instability

摘要： Background: Armed conflict increases the occurrence of adverse obstetrical outcomes especially in low and middle-income countries. However, there is paucity of data on obstetrical outcomes in the South-West and North-West Regions of Cameroon since the onset of the socio-political instability. Objectives: Our aim was to evaluate obstetrical outcomes in the Buea and Bamenda Regional Hospitals, Cameroon during the period of socio-political instability. Methods: A hospital-based retrospective cohort study was carried out at the aforementioned hospitals. Data was collected from case notes of pregnant women before the period of socio-political instability (from January 1, 2014 to December 31, 2016) and during the period of socio-political instability (from January 1, 2017 to October 31, 2019). The Chi square and Fischer’s exact test were used to compare categorical variables where appropriate and modeled into multivariate analysis. A p-value Results: The mean maternal age was 27.09 (±5.25) years, before and during the conflict. The mean weight of neonates (regardless of gestational age) during the conflict was significantly higher [3.28 (±0.65) kg] compared to that before the conflict [3.21 ± (0.52) kg] (p yrs [OR = 1.97;CI (1.16 - 3.37), p = 0.01], and delivery during the period of socio-political instability [OR = 1.97;CI (1.16 - 3.37)], p = 0.01 and [OR = 1.89;CI (1.53 - 2.33)], p Conclusion: This study identifies increased incidence of adverse maternal outcomes in mothers exposed to socio-political instability.

摘要： The cone-jet in electrohydrodynamic atomization has been widely applied into numerous industrial fields owing to micro-sized drops with narrow distribution and high charge.The electrified jet emits from a single capillary sheathed with quartz tube is visualized versus operating parameters and physical properties,and breakup instabilities are also discussed.The range of operating parameters for a steady conejet broadens,as well as the minimum flow rate.Taylor cone angle decreases with an increase in flow rate,while increases as electric potential increasing.The jet breakup length decreases with an increase in flow rate and conductivity,while increases as electric potential increasing.The diffusion angle increases as flow rate increasing,while decrease as electric potential and conductivity increasing.Much clearer whipping instabilities are observed with an increase in“electro-Weber”number and conductivity.The completion in disturbance or/and suppression from axial and radial stresses,drag force dominates the variation.Meanwhile,for a large flow rate,the transition from varicose instabilities to whipping instabilities is found.The whipping instabilities are clearly observed for high conductivity due to much more free ions in liquid.For much higher conductivity,an intermittent electrified jet appears and shows an umbrella plume,and breakup length sharply shortens.

摘要： In this paper,we are concerned with the long time behavior of the piecewise smooth solutions to the generalized Riemann problem governed by the compressible isothermal Euler equations in two and three dimensions.A non-existence result is established for the fan-shaped wave structure solution,including two shocks and one contact discontinuity which is a perturbation of plane waves.Therefore,unlike in the one-dimensional case,the multi-dimensional plane shocks are not stable globally.Moreover,a sharp lifespan estimate is established which is the same as the lifespan estimate for the nonlinear wave equations in both two and three space dimensions.

摘要： Mixed halide perovskites(MHPs)have attracted atten-tion due to their tunability of optoelectronic properties and es-pecially the bandgap,which is useful for tandem solar cells.Un-fortunately,MHPs undergo phase separation under illumina-tion.It can form low-bandgap iodide-rich phases as charge re-combination centers,causing the reduction of open-circuit voltage(Voc)and device photoinstability.To address this is-sue,many approaches have been used[1].

摘要： Introduction: A new electromechanical instrument has been developed to measure relative dorsal mobility of the first ray in an objective and reliable way by simulating ground reaction forces during gait. This device equally applies a standardized, electronically controlled, and precise force under the first metatarsal head M1 as well as under the heads of the lesser metatarsals M2 to M5. The relative dorsal mobility between these two bearings is then measured. The purpose of this study is to assess the intra- and inter-examiners reliabilities of the measurements obtained with this device. Methods: The protocol included two examiners and 36 feet (18 volunteers with healthy feet and no history of forefoot disorders). A total of nine measurements were performed on each foot separated into three sets of three trials for the assessment of inter-rater and intra-rater reliability. For this purpose, the interclass correlation coefficient (ICC), the error of measurement (SEM) and the Bland and Altman (B&A) graphical analysis were computed. Results: Excellent ICC values (≥0.91) were obtained with the novel device for inter-rater and intra-rater reliability when using the FRRM calculation. The B&A analysis presented a bias between examiners of -0.25 mm ranging from -1.66 to 1.18 mm. Conclusion: This study demonstrated the capability of the developed device to reliably measure the relative dorsal mobility of the first ray of the foot. This is a promising first step for further studies to better understand, qualify and quantify first ray hypermobility.

摘要： Instability is an inherent problem with the attenuation compensation methods and has been partially relieved by using the inverse scheme.However,the conventional inversion-based attenuation compensation approaches ignore the important prior information of the seismic dip.Thus,the compensated result appears to be distorted spatial continuity and has a low signal-to-noise ratio(S/N).To alleviate this issue,we have incorporated the seismic dip information into the inversion framework and have developed a dip-constrained attenuation compensation(DCAC)algorithm.The seismic dip information,calculated from the poststack seismic data,is the key to construct a dip constraint term.Benefiting from the introduction of the seismic dip constraint,the DCAC approach maintains the numerical stability and preserves the spatial continuity of the compensated result.Synthetic and field data examples demonstrate that the proposed method can not only improve seismic resolution,but also protect the continuity of seismic data.

摘要： Organo-lead halide perovskites(OHPs) possess superior optoelectronic properties and have achieved an amazing certified power conversion efficiency(PCE) of 25.5% in perovskite solar cells(PSCs)[1]. Recent studies revealed that the organic cations such as methylammonium(MA+) and formamidinium(FA+) and anions with weak electronegativity such as I-in OHPs were causing instability.

摘要： Amid the ravaging COVID-19 pandemic, the 22nd China-EU leaders'' meeting held on June 22 boosted much-needed confidence in the global fight against the virus and offered more certainty in a time of unprecedented instability.

摘要： Using a new functional analysis tool, multiscale window transform(MWT), and the MWT-based localized multiscale energetics analysis and canonical transfer theory, this study reconstructs the Kuroshio system on three scale windows, namely,the mean flow window, the interannual-scale(low-frequency) window, and the transient eddy window, and investigates the climatological characteristics of the intricate nonlinear interactions among these windows. Significant upscale energy transfer is observed east of Taiwan, where the mean Kuroshio current extracts kinetic energy from both the interannual and eddy windows.It is found that the canonical transfer from the interannual variability is an intrinsic source that drives the eddy activities in this region. The multiscale variabilities of the Kuroshio in the East China Sea(ECS) are mainly controlled by the interaction between the mean flow and the eddies.The mean flow undergoes mixed instabilities(i.e., both barotropic and baroclinic instabilities) in the southern ECS, while it is barotropically stable but baroclinically unstable to the north. The multiscale interactions are found to be most intense south of Japan, where strong mixed instabilities occur;both the canonical transfers from the mean flow and the interannual scale are important mechanisms to fuel the eddies. It is also found that the interannual-scale energy mainly comes from the barotropically unstable jet, rather than the upscale energy transfer from the high frequency eddies.

摘要： BACKGROUND Based on the breakthrough of genomics analysis, The Cancer Genome Atlas Research Group recently proposed an integrative genomic analysis, dividing gastric cancer(GC) into four subtypes, characterized by the chromosomal instability(CIN) status. However, the CIN status of GC is still vaguely characterized and lacking the valuable easy-to-use CIN markers to diagnosis in molecular and histological detection.AIM To explore the associations of CIN with downstream lipidomics profiles.METHODS We collected cancerous and noncancerous tissue samples from 18 patients with GC; the samples were divided into CIN and non-CIN types based on the system of The Cancer Genome Atlas Research Group and 409 sequenced oncogenes and tumor suppressor genes. We identified the lipidomics profiles of the GC samples and samples of their adjacent noncancerous tissues by using liquid chromatography–mass spectrometry. Furthermore, we selected leading metabolites based on variable importance in projection scores of > 1.0 and P <0.05.RESULTS Twelve men and six women participated in this study; the participants had a median age of 67.5 years(range, 52–87 years) and were divided into CIN(n = 9)and non-CIN(n = 9) groups. The GC samples exhibited distinct profiles of lysophosphocholine, phosphocholine, phosphatidylethanolamine,phosphatidylinositol, phosphoserine, sphingomyelin, ceramide, and triglycerides compared with their adjacent noncancerous tissues. The glycerophospholipid levels(phosphocholine, phosphatidylethanolamine, and phosphatidylinositol)were 1.4-to 2.3-times higher in the CIN group compared with the non-CIN group(P < 0.05). Alterations in the glycerolipid and glycerophospholipid pathways indicated progression of GC toward CIN.CONCLUSION The lipidomics profiles of GC samples were distinct from those of their adjacent noncancerous tissues. CIN status of GC is primarily associated with downstream lipidomics in the glycerophospholipid pathway.