Articles de revues sur le sujet « D-separation criterion »

This article proposes the usage of the d-separation criterion in Markov Boundary Discovery algorithms, instead of or alongside the statistical tests of conditional independence these algorithms usually rely on. This is a methodological improvement applicable when designing, studying or improving such algorithms, but it is not applicable for productive use, because computing the d-separation criterion requires complete knowledge of a Bayesian network. Yet Bayesian networks can be made available to the algorithms when studied in controlled conditions. This approach has the effect of removing sources of suboptimal behavior, allowing the algorithms to perform at their theoretical best and providing insights about their properties. The article also discusses an extension of this approach, namely to use d-separation as a complement to the usual statistical tests performed on synthetic datasets in order to ascertain the overall accuracy of the tests chosen by the algorithms, for further insights into their behavior. To exemplify these two approaches, two Markov Boundary Discovery algorithms were used, namely the Incremental Association Markov Blanket algorithm and the Iterative Parent–Child-Based Search of Markov Blanket algorithm. Firstly, these algorithms were configured to use d-separation alone as their conditional independence test, computed on known Bayesian networks. Subsequently, the algorithms were configured to use the statistical G-test complemented by d-separation to evaluate their behavior on synthetic data.

Corrosion in deadlegs occurs as a result of water separation due to the very low flow velocity. This work aims to investigate the effect of geometry and orientation on flow field and oil/water separation in deadlegs in an attempt for the development of a deadleg criterion. The investigation is based on the solution of the mass and momentum conservation equations of an oil/water mixture together with the volume fraction equation for the secondary phase. Results are obtained for two main deadleg orientations and for different lengths of the deadleg in each orientation. The considered fluid mixture contains 90% oil and 10% water (by volume). The deadleg length to diameter ratio (L/D) ranges from 1 to 9. The results show that the size of the stagnant fluid region increases with the increase of L/D. For the case of a vertical deadleg, it is found that the region of the deadleg close to the header is characterized by circulating vortical motions for a length l≈3 D while the remaining part of the deadleg occupied by a stagnant fluid. In the case of a horizontal deadleg, the region of circulating flow extends to 3–5 D. The results also indicated that the water volumetric concentration increases with the increase of L/D and is influenced by the deadleg orientation. The streamline patterns for a number of cases were obtained from flow visualization experiments (using 200 mW Argon laser) with the objective of validating the computational model.

Pearl and Dechter (1996) claimed that the d-separation criterion for conditional independence in acyclic causal networks also applies to networks of discrete variables that have feedback cycles, provided that the variables of the system are uniquely determined by the random disturbances. I show by example that this is not true in general. Some condition stronger than uniqueness is needed, such as the existence of a causal dynamics guaranteed to lead to the unique solution.

This paper describes laboratory experiments on the flow over a three-dimensional hill in a rotating fluid. The experiments were carried out in towing tanks, placed on rotating tables. Rotation is found to have a strong influence on the separation behind the hill. The topology of the separation is found to be the same for all the flows examined. The Rossby number R in the experiments is of order 1, the maximum value being 6. The separated flow is dominated by a single trailing vortex. In the majority of cases the surface stress field has a single separation line and there are no singular points. In a few experiments at the highest Rossby numbers the observations suggest more complex stress fields but the results are inconclusive.A criterion for flow separation is sought. For values of D/L > 1, where D is the depth of the flow and L the lengthscale of the hill, separation is found to be primarily dependent on R. At sufficiently small values of R separation is suppressed and the flow remains fully attached.Linear theory is found to give a good estimate for the critical value of R for flow separation. For hills with a moderate slope (slope ≤ 1) this critical value is around 1, decreasing with increasing slope. It is postulated that the existence of a single dominant trailing vortex is due to the uplifting and subsequent turning of transverse vorticity generated by surface pressure forces upstream of the separation line.

The shifted pseudoisotropic multivariate distributions are shown to satisfy Ross’ stochastic dominance criterion for two-fund monetary separation in the case with risk-free investment opportunity and furthermore to admit the Capital Asset Pricing Model under an embedding inLαcondition if1<α≤2, with the betas given in an explicit form. For theα-symmetric subclass, the market without risk-free investment opportunity admits2d-fund separation ifα=1+1/(2d-1),d∈N, generalizing the classical elliptical cased=1, and we also give the precise number of funds needed, from which it follows that we cannot, except degenerate cases, have a CAPM without risk-free opportunity. For the symmetric stable subclass, the index of stability is only of secondary interest, and several common restrictions in terms of that index can be weakened by replacing it by the (no smaller) indices of symmetry/of embedding. Finally, dynamic models with intermediate consumption inherit the separation properties of the static models.

Multisensory processing is of vital importance for survival in the external world. Brain circuits can both integrate and separate visual and vestibular senses to infer self-motion and the motion of other objects. However, it is largely debated how multisensory brain regions process such multisensory information and whether they follow the Bayesian strategy in this process. Here, we combined macaque physiological recordings in the dorsal medial superior temporal area (MST-d) with modeling of synaptically coupled multilayer continuous attractor neural networks (CANNs) to study the underlying neuronal circuit mechanisms. In contrast to previous theoretical studies that focused on unisensory direction preference, our analysis showed that synaptic coupling induced cooperation and competition in the multisensory circuit and caused single MST-d neurons to switch between sensory integration or separation modes based on the fixed-criterion causal strategy, which is determined by the synaptic coupling strength. Furthermore, the prior of sensory reliability was represented by pooling diversified criteria at the MST-d population level, and the Bayesian strategy was achieved in downstream neurons whose causal inference flexibly changed with the prior. The CANN model also showed that synaptic input balance is the dynamic origin of neuronal direction preference formation and further explained the misalignment between direction preference and inference observed in previous studies. This work provides a computational framework for a new brain-inspired algorithm underlying multisensory computation.

AbstractWe investigate global instability and vortex shedding in the separated laminar boundary layer beneath internal solitary waves (ISWs) of depression in a two-layer stratified fluid by performing high-resolution two-dimensional direct numerical simulations. The simulations were conducted with waves propagating over a flat bottom and shoaling over relatively mild $(S= 0. 05)$ and steep $(S= 0. 1)$ slopes. Over a flat bottom, the potential for vortex shedding is shown to be directly dependent on wave amplitude, for a particular stratification, owing to increase of the adverse pressure gradient ($\mathrm{d} P/ \mathrm{d} x\gt 0$ for leftward propagating waves) beneath the trailing edge of larger amplitude waves. The generated eddies can ascend from the bottom boundary to as high as 33 % of the total depth in two-dimensional simulations. Over sloping boundaries, global instability occurs beneath all waves as they steepen. For the slopes considered, vortex shedding begins before wave breaking and the vortices, shed from the bottom boundary, can reach the pycnocline, modifying the wave breaking mechanism. Combining the results over flat and sloping boundaries, a unified criterion for vortex shedding in arbitrary two-layer continuous stratifications is proposed, which depends on the momentum-thickness Reynolds number and the non-dimensionalized ISW-induced pressure gradient at the point of separation. The criterion is generalized to a form that may be readily computed from field data and compared to published laboratory experiments and field observations. During vortex shedding events, the bed shear stress, vertical velocity and near-bed Reynolds stress were elevated, in agreement with laboratory observations during re-suspension events, indicating that boundary layer instability is an important mechanism leading to sediment re-suspension.

The onset of boundary layer separation in the unbounded flow around a circular cylinder is determined directly with a numerical experiment with accuracy to the second decimal point of the Reynolds number, Re. The governing equations are the steady state, two dimensional Navier–Stokes equations, which are solved with Galerkin finite elements. A new criterion, the entrance ratio [Formula: see text] with D the diameter of the cylinder and L the entrance length of the domain, is introduced in addition to the traditional blockage ratio; the aim is to establish conditions for unbounded flow in both flow directions. A hypothesis is formulated and verified for the onset of separation leading to the conclusion that this flow undergoes a supercritical pitchfork bifurcation with respect to fixed points on the boundary. Results are presented for various blockage ratios, B, in the range [Formula: see text] and constant entrance ratio [Formula: see text] until asymptotic behavior is observed for the onset of separation in the Reynolds number, in the angle and the length of the smallest eddy. Onset of separation occurs in the region [Formula: see text]. The bifurcation diagram of the flow is calculated. Streamlines of the flow domain before and after the bifurcation point are shown, including images of the smallest possible eddies. In addition, coefficients of base suction and total drag are computed and shown in the regime [Formula: see text]. The results are compared with available laboratory and numerical measurements.

We report wall-resolved large-eddy simulation (LES) of flow over a grooved cylinder up to the transcritical regime. The stretched-vortex subgrid-scale model is embedded in a general fourth-order finite-difference code discretization on a curvilinear mesh. In the present study $32$ grooves are equally distributed around the circumference of the cylinder, each of sinusoidal shape with height $\unicode[STIX]{x1D716}$, invariant in the spanwise direction. Based on the two parameters, $\unicode[STIX]{x1D716}/D$ and the Reynolds number $Re_{D}=U_{\infty }D/\unicode[STIX]{x1D708}$ where $U_{\infty }$ is the free-stream velocity, $D$ the diameter of the cylinder and $\unicode[STIX]{x1D708}$ the kinematic viscosity, two main sets of simulations are described. The first set varies $\unicode[STIX]{x1D716}/D$ from $0$ to $1/32$ while fixing $Re_{D}=3.9\times 10^{3}$. We study the flow deviation from the smooth-cylinder case, with emphasis on several important statistics such as the length of the mean-flow recirculation bubble $L_{B}$, the pressure coefficient $C_{p}$, the skin-friction coefficient $C_{f\unicode[STIX]{x1D703}}$ and the non-dimensional pressure gradient parameter $\unicode[STIX]{x1D6FD}$. It is found that, with increasing $\unicode[STIX]{x1D716}/D$ at fixed $Re_{D}$, some properties of the mean flow behave somewhat similarly to changes in the smooth-cylinder flow when $Re_{D}$ is increased. This includes shrinking $L_{B}$ and nearly constant minimum pressure coefficient. In contrast, while the non-dimensional pressure gradient parameter $\unicode[STIX]{x1D6FD}$ remains nearly constant for the front part of the smooth cylinder flow, $\unicode[STIX]{x1D6FD}$ shows an oscillatory variation for the grooved-cylinder case. The second main set of LES varies $Re_{D}$ from $3.9\times 10^{3}$ to $6\times 10^{4}$ with fixed $\unicode[STIX]{x1D716}/D=1/32$. It is found that this $Re_{D}$ range spans the subcritical and supercritical regimes and reaches the beginning of the transcritical flow regime. Mean-flow properties are diagnosed and compared with available experimental data including $C_{p}$ and the drag coefficient $C_{D}$. The timewise variation of the lift and drag coefficients are also studied to elucidate the transition among three regimes. Instantaneous images of the surface, skin-friction vector field and also of the three-dimensional Q-criterion field are utilized to further understand the dynamics of the near-surface flow structures and vortex shedding. Comparison of the grooved-cylinder flow with the equivalent flow over a smooth-wall cylinder shows structural similarities but significant differences. Both flows exhibit a clear common signature, which is the formation of mean-flow secondary separation bubbles that transform to other local flow features upstream of the main separation region (prior separation bubbles) as $Re_{D}$ is increased through the respective drag crises. Based on these similarities it is hypothesized that the drag crises known to occur for flow past a cylinder with different surface topographies is the result of a change in the global flow state generated by an interaction of primary flow separation with secondary flow recirculating motions that manifest as a mean-flow secondary bubble. For the smooth-wall flow this is accompanied by local boundary-layer flow transition to turbulence and a strong drag crisis, while for the grooved-cylinder case the flow remains laminar but unsteady through its drag crisis and into the early transcritical flow range.

Acetylcholinesterase has been isolated from bovine erythrocyte membranes by affinity chromatography using a m-trimethylammonium ligand. The purified enzyme had hydrophobic properties by the criterion of phase partitioning into Triton X-114. The activity of the hydrophobic enzyme was seen as a slow-moving band in nondenaturing polyacrylamide gels. After treatment with phosphatidylinositol-specific phospholipase C, another form of active enzyme was produced that migrated more rapidly toward the anode in these gels. This form of the enzyme partitioned into the aqueous phase in Triton X-114 phase separation experiments and was therefore hydrophilic. The hydrophobic form bound to concanavalin A in the absence of Triton X-100. As this binding was partially prevented by detergent, but not by α-methyl mannoside, D-glucose, or myo-inositol, it is in part hydrophobic. Erythrocyte cell membranes showed acetylcholinesterase activity present as a major form, which was hydrophobic by Triton X-114 phase separation and in nondenaturing gel electrophoresis moved at the same rate as the purified enzyme. In the membrane the enzyme was more thermostable than when purified in detergent. The hydrophobic enzyme isolated, therefore, represents a native form of the acetylcholinesterase present in the bovine erythrocyte cell membrane, but in isolation its stability becomes dependent on amphiphile concentration. Its hydrophobic properties and lectin binding are attributable to the association with the protein of a lipid with the characteristics of a phosphatidylinositol.Key words: acetylcholinesterase, bovine erythrocytes, phosphatidylinositol-specific phospholipase C, phase separation, affinity chromatography.

Erosion geometry effects on the mode I stress intensity factor (SIF) for a crack emanating from an erosion’s deepest point in a multiply eroded, autofrettaged, pressurized, thick-walled cylinder are investigated. The problem is solved via the finite element method (FEM). Autofrettage, based on von Mises yield criterion, is simulated by thermal loading and SIFs are determined by the nodal displacement method. SIFs are evaluated for a variety of relative crack depths, a0/t=0.01-0.40, and crack ellipticities, a0/c=0.5-1.5, emanating from the tip of erosions of different geometry, namely: (a) semi-circular erosions of relative depths of 1–10 percent of the cylinder’s wall thickness, t; (b) arc erosions for several dimensionless radii of curvature, r′/t=0.05-0.4; and (c) semi-elliptical erosions with ellipticities of d/h=0.3-2.0. The erosion separation angle, α, is taken from 7 to 360 deg. Deep cracks are found to be almost unaffected by the erosion. The effective SIF for relatively short cracks is enhanced by the presence, separation distance and geometry of the erosion, as well as the crack geometry, and may result in a significant decrease in the vessel’s fatigue life of up to an order of magnitude.

An experimental study of bluff bodies in confinement is presented. Two Reynolds matched rigs (pipe diameters: $D=40~\text{mm}$ and $D=194~\text{mm}$) are used to derive a picture of the flow topology of the primary-shedding mode (Kármán vortex, mode-I). Confined bluff bodies create an additional spectral mode (mode-II). This is caused by the close coupling of the shedder blockage and the wall and is unique to the confined bluff-body problem. Under certain conditions, modes-I and II can interact, resulting in a lock-on, wherein the modes cease to exist at independent frequencies. The topological effects of mode interaction are demonstrated using flow visualisation. Furthermore, the scaling of mode-II is explored. The two experimental facilities span Reynolds numbers (based on the shedder diameter, $d$) $10^{4}<Re_{d}<10^{5}$ and bulk Mach numbers $0.02<M_{b}<0.4$. Bluff bodies with a constant blockage ratio ($d/D$), forebody shape and various splitter-plate lengths ($l$) and thicknesses ($t$) are used. Results indicate that the flow topology changes substantially between short ($l<d$) and long ($l>d$) tailed geometries. Surface flow visualisation indicates that the primary vortex becomes anchored on the tail when $l\gtrsim 3h$ ($2h=d-t$). This criterion prohibits the development of such a topology for short-tailed geometries. When mode interaction occurs, which it does exclusively in long-tailed cases, the tail-anchored vortex pattern is disrupted. The onset of mode-II occurs at approximately the same Reynolds number in both rigs, although the associated dimensionless frequency is principally a function of Mach number. Accordingly, mode interaction is avoided in the larger-scale rig, due to the increased separation of the modal frequencies.

Multidimensional public key cryptography is a candidate for post-quantum cryptography, and it makes it possible to generate particularly short signatures and quick verification. The Rainbow signature scheme proposed by J. Dean and D. Schmidt is such a multidimensional cryptosystem and it is considered to be protected against all known attacks. The need for research on Rainbow ES is justified by the fact that there is a need to develop and adopt a post-quantum national securities standard, and that in the process of the US NIST competition on the mathematical basis of cryptographic transformation method Rainbow, promising results. Therefore, it is considered important to take them into account and use them in Ukraine. The Rainbow signature scheme can be implemented simply and efficiently using linear algebra methods over a small finite field and, in particular, creates shorter signatures than those used in RSA and other post-quantum signatures [1]. In the 2nd round of NIST PQC, protected sets of Rainbow parameters are offered and several attacks on them are analyzed [1]. When comparing ES, preference is given to ES algorithms that have been selected according to unconditional criteria, as well as those that have better indicators for integral conditional criteria, because such a technique is more rational. In particular, the Rainbow-Band-Separation (RBS) attack [2] is the best known Rainbow attack with a certain set of parameters and is important. The Rainbow-Band-Separation attack restores the Rainbow secret key by solving certain systems of quadratic equations, and its complexity is measured by a well-known measure called the degree of regularity. However, as a rule, the degree of regularity is greater than the degree of solution in experiments, and it is impossible to obtain an accurate estimate. The paper proposes a new indicator of the complexity of the Rainbow-Band-Separation attack using F4 algorithm, which gives a more accurate estimate compared to the indicator that uses the degree of regularity.
 The aim of the work is a comparative analysis of ES based on MQ-transformations on the criterion of stability-complexity and an attempt to understand the security of Rainbow against RBS attack using F4.

Dipole moments were measured for a series of substituted benzenes, biphenyls, terphenyls, C-monoaryl- and C,C′-diaryl-p-carboranes. For the donor–bridge–acceptor systems, Me2N–X–NO2, where X is 1,4-phenylene, biphenyl-4,4′-diyl, terphenyl and 1,4-C6H4-p-CB10H10C-1,4-C6H4, the measured interaction dipole moments are 1.36, 0.74, 0.51 and 0.00 D, respectively. The magnitude of the dipole moment reflects the ability of the bridge to transmit electronic effects between donor and acceptor groups. Thus, whilst the 1,4-phenylene bridges allow moderate electronic interactions between the remote groups, the p-carboranediyl unit is less efficient as a conduit for electronic effects. Averaged dipole moments computed at the DFT (B3LYP/6-31G*) level of theory from two distinct molecular conformers are in good agreement with the experimental values. Examination of the calculated electronic structures provides insight into the nature of the interactions between the donor and acceptor moieties through these 2D and 3D aromatic bridges. The most significant cooperative effect of the bridge on the dipole moment occurs in systems where there is some overlap between the HOMO and LUMO orbitals. This orbital overlap criterion may help to define the difference between “push-pull” systems in which electronic effects are mediated by the bridging moiety, and simpler systems in which the bridge acts as an electronically innocent spacer unit and through-space charge transfer/separation is dominant.

This study aims to obtain interactive and innovative learning media. It is hoped that the use of this media can stimulate the thoughts, feelings, interests and attention of students so that the learning process can run well. This research is a type of development research or known as Research & Development. One of these development models that is in accordance with the development of multimedia-based learning media is the 4-D model. Student learning outcomes after using the Science practicum video based on a scientific approach to substance classification material and its changes in the acid-base video small group test obtained an average score of 91 with the criteria of "Very Good" meaning that the student's grades were better than before. Based on the results of these tests, it can be concluded that the increase in student learning test results in the science practicum video media based on a scientific approach to the topic of substance classification and its changes to the acid-base video from the small group trial increased by 0.70 in the range g ? 0.7, which can be classified as category "High". Meanwhile, student learning outcomes after using the science practicum video based on a scientific approach to the topic of substance classification and its changes in the small group test of the mixed separation video obtained an average score of 77 with the criterion "Good", meaning that the student's grades were better than before. Based on the results of these tests, it can be concluded that the increase in student learning test results in the science practicum video media based on a scientific approach to the topic of substance classification and its changes in the video separation of mixtures from small group trials has an increase of 0.63 included in the range g ? 0.7, which can be classified as category "Medium". Student learning outcomes after using the Science practicum video based on a scientific approach to the topic of substance classification and its changes in the acid-base video field test obtained an average score of 76.36 with the criterion "Good", meaning that the student's score is better than before. The increase in learning outcomes of science practicum video media based on a scientific approach to the topic of substance classification and its changes for acid-base video field tests is calculated using the gain score. The product of the development of science practicum video media based on a scientific approach to the topic of substance classification and its changes is a practicum video media that has been developed by taking into account learning aspects and media aspects as practicum media in learning. The product development research that has been carried out is directed at producing a practicum video media product based on a scientific approach to the topic of substance classification and its changes for seventh grade junior high school students which is effectively used to improve student learning outcomes.
 
 
 

This paper presents a calculation and experimental technique for determining stress intensity factors in an imitation model of a titanium alloy disk. We studied a low-pressure compressor disk of a gas turbine engine (GTE) D-36. During operations, there occur fatigue cracks initiated and developed in the slot fillet under the blade at the place of transition of the bottom to the lateral surface of the inter-groove projection, which lead to a separation of the disk’s part within its rim. The mixed-mode crack growth occured in the compressor disks. Based on the principles of imitation modeling, the geometry and loading condition of the imitation model of the compressor disk was developed. The fatigue test of the imitation model was carried out with a frequency of 5 Hz, at room temperature and with stress ratio Rc = 0.1, by means of a biaxial testing machine. The crack growth was monitored using an optical microscope. The criterion for failure was the condition for reaching a growing crack of the compensation hole. During the test, the positions and sizes of the crack fronts were fixed, which are the basis for the numerical calculation of the fracture resistance parameters. In the order of the numerical studies, six three-dimensional finite element models with different positions and sizes of the crack fronts are considered. The results of the numerical calculations based on the finite element method were used to determine the distributions of elastic and plastic stress intensity factors along each crack front. We demonstrated the advantages of the calculation and experimental methods for solving the problems of interpretation and prediction of the crack growth in the rotating disks of turbomachines using the methods of fracture mechanics.

Abstract. A new methodology for performing long-term source apportionment (SA) using positive matrix factorization (PMF) is presented. The method is implemented within the SoFi Pro software package and uses the multilinear engine (ME-2) as a PMF solver. The technique is applied to a 1-year aerosol chemical speciation monitor (ACSM) dataset from downtown Zurich, Switzerland. The measured organic aerosol mass spectra were analyzed by PMF using a small (14 d) and rolling PMF window to account for the temporal evolution of the sources. The rotational ambiguity is explored and the uncertainties of the PMF solutions were estimated. Factor–tracer correlations for averaged seasonal results from the rolling window analysis are higher than those retrieved from conventional PMF analyses of individual seasons, highlighting the improved performance of the rolling window algorithm for long-term data. In this study four to five factors were tested for every PMF window. Factor profiles for primary organic aerosol from traffic (HOA), cooking (COA) and biomass burning (BBOA) were constrained. Secondary organic aerosol was represented by either the combination of semi-volatile and low-volatility organic aerosol (SV-OOA and LV-OOA, respectively) or by a single OOA when this separation was not robust. This scheme led to roughly 40 000 PMF runs. Full visual inspection of all these PMF runs is unrealistic and is replaced by predefined user-selected criteria, which allow factor sorting and PMF run acceptance/rejection. The selected criteria for traffic (HOA) and BBOA were the correlation with equivalent black carbon from traffic (eBCtr) and the explained variation of m/z 60, respectively. COA was assessed by the prominence of a lunchtime concentration peak within the diurnal cycle. SV-OOA and LV-OOA were evaluated based on the fractions of m/z 43 and 44 in their respective factor profiles. Seasonal pre-tests revealed a non-continuous separation of OOA into SV-OOA and LV-OOA, in particular during the warm seasons. Therefore, a differentiation between four-factor solutions (HOA, COA, BBOA and OOA) and five-factor solutions (HOA, COA, BBOA, SV-OOA and LV-OOA) was also conducted based on the criterion for SV-OOA. HOA and COA contribute between 0.4–0.7 µg m−3 (7.8 %–9.0 %) and 0.7–1.2 µg m−3 (12.2 %–15.7 %) on average throughout the year, respectively. BBOA shows a strong yearly cycle with the lowest mean concentrations in summer (0.6 µg m−3, 12.0 %), slightly higher mean concentrations during spring and fall (1.0 and 1.5 µg m−3, or 15.6 % and 18.6 %, respectively), and the highest mean concentrations during winter (1.9 µg m−3, 25.0 %). In summer, OOA is separated into SV-OOA and LV-OOA, with mean concentrations of 1.4 µg m−3 (26.5 %) and 2.2 µg m−3 (40.3 %), respectively. For the remaining seasons the seasonal concentrations of SV-OOA, LV-OOA and OOA range from 0.3 to 1.1 µg m−3 (3.4 %–15.9 %), from 0.6 to 2.2 µg m−3 (7.7 %–33.7 %) and from 0.9 to 3.1 µg m−3 (13.7 %–39.9 %), respectively. The relative PMF errors modeled for this study for HOA, COA, BBOA, LV-OOA, SV-OOA and OOA are on average ±34 %, ±27 %, ±30 %, ±11 %, ±25 % and ±12 %, respectively.

Calculations (B3LYP/6-31G(d)) have been used to assess the aromaticity of 5-X substituted indenyl (4) and cyclopentadienyl (5) cations with X = O–, NH2, OCH3, CH3, F, H, CN, and N2+. Two criteria were used, the aromatic stabilization energy (ASE), as determined by isodesmic reactions, and bond alternation, as determined from the Julg index (A) on the basis of carbon–carbon bond lengths. Substituent effects on the singlet state of the cyclopentadienyl cations resulted in significant decreases in antiaromatic character for electron-donating groups as indicated by larger A values (A = –0.25 for X = H and +0.26 for X = NH2). These decreases paralleled increases in the C-2—C-3 bond length and good linear correlations were obtained between A vs. the C-2—C-3 bond length and A vs. the ASE. These effects were rationalized by the stabilization by the electron-donating groups of the positive charge at C-5 generated as a consequence of a Jahn–Teller distortion leading to a lowest energy singlet state with a HOMO of a2 symmetry. In contrast, the lowest energy triplet state for each of the substituted cyclopentadienyl cations has little bond alternation (A > 0.9) and, by this criterion, is not significantly antiaromatic. The triplet state is more stable than the singlet state for the unsubstituted case and those with electron-withdrawing groups (ΔEST = –11.3 and –9.3 kcal/mol for X = H and CN, respectively) (1 cal = 4.184 J), but less stable for electron-donating groups (ΔEST = +15.0 kcal/mol for X = NH2). For the indenyl cations 4, the ASE values were almost independent of the substituent and the A values only decreased slightly for electron-donating groups. The A values also indicated that the indenyl cations could be divided into two moieties, an X-substituted pentadienyl cation with considerable delocalization and little bond alternation, and a 2,3-butadiene one with considerable bond alternation. This separation also placed the major portion of the positive charge on the pentadienyl part. The lack of symmetry in the substituted indenyl cations rationalizes the selective reactivity of the 5-methoxy-substituted cation at C-1. Finally, the resonance stabilization energies (RSE) of the substituted cations gave a linear correlation with the RSEs of 4-substituted benzylic cations.Key words: indenyl cations, cyclopentadienyl cations, substituent effects, stabilization energies.

Abstract The goal of this study is to document differences in the convective structure and motion of long-track, severe-wind-producing MCSs from short-track severe-wind-producing MCSs in relation to the mean wind. An ancillary goal is to determine if these differences are large enough that some criterion for MCS motion relative to the mean wind could be used in future definitions of “derechos.” Results confirm past investigations that well-organized MCSs, including those that produce derechos, tend to move faster than the mean wind, exhibiting a significantly larger degree of propagation (component of MCS motion in addition to the component contributed by the mean flow). Furthermore, well-organized systems that produce shorter-track swaths of damaging winds likewise tend to move faster than the mean wind with a significant propagation component along the mean wind. Therefore, propagation in the direction of the mean wind is not necessarily a characteristic that can be used to distinguish derechos from nonderechos. However, there is some indication that long-track damaging wind events that occur without large-scale or persistent bow echoes and mesoscale convective vortices (MCVs) require a strong propagation component along the mean wind direction to become long lived. Overall, however, there does not appear to be enough separation in the motion characteristics among the MCS types to warrant the inclusion of a mean-wind criterion into the definition of a derecho at this time.

Abstract Introduction: Flow cytometry (FCM) as recommended by European LeukemiaNet (ELN), is a co-criterion in MDS diagnostics. The aims of the present study were (1) to test whether the FCM diagnostic parameters have an impact on overall survival (OS); and (2) a computational algorithm could improve the identification of aberrant expression and/or cell population frequencies with prognostic importance. Methods: FCM was performed in bone marrow (BM) of 399 patients cytomorphologically classified as MDS. Cell populations were identified based on ELN recommended 55 parameters (Porwit et al., 2014), including: progenitor cells (PC), granulopoiesis (G), monopoiesis (M), nucleated red cells (NRC) and other cells (e.g. lymphocytes). Reference ranges were based on control BM (C-RR) and a quartile analysis (Q-A), to identify the parameters with an optimum separation of overall survival (OS). OS was assessed following univariate and multivariable Cox proportional hazards regression analysis using log-rank likelihood test: C-RR or Q-A (model A, C) and C-RR or Q-A with adjustment for patients developing acute myeloid leukemia during disease course (model B, D). Multivariate survival analysis, Kaplan Meier curves, and receiver operating characteristic curve (ROC) were used to develop prognostic FCM-scores (FCM-A to D) and tested for their independent prognostic value versus known prognostic parameters (age, sex, IPSS-R) as well as diagnostic FCM-scores (Ogata-, FCSS-, iFS-score). A summary of the analytical pipeline is shown in Figure 1A. Moreover, a sensitivity analysis for TP53 mutation distribution among the scores was performed (n=108) and a reliability analysis exploring the scores distribution among healthy donors (n=77) and MDS (n=399). In addition to expert gating ,T-REX pipeline (Barone, S. et al, 2020) was applied on a subset of patients (n=20) to check the feasibility of using unsupervised machine learning approach in identifying the FCM parameters incorporated in models A-D, and its ability to differentiate between the low (0,1) and high (≥2 ) scored patients. Results: The multivariable regression analysis identified 9 FCM parameters with independent prognostic impact on OS (detailed in Figure 1B). Prognostic FCM-scores based on these independent parameters were calculated for each model and dichotomized into high (≥2) and a low (0-1) scores. Thus, FCM-scores A and B, (reference ranges C-RR), outperformed FCM-scores C and D, (reference ranges Q-A): (FCM-A: HR (95 %CI) 3.20 (2.15 - 4.48); FCM-B: 4.08 (2.54 - 6.55); FCM-C: 2.03 (1.40 - 1.84); FCM-D: 2.30 (1.60 - 3.32)), as well as the diagnostic FCM-scores, as Ogata-score, FCSS and iFS (2.00 (1.29 - 3.11); 1.68 (0.99 - 2.86), 1.56 (0.92 - 2.65)). Interestingly, the new prognostic FCM-scores allowed a better prognostic grading than IPSS-R (HR (95 %CI): 2.37 (1.61-3.49)). Kaplan Meier survival curves stratified by FCM-score A and B showed a highly significant overall survival benefit for patients with a low score (p<.0001) (Figure 1C). Of note, performing ROC analysis, the FCM-A and FCM-B scores are independent of known prognostic variables as age, sex and IPSS-R, Area under the curve (AUC): 0.69, and 0.71 vs. 0.47, 0.46 and 0.62. Finally, we could clearly discriminate two prognostic subgroups within the IPSS-R low risk (IPSS-R<3.0) as well as high risk (IPSS-R≥3.0) patients (p<.0001). The TP53 mutation distribution did not differ among low and high score groups (wtTP53 lowScoreA (48.96%)/high ScoreA (51.04%) vs mTP53 lowScoreA (58.33%)/high ScoreA (41.67%) p>0.054). Healthy donors presented a high proportion of low score distribution (>87%) which differed from the MDS group (HD lowScoreA (90.91%)/high ScoreA (9.09) vs MDS lowScoreA (52.13%)/high ScoreA (47.87%) p<.0001). Additionally the T-REX pipeline was able to identify clear differences in expression of significant parameters between the low and high scoring patients in both model A and B (example of CD33 in Figure 1D). Conclusion: We have generated two novel prognostic scores based on distinct FCM characteristics which could predict overall survival in MDS patients. FCM-scores A and B discriminate MDS patients with better overall survival outperforming IPSS-R as well as Ogata, FCSS and iFS scores. The T-REX machine learning has independently identified the same differences in models A and B, which highlights the potential of unsupervised approaches for future use in diagnostic FCM labs. Figure 1 Figure 1. Disclosures Farzaneh: Autolus: Consultancy, Current equity holder in publicly-traded company. Harrison: Incyte Corporation: Speakers Bureau; Shire: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Promedior: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sierra Oncology: Honoraria; Gilead Sciences: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AOP Orphan Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Geron: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Keros: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Galacteo: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; CTI BioPharma: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Constellation Pharmaceuticals: Research Funding. Platzbecker: Celgene/BMS: Honoraria; Geron: Honoraria; Janssen: Honoraria; Novartis: Honoraria; Takeda: Honoraria; AbbVie: Honoraria. Kordasti: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Alexion: Honoraria; Beckman Coulter: Honoraria.

This research evaluated the effectiveness and feasibility of two-phase (separation acid and methanogenic phases) anaerobic digestion of simulated sewage sludge using a UASB-UASB (upflow anaerobic sludge blanket) process. Predictive models of chemical oxygen demand (COD) (soluble) removal efficiency and CH4 gas production during loading maximization and the recovery (after failure) period were made. The optimum hydraulic retention time (HRT) for the A-UASB was about 1.0 d; for the M-UASB system, two different optimum HRTs were evident, depending on the operational mode. When the UASB-UASB system was run under the maximum loading possible, the best HRT in the M-UASB was about 2.0 d, to achieve high COD removal and concurrent optimum CH4 production; after deliberate overloading, to induce failure, and subsequent system recovery, the predicted optimum HRT in the methane unit was about 2.7 d, to achieve concurrent adequate CH4 production and COD removal. There also appeared to be a restructuring of the bacterial community inside the M-UASB, during the recovery period. For overall design purposes, optimum operating HRTs of 1 and 2 d, with an internal recycle rate of 1.6 and 2.5 times the influent flow rate, are recommended for A- and M-UASBs, respectively; a conservative organic loading rate of 19 kg COD (total)/(m3∙d) is suggested. Finally, the optimum HRTA-UASB/HRTM-UASB ratio was found to be about 0.63 and HRTA-UASB/HRTsystem was 0.38, which are within the boundaries of this research project. Key words: anaerobic sludge treatment, design criteria, optimum system loading capacity, two-phase anaerobic stabilization, upflow anaerobic sludge blanket.

This paper used large deformation finite element theory, updated Lagrangian formulation, finite difference method, and incremental theory to develop a three-dimensional thermo-elastic-plastic simulation model for a tool with chip breaker. Both the critical strain energy density theory and the tool feed geometrical location were introduced as the chip separation criterion for cutting. The algorithm of tool movement geometrical limitations was used to examine and correctly the node so as to conform to real cutting conditions. In this model, the tool moved step by step in the simulation, which ran from the initial contact between tool and workpiece to the formation of steady cutting force. Finally, the numerical simulation model proposed in this paper was used to analyze the changes in workpiece and chip shapes, stress, strain rate, residual stress, temperature and cutting force of mild steel workpiece under different chip breaker lengths. The results were also compared with those from tools without chip breaker. The findings indicate that the chip breaker length affects the shorter the chip breaker length, the better the effects of chip breaker, and the lower the values of the aforementioned physical properties.

This paper presents a comparative performance study of single-stage desalination processes with major configurations of membrane distillation (MD) modules. MD modules covered in this study are (a) direct contact MD (DCMD), (b) vacuum MD (VMD), (c) sweeping gas MD (SGMD), and (d) air gap MD (AGMD). MD-based desalination processes are simulated with rigorous theoretical MD models supported by molecular thermodynamic property models for the accurate calculation of performance metrics. The performance metrics considered in MD systems are permeate flux and energy efficiency, i.e., gained output ratio (GOR). A general criterion is established to determine the critical length of these four MDs (at fixed width) for the feasible operation of desalination in a wide range of feed salinities. The length of DCMD and VMD is restricted by the feed salinity and permeate flux, respectively, while relatively large AGMD and SGMD are allowed. The sensitivity of GOR flux with respect to permeate conditions is investigated for different MD configurations. AGMD outperforms other configurations in terms of energy efficiency, while VMD reveals the highest permeate production. With larger MD modules, utilization of thermal energy supplied by the hot feed for evaporation is in the order of VMD > AGMD > SGMD > DCMD. Simulation results highlight that energy efficiency of the overall desalination process relies on the efficient recovery of spent for evaporation, suggesting potential improvement in energy efficiency for VMD-based desalination.

Summary Continuing reservoir management at mature stages often concentrates on delineating pockets of remaining mobile oil. This is becoming a major task for reservoir geologists and petrophysicists. Many old fields are coming up for reactivation as investment opportunities and there is an overall expectation that modern techniques can lead to additional recovery of between 10 and 20%. In this article we will discuss the screening criteria related to reservoir architecture, accumulation condition and production history. The mobile oil remaining can be found in a number of predictable locations in reservoirs depending on their structural style and facies. Attic oil along faults is perhaps the most simple configuration but sizeable volumes of remaining oil can also occur as a function of reservoir stratification and lateral discontinuity. A systematic overview of the different play types has been compiled based on structural or stratigraphic lateral continuity and vertical reservoir connectivity. Screening criteria have been derived on the basis of field examples and models for four play types. The screening criteria specify minimum conditions which may lead to economic re-development with horizontal sidetracks from existing wells. In addition recommendations are given with respect to data gathering to confirm the presence of economically viable targets. Introduction Numerous oil fields that have been in production for many years are currently being reviewed to evaluate options for increasing their ultimate recovery. The task involves determination of the volume and location of remaining mobile oil and subsequently the technical and economic assessment of methods to recover this oil. The first part of this task is often difficult because of the poor quality of the data often associated with old fields. Nevertheless, certain basic data are usually available and the purpose of this article is to provide first round screening criteria based on these data in order to select those reservoirs for which re-development schemes are more likely to be economical. For the reservoirs selected, further study and some additional data acquisition will be warranted. The data that may be expected to be present consist of well logs, limited core measurements, basic facies descriptions, original oil-in-place and cumulative production figures, structure maps and well positions. Having access to well completion data is also essential. Individual well performance data are often difficult to obtain. The proposed screening scheme is based on a classification of the types of remaining oil configurations. Once such a potential oil pocket has been recognized, an attempt is made to assess its economic value by estimating a number of parameters with a limited degree of accuracy. Dip, original accumulation conditions, bedding thickness, reservoir profile, porosity distribution and original oil saturation can often be determined satisfactorily. More detailed reservoir architecture and particularly permeability distributions are more difficult to obtain. The classification scheme for mobile remaining oil pockets consists of a division into reservoirs with either high or low vertical permeability/connectivity and a further subdivision into types with a high and low horizontal connectivity. In this article four major types of mobile remaining oil configurations, representing the four combinations of high and low vertical and horizontal conductivity, are discussed. The screening criteria presented are based on re-development with pairs of horizontal sidetracks from existing wells. A cost of $1,000,000 has been assumed per job for re-entering the hole, milling the casing and drilling and completion of the two sidetracks each of 300 m length. This is based on a variety of cost estimates obtained for land operations. The economic analysis based on this method and on the cost level shows a remarkably large scope for re-development of reservoirs with oil rims, attic oil cases in faulted reservoirs and layer cake reservoirs with beds of contrasting permeability. Fluvial labyrinth type reservoirs1 are much more difficult to re-develop but a number of observations are made to suggest more favorable configurations. Classification of Remaining Mobile Oil Configurations The retention of mobile oil in sufficiently large volumes to allow economic re-development is largely controlled by the presence of heterogeneous pressure distribution and the fluid density and viscosity contrasts. This article is restricted to sandstone reservoirs containing light oil that have been developed with vertical wells and produced under reasonable draw-down conditions. In view of the potential for recompletion and infill drilling, the most important heterogeneities are faults, boundaries of genetic units, large permeability contrasts and baffles to flow such as shale intercalations. Following the subdivisions of clastic reservoirs into layer cake, jigsaw puzzle and labyrinth types one can already predict a number of typical oil displacement patterns. By considering major large scale heterogeneities we can subdivide the reservoirs into types with a high vertical conductivity and those in which stratification and low permeable intercalations result in low vertical conductivity. Next we can make a further distinction between layer cake reservoirs with a high degree of lateral continuity of the beds and reservoirs where the lateral continuity is limited by faults or pinchouts of the sand bodies. This leads to the scheme shown in Fig. 1. To the first category, A, we can attribute oil-rim reservoirs with a high vertical conductivity in which unproducible oil columns are left between the vertical wells as a result of cusping and coning. Poor lateral continuity can be formed by a normal fault (B1) which, even when nonsealing over the juxtaposed reservoir interval, traps oil in the up-thrown block against the caprock in the down-thrown block. Depending on the throw of the fault, the structural dip and the distance of the vertical wells from the fault, a volume of oil will remain when the well water runs out. In labyrinth reservoirs one finds updip stratigraphic traps (B2) especially in low net/gross (N/G) cases. In such cases we also encounter poor sweep efficiency unless the well spacing is small (D). Poor sweep can also result from stratification with large permeability contrast between the beds, particularly when these are separated by impermeable intercalations (C). This situation is quite common in layer cake reservoirs. Even without impermeable separations crossflow may be limited if the vertical permeability of the low permeability layer is low. This situation frequently occurs in fluvial labyrinth reservoirs and this can occur in combination with configurations B1 and D.

AbstractIn this work, we propose a different “surgical modified model” for the construction of counterfactual variables under non-parametric structural equation models. This approach allows the simultaneous representation of counterfactual responses and observed treatment assignment, at least when the intervention is done in one node. Using the new proposal, the d-separation criterion is used to verify conditions related with ignorability or conditional ignorability, and a new proof of the back door theorem is provided under this framework

Abstract Flow around a cube is numerically studied in the laminar vortex shedding regime at Re = 276. The objective is to examine the three dimensional vortex shedding mechanism and understand the temporal behaviour of the wake. Hairpin vortices were identified using λ2 criterion. The wake of the cube sheds paired hairpin vortices which moves in the streamwise direction and attains a constant shape with time. The analysis of separation distance and angular orientation of hairpin vortices for flow around a cube are presented here for the first time in the literature. The separation (d) between the paired hairpin vortices scales as t−1/2. The orientation of hairpin vortices change with time and attain a near-normal orientation with respect to the axial direction. A quasi-periodic nature of the flow has been revealed by the phase plots. The drag and side forces generated due to the flow are studied with pressure force mostly contributing to the drag. One of the side force coefficients dominates owing to the asymmetry of the wake in one plane and symmetry in the other orthogonal streamwise plane. These results clearly bring out the asymmetric nature of flow in the shedding regime.

A new progressive damage model for the three-dimensional (3 D) woven carbon/carbon (C/C) composites is developed at fiber-matrix level using the micromechanics method. A woven architecture based Representative Volume Element (RVE) model composed of yarns, matrix and yarn/matrix interface is constructed, in which the manufacturing void defects are accounted for. The fiber-matrix concentric cylinder model is employed as a repeating unit cell to represent the yarn, and the matrix micro strain field is computed analytically by the micromechanics method. The maximum stain criteria is utilized for fiber longitudinal breakage, and the Von-Mises criterion is applied for the damage initiation of matrix in both intra-yarns and inter-yarns. The damaged fiber and matrix are modeled by the stiffness degradation method combined with exponential damage evolution equations. The zero thickness cohesive elements governed by bilinear traction-separation constitutive are adopted for yarn/matrix interfacial debonding behavior. The micro progressive damage and failure behavior of the 3 D woven C/C composites subjected to tension is implemented through a developed user-defined material subroutine in commercial software ABAQUS. The predicted stress-strain response is in a good agreement with experimental results. In addition, the effect of manufacturing void defects is also examined by the developed model.

This study aims to formulate the mitigation and adaptation of community in Pagar Alam City using Analytical Hierarchy Process (AHP) techniques. The analysis result shows determining mitigation, physical, educational, and socio-economic use is used as a criterion with 8 alternative policies, i.e a) Participatory mapping to determine the hazards and risks of disasters; b) Increasing public awareness of volcanic earthquake disasters and their mitigation; c) Increasing coordination of related agencies; d) reviving wisdom local; e) building communication networks in the community; f) developing sister village programs; g) managing and structuring disaster-prone areas to reduce the threat of disasters, and h) programs to improve community preparedness in disaster management. Furthermore, adaptation has 3 criteria, physical, social, cultural and economic. Alternative as well as a priority in the implementation of successive volcanic earthquake adaptation, i.e a) changes in house construction to be earthquake resistant as a form of adaptation to earthquake disasters; b) Making youth as a driving factor in disaster risk reduction and increasing regional resilience; c) Application of local wisdom in daily life days; d) Building a culture of safety and resilience by using knowledge of innovation and education; e) evacuation routes are accompanied by signs and preparing basic needs; f) doing alternative work to meet financial needs; g) locating new homes closer to the main road, and h) separation of protected areas and clear cultivation areas

AbstractWe have carried out highly resolved simulations of turbulent open channel flows. The channel wall is covered with different filamentous layers sharing the same thickness ($$h=0.1H$$ h = 0.1 H , where H is the open channel height) and bulk Reynolds number (i.e., $$Re_b=U_bH/\nu $$ R e b = U b H / ν , , $$U_b$$ U b is the bulk velocity and $$\nu $$ ν the kinematic fluid viscosity). The layers are composed of rigid, slender cylindrical filaments mounted perpendicular to the bottom wall. We have selected two layer configurations characterised by filament spacing ratios of $$\Delta S/H=\pi /24\simeq 0.13$$ Δ S / H = π / 24 ≃ 0.13 and $$\Delta S/H=\pi /32\simeq 0.098$$ Δ S / H = π / 32 ≃ 0.098 . The geometrical features of the two layers, allow to classify them as transitional canopies ($$\lambda =dh/\Delta S^2\simeq 0.15$$ λ = d h / Δ S 2 ≃ 0.15 , where d is the filament diameter, i.e. dh is the filament frontal area) (Monti et al. 2020), which is defined as the separation between the sparse-dense asymptotic regimes, proposed by Nepf (2012). While the physical characterisation of the two asymptotic regimes is fairly understood, the transitional conditions remain an open question since the physical characteristics unique to the sparse and dense scenarios coexist in the transitional regime. By resolving every single filament with the aid of an immersed boundary technique in the framework of a Large Eddy formulation, we report the physical mechanisms that emerge at the onset of different regimes (chosen values of $$\lambda $$ λ fall on the verge between a dense and a sparse condition) and verify the criterion associated with the inception of the transition regime.

AbstractIncreasing demands to obtain chemicals via greener and more sustainable materials and processes introduces concepts that should be considered and applied from lab to larger scales. Obtaining bioactive chemicals from agro-industrial non-food biomass waste can combine benign techniques and bio-circular economy to reach this goal. After extraction, evaluating profitability and environmental impacts to decide whether separation – and to what extent – is necessary or not is indispensable. This could be integrated into an approach known as sufficiency, as an important criterion for sustainability. From this perspective, Brazil’s annual generation of 8 million tons of orange waste is relevant, since citrus waste has large amounts of high-value compounds, such as pectin, d-limonene and flavonoids. This case study aimed at developing and comparing green and sustainable analytical methods to obtain flavonoids from orange peel. Homogenizer, ultrasound and microwave-assisted extractions were employed using chemometric tools, considering time, sample/solvent ratio, temperature and ethanol concentration as variables to obtain extracts containing hesperidin, naringenin, hesperetin and nobiletin. The bioactive flavonoids were determined by high-performance liquid chromatography (HPLC-UV). Microwave extraction was the most efficient method for obtaining the majority of flavonoids studied, six times more for hesperidin. Moreover, orange waste from different farming models showed diverse chemical profiles showing the importance of this alternative in natural product resources.

Abstract In this paper, the total eclipsing binary WISE J185503.7+592234 (hereinafter J185503), whose mass ratio is around the mass ratio limit, was observed and investigated for the first time. The stellar atmospheric parameters of the primary (more massive) component were calculated by the spectral fitting, and the following results are obtained: Teff = 5747 ±25 K, [Fe/H] = -0.16±0.04 dex, logg= 4.78 ±0.05 cms−2. Although J185503 has a very small amplitude ( ∼ 0.17 mag in V band) and a short period (0.2800782 d), its light curves exhibit total eclipses (eclipse duration: ∼ 40 minutes, which is about 0.1 phase). The light curves derived from TESS exhibit some unusual behavior, such as inversion of the O’Connell effect, exchange of occultation, and transit depths. Photometric solutions obtained from the multi-band observations suggest that J185503 has a particularly low mass ratio (q=0.0514) and a moderate contact degree of $26\%$. Based on 103 newly determined times of minimum spanning 14 years, a secular period decrease was found, which is calculated to be dP/dt = −2.24 × 10−7 days yr−1. Through analyzing the instability criterion, such as the instability separation, the instability mass ratio, and the ratio of spin angular momentum (Jspin) to the orbital angular momentum (Jorb), J185503 can be regarded as a progenitor of luminous red novae.

AbstractContrast sensitivity for a Gabor signal is affected by collinear high-contrast Gabor flankers. The flankers reduce (inhibitory effect) or increase (facilitatory effect) sensitivity, at short (2λ) and intermediate (6λ) target-to-flanker separation respectively. We investigated whether these inhibitory/facilitatory sensitivity effects are modulated by transcranial random noise stimulation (tRNS) applied to the occipital and frontal cortex of human observers during task performance. Signal detection theory was used to measure sensitivity (d’) and the Criterion (C) in a contrast detection task, performed with sham or tRNS applied over the occipital or the frontal cortex. After occipital stimulation results show a tRNS-dependent increased sensitivity for the single Gabor signal of low but not high contrast. Moreover, results suggest a dissociation of the tRNS effect when the Gabor signal is presented with the flankers, consisting in a general increased sensitivity at 2λ where the flankers had an inhibitory effect (reduction of inhibition) and a decreased sensitivity at 6λ where the flankers had a facilitatory effect on the Gabor signal (reduction of facilitation). After a frontal stimulation, no specific effect of the tRNS was found. We account for these complex interactions between tRNS and flankers by assuming that tRNS not only enhances feedforward input from the Gabor signal to the cortex, but also enhances the excitatory or inhibitory lateral intracortical input from the flankers. The boosted lateral input depends on the excitation-inhibition (E/I) ratio, namely when the lateral input is weak, it is boosted by tRNS with consequent modification of the contrast-dependent E/I ratio.

Existing studies of correlation between the experience of owning and caring for a pet with the psycho-mental state of a person confirm the relevance of this scientific problem. It was substantiated that lockdown restrictions in this context turned out to be a significant factor, as they affect all parts of a personal life, in particular, psychological and social health. The empirical basis of the study is represented by methods: The Hospital Anxiety and Depression Scale (HADS; Zigmond & Snaith), Budner's Intolerance of Ambiguity Scale (IAS), UCLA (University of California, Los Angeles) Loneliness Scale (D. Russell, L. A. Peplau, M. L. Ferguson), K. L. Milutina`s Responsible Pet Attitude Scale", author's questionnaire for understanding the pets behavior. For statistical data analysis we used Chi-square; descriptive statistics, Duncan's Multiple Range test (DMRT), Scheffé's Test for Multiple Comparisons contingency tables, One-way ANOVA, Fisher's F-test, Spearman rank correlation coefficient, Kolmogorov–Smirnov test (KS test), Livigne's homogeneity criterion. The study sample consisted of 79 people, their age ranged from 16 to 26 years. Sex distribution: men - 20.2% (16), women - 79.4% (63). The study found that people who have animals have lower rates of depression and anxiety than non-owners do, but higher rates of intolerance to the unknown. It has been shown that people who give more care to their pets are slightly less depressed than those who do not pay attention to their pets. We found that anxiety does not significantly depend on the care of animals. The dynamics and causal relationship between animal care and anxiety remain controversial. As the prospects for further research, we see the empirical clarification of the young owner-pet relationship features depending on the owner`s separation from his family, functionality of this family, the purpose for buying and owning a pet; We also find interesting the study of the correlation between pet ownership and tolerance to the unknown. An important observation issue remains the consideration of ways to improve the psycho-emotional state of youth.

Introduction: Care for patients with stage D heart failure (HF) is becoming increasingly complex in the era of mechanical circulatory support (MCS). However, an operational consensus definition of stage D HF is currently lacking. Hypothesis: Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profiles better identify outpatients with stage D HF compared to European Society of Cardiology Heart Failure Association (ESC-HFA) criteria and physician assessment. Methods: We evaluated 474 outpatients with systolic HF (ejection fraction [EF] <40%) who received care in Q1 2012 and have not previously received advanced therapies (age, 61±15 years; 35.4% women; 44.7% white, 46.8% black; EF 24±10%; 67.2% with ischemic heart disease; 6.3% on home inotropes). We applied INTERMACS profiles (defining stage D as profiles 2-5) and ESC-HFA criteria to identify stage D HF, and compared with physician-derived stage D identification based on evaluations for advanced therapies (MCS, heart transplant, or palliative care). We then compared 3-year mortality across definitions. Results: INTERMACS profiles, ESC-HFA criteria, and physicians identified 50 (10.5%), 59 (12.4%), and 64 (13.5%) of 474 patients, respectively, as having stage D HF. Concordance between definitions was low, with κ =0.35 (optimal: 1.0). After a median of 3.1 years (1.6, 3.3), 95 patients died (3-year mortality: 21.4%). In addition, 24 patients received MCS and 11 received heart transplant. Mortality was 51.2%, 43.7%, and 34.5% for INTERMACS-, ESC-HFA-, and physician-identified stage D HF patients, respectively ( Figure 1 ). The INTERMACS definition provided the best prognostic separation between stage D and C HF patients, as measured by the Royston’s R 2 statistic ( Figure 1 ). Conclusions: INTERMACS profiles provide a reasonable alternative for the identification of stage D patients in ambulatory systolic HF populations and offer better prognostic information than the ESC-HFA criteria.

Introduction I have this somewhat diffuse concern that at some point, I am in an appointment procedure ... and people say: ‘He has to ... be on social media, [and] have followers ..., because otherwise he can’t say anything about the field of research, otherwise he won’t identify with it … and we need a direct connection to legitimise our discipline in the population!’ And this is where I think: ‘For God’s sake! No, I really don’t want that.’ (Postdoc) Social media such as Facebook or Twitter have become an integral part of many people’s everyday lives and have introduced severe changes to the ways we communicate with each other and about ourselves. Presenting ourselves on social media and creating different online personas has become a normal practice (Vorderer et al. 270). While social media such as Facebook were at first mostly used to communicate with friends and family, they were soon also used for work-related communication (Cardon and Marshall). Later, professional networks such as LinkedIn, which focus on working relations and career management and special interest networks, such as the academic social networking sites (ASNS) Academia.edu and ResearchGate, catering specifically to academic needs, emerged. Even though social media have been around for more than 15 years now, academics in general and German academics in particular are rather reluctant users of these tools in a work-related context (König and Nentwich 175; Lo 155; Pscheida et al. 1). This is surprising as studies indicate that the presence and positive self-portrayal of researchers in social media as well as the distribution of articles via social networks such as Academia.edu or ResearchGate have a positive effect on the visibility of academics as well as the likelihood of their articles being read and cited (Eysenbach; Lo 192; Terras). Gruzd, Staves, and Wilk even assume that the presence in online media could become a relevant criterion in the allocation of scientific jobs. Science is a field where competition for long-term positions is high. In 2017, only about 17% of all scientific personnel in Germany had permanent positions, and of these 10% were professors (Federal Statistical Office 32). Having a professorship is therefore the best shot at obtaining a permanent position in the scientific field. However, the average vocational age is 40 (Zimmer et al. 40), which leads to a long phase of career-related uncertainty. Directing attention to yourself by acquiring knowledge in the use of social media for professional self-representation might offer a career advantage when trying to obtain a professorship. At the same time, social media, which have been praised for giving a voice to the unheard, become a tool for the exclusion of scholars who might not want or be able to use these tools as part of their work and career-related communication, and might remain unseen and unheard. The author obtained current data on this topic while working on a project on Mediated Scholarly Communication in Post-Normal and Traditional Science under the project lead of Corinna Lüthje. The project was funded by the German Research Foundation (DFG). In the project, German-speaking scholars were interviewed about their work-related media usage in qualitative interviews. Among them were users and non-users of social media. For this article, 16 interviews with communication scholars (three PhD students, six postdocs, seven professors) were chosen for a closer analysis, because of all the interviewees they described the (dis)advantages of career-related social media use in the most detail, giving the deepest insights into whether social media contribute to a social exclusion of academics or not. How to Define Social Exclusion (in Academia)? The term social exclusion describes a separation of individuals or groups from mainstream society (Walsh et al.). Exclusion is a practice which implies agency. It can be the result of the actions of others, but individuals can also exclude themselves by choosing not to be part of something, for example of social media and the communication taking part there (Atkinson 14). Exclusion is an everyday social practice, because wherever there is an in-group there will always be an out-group. This is what Bourdieu calls distinction. Symbols and behaviours of distinction both function as signs of demarcation and belonging (Bourdieu, Distinction). Those are not always explicitly communicated, but part of people’s behaviour. They act on a social sense by telling them how to behave appropriately in a certain situation. According to Bourdieu, the practical sense is part of the habitus (Bourdieu, The Logic of Practice). The habitus generates patterns of action that come naturally and do not have to be reflected by the actor, due to an implicit knowledge that is acquired during the course of (group-specific) socialisation. For scholars, the process of socialisation in an area of research involves the acquisition of a so-called disciplinary self-image, which is crucial to building a disciplinary identity. In every discipline it contains a dominant disciplinary self-image which defines the scientific perspectives, practices, and even media that are typically used and therefore belong to the mainstream of a discipline (Huber 24). Yet, there is a societal mainstream outside of science which scholars are a part of. Furthermore, they have been socialised into other groups as well. Therefore, the disciplinary mainstream and the habitus of its members can be impacted upon by the societal mainstream and other fields of society. For example, societally mainstream social media, such as Twitter or Facebook, focussing on establishing and sustaining social connections, might be used for scholarly communication just as well as ASNS. The latter cater to the needs of scholars to not just network with colleagues, but to upload academic articles, share and track them, and consume scholarly information (Meishar-Tal and Pieterse 17). Both can become part of the disciplinary mainstream of media usage. In order to define whether and how social media contribute to forms of social exclusion among communication scholars, it is helpful to first identify in how far their usage is part of the disciplinary mainstream, and what their including features are. In contrast to this, forms of exclusion will be analysed and discussed on the basis of qualitative interviews with communication scholars. Including Features of Social Media for Communication Scholars The interviews for this essay were first conducted in 2016. At that time all of the 16 communication scholars interviewed used at least one social medium such as ResearchGate (8), Academia.edu (8), Twitter (10), or Facebook (11) as part of their scientific workflow. By 2019, all of them had a ResearchGate and 11 an Academia.edu account, 13 were on Twitter and 13 on Facebook. This supports the notion of one of the professors, who said that he registered with ResearchGate in 2016 because "everyone’s doing that now!” It also indicates that the work-related presence especially on ResearchGate, but also on other social media, is part of the disciplinary mainstream of communication science. The interviewees figured that the social media they used helped them to increase their visibility in their own community through promoting their work and networking. They also mentioned that they were helpful to keep up to date on the newest articles and on what was happening in communication science in general. The usage of ResearchGate and Academia.edu focussed on publications. Here the scholars could, as one professor put it, access articles that were not available via their university libraries, as well as “previously unpublished articles”. They also liked that they could see "what other scientists are working on" (professor) and were informed via e-mail "when someone publishes a new publication" (PhD student). The interviewees saw clear advantages to their registration with the ASNS, because they felt that they became "much more visible and present" (postdoc) in the scientific community. Seven of the communication scholars (two PhD students, three postdocs, two professors) shared their publications on ResearchGate and Academia.edu. Two described doing cross-network promotion, where they would write a post about their publications on Twitter or Facebook that linked to the full article on Academia.edu or ResearchGate. The usage of Twitter and especially Facebook focussed a lot more on accessing discipline-related information and social networking. The communication scholars mentioned that various sections and working groups of professional organisations in their research field had accounts on Facebook, where they would post news. A postdoc said that she was on Facebook "because I get a lot of information from certain scientists that I wouldn’t have gotten otherwise". Several interviewees pointed out that Twitter is "a place where you can find professional networks, become a part of them or create them yourself" (professor). On Twitter the interviewees explained that they were rather making new connections. Facebook was used to maintain and intensify existing professional relationships. They applied it to communicate with their local networks at their institute, just as well as for international communication. A postdoc and a professor both mentioned that they perceived that Scandinavian or US-American colleagues were easier to contact via Facebook than via any other medium. One professor described how he used Facebook at international conferences to arrange meetings with people he knew and wanted to meet. But to him Facebook also catered to accessing more personal information about his colleagues, thus creating a new "mixture of professional respect for the work of other scientists and personal relationships", which resulted in a "new kind of friendship". Excluding Features of Social Media for Communication Scholars While everyone may create an Academia.edu, Facebook, or Twitter account, ResearchGate is already an exclusive network in itself, as only people working in a scientific field are allowed to join. In 2016, eight of the interviewees and in 2019 all of them had signed up to ResearchGate. So at least among the communication scholars, this did not seem to be an excluding factor. More of an issue was for one of the postdocs that she did not have the copyright to upload her published articles on the ASNS and therefore refrained from uploading them. Interestingly enough, this did not seem to worry any of the other interviewees, and concerns were mostly voiced in relation to the societal mainstream social media. Although all of the interviewees had an account with at least one social medium, three of them described that they did not use or had withdrawn from using Facebook and Twitter. For one professor and one PhD student this had to do with the privacy and data security issues of these networks. The PhD student said that she did not want to be reminded of what she “tweeted maybe 10 years ago somewhere”, and also considered tweeting to be irrelevant in her community. To her, important scientific findings would rather be presented in front of a professional audience and not so much to the “general public”, which she felt was mostly addressed on social media. The professor mentioned that she had been on Facebook since she was a postdoc, but decided to stop using the service when it introduced new rules on data security. On one hand she saw the “benefits” of the network to “stay informed about what is happening in the community”, and especially “in regards to the promotion of young researchers, since some of the junior research groups are very active there”. On the other she found it problematic for her own time management and said that she received a lot of the posted information via e-mail as well. A postdoc mentioned that he had a Facebook account to stay in contact with young scholars he met at a networking event, but never used it. He would rather connect with his colleagues in person at conferences. He felt people would just use social media to “show off what they do and how awesome it is”, which he did not understand. He mentioned that if this “is how you do it now … I don't think this is for me.” Another professor described that Facebook "is the channel for German-speaking science to generate social traffic”, but that he did not like to use it, because “there is so much nonsense ... . It’s just not fun. Twitter is more fun, but the effect is much smaller", as bigger target groups could be reached via Facebook. The majority of the interviewees did not use mainstream social media because they were intrinsically motivated. They rather did it because they felt that it was expected of them to be there, and that it was important for their career to be visible there. Many were worried that they would miss out on opportunities to promote themselves, network, and receive information if they did not use Twitter or Facebook. One of the postdocs mentioned, for example, that she was not a fan of Twitter and would often not know what to write, but that the professor she worked for had told her she needed to tweet regularly. But she did see the benefits as she said that she had underestimated the effect of this at first: “I think, if you want to keep up, then you have to do that, because people don’t notice you.” This also indicates a disciplinary mainstream of social media usage. Conclusion The interviews indicate that the usage of ResearchGate in particular, but also of Academia.edu and of the societal mainstream social media platforms Twitter and Facebook has become part of the disciplinary mainstream of communication science and the habitus of many of its members. ResearchGate mainly targets people working in the scientific field, while excluding everyone else. Its focus on publication sharing makes the network very attractive among its main target group, and serves at the same time as a symbol of distinction from other groups (Bourdieu, Distinction). Yet it also raises copyright issues, which led at least one of the participants to refrain from using this option. The societal mainstream social media Twitter and Facebook, on the other hand, have a broader reach and were more often used by the interviewees for social networking purposes than the ASNS. The interviewees emphasised the benefits of Twitter and Facebook for exchanging information and connecting with others. Factors that led the communication scholars to refrain from using the networks, and thus were excluding factors, were data security and privacy concerns; disliking that the networks were used to “show off”; as well as considering Twitter and Facebook as unfit for addressing the scholarly target group properly. The last statement on the target group, which was made by a PhD student, does not seem to represent the mainstream of the communication scholars interviewed, however. Many of them were using Twitter and Facebook for scholarly communication and rather seemed to find them advantageous. Still, this perception of the disciplinary mainstream led to her not using them for work-related purposes, and excluding her from their advantages. Even though, as one professor described it, a lot of information shared via Facebook is often spread through other communication channels as well, some can only be received via the networks. Although social media are mostly just a substitute for face-to-face communication, by not using them scholars will miss out on the possibilities of creating the “new kind of friendship” another professor mentioned, where professional and personal relations mix. The results of this study show that social media use is advantageous for academics as they offer possibilities to access exclusive information, form new kinds of relations, as well as promote oneself and one’s publications. At the same time, those not using these social media are excluded and might experience career-related disadvantages. As described in the introduction, academia is a competitive environment where many people try to obtain a few permanent positions. By default, this leads to processes of exclusion rather than integration. Any means to stand out from competitors are welcome to emerging scholars, and a career-related advantage will be used. If the growth in the number of communication scholars in the sample signing up to social networks between 2016 to 2019 is any indication, it is likely that the networks have not yet reached their full potential as tools for career advancement among scientific communities, and will become more important in the future. Now one could argue that the communication scholars who were interviewed for this essay are a special case, because they might use social media more actively than other scholars due to their area of research. 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