Absolute Sign Research Articles

Challenges in the diagnosis of growing teratoma syndrome: two case reports

Growing teratoma syndrome (GTS) is reported to have an incidence of 1.9–7.6% among all germ cell tumours (GCT) and is often mistaken for tumor progression. There are no absolute signs or symptoms of GTS but it can be suspected based on the following criteria: the normalization of tumour markers, the enlargement of the mass and the presence in the tumour of mature teratoma cells alone. A delayed tumor resection in GTS can result in higher surgical risks and/or the infeasibility of complete resection. In 72–83% of cases, incomplete resection leads to relapses in the form of mature teratoma growth. A repeat biopsy is recommended in all patients with suspected GTS so that to avoid chemotherapy that would be ineffective in this disease. The article reports two clinical cases of GTS illustrating challenges inherent in the diagnosis of this syndrome. In each case, the parents gave consent to the use of their child's data, including photographs, for research purposes and in publications.

К методике оценки метрических данных по основным абсолютным признакам и указателям скелета человека (по антропологическим материалам некрополей г.Самары XVIII-XIX вв.)

К методике оценки метрических данных по основным абсолютным признакам и указателям скелета человека (по антропологическим материалам некрополей г.Самары XVIII-XIX вв.)

Composite Absolute Value and Sign Forecasts

This paper introduces composite absolute value and sign (CAVS) forecasts, a nonlinear framework that combines forecasts of the sign and absolute value of a time series into conditional mean forecasts. In contrast to linear models, the proposed framework allows different predictors to separately impact the sign and absolute value of the target series. Among other results, I show that the conditional mean can be accurately approximated by the product of mean squared error optimal sign and absolute value forecasts. An empirical application using the FRED-MD dataset shows that CAVS forecasts substantially outperform linear forecasts for series that exhibit persistent volatility dynamics, such as output and interest rates.

Acute Lung Inflammation: The Crisis of Etiotropic Treatment and The Logic of Its Solutions

Modern ideas about the nature of acute inflammatory processes in the lungs are focused on the leading significance of the etiology of the disease. The predominance of this concept defines etiotropic therapy as the basis for providing medical care to this category of patients. In fact, the causative agent of acute pneumonia in most patients remains unknown or the accuracy of its diagnosis is questionable. At the same time, the targeted use of etiotropic drugs is always delayed due to the delay in the results of microbiological diagnostics. Recently, these difficulties of etiotropic therapy have been compounded by an increase in the number of patients with viral lung inflammation and the lack of effective antiviral drugs. The paradoxical and illogical nature of the situation is supplemented by a discrepancy between the intended and actual goals of diagnosis and treatment. Declaring the leading role of pathogens in the development and severity of AP, the assessment of the condition of patients and their further observation within the existing concept of views are based on signs and tests that are due to the pathogenesis of the disease and do not depend directly on its etiology. For example, a cardinal diagnostic test such as an x-ray reflects inflammatory changes in the lung tissue and their dynamics, without having absolute etiological signs. Changes in the parameters of respiration, gas exchange and hemodynamics are the result of impaired lung function as a result of inflammation, regardless of its pathogen.

Absolute hypodensity sign by noncontrast computed tomography as a reliable predictor for early hematoma expansion

ObjectiveEarly hematoma expansion in intracerebral hemorrhage (ICH) patients is strongly associated with poor outcome and potentially preventable if high-risk patients are timely identified. We aimed to investigate whether a novel sign detected by noncontrast computed tomography (NCCT) named absolute hypodensity sign (AHS) was an appropriate candidate for hematoma expansion prediction. Materials and MethodsSpontaneous ICH patients all underwent baseline NCCT scan within 6 h after ICH onset and the follow-up NCCT scan within 24 h after initial CT scan. AHS was defined as a hypoattenuating area with a distinct margin within the hematoma, the minimal density of which should be ≤30 Hounsfeld units. We used univariate and multivariate logistic regression analyses for determining the association between hematoma expansion and the presence of AHS. We also compared the diagnostic efficacy with blend sign and black hole sign. ResultsA total of 348 ICH patients were included, 87 of which were found hematoma expansion. AHS was positive in 76 patients (21.8%) (κ = 0.88 for interrater reliability) and 63.2% of the patients with hematoma expansion were observed AHS. The multivariate logistic regression analysis demonstrated AHS was an independent predictor for hematoma expansion (odds ratio: 33.454, 95% confidence interval: 13.628–82.126, P < 0.001). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of AHS for hematoma expansion prediction were 63.2%, 92.0%, 72.4%, 88.2%, 84.8%, respectively, which were higher than blend sign and black hole sign except the specificity of black hole sign. ConclusionOur findings indicate AHS is a reliable predictor for early hematoma expansion due to its feasibility and convenience for clinical practice.

Detection and Classification of Muscle Activation in EMG Data Acquired by Myo Armband

Electromyogram (EMG) signals are signals that contain information about contractions in the muscles. EMG signals are personal and express which muscles contract at what intensity. In detecting these signals, Myo armband has been used frequently in recent years. There are eight EMG sensors, accelerometer sensors and gyroscopes on the Myo armband. These eight EMG sensors settle on different muscles on the arm and measure the contraction intension of the muscles during gesture. In this way, the gesture using the information of which of the eight sensors is contracted can be recognized. Myo armband acquire EMG data with a sampling frequency of 200 Hz. In this study, EMG data was acquired by repeating 10 times 4 different hand gestures by 4 subject by attaching Myo armband to the right forearm. First, a high pass filter was applied to eliminate the noise from the acquired data and then the times when the hand gesture started and ended were determined. The aim of this study is to propose a new method to the literature to find the start and the end times of hand gesture at this point. Five time domain features of the preprocessed EMG signals were extracted. These features were root mean squire (RMS), mean absolute value (MAV), zero crossing (ZC), waveform length (WL) and slope sign change (SSC). Sequential forward selection was made in order to find the most successful feature set among the extracted features. For classification, SVM and KNN algorithms were used. As a result of the study, SVM algorithm with the WL feature gave the best result and 98.75% performance was achieved. The result obtained was compared with the studies in the literature. In addition, other methods in the literature used to find the times when the gesture starts and ends were applied to the dataset used in this study and the results were shown.

Strain reconfigurable spin-wave transport in the lateral system of magnonic stripes

We demonstrate the possibility of controlling dipole spin-wave coupling in the lateral array of ferromagnetic stripes using local strains. Lateral system of magnonic stripes with a piezoelectric layer is fabricated and tested with microwave and Brillouin light scattering spectroscopy. The mechanisms of controlling the dipole coupling of spin waves by elastic strains localized in the region of maximums of the electric field strength are revealed. It is shown that when the absolute value and sign of the electric field are changed, it is possible to effectively control the properties of the propagating spin waves and the spatial distribution of the intensity of the dynamic magnetization in the lateral structure. We emphasize that the spin-wave intermodal coupling can be tuned with the external electric field in the adjacent magnonic stripes. Formation of channel for spin-wave edge mode propagation is observed experimentally in the vicinity of the gap between adjacent stripes. Effective control of the spin-wave coupling by changing the gap is demonstrated. From an applied point of view, the results can be used in information processing devices with electric and magnetic field tunability.

High-Resolution ENDOR Spectroscopy Combined with Quantum Chemical Calculations Reveals the Structure of Nitrogenase Janus Intermediate E4(4H).

We have shown that the key state in N2 reduction to two NH3 molecules by the enzyme nitrogenase is E4(4H), the "Janus" intermediate, which has accumulated four [e-/H+] and is poised to undergo reductive elimination of H2 coupled to N2 binding and activation. Initial 1H and 95Mo ENDOR studies of freeze-trapped E4(4H) revealed that the catalytic multimetallic cluster (FeMo-co) binds two Fe-bridging hydrides, [Fe-H-Fe]. However, the analysis failed to provide a satisfactory picture of the relative spatial relationships of the two [Fe-H-Fe]. Our recent density functional theory (DFT) study yielded a lowest-energy form, denoted as E4(4H)(a), with two parallel Fe-H-Fe planes bridging pairs of "anchor" Fe on the Fe2,3,6,7 face of FeMo-co. However, the relative energies of structures E4(4H)(b), with one bridging and one terminal hydride, and E4(4H)(c), with one pair of anchor Fe supporting two bridging hydrides, were not beyond the uncertainties in the calculation. Moreover, a structure of V-dependent nitrogenase resulted in a proposed structure analogous to E4(4H)(c), and additional structures have been proposed in the DFT studies of others. To resolve the nature of hydride binding to the Janus intermediate, we performed exhaustive, high-resolution CW-stochastic 1H-ENDOR experiments using improved instrumentation, Mims 2H ENDOR, and a recently developed pulsed-ENDOR protocol ("PESTRE") to obtain absolute hyperfine interaction signs. These measurements are coupled to DFT structural models through an analytical point-dipole Hamiltonian for the hydride electron-nuclear dipolar coupling to its "anchoring" Fe ions, an approach that overcomes limitations inherent in both experimental interpretation and computational accuracy. The result is the freeze-trapped, lowest-energy Janus intermediate structure, E4(4H)(a).

Synthesis of Arts in Serge Diaghilev`s Seasons as a Dialogue of Cultures: the Post-reality of Interpretative Paradigm

The article analyzes the understanding of culture through the globalization of cultural potential in principle and a peculiar synthesis, synchresis and intentional processes that form the universal cultural and historical potential, which needs its interpretation in art. In this context, the experience of S. Diaghilev’s seasons shows the very essence of culture as a dynamic integrity. This image was high not only at the beginning of the 20th century, but also still remains relevant today. The aim of the study is to determine the interaction between the pieces of art, which were played in S. Diaghilev’s seasons as a synthesis of arts and dialogue of cultures. The study uses the intentional method in order to identify and research the acts of consciousness that are involved in the consideration of S. Diaghilev’s reality. In addition, comparative and systematic approaches are used. A comparative approach allows comparing various cultural phenomena, styles and genres, types of arts in the context of their occurrence. The system and polysystemic approaches allows determining the principles of holism (system dominant) and anti-holism (the dominant of the system part) as an opportunity to find phenomena of cultural practices in various system configurations: social, ideological, advertising, virtual, etc. The scientific novelty lies in the fact that in S. Diaghilev’s season the end of the twentieth century - the beginning of the twenty-first century are defined in the context of a certain cultural auto-reflection, as there were events that are now referred to as global. At that time, they were defined as urbanizing, transformative, and integrative. The great sense in this context is that the creative groups were formed on the edge of cultural institutions that formed the newest reality of cultural development. Conclusions. It is proved that the synthesis of arts is impossible without dialogue of cultures, and dialogue is impossible without synthesis. Culture is in some way an art that is a culture. This deep identity of art with culture suggests that both are reality, if it is associated with the fine potential (aesthetic, ethical, anthropological, etc.), and is characterized as competence, proficiency, art, creativity, which point to the spiritual flow of the humanity potential as a spiritual measurements in its absolute signs.

A novel feature extraction method for machine learning based on surface electromyography from healthy brain

Feature extraction is one of most important steps in the control of multifunctional prosthesis based on surface electromyography (sEMG) pattern recognition. In this paper, a new sEMG feature extraction method based on muscle active region is proposed. This paper designs an experiment to classify four hand motions using different features. This experiment is used to prove that new features have better classification performance. The experimental results show that the new feature, active muscle regions (AMR), has better classification performance than other traditional features, mean absolute value (MAV), waveform length (WL), zero crossing (ZC) and slope sign changes (SSC). The average classification errors of AMR, MAV, WL, ZC and SSC are 13%, 19%, 26%, 24% and 22%, respectively. The new EMG features are based on the mapping relationship between hand movements and forearm active muscle regions. This mapping relationship has been confirmed in medicine. We obtain the active muscle regions data from the original EMG signal by the new feature extraction algorithm. The results obtained from this algorithm can well represent hand motions. On the other hand, the new feature vector size is much smaller than other features. The new feature can narrow the computational cost. This proves that the AMR can improve sEMG pattern recognition accuracy rate.

A Study of Movement Classification of the Lower Limb Based on up to 4-EMG Channels

The number and position of sEMG electrodes have been studied extensively due to the need to improve the accuracy of the classification they carry out of the intention of movement. Nevertheless, increasing the number of channels used for this classification often increases their processing time as well. This research work contributes with a comparison of the classification accuracy based on the different number of sEMG signal channels (one to four) placed in the right lower limb of healthy subjects. The analysis is performed using Mean Absolute Values, Zero Crossings, Waveform Length, and Slope Sign Changes; these characteristics comprise the feature vector. The algorithm used for the classification is the Support Vector Machine after applying a Principal Component Analysis to the features. The results show that it is possible to reach more than 90% of classification accuracy by using 4 or 3 channels. Moreover, the difference obtained with 500 and 1000 samples, with 2, 3 and 4 channels, is not higher than 5%, which means that increasing the number of channels does not guarantee 100% precision in the classification.

A Numerical Study of the Force Effects of Solar Radiation on Spacecraft Surfaces Considering their Real Geometry

The effect of solar radiation on two typical external surfaces of a spacecraft is studied using numerical simulation by considering real geometry (geometry deviation from the nominal shape). The results of simulation are presented in this paper. Geometry deviations are simulated by two types of regular external heterogeneities. We compare the force and torque characteristics of solar radiation on nonuniform surfaces with similar characteristics for nominal surfaces and we find that the disagreement between them can reach 90% both in absolute value and sign. This means that it is necessary to consider the deviations in geometry from nominal for proper design and operation of spacecraft.

Evidence of depolarization and ellipticity of high harmonics driven by ultrashort bichromatic circularly\xa0polarized fields

High harmonics generated by counter-rotating laser fields at the fundamental and second harmonic frequencies have raised important interest as a table-top source of circularly polarized ultrashort extreme-ultraviolet light. However, this emission has not yet been fully characterized: in particular it was assumed to be fully polarized, leading to an uncertainty on the effective harmonic ellipticity. Here we show, through simulations, that ultrashort driving fields and ultrafast medium ionization lead to a breaking of the dynamical symmetry of the interaction, and consequently to deviations from perfectly circular and fully polarized harmonics, already at the single-atom level. We perform the complete experimental characterization of the polarization state of high harmonics generated along that scheme, giving direct access to the ellipticity absolute value and sign, as well as the degree of polarization of individual harmonic orders. This study allows defining optimal generation conditions of fully circularly polarized harmonics for advanced studies of ultrafast dichroisms.

Is Pseudomeningocele an Absolute Sign of Root Avulsion Brachial Plexus Injury?

The finding of pseudomeningocele from cervical myelogram is widely accepted as a pathognomonic sign for diagnosing root avulsion in brachial plexus injury. In general, motor power in this setting should be absent. However, in clinical practice, we observed that motor power in some patients was still preserved. The objective of this study is to evaluate the accuracy of pseudomeningocele from cervical myelogram for predicting root avulsion in brachial plexus injury. We retrospectively reviewed 201 patients with brachial plexus injury from 2007-2011. Four patients were excluded due to open wound injury. Motor power of the key muscle of each nerve root was evaluated by skilled hand surgeons. All cervical myelogram was interpreted by radiologists. Sensitivities, specificities, positive predictive values and negative predictive values were calculated with 95% confidence interval. Thirty and 29% of pseudomeningocele occurred at C7 and C8 level, respectively. The sensitivity of pseudomeningocele of each root from C5 to T1 was low (range, 10-62%). The specificity was high only at C5 (91%) and T1 (96.2%). Over 20% of patients with pseudomeningocele at C6-8 levels had some motor function. The initial muscle power of these patients was M1 or M2 and 70% of them recovered to at least M3 at the final follow-up. Pseudomeningocele is not an absolute sign for diagnosing of root avulsion in brachial plexus injury due to its high false positive rate when compared with preoperative motor function of each root. Careful examination of the key muscle of each root is extremely crucial to prevent unnecessary operation on that cervical nerve root.

HOW DOES PRE-SERVICE MATHEMATICS TEACHER PROVE THE LIMIT OF A FUNCTION BY FORMAL DEFINITION?

The purpose of this study was to investigate the flow of thought of the pre-service mathematics teachers through the answers of a function limit evaluation by formal definition. This study used a qualitative approach with descriptive method. The research subjects were the students of mathematics education department of Universitas Serang Raya, Indonesia. After analyzing the students’ written answers, we interviewed the subjects to get further explanation on their strategies and common mistakes. This study found that based on the students’ results in the function limit evaluation by formal definition, there were common strategies, i.e. (1) preparing the proof and (2) proving. The stage of preparing the proof consisted of (1) determining delta value by the final statement of formal definition, (2) substituting the given f(x) and L process, (3) simplifying value in the absolute sign, (4) solving the inequality, and (5) finding the delta value. The stage of proving consisted of (1) stating positive epsilon, (2) defining delta, (3) stating positive delta, (4) substituting the constants and delta values in the initial statement of formal definition, and (5) solving the inequality to create the final inequality statement of the formal definition.

Extreme malleability of preferences: Absolute preference sign changes under uncertainty

AbstractMalleability of preferences is a central tenet of behavioral decision theory. How malleable preferences really are, however, is a topic of debate. Do preference reversals imply preference construction? We argue that to claim preferences are construed, a demonstration of more extreme preference malleability than simple preference reversals is required: absolute preference sign changes within participants. If respondents value a prospect positively in 1 condition but negatively in a different condition, preferences cannot be considered stable. Such absolute preference sign changes are possible under uncertainty. In 2 incentive‐compatible experiments, we found participants were willing to pay to take part in a gamble and also demanded to be compensated to take part in a subsequent gamble with identical outcomes and probabilities. Such absolute preference sign changes within participants led to simultaneous risk aversion and risk seeking for the same risky prospect, suggesting that, at least in the domain of risky decisions, consumers' preferences are indeed malleable and construed.

Subject-independent hand gesture recognition using normalization and machine learning algorithms

Hand gestures can be recognized using the upper limb’s electromyography (EMG) that measures the electrical activity of the skeletal muscles. However, generalization of muscle activities for a particular hand gesture is challenging due to between-subject variations in EMG signals. To improve the gesture recognition accuracy without training the machine learning algorithm subject specifically, the time-domain EMG features are normalized to the area under the averaged root mean square curve (AUC-RMS). Results are compared with both original EMG features and EMG features extracted from the signals that are normalized to the maximum peak value. Ten male adult subjects age ranging 20–37 years performed three hand gestures including fist, wave in, and wave out for ten to twelve times. The four basic time domain features including mean absolute value, zero crossing, waveform length, and slope sign change were extracted from the active EMG signals of each channel. Five machine learning algorithms, namely, k-Nearest Neighbor (kNN), Discriminant Analysis (DA), Naïve Bayes (NB), Random Forest (RF), and Support Vector Machine (SVM) were used to classify the three different hand gestures. The results showed that the performance metrics such as accuracy, F1-score, Matthew correlation coefficient, and Kappa score were improved when using the both normalization methods compared to the original EMG features. However, normalization to the AUC-RMS value resulted in substantially more accurate gesture recognition compared to features extracted from signal normalized to maximum peak value using kNN, NB, and RF (p < 0.05). The developed approach of classifying different hand gestures will be useful in human-computer interaction as well as in controlling devices including prosthesis, virtual objects, and wheelchair.

Multivariate Return Decomposition: Theory and Implications

ABSTRACTIn this paper, we propose a model based on multivariate decomposition of multiplicative – absolute values and signs – components of asset returns. In the m-variate case, the marginals for the m absolute values and the binary marginals for the m directions are linked through a 2m-dimensional copula. The approach is detailed in the case of a bivariate decomposition. We outline the construction of the likelihood function and the computation of different conditional measures. The finite-sample properties of the maximum likelihood estimator are assessed by simulation. An application to predicting bond returns illustrates the usefulness of the proposed method.

Technical note: Fu–Liou–Gu and Corti–Peter model performance evaluation for radiative retrievals from cirrus clouds

Abstract. We compare, for the first time, the performance of a simplified atmospheric radiative transfer algorithm package, the Corti–Peter (CP) model, versus the more complex Fu–Liou–Gu (FLG) model, for resolving top-of-the-atmosphere radiative forcing characteristics from single-layer cirrus clouds obtained from the NASA Micro-Pulse Lidar Network database in 2010 and 2011 at Singapore and in Greenbelt, Maryland, USA, in 2012. Specifically, CP simplifies calculation of both clear-sky longwave and shortwave radiation through regression analysis applied to radiative calculations, which contributes significantly to differences between the two. The results of the intercomparison show that differences in annual net top-of-the-atmosphere (TOA) cloud radiative forcing can reach 65 %. This is particularly true when land surface temperatures are warmer than 288 K, where the CP regression analysis becomes less accurate. CP proves useful for first-order estimates of TOA cirrus cloud forcing, but may not be suitable for quantitative accuracy, including the absolute sign of cirrus cloud daytime TOA forcing that can readily oscillate around zero globally.

1D and 2D diffusion pore imaging on a preclinical MR system using adaptive rephasing: Feasibility and pulse sequence comparison

Diffusion pore imaging (DPI) has recently been proposed as a means to acquire images of the average pore shape in an image voxel or region of interest. The highly asymmetric gradient scheme of its sequence makes it substantially demanding in terms of the hardware of the NMR system. The aim of this work is to show the feasibility of DPI on a preclinical 9.4T animal scanner. Using water-filled capillaries with an inner radius of 10μm, four different variants of the DPI sequence were compared in 1D and 2D measurements. The pulse sequences applied cover the basic implementation using one long and one temporally narrow gradient pulse, a CPMG-like variant with multiple refocusing RF pulses as well as two variants splitting up the long gradient and distributing it on either side of the refocusing pulse. Substantial differences between the methods were found in terms of signal-to-noise ratio, contrast, blurring, deviations from the expected results and sensitivity to gradient imperfections. Each of the tested sequences was found to produce characteristic gradient mismatches dependent on the absolute value, direction and sign of the applied q-value. Read gradients were applied to compensate these mismatches translating them into time shifts, which enabled 1D DPI yielding capillary radius estimations within the tolerances specified by the manufacturer. For a successful DPI application in 2D, a novel gradient amplitude adaption scheme was implemented to correct for the occurring time shifts. Using this adaption, higher conformity to the expected pore shape, reduced blurring and enhanced contrast were achieved. Images of the phantom’s pore shape could be acquired with a nominal resolution of 2.2μm.