucial protective effects against cardiovascular diseases, but the role of TRPV5 in AAA has yet to be reported. In this study, ApoE−/− mice were intraperitoneally injected with AAV-GFP or AAV-TRPV5. After 30 days, mice were further administered with angiotensin II (Ang II, 1.44 mg/kg/day) by using osmotic pumps to induce the AAA model or Saline for 28 days, (i.e., Saline + AAV-GFP, Saline + AAV-TRPV5, Ang II + AAV-GFP and Ang II + AAV-TRPV5 groups were established). Compared with the control group, the incidence of AAA and the maximal diameter of the abdominal aorta markedly decreased in Ang II + AAV-TRPV5, which was detected by vascular ultrasound at 28 day. Meanwhile, less collagen and elastin degradation were observed in the Ang II + AAV-TRPV5 group by using Masson and Elastin stains. Moreover, more α-SMA and less MMP2 was observed in the abdominal aortas collected at 28 day by immunohistochemistry. In vitro, primary mouse vascular smooth muscle cells (VSMCs) were treated with Ang II (1 μM) to induce phenotype switch. Sh-TRPV5 and AdTRPV5 were used to transfect VSMCs. PCR and Western blotting were used to access the expression of contractile marker, including α-SMA and SM-22α. The results showed that the mRNA and protein level of α-SMA and SM-22α were decreased under the stimulation of Ang II, but could be attenuated by TRPV5 overexpression. The cell scratch assay demonstrated that the migration ability of VSMCs was increased in Ang II treated group and could be ameliorated by TRPV5 overexpression. Above all, VSMCs transformed from the contractile into secretory phenotype under Ang II stimuli, but could be rescued by TRPV5 overexpression. Furthermore, TRPV5 overexpression suppressed the increased expression of KLF4 induced by Ang II treatment in VSMCs. The data demonstrated that TRPV5 could inhibit AAA formation and play a critical role in the VSMC phenotype switch by downregulating KLF4, suggesting TRPV5 as a new strategy for treating AAA.
•TRPV5 overexpression in VSMCs prevents Ang II-induced AAA formation in ApoE−/− mice.•TRPV5 overexpression suppresses Ang II-induced VSMC phenotype switch.•TRPV5 overexpression suppresses Ang II-induced VSMC phenotype switch via the downregulation of KLF4.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The composited cementitious materials usually have superior performance; for example, using limestone powder (LP) and fly ash (FA) as the admixtures of cement in concrete/mortar is a popular way of ...improving the properties of concrete/mortar structures. In this work, we performed experimental tests to study the hydration process and pore distribution in mortar containing different ratios of LP and FA. Based on the results of mercury intrusion porosimetry (MIP), a numerical mortar model with random pore is built. The model can reflect the synergistic hydration interaction and filling effect caused by the admixtures of LP and FA. After analyzing the hydration process, the coupled chemical–thermal–mechanical method was used to simulate the characteristics of mortar containing LP and FA. The coupling model can simulate the “hump-type” hydration acceleration stage of the mortar at early age, which is specifically caused by the LP, proved in the experimental test. Additionally, the special, “hump-type” stage is important to enhance the early strength of the mortar. At different levels of admixture content, the random pore model and coupled method can predict the evolution process of the mechanical properties well, at early age and for long-term strength. Both experimental and numerical results suggest that the mortar containing admixtures of the proper ratio of LP to FA have good mechanical properties, which can be applied to engineering structures.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Diphenyl carbonate was used as a diluent to prepare microporous polyvinylidene fluoride (PVDF) membrane via thermally induced phase-separation method. The liquid-liquid phase-separation phenomenon ...was found in PVDF/diphenyl carbonate system during the thermally induced phase-separation process. The monotectic point of this system appeared at a high polymer concentration approximately 56 wt %. This suggested that PVDF membrane with a bicontinuous or cellular structure could be obtained when the PVDF concentration was less than this point value. The effects of polymer concentration and quenching temperature on the membrane structure, porosity, and tensile strength were also investigated. The results showed that low polymer concentration and high quenching temperature led to a large pore size membrane. The tensile strength of the membrane increased with increase in the polymer concentration, but the porosity of the membrane decreased. On condition that the PVDF concentration was higher than 60 wt %, only polymer crystallization occurred and a typical compact spherulitic structure was obtained.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Daytime napping is common in many regions around the world and has been an important part of people's daily life. Daytime napping has attracted increasing attention in recent years. Thus, we ...conducted a meta‐analysis to evaluate the relationship between daytime napping and stroke, and help reduce the risk of stroke by improving living habits. The Embase, PubMed, Web of Science and PsycINFO databases were searched for cohort studies published before October 2020 and eight eligible studies with 524,408 participants and 5,875 stroke cases were included in the final analysis. The pooled relative risk (RR) of stroke was 1.47 (95% confidence interval CI: 1.24–1.74; p < .001) with significant heterogeneity (I2 = 58%, p for heterogeneity = 0.02). However, the heterogeneity decreased when the study in which adjusting for sleep duration and stratifying the results based on sleep duration was not performed was excluded (RR: 1.38; 95% CI: 1.19–1.60, I2 = 44%, p for heterogeneity = 0.10). In dose–response analysis, the linear trend indicated that for every 10‐min increase in daytime napping, the risk of stroke increased by 3%. Further well‐designed large studies are needed to explore the effects of daytime napping on stroke and the underlying biological mechanisms.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Fire metrics such as fire front location and rate of spread (ROS) are critical to understanding the behavior of prescribed fires and wildfires. This paper proposes a new method for prescribed grass ...fire evolution mapping and ROS measurement using multitemporal thermal orthomosaics collected by a small fixed-wing Unmanned Aircraft System (UAS) at low altitudes. The proposed method provides a low-cost, safe, and effective solution for active grass fire monitoring and fire metric measurement in areas that may be challenging for a typical rotor-wing UAS to cover due to endurance and size constraints. The proposed method is demonstrated using a prescribed grass fire data set collected by the KHawk fixed-wing UAS over a 13 ha. Kansas tallgrass prairie field on 8 October 2019. Repeat-pass thermal images collected by the KHawk UAS during about 10 min of the burning were grouped and processed to produce multitemporal orthomosaics with a spatial resolution of about
m and a horizontal position error of about 1.5 m. The resulting orthomosaics were further processed for fire front extraction and the measurement of fire front location and ROS. The head fire ROS of this grass burn was observed to be between 0.2 and 0.4
with a mean value of 0.27
.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
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