Validation of GPS-derived long-term trend in the atmospheric water vapor using homogenized radiosonde data

Atmospheric water vapor is important for the Earth’s energy balance due to its ability of absorbing and trapping long wave radiation emitted from the Earth’s surface. Therefore, measurements of the atmospheric water vapor content are of very interest for meteorology and climatology. Based on the path delay, which radio signals undergo when propagating through the neutral atmosphere, the Global Positioning System (GPS) measurements can be used to derive the atmospheric integrated water vapor (IWV). With a relatively high temporal resolution, continuously improved spatial density, and less expensive receivers, ground-based GPS measurement has been identified as a useful technique to monitor long-term variations in the IWV. This study will focus on investigating uncertainties of long-term IWV trend obtained from the NCAR global, 2-hourly ground-based GPS IWV dataset. The IWV trends were estimated for approximate 70 GPS sites covering the time period from 1997 to 2011. The GPS-IWV trends will be validated against that from the co-located and homogenized NCAR radiosonde data. The estimated GPS IWV trend consists of two types of uncertainties. The first type is larger in magnitude and is caused by short-term IWV variations (natural variability of the weather), which is not described by the model used for the trend estimation. This type will be investigated by using a statistical model and comparing the GPS IWV trends to the “true” IWV trends estimated from the radiosonde data during 1973-2011. The second type has smaller amplitude and is mainly caused by systematic errors in the GPS data, such as elevation-angle-dependent errors and changes of the GPS antenna and mask. A comparison with the homogenized radiosonde data will help us understand and quantify this type of uncertainty

Event-based Global Stabilization of Linear Systems via a Saturated Linear Controller

SUMMARY This paper investigates the problem of event-based linear control of systems subject to input saturation. First, for discrete-time systems with neutrally stable or double-integrator dynamics, novel event-triggered control algorithms with non-quadratic event-triggering conditions are proposed to achieve global stabilization. Compared with the quadratic event-triggering conditions, the non-quadratic ones can further reduce unnecessary control updates for the input-saturated systems. Furthermore, for continuous-time systems with neutrally stable or double-integrator dynamics, since that an inherent lower bound of the inter-event time does not exist for systems subject to input saturation, novel event-triggered control algorithms with an appropriately selected minimum inter-event time are proposed to achieve global stabilization. Finally, numerical examples are provided to illustrate the theoretical results

Structural and abnormal electrical properties of excess PbO-doped lead lanthanum titanate thin films

Lead lanthanum titanate (PLT) thin films with excess PbO (from 0 to 20 mol%) were prepared by a metal-organic decomposition process. The ferroelectric properties and current-voltage (C -V ) characteristics of PLT films were investigated as a function of the excess PbO. Abnormal ferroelectric and C -V properties were observed in PLT films with excess PbO. The polarization against applied electric field (P -E ) hysteresis loops were pinched before saturation of polarization of the films, and C -V curves had four peaks instead of the two peaks found in the normal C -V curves. The abnormal level of the hysteresis loops and C -V curves deteriorate with increasing concentrations of excess PbO in the films. Electron probe microanalysis has revealed that there is excess Pb in PLT thin films. Auger electron spectroscopy has detected that the Pb accumulates at the interfaces between the thin film and the bottom electrode. Meanwhile, transmission electron microscopy has found that PbO nanocrystals on the interface between the PLT thin film and the bottom electrode, and clusters of vacancies and interstitials, in particular, exist in the PLT grains. Therefore, a part of the excess PbO may accumulate at the domain wall of the grains and the grain boundaries and the interface between the bottom electrode and film during the thermal annealing process of the films. Meanwhile, the oxygen vacancies of the grains will increase with the increasing concentration of the excess PbO in the films. The excess PbO and oxygen vacancies act as pinning centres and have a strong pinning effect on the domains. When the poling voltage is not large enough, part of the domains can overcome the force of the pinning, and abnormal ferroelectric and C -V properties were observed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48906/2/d00703.pd

Efficacy and safety of prophylactic intraoperative sac embolization in EVAR for abdominal aortic aneurysm: A meta-analysis

ObjectiveWe aimed to investigate the effectiveness and safety of prophylactic sac embolization during endovascular aneurysm repair (EVAR) in patients suffering from abdominal aortic aneurysms.MethodsWe performed a systematic literature search of PubMed, Web of Science, EMbase, Cochrane Library, China National Knowledge Infrastructure (CNKI), VIP, Wanfang and China Biomedical Literature Database (CBM) to identify studies evaluating the outcomes of sac embolization vs. no embolization among patients who had received EVAR. The time limit of the search was from the establishing database to July 22, 2022. Outcome measures involved the type II endoleak rate, the other endoleak rate, the reintervention rate, mortality, and operation time. Fixed (no heterogeneity) or random effects models were constructed for each outcome. The outcomes are represented as the odds ratio (OR) with a 95% confidence interval (CI).ResultsAmong the 2,622 studies screened, 13 studies involving 747 participants were included in the review. The incidence of early-term type II endoleak (OR = 0.2, 95% CI (0.13,0.31), P < 0.00001), mid-term type II endoleak (OR = 0.23, 95% CI (0.15,0.37), P < 0.00001), late-term type II endoleak (OR = 0.27, 95% CI (0.16,0.46), P < 0.00001) and reintervention (OR = 0.50, 95% CI (0.37,0.78), P = 0.002) within the sac embolization group were significantly lower than those in the non-embolization group. No significant differences were observed between the two groups were found for the other endoleak rates (OR = 0.67, 95% CI (0.34,1.32), P = 0.25), mortality (OR = 0.64, 95% CI (0.25,1.66), P = 0.36) and operation time operation (MD = 5.76, 95% CI (-8.30,19.83), P = 0.42).ConclusionsEVAR combined with sac embolization effectively reduces the incidence of type II endoleak and the reintervention rate without enhancing the operation time. Therefore, more high-quality studies are still needed for validation due to the limited amount and quality of included literature.Systematic Review Registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022365648

Biodegradable Thermosensitive Hydrogel for SAHA and DDP Delivery: Therapeutic Effects on Oral Squamous Cell Carcinoma Xenografts

Background: OSCC is one of the most common malignancies and numerous clinical agents currently applied in combinative chemotherapy. Here we reported a novel therapeutic strategy, SAHA and DDP-loaded PECE (SAHA-DDP/PECE), can improve the therapeutic effects of intratumorally chemotherapy on OSCC cell xenografts. Objective/Purpose: The objective of this study was to evaluate the therapeutic efficacy of the SAHA-DDP/PECE in situ controlled drug delivery system on OSCC cell xenografts. Methods: A biodegradable and thermosensitive hydrogel was successfully developed to load SAHA and DDP. Tumorbeared mice were intratumorally administered with SAHA-DDP/PECE at 50 mg/kg (SAHA) +2 mg/kg (DDP) in 100 ul PECE hydrogel every two weeks, SAHA-DDP at 50 mg/kg(SAHA) +2 mg/kg(DDP) in NS, 2 mg/kg DDP solution, 50 mg/kg SAHA solution, equal volume of PECE hydrogel, or equal volume of NS on the same schedule, respectively. The antineoplastic actions of SAHA and DDP alone and in combination were evaluated using the determination of tumor volume, immunohistochemistry, western blot, and TUNEL analysis. Results: The hydrogel system was a free-flowing sol at 10uC, become gel at body temperature, and could sustain more than 14 days in situ. SAHA-DDP/PECE was subsequently injected into tumor OSCC tumor-beared mice. The results demonstrated that such a strategy as this allows the carrier system to show a sustained release of SAHA and DDP in vivo, and coul

Riccati equation and event-triggered control for constrained systems

abstractMechanical EngineeringDoctoralDoctor of Philosoph

Validation of GPS-derived long-term trend in the atmospheric water vapor using homogenized radiosonde data

Atmospheric water vapor is important for the Earth’s energy balance due to its ability of absorbing and trapping long wave radiation emitted from the Earth’s surface. Therefore, measurements of the atmospheric water vapor content are of very interest for meteorology and climatology. Based on the path delay, which radio signals undergo when propagating through the neutral atmosphere, the Global Positioning System (GPS) measurements can be used to derive the atmospheric integrated water vapor (IWV). With a relatively high temporal resolution, continuously improved spatial density, and less expensive receivers, ground-based GPS measurement has been identified as a useful technique to monitor long-term variations in the IWV. This study will focus on investigating uncertainties of long-term IWV trend obtained from the NCAR global, 2-hourly ground-based GPS IWV dataset. The IWV trends were estimated for approximate 70 GPS sites covering the time period from 1997 to 2011. The GPS-IWV trends will be validated against that from the co-located and homogenized NCAR radiosonde data. The estimated GPS IWV trend consists of two types of uncertainties. The first type is larger in magnitude and is caused by short-term IWV variations (natural variability of the weather), which is not described by the model used for the trend estimation. This type will be investigated by using a statistical model and comparing the GPS IWV trends to the “true” IWV trends estimated from the radiosonde data during 1973-2011. The second type has smaller amplitude and is mainly caused by systematic errors in the GPS data, such as elevation-angle-dependent errors and changes of the GPS antenna and mask. A comparison with the homogenized radiosonde data will help us understand and quantify this type of uncertainty

Event-triggered control over noisy feedback channels

In this paper, the stability of a discrete-time event-triggered control system over noisy feedback channels is analyzed. The transmission between the controller and the actuator is triggered by an event involving estimated control, desirable control, and a trigger threshold. It is revealed that if the trigger threshold is less than a bound determined by the system and controller matrices, then the closed-loop system is mean square stable. In addition, two equivalent conditions based on algebraic Riccati inequality/equation (ARI/ARE) are proposed to facilitate further analysis