On the Structure of Symplectic Mappings. The Fast Lyapunov Indicator: A Very Sensitive Tool

Author(s):  
Claude Froeschlé ◽  
Elena Lega
1964 ◽  
Vol 11 (01) ◽  
pp. 085-093
Author(s):  
W. F Blatt ◽  
JL Gray ◽  
H Jensen

SummaryA sensitive tool has been described for measuring fibrinolysis in reconstituted systems using thrombelastography. Activator mixtures with no appreciable proteolytic activity can similarly be tested in this system when the fibrinogen utilized has sufficient plasminogen present. Exposure of human plasminstreptokinase mixtures formed at pH 7.0 to acid conditions produced a striking loss of activator activity which could not be ascribed to low pH lability of the components, nor to plasmin action on the SK at pH 2.0. This is additional evidence for the hypothesis that human plasmin interacts with SK to form a complex capable of converting human and bovine plasminogen to plasmin.


2020 ◽  
Vol 33 (6) ◽  
pp. 735-742
Author(s):  
Meliha Demiral ◽  
Mehmet Salih Karaca ◽  
Edip Unal ◽  
Birsen Baysal ◽  
Rıza Taner Baran ◽  
...  

AbstractBackgroundsLimitations in the evaluation of the pituitary size and changes according to pubertal status make its validity questionable. Recently, in a small-scale study, pons ratio (PR) has been suggested as a more sensitive tool for diagnosis and etiological evaluation of growth hormone deficiency (GHD). The aim of the study is to evaluate the diagnostic value of PR in the diagnosis of GHD.MethodsWe retrospectively evaluated the pituitary magnetic resonance imaging (MRI) of 133 patients with a diagnosis of GHD. Primary axis (PA) was assigned as a line crossing the mid-sagittal dorsum sella and fourth ventricle. PR was defined as the pons height above the PA divided by total pons height. The PR of patients with GHD was compared to subjects without GHD.ResultsStudy included 133 patients with GHD and 47 controls. In total, 121 (91%) patients had isolated GHD and 12 (9%) patients had multiple pituitary hormone deficiency. The PR of the patient group (mean: 0.32 ± 0.89; range: 0.14–0.63) was significantly higher than controls (mean: 0.26 ± 0.067; range 0.19–0.44) (p: 0.000). The optimal cut-off value of PR for GHD diagnosis was 0.27 (sensitivity 71% specificity 56%). There was a negative correlation between anterior pituitary height (APH)-SDS and PR (p: 0.002; r: −0.27). APH was increased, but PR remained unchanged in pubertal patients (p: 0.089).ConclusionsPR measurement is a noninvasive, practical method with a cost-benefit clinical value. As it is not affected by pubertal status, PR is potentially a more sensitive tool for evaluation of pituitary gland in GHD patients compared to APH.


2021 ◽  
Vol 108 (Supplement_2) ◽  
Author(s):  
A Bhojwani ◽  
M Ahmed ◽  
F Mahmood ◽  
C Sellahewa ◽  
C Desai

Abstract Introduction Lower gastrointestinal bleeding (LGIB) accounts for 3% of all surgical referrals in the UK, with an in-hospital mortality of 3.4%. The BSG 2019 guidelines recommend risk stratification as per Oakland scoring, inpatient lower GI endoscopy for admissions and CT-angiography for unstable patients. This study evaluates the delivery of these outcomes in a district hospital setting. Method Retrospective audit assessing all acute LGI bleed admissions from 01-07-2019 to 28-02-2020 at Russells Hall Hospital. Shock Index (SI) and Oakland score used to stratify patients into unstable, stable-major and stable-minor LGIB. Compliance with BSG standards was assessed by review of investigations and emergent patient management. Results 143 patients (Median age = 70years) evaluated, with 64 admissions having no formal risk stratification (OAKLAND-score) documented. Only 12 admissions underwent inpatient LGI endoscopy with sigmoid diverticulosis the most common pathology (39.3%). CT-angiogram was the initial investigation for 75% of patients admitted with unstable LGIB. Conclusions OAKLAND-scoring is a sensitive tool to stratify LGIB patients based on clinical parameters. Application of BSG-2019 guidelines and developing consistency in management is challenged by the lack of routine access to LGI endoscopy and tools to manage bleeding endoscopically.


Author(s):  
Tamara van Donge ◽  
Anne Smits ◽  
John van den Anker ◽  
Karel Allegaert

Background: Disentangling renal adverse drug reactions from confounders remains a major challenge to assess causality and severity in neonates, with additional limitations related to the available tools (modified Kidney Disease Improving Global Outcome, or Division of Microbiology and Infectious Diseases pediatric toxicity table). Vancomycin and amikacin are nephrotoxic while still often prescribed in neonates. We selected these compounds to assess their impact on creatinine dynamics as a sensitive tool to detect a renal impairment signal. Methods: A recently developed dynamical model that characterized serum creatinine concentrations of 217 extremely low birth weight (<1000 g, ELBW) neonates (4036 observations) was enhanced with data on vancomycin and/or amikacin exposure to identify a potential effect of antibiotic exposure by nonlinear mixed-effects modelling. Results: Seventy-seven percent of ELBW patients were exposed to either vancomycin or amikacin. Antibiotic exposure resulted in a modest increase in serum creatinine and a transient decrease in creatinine clearance. The serum creatinine increase was dependent on gestational age, illustrated by a decrease with 56% in difference in serum creatinine between a 24 or 32-week old neonate, when exposed in the 3rd week after birth. Conclusions: A previously described model was used to explore and quantify the impact of amikacin or vancomycin exposure on creatinine dynamics. Such tools serve to explore minor changes, or compare minor differences between treatment modalities.


2005 ◽  
Vol 22 (3) ◽  
pp. 389-399 ◽  
Author(s):  
Marc Pouliot ◽  
Simon Grondin

One of the features of the auditory system is its ability to efficiently process events that occur in rapid succession. The aim of the present study is to propose a new way of investigating sensitivity to auditory tempo changes. More specifically, it proposes to compare the relative sensitivity (bias) to acceleration and deceleration in both musical and monotonal conditions. Bias was measured with (1) a conventional psychophysical method known as the method of constant stimuli (MCS) and (2) a so-called method of dynamic stimuli (MDS). The latter method consists in responding with a finger press as soon as a near-continual tempo change is detected. With the MCS, there was no preference, as estimated by the point of subjective equality, between acceleration and deceleration in the monotonal condition, but there was a preference in the musical condition that indicated more facility for estimating decelerations than accelerations. The results obtained with the MDS are consistent with the MCS results, given that the response time was faster for decelerations than accelerations in the musical condition but not in the monotonal condition. We conclude that the MDS is a sensitive tool for investigating slight tempo variations.


2016 ◽  
Vol 59 (2) ◽  
pp. 317-329 ◽  
Author(s):  
Ling-Yu Guo ◽  
Phyllis Schneider

Purpose To determine the diagnostic accuracy of the finite verb morphology composite (FVMC), number of errors per C-unit (Errors/CU), and percent grammatical C-units (PGCUs) in differentiating school-aged children with language impairment (LI) and those with typical language development (TL). Method Participants were 61 six-year-olds (50 TL, 11 LI) and 67 eight-year-olds (50 TL, 17 LI). Narrative samples were collected using a story-generation format. FVMC, Errors/CU, and PGCUs were computed from the samples. Results All of the three measures showed acceptable to good diagnostic accuracy at age 6, but only PGCUs showed acceptable diagnostic accuracy at age 8 when sensitivity, specificity, and likelihood ratios were considered. Conclusion FVMC, Errors/CU, and PGCUs can all be used in combination with other tools to identify school-aged children with LI. However, FVMC and Errors/CU may be an appropriate diagnostic tool up to age 6. PGCUs, in contrast, may be a sensitive tool for identifying children with LI at least up to age 8 years.


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