scholarly journals Investigation of nonlinearity in inverse problems of satellite dynamics

Author(s):  
E. E. Shmidt ◽  
◽  
M. A. Banshchikova ◽  
V. A. Avduyshev ◽  
◽  
...  

The report presents the results of a study of the total and intrinsic nonlinearities as applied to the outer satellites of Jupiter observed on a short arc. The relationship between the nonlinearities and the conditions of satellite observations is revealed. In particular, it is shown that the total nonlinearity is very strong when the observation period is less than 0.1 of the orbital period, while the intrinsic nonlinearity is weak enough for all satellites, which indicates the possibility of using nonlinear methods for adequate modeling of their orbital uncertainty.

2012 ◽  
Vol 32 (S 01) ◽  
pp. S39-S42 ◽  
Author(s):  
S. Kocher ◽  
G. Asmelash ◽  
V. Makki ◽  
S. Müller ◽  
S. Krekeler ◽  
...  

SummaryThe retrospective observational study surveys the relationship between development of inhibitors in the treatment of haemophilia patients and risk factors such as changing FVIII products. A total of 119 patients were included in this study, 198 changes of FVIII products were evaluated. Results: During the observation period of 12 months none of the patients developed an inhibitor, which was temporally associated with a change of FVIII products. A frequent change of FVIII products didn’t lead to an increase in inhibitor risk. The change between plasmatic and recombinant preparations could not be confirmed as a risk factor. Furthermore, no correlation between treatment regimens, severity, patient age and comorbidities of the patients could be found.


2021 ◽  
Vol 11 (5) ◽  
pp. 328
Author(s):  
Michael Leutner ◽  
Nils Haug ◽  
Luise Bellach ◽  
Elma Dervic ◽  
Alexander Kautzky ◽  
...  

Objectives: Diabetic patients are often diagnosed with several comorbidities. The aim of the present study was to investigate the relationship between different combinations of risk factors and complications in diabetic patients. Research design and methods: We used a longitudinal, population-wide dataset of patients with hospital diagnoses and identified all patients (n = 195,575) receiving a diagnosis of diabetes in the observation period from 2003–2014. We defined nine ICD-10-codes as risk factors and 16 ICD-10 codes as complications. Using a computational algorithm, cohort patients were assigned to clusters based on the risk factors they were diagnosed with. The clusters were defined so that the patients assigned to them developed similar complications. Complication risk was quantified in terms of relative risk (RR) compared with healthy control patients. Results: We identified five clusters associated with an increased risk of complications. A combined diagnosis of arterial hypertension (aHTN) and dyslipidemia was shared by all clusters and expressed a baseline of increased risk. Additional diagnosis of (1) smoking, (2) depression, (3) liver disease, or (4) obesity made up the other four clusters and further increased the risk of complications. Cluster 9 (aHTN, dyslipidemia and depression) represented diabetic patients at high risk of angina pectoris “AP” (RR: 7.35, CI: 6.74–8.01), kidney disease (RR: 3.18, CI: 3.04–3.32), polyneuropathy (RR: 4.80, CI: 4.23–5.45), and stroke (RR: 4.32, CI: 3.95–4.71), whereas cluster 10 (aHTN, dyslipidemia and smoking) identified patients with the highest risk of AP (RR: 10.10, CI: 9.28–10.98), atherosclerosis (RR: 4.07, CI: 3.84–4.31), and loss of extremities (RR: 4.21, CI: 1.5–11.84) compared to the controls. Conclusions: A comorbidity of aHTN and dyslipidemia was shown to be associated with diabetic complications across all risk-clusters. This effect was amplified by a combination with either depression, smoking, obesity, or non-specific liver disease.


2021 ◽  
pp. 000313482198903
Author(s):  
Mitsuru Ishizuka ◽  
Norisuke Shibuya ◽  
Kazutoshi Takagi ◽  
Hiroyuki Hachiya ◽  
Kazuma Tago ◽  
...  

Objective To explore the impact of appendectomy history on emergence of Parkinson’s disease (PD). Background Although there are several studies to investigate the relationship between appendectomy history and emergence of PD, the results are still controversial. Methods We performed a comprehensive electronic search of the literature (the Cochrane Library, PubMed, and the Web of Science) up to April 2020 to identify studies that had employed databases allowing comparison of emergence of PD between patients with and those without appendectomy history. To integrate the impact of appendectomy history on emergence of PD, a meta-analysis was performed using random-effects models to calculate the risk ratio (RR) and 95% confidence interval (CI) for the selected studies, and heterogeneity was analyzed using I2 statistics. Results Four studies involving a total of 6 080 710 patients were included in this meta-analysis. Among 1 470 613 patients with appendectomy history, 1845 (.13%) had emergences of PD during the observation period, whereas among 4 610 097 patients without appendectomy history, 6743 (.15%) had emergences of PD during the observation period. These results revealed that patients with appendectomy history and without appendectomy had almost the same emergence of PD (RR, 1.02; 95% CI, .87-1.20; P = .83; I2 = 87%). Conclusion This meta-analysis has demonstrated that there was no significant difference in emergence of PD between patients with and those without appendectomy history.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Maocai Wang ◽  
Xin Luo ◽  
Guangming Dai ◽  
Xiaoyu Chen

Grid point technique is a classical method in computing satellite constellation coverage to the ground regions. Aiming at improving the low computational efficiency of the conventional method, a method using latitude stripe division is proposed, which has high efficiency, and we name it latitude stripe method. After dividing the target region into several latitude stripes, the coverage status of each latitude stripe is computed by means of the spherical geometry relationship in the first orbital period. The longitude coverage intervals in the remaining orbital periods are computed by sliding the coverage status in the first orbital period. Based on this method, the instantaneous and cumulative coverage in simulation time can be calculated more efficiently. As well, the relationship between the cumulative coverage and altitude can be computed fast by this method, which could be used in the optimized design of repeating sun-synchronous orbits. The comparison between the conventional grid point method and the latitude stripe method shows that the latitude stripe method has high efficiency and accuracy. Through various case studies, the optimization in repeating sun-synchronous orbits design is successfully represented.


Development ◽  
1984 ◽  
Vol 79 (1) ◽  
pp. 165-181
Author(s):  
Nigel Holder ◽  
Susan Reynolds

A relationship between pattern formation and field shape is established following the formation of rounded blastemas on lower arm limb stumps after treatment with vitamin A. Pattern formation is not affected by alteration in blastemal shape caused by removal of the dermis from the thigh region of the leg. We conclude, therefore, that blastemal shape does not play a causal role in establishing limb pattern. Data relating the number of cells present between the cardinal axial poles of blastemas and the size of blastemas is discussed in terms of short arc intercalation and short range cell—cell interactions during pattern regulation.


Author(s):  
Yumi Henmi ◽  
Gyo Itani

Abstract Many alpheid shrimps live symbiotically on the body surface or inside the bodies of other invertebrates, while others use burrows made by other animals. The burrow symbiosis of alpheid shrimps is poorly studied in the context of ecology, probably because the cryptic infaunal nature of the relationship is hard to observe. The limited knowledge of the pattern of burrow use by alpheid shrimps leaves a gap in our understanding of their evolutionary history. We described and compared the behavior of Stenalpheops anacanthus  Miya, 1997 and Athanas japonicus  Kubo, 1936, two alpheid species living symbiotically in the burrows of the same host, Upogebia yokoyai  Makarov, 1938. We found that both alpheid species used U. yokoyai burrows in aquaria, but their burrow use patterns were quite different. The average time taken for S. anacanthus to enter the burrow for the first time was much shorter (1 min) than that of A. japonicus (13 min). Subsequently, S. anacanthus made longer use of the burrow (80% of the observation period) than A. japonicus (49%). The tail-first exit frequency, which may indicate a sudden expulsion from the burrow by the host, was more frequent in A. japonicus (25%) than in S. anacanthus (7%). Such differences could be attributed to the nature of the symbiotic relationship, obligate in S. anacanthus but facultative in A. japonicus. Because of the diversity of symbiotic lifestyles, there is considerable potential to study the ecology and evolutionary biology of burrow-symbiotic alpheids further.


2012 ◽  
Vol 56 (3) ◽  
pp. 287-292
Author(s):  
Janusz Zbylut ◽  
Marek Gehrke ◽  
Edward Malinowski

Abstract The aim of the study was to find the relationship between some postpartum disorders and pregnancy losses (PL), and the influence of PL on further fertility of Holstein-Friesian dairy cows. The 1,056 pregnancies and 906 calving intervals (CI) of 378 cows during the nine-year observation period were analysed. The average milk yield during this period increased from 7,500 to 10,500 kg/305 d of lactation. All cows up to 4 weeks after calving were gynecologically examined and cases of genital tract disorders were recorded and treated. Artificial inseminations (AI) were made using commercial frozen/thawed semen. In cows with silent ovulation, oestrus was induced by injection of PGF2α or programmes using PGF2α and GnRH, or hCG were applied. Pregnancy was diagnosed with the use of ultrasonography or foetal membrane slip only from 30 and 42 d after service, respectively, and re-diagnosed between 70 and 90 d after AI. The cases of „early foetal loss” up to 90 d and „mid-to-late PL” between 91 and 260 d after AI were recorded. Endometritis was noted in 31.8%, ovarian cysts in 8.5%, whereas ovarian inactivity in 4.6% of cows. Early PL was observed in 5.2%, whereas mid-to-late PL in 6.8% of cows (total 12%). From all analysed factors, the influence of delayed or periodical lack of ovarian activity was significant with regard to early PL (P=0.029). The probability of early PL increased when besides the diagnosis of ovarian inactivity, AI was made following an induced oestrus (P=0.003). CI for cows, which did not lost pregnancy amounted 442.9 d. The early, mid-to-late and multiple PL extended the CI to 579.6, 661.1 and 657.7 d, respectively (P<0.05). Concurrently, CI for cows with “early foetal loss” was significantly shorter comparing to cows with “mid-to-late foetal loss” (579.6 d vs.661.1 d; P<0.05). On average 2.6 inseminations for one pregnancy were needed, and each PL increased the AI index. Significant differences were stated after early and multiple foetal losses (5.2 and 5.1 vs. 2.6; P<0.05).


Sign in / Sign up

Export Citation Format

Share Document