Calibration Method of Accelerometer Based on Rotation Principle Using Double Turntable Centrifuge

For linear accelerometers, calibration with a precision centrifuge is a key technology, and the input acceleration imposed on the accelerometer should be accurately obtained in the calibration. However, there are often errors in the installation of sample that make the calibration inaccurate. To solve installation errors and obtain the input acceleration in the calibration of the accelerometer, a calibration method based on the rotation principle using a double turntable centrifuge is proposed in this work. The key operation is that the sub-turntable is rotated to make the input axis of the accelerometer perpendicular to the direction of the centripetal acceleration vector. Models of installation errors of angle and radius were built. Based on these models, the static radius and input acceleration can be obtained accurately, and the calibration of the scale factor, nonlinearity and asymmetry can be implemented. Using this method, measurements of the MEMS accelerometer with a range of ±30 g were carried out. The results show that the discrepancy of performance obtained from different installation positions was smaller than 100 ppm after calibrating the input acceleration. Moreover, the results using this method were consistent with those using the back-calculation method. These results demonstrate that the effectiveness of our proposed method was confirmed. This method can measure the static radius directly eliminating the installation errors of angle and radius, and it simplifies the accelerometer calibration procedure.

Growth Modeling of the Giant Electric Ray Narcine entemedor in the Southern Gulf of California: Analyzing the Uncertainty of Three Data Sets

The age and growth rate of the giant electric ray, Narcine entemedor, was estimated using growth bands deposited in the vertebral centra of 245 specimens. Differences in size and age distribution were found between the sexes, a pattern that suggests the annual deposition of band pairs, possibly occurring in April. Multimodel inference and back-calculation were performed to three age data sets of females considering their reproductive cycle and time of capture, among which the von Bertalanffy growth function was found to be the most appropriate (L∞ = 81.87 cm TL, k = 0.17 year−1). Our research supports the idea that age can be determined via biological features such as birth date and growth band periodicity. We concluded that N. entemedor is of a moderate body size, moderate longevity and is a fast-growing elasmobranch species.

Quantifying and reducing researcher subjectivity in the generation of climate indices from documentary sources

The generation of index-based series of meteorological phenomena, derived from narrative descriptions of weather and climate in historical documentary sources, is a common method to reconstruct past climatic variability. This study is the first to explicitly examine the degree of inter-rater variability in producing such series, a potential source of bias in index-based analyses. Two teams of raters were asked to produce a five-category annual rainfall index series for the same dataset, consisting of transcribed narrative descriptions of meteorological variability for 11 ‘rain-years’ in nineteenth-century Lesotho, originally collected by Nash and Grab (2010). One group of raters (n = 71) comprised of students studying for postgraduate qualifications in climatology or a related discipline; the second group (n = 6) consisted of professional meteorologists and historical climatologists working in southern Africa. Inter-rater reliability was high for both groups, at r = 0.99 for the student raters and r = 0.94 for the professional raters, although ratings provided by the student group disproportionately averaged to the central value (0: normal/seasonal rains) where variability was high. Back-calculation of intraclass correlation using the Spearman-Brown prediction formula showed that a target reliability of 0.9 could be obtained with as few as eight student raters, and four professional raters. This number reduced to two when examining a subset of the professional group (n = 4) who had previously published historical climatology papers on southern Africa. We therefore conclude that variability between researchers should be considered minimal where index-based climate reconstructions are generated by trained historical climatologists working in groups of two or more.

Towards a Standard Method for Estimating Fragmentation Rates in Emulsification Experiments

The fragmentation rate function connects the fundamental drop breakup process with the resulting drop size distribution and is central to understanding or modeling emulsification processes. There is a large interest in being able to reliably measure it from an emulsification experiment, both for generating data for validating theoretical fragmentation rate function suggestions and as a tool for studying emulsification processes. Consequently, several methods have been suggested for measuring fragmentation rates based on emulsion experiments. Typically, each study suggests a new method that is rarely used again. The lack of an agreement on a standard method has become a substantial challenge. This contribution critically and systematically analyses four influential suggestions of how to measure fragmentation rate in terms of validity, reliability, and sensitivity to method assumptions. The back-calculation method is identified as the most promising—high reliability and low sensitivity to assumption—whereas performing a non-linear regression on a parameterized model (as commonly suggested) is unsuitable due to its high sensitivity. The simplistic zero-order method is identified as an interesting supplemental tool that could be used for qualitative comparisons but not for quantification.

Novel insights into the management of German patients with very high cardiovascular risk eligible for PCSK9 inhibitor treatment: baseline characteristics from the PERI-DYS study

Background The reasons why patients are treated or not with PCSK9 inhibitors (PCSK9i) are incompletely understood. In Germany, access to PCSK9i is limited by local regulations and many high-risk cardiovascular patients do not receive these therapies. The PERI-DYS study aims to describe and compare two groups of dyslipidaemia patients at very high CV risk: those treated with PCSK9i compared with patients qualifying for but not treated with PCSK9i. Methods Observational study with up to 2000 consented patients, documented mainly by office-based cardiologists or physicians in lipid ambulances with data extracted from patient charts. Lipid lowering treatment (LLT) at enrolment includes ongoing PCSK9i use, newly initiated PCSK9i, statins, ezetimibe, and lipoprotein apheresis. Patients are followed for up to 3 years, with visits every 6±2 months to record LLT (drugs, dosing), other CV medications, lipid and glucose values, blood pressure, clinical events (major adverse cardiac and cerebrovascular events) and adverse drug reactions. Results As of 05 March 2021, 1488 patients have been enrolled across 70 sites. The majority of patients (91.5%) had heterozygous familial or non-familial hypercholesterolemia or mixed dyslipidaemia. At enrolment, 49.4% of patients were receiving PCSK9i (35.4% ongoing and 14.0% newly treated). Among PCSK9i users, the majority were receiving evolocumab 140 mg (n=567, 38.1% of all enrolled patients). There were no major differences in demographics and non-lipid lowering medication, with the exception of more females in the PCSK9i group. The estimated untreated LDL-C based on “back-calculation” was higher in patients who were on ongoing PCSK9i therapy than in those not on PCSK9i or newly treated with PCSK9i (Table 1). Physician-reported statin intolerance was much more common in the two PCSK9i groups compared with the non-PCSK9i group (67% versus 14%). Patients in the PCSK9i groups received fewer concomitant statins. Mean on-treatment total cholesterol and LDL-C were considerably lower in patients who were on ongoing PCSK9i compared to non-PCSK9i. Overall, nicotinic acid, fibrates, cholestagel, and omega-3 fatty acids were rarely used (data not shown). Conclusions Patients treated with PCSK9i and those qualifying for but not treated with PCSK9i had similar baseline characteristics, but the former had higher estimated untreated LDL-C values and a higher rate of statin intolerance. Ongoing follow-up will determine the prognostic importance of these findings. FUNDunding Acknowledgement Type of funding sources: Private company. Main funding source(s): Amgen GmbH Germany

The Multipole Structure and Symmetry Classification of Even-Type Deviators Decomposed from the Material Tensor

The number of distinct components of a high-order material/physical tensor might be remarkably reduced if it has certain symmetry types due to the crystal structure of materials. An nth-order tensor could be decomposed into a direct sum of deviators where the order is not higher than n, then the symmetry classification of even-type deviators is the basis of the symmetry problem for arbitrary even-order physical tensors. Clearly, an nth-order deviator can be expressed as the traceless symmetric part of tensor product of n unit vectors multiplied by a positive scalar from Maxwell’s multipole representation. The set of these unit vectors shows the multipole structure of the deviator. Based on two steps of exclusion, the symmetry classifications of all even-type deviators are obtained by analyzing the geometric symmetry of the unit vector sets, and the general results are provided. Moreover, corresponding to each symmetry type of the even-type deviators up to sixth-order, the specific multipole structure of the unit vector set is given. This could help to identify the symmetry types of an unknown physical tensor and possible back-calculation of the involved physical coefficients.

HPLC Method to Resolve, Identify and Quantify Guanine Nucleotides Bound to the GTPase Ras

The Ras superfamily of small G proteins play central roles in diverse signaling pathways. Superfamily members act as molecular on-off switches defined by their occupancy with GTP or GDP, respectively. In vitro functional studies require loading with a hydrolysis-resistant GTP analogue to increase the on-state lifetime, as well as knowledge of fractional loading with activating and inactivating nucleotides. The present study describes a method combining elements of previous approaches with new, optimized features to analyze the bound nucleotide composition of a G protein loaded with activating (GMPPNP) or inactivating (GDP) nucleotide. After nucleotide loading, the complex is washed to remove unbound nucleotides then bound nucleotides are heat-extracted and subjected to ion-paired, reverse-phase HPLC-UV to resolve, identify and quantify the individual nucleotide components. These data enable back-calculation to the nucleotide composition and fractional activation of the original, washed G protein population prior to heat extraction. The method is highly reproducible. Application to multiple HRas preparations and mutants confirms its ability to fully extract and analyze bound nucleotides, and to resolve the fractional on- and off-state populations. Furthermore, the findings yield a novel hypothesis for the molecular disease mechanism of Ras mutations at the E63 and Y64 positions.