Surprising Effect Research Articles

A study of progressive hedging for stochastic integer programming

Motivated by recent literature demonstrating the surprising effectiveness of the heuristic application of progressive hedging (PH) to stochastic mixed-integer programming (SMIP) problems, we provide theoretical support for the inclusion of integer variables, bridging the gap between theory and practice. We provide greater insight into the following observed phenomena of PH as applied to SMIP where optimal or at least feasible convergence is observed. We provide an analysis of a modified PH algorithm from a different viewpoint, drawing on the interleaving of (split) proximal-point methods (including PH), Gauss–Seidel methods, and the utilisation of variational analysis tools. Through this analysis, we show that under mild conditions, convergence to a feasible solution should be expected. In terms of convergence analysis, we provide two main contributions. First, we contribute insight into the convergence of proximal-point-like methods in the presence of integer variables via the introduction of the notion of persistent local minima. Secondly, we contribute an enhanced Gauss–Seidel convergence analysis that accommodates the variation of the objective function under mild assumptions. We provide a practical implementation of a modified PH and demonstrate its convergent behaviour with computational experiments in line with the provided analysis.

Laser-induced weight variation of liquids and solids

We performed measurements of weight in transparent materials such as liquid water, ice, and a quartz crystal when they are beamed by a laser. We detected weight variations in all cases of these materials, with magnitudes of the order of tenths to hundreds of milligrams of force. The highest value obtained was for ice, and the most interesting effect was the clear variation in weight that occurred for beams in both vertical or horizontal directions. Such a phenomenon cannot be caused by radiation pressure, reaction by vaporization, ejection of matter by heating, or piezoelectricity. The experimental results are also in accordance with the theoretical forecast proposed in our previous studies where the variation in the weight can be explained by the reaction force of the myriad of electric dipoles of the transparent dielectric previously entangled with the external environment when polarized to the component of the electric field of the propagating laser light. This new and surprising effect can be exploited to reach significant values so that it has future applications related to propulsion without fuel in aerospace or aquatic vehicles.

Temperature separation under compression of moderately coupled plasma

In moderately coupled plasmas, a significant fraction of the internal energy resides in electric fields. As these plasmas are heated or compressed, the shifting partition of energy between particles and fields leads to surprising effects, particularly when ions and electrons have different temperatures. In this work, quasi-equations of state (quasi-EOS) are derived for two-temperature moderately coupled plasma in a thermodynamic framework and expressed in a simple form. These quasi-EOS readily yield expressions for correlation heating, in which heating of the electrons causes a rapid increase in ion temperature even in the absence of collisional energy exchange between species. It is also shown that, remarkably, compression of moderately coupled plasma drives a temperature difference between electrons and ions, even when the species start at equal temperatures. These additional channels for ion heating may be relevant in designing ignition schemes for inertial confinement fusion.

Interactions enhance dispersion in fluctuating channels via emergent flows

Understanding particle motion in narrow channels can guide progress in numerous applications, from filtration to vascular transport. Thermal or active fluctuations of fluid-filled channel walls can slow down or increase the dispersion of tracer particles via entropic trapping in the wall bulges or hydrodynamic flows induced by wall fluctuations, respectively. Previous studies concentrated primarily on the case of a single Brownian tracer. Here, we address what happens when there is a large ensemble of interacting Brownian tracers – a common situation in applications. Introducing repulsive interactions between tracer particles, while ignoring the presence of a background fluid, leads to an effective flow field. This flow field enhances tracer dispersion, a phenomenon reminiscent of that seen for single tracers in incompressible background fluid. We characterise the dispersion by the long-time diffusion coefficient of tracers numerically and analytically with a mean-field density functional analysis. We find a surprising effect where an increased particle density enhances the diffusion coefficient, challenging the notion that crowding effects tend to reduce diffusion. Here, inter-particle interactions push particles closer to the fluctuating channel walls. Interactions between the fluctuating wall and the now-nearby particles then drive particle mixing. Our mechanism is sufficiently general that we expect it to apply to various systems. In addition, our perturbation theory quantifies dispersion in generic advection–diffusion systems.

Notes on inverse Compton scattering

The paper considers some kinematic conditions for the inverse Compton scattering of photons by relativistic electrons and the polarizations of colliding particles, which affect the value of the differential cross section of the process. A significant influence of the electron and photon helicity on the value of the cross section was found. In the ultrarelativistic case, a surprising effect of an almost twofold increase in the cross section of scattering in the direction of the initial electron momentum was also discovered, when the initial photon momentum is perpendicular to that of the initial electron.

Influence of Siliconized Zn-Graphene Oxide Complex Nanoparticles on the Microstructure and Mechanical Properties of AA5083: Focus on Gas Metal Arc Welding

Aluminum alloy 5083 has low density, mechanical properties, high corrosion resistance, and high welding capability. Due to high thermal conductivity, specific heat, and latent heat, as well as the relatively high coefficient of thermal expansion of aluminum, achieving a connection with good mechanical properties is always very important. This study aimed to investigate nanoparticles’ surprising and unexpected effects in forming various microstructures, which directly improve the mechanical properties of the welding process as a new and surprising idea. The effects of siliconized Zn-graphene oxide complex nanoparticles on weld geometry, mechanical properties, and microstructure of AA5083 were investigated. The gas metal arc welding process welded the samples, and different amounts of nanoparticles were investigated. The results reveal that utilizing nanoparticles can be affected by the weld geometry and the properties of weld metal. 0.25 g of nanoparticles had low face reinforcement, and the bead width and penetration depth dramatically increased. The presence of nanoparticles inside the molten zone and its effect on grain size improved mechanical properties, according to the Hall–Petch relationship. The ultimate tensile strength and yield strength of the S0.25 sample increased by 58.24 and 28.28%, respectively, compared to the welded sample without the presence of nanoparticles. Also, the ductility of this sample during the failure test showed that elongation increased by 36.75%.

The effects of sales surprise on inventory turnover: An empirical study

The effects of sales surprise on inventory turnover: An empirical study

Wordplay in 1 Corinthians

Abstract This essay provides the first attempt at a complete inventory and assessment of the use of wordplay in 1 Corinthians. It is organized by attending to the various linguistic features that are exploited to create wordplays. These include the use of different lexemes based on the same root (i.e., sharing etymology; compound words) used in close proximity; the use of the same lexeme but with different meanings in different genders, used in close proximity to exploit the euphony; the use of the same word/lexeme with different meanings in close proximity; the use of the same word with the same meaning twice in close proximity but in a context that plays on an inversion or twist while also exploiting the soundplay; and the use of different lexemes with similar sounds employed for the sake of the surprising rhetorical effect of connecting the two words. It also analyses the kinds of wordplay opportunities that each linguistic feature tends to provide or create. Additionally, it discusses the challenges that different wordplays create for translation (with a focus on translation into English). In the process, the ubiquity and significance of wordplays in 1 Corinthians is demonstrated.

Fluctuating temperatures have a surprising effect on disease transmission.

Theory predicts that temperature fluctuations should reduce performance near an organism's thermal optimum. A new study in PLOS Biology found fluctuations increased parasite transmission instead, highlighting questions about how climate change will impact infectious diseases.

Better together: Non-additive interactions between schizophrenia risk genes

Zhang, Zhang, Forrest etal combine allele-specific open chromatin (ASoC) mapping and CRISPR-editing to evaluate the functional impact of schizophrenia risk variants on human neuronal gene expression, synaptic development, and function. In doing so, they uncover surprising non-additive effects between target genes regulated by the same risk variant.

An eye-tracking-with-EEG coregistration corpus of narrative sentences

We present the Radboud Coregistration Corpus of Narrative Sentences (RaCCooNS), the first freely available corpus of eye-tracking-with-EEG data collected while participants read narrative sentences in Dutch. The corpus is intended for studying human sentence comprehension and for evaluating the cognitive validity of computational language models. RaCCooNS contains data from 37 participants (3 of which eye tracking only) reading 200 Dutch sentences each. Less predictable words resulted in significantly longer reading times and larger N400 sizes, replicating well-known surprisal effects in eye tracking and EEG simultaneously. We release the raw eye-tracking data, the preprocessed eye-tracking data at the fixation, word, and trial levels, the raw EEG after merger with eye-tracking data, and the preprocessed EEG data both before and after ICA-based ocular artifact correction.

Stimulus expectations do not modulate visual event-related potentials in probabilistic cueing designs

Humans and other animals can learn and exploit repeating patterns that occur within their environments. These learned patterns can be used to form expectations about future sensory events. Several influential predictive coding models have been proposed to explain how learned expectations influence the activity of stimulus-selective neurons in the visual system. These models specify reductions in neural response measures when expectations are fulfilled (termed expectation suppression) and increases following surprising sensory events. However, there is currently scant evidence for expectation suppression in the visual system when confounding factors are taken into account. Effects of surprise have been observed in blood oxygen level dependent (BOLD) signals, but not when using electrophysiological measures. To provide a strong test for expectation suppression and surprise effects we performed a predictive cueing experiment while recording electroencephalographic (EEG) data. Participants (n=48) learned cue-face associations during a training session and were then exposed to these cue-face pairs in a subsequent experiment. Using univariate analyses of face-evoked event-related potentials (ERPs) we did not observe any differences across expected (90% probability), neutral (50%) and surprising (10%) face conditions. Across these comparisons, Bayes factors consistently favoured the null hypothesis throughout the time-course of the stimulus-evoked response. When using multivariate pattern analysis we did not observe above-chance classification of expected and surprising face-evoked ERPs. By contrast, we found robust within- and across-trial stimulus repetition effects. Our findings do not support predictive coding-based accounts that specify reduced prediction error signalling when perceptual expectations are fulfilled. They instead highlight the utility of other types of predictive processing models that describe expectation-related phenomena in the visual system without recourse to prediction error signalling.

Aztreonam is a novel chemical inducer that promotes Agrobacteium transformation and lateral root development in soybean.

Agrobacterium-mediated soybean transformation is the simplest method of gene transfer. However, the low transformation due to the intractable nature of soybean genotypes hinders this process. The use of biochemicals (acetosyringone, cinnamic acid, flavonoids, etc.) plays an important role in increasing soybean transformation. These biochemicals induce chemotaxis and virulence gene activation during the infection process. Here we identified a biochemical, aztreonam (a monobactam), for high agrobacterium-mediated transformation in soybean. The soybean explants from three genotypes were inoculated with A. tumefaciens (GV3101) harboring the pMDC32 vector containing hpt or the GmUbi-35S-GUS vector containing the GUS gene during two separate events. High transient GUS expression was obtained during cotyledon explant culture on MS media supplemented with 2.5 mg/L aztreonam. The aztreonam-treated explants showed high efficiency in transient and stable transformation as compared to the untreated control. The transformation of aztreonam-treated explants during seed imbibition resulted in an average of 21.1% as compared to 13.2% in control by using the pMDC32 vector and 28.5 and 20.7% while using the GUS gene cassette, respectively. Based on these findings, the metabolic analysis of the explant after aztreonam treatment was assessed. The high accumulation of flavonoids was identified during an untargeted metabolic analysis. The quantification results showed a significantly high accumulation of the four compounds, i.e., genistein, apigenin, naringenin, and genistin, in cotyledon explants after 18 hours of aztreonam treatment. Alongside this, aztreonam also had some surprising effects on root elongation and lateral root formation when compared to indole-3-butyric acid (IBA). Our findings were limited to soybeans. However, the discovery of aztreonam and its effect on triggering flavonoids could lead to the potential role of aztreonam in the agrobacterium-mediated transformation of different crops.

I materiali di Villa Garzoni (Collodi)

Villa Garzoni and its garden are an extraordinary example of 18th-century Tuscan taste and culture. They are located on the slope of a hill at the mouth of the Pescia di Collodi stream in the Pescia plain (northern Tuscany). The garden presents scenographic and surprise effects that are part of a single decorative ensemble of great stylistic coherence. The steeply sloping terrain influenced the planimetric organisation, which develops along a central axis of symmetry, with an arrangement of terraces. In this paper the results of a diagnostic campaign performed on the materials of the villa and garden are reported. Stones, mortars and plasters were identified and analysed according to a well-established chemical and minero petrographic approach. Local and imported stones, raw materials and technologies used for the preparation of mortars and plasters, materials used for decoration were identified. To plan the best restoration approach their state of conservation was assess.

The effect of environmental information on evolution of cooperation in stochastic games

Many human interactions feature the characteristics of social dilemmas where individual actions have consequences for the group and the environment. The feedback between behavior and environment can be studied with the framework of stochastic games. In stochastic games, the state of the environment can change, depending on the choices made by group members. Past work suggests that such feedback can reinforce cooperative behaviors. In particular, cooperation can evolve in stochastic games even if it is infeasible in each separate repeated game. In stochastic games, participants have an interest in conditioning their strategies on the state of the environment. Yet in many applications, precise information about the state could be scarce. Here, we study how the availability of information (or lack thereof) shapes evolution of cooperation. Already for simple examples of two state games we find surprising effects. In some cases, cooperation is only possible if there is precise information about the state of the environment. In other cases, cooperation is most abundant when there is no information about the state of the environment. We systematically analyze all stochastic games of a given complexity class, to determine when receiving information about the environment is better, neutral, or worse for evolution of cooperation.

A New Hope for Treating Obesity Pandemic

A new class of drugs is transforming obesity treatment in an unprecedented manner. Scientists are amazed by their potency in the treatment of obesity. Glucagon-like peptide 1 (GLP-1) analogs are a class of medications used to treat type 2 diabetes mellitus. These analogs mimic the action of GLP-1, a hormone released by the intestine in response to food intake. GLP-1 analogs have been extensively studied, and scientists have made several important discoveries about their effects and potential therapeutic applications. GLP-1 analogs have shown significant efficacy in improving glycemic control in patients with type 2 diabetes. They stimulate insulin secretion from pancreatic beta cells, suppress glucagon secretion (which reduces hepatic glucose production), and slow down gastric emptying, leading to reduced postprandial glucose levels. Apart from their controlling glycemic index, GLP-1 analogs are shown to offer cardio-protective, reno-protective, and neuroprotective benefits. However, their most surprising and potent effects have been observed in the context of weight loss. Two drugs from this class, semaglutide, and tripeptide, have shown efficacy in recent clinical trials. Tirzepatide was effective in significantly reducing body weight in about half of the participants in a recent clinical trial. In another trial, semaglutide was able to reduce 20% of the body weight of about one-third of the participants. However, not everyone is benefiting from these medications. There are still significant challenges in determining who will benefit from these medications and to what extent. These challenges are currently being addressed. It has been observed that the new drugs work best in people who become hungry in between meals. People with obesity can be classified into four categories; those who need to eat more to reach fullness; those who reach fullness with a regular-sized meal but feel hungry again soon (hungry gut); those who eat to cope with emotions; and those with a relatively slow metabolism. It is not known why people with a ‘hungry gut’ respond most effectively to the new drugs, but one hypothesis suggests that these patients have low levels of GLP-1 hormones, and that’s why they have obesity. When they get a replacement in the form of GLP-1 analogs, they do extremely well. Another study with a GLP-1-mimicking drug called liraglutide found that patients with low GLP-1 levels reduced twice as much weight compared to the general population after using the drug for one year. Both semaglutide and tripeptide are given once weekly, thus increasing treatment compliance. Because of their weekly regimen, the drugs will also help people with erratic schedules and work shifts. Some of the other medications have to be taken at a certain time of day, which can be difficult for those with irregular sleep schedules. Another important question is to find out how long these drugs' weight loss benefits remain. One study concluded that semaglutide’s weight-reducing effects last as long as the patients remain on medication. This means that these drugs will be given chronically to obese patients. Whether ‘chronic’ means ‘life-long’ in this context is still to be determined. Perhaps an even more important question that clinicians face is determining how much weight loss is too much, especially when muscle loss is also involved. More research is needed to find a balance where these drugs are used not only for weight reduction but to treat a person for health, prevent disease, and improve quality of life.

Defending Black-Box Skeleton-Based Human Activity Classifiers

Skeletal motions have been heavily relied upon for human activity recognition (HAR). Recently, a universal vulnerability of skeleton-based HAR has been identified across a variety of classifiers and data, calling for mitigation. To this end, we propose the first black-box defense method for skeleton-based HAR to our best knowledge. Our method is featured by full Bayesian treatments of the clean data, the adversaries and the classifier, leading to (1) a new Bayesian Energy-based formulation of robust discriminative classifiers, (2) a new adversary sampling scheme based on natural motion manifolds, and (3) a new post-train Bayesian strategy for black-box defense. We name our framework Bayesian Energy-based Adversarial Training or BEAT. BEAT is straightforward but elegant, which turns vulnerable black-box classifiers into robust ones without sacrificing accuracy. It demonstrates surprising and universal effectiveness across a wide range of skeletal HAR classifiers and datasets, under various attacks. Appendix and code are available.

Constructive role of shot noise in the collective dynamics of neural networks.

Finite-size effects may significantly influence the collective dynamics of large populations of neurons. Recently, we have shown that in globally coupled networks these effects can be interpreted as additional common noise term, the so-called shot noise, to the macroscopic dynamics unfolding in the thermodynamic limit. Here, we continue to explore the role of the shot noise in the collective dynamics of globally coupled neural networks. Namely, we study the noise-induced switching between different macroscopic regimes. We show that shot noise can turn attractors of the infinitely large network into metastable states whose lifetimes smoothly depend on the system parameters. A surprising effect is that the shot noise modifies the region where a certain macroscopic regime exists compared to the thermodynamic limit. This may be interpreted as a constructive role of the shot noise since a certain macroscopic state appears in a parameter region where it does not exist in an infinite network.

Effect of 6-hydroxydopamine increase the glutathione level in SH-SY5Y human neuroblastoma cells.

Treatment of human neuroblastoma SH-SY5Y cells with a catecholaminergic neurotoxin, 6-hydroxydopamine (6-OHDA) is an acknowledged in vitro experimental model of Parkinson disease (PD). A decrease in the glutathione content occurs in PD. Higher concentrations of 6-OHDA lowered the glutathione level in SH-SY5Y cells, nonetheless, we and other authors found a considerable increase in these cells' glutathione content after 24 h treatment with 60 μM 6-OHDA. A synthetic antioxidant, 4-aminotetramethylpiperidine-1-oxyl (4-AT) exerted a similar effect. The aim of the present study was to explain this surprising effect by monitoring the time course of changes in the levels of reduced (GSH) and oxidized glutathione (GSSG), total antioxidant activity (TAC) of human neuroblastoma cell SH-SY5Y extracts as well as the level of reactive oxygen species and activities of enzymes of glutathione metabolism after treatment of the cells with 60 µM 6-OHDA and/or 4-AT for 30 min - 24 h. A transient decrease in the level of GSH and TAC of cell extracts, increase in the level of GSSG, and decrease in the activities of glutathione peroxidase, glutathione reductase, glutathione S-transferase and γ-glutamyl-cysteine ligase activities were found followed by normalization or overshoot of the GSH level, TAC and enzyme activities. Increased activity of γ-glutamyl-cysteine ligase activity starting after 4-6 h was responsible for the elevation of the level of GSH and TAC in cells treated with 6-OHDA, 4-AT, and both compounds. The 6-OHDA-induced increase in the GSH content is a result of an overcompensatory response. The antioxidant 4-AT may be useful for the induction of an increase in the level of GSH in neural cells, without the negative effect of 6-OHDA.

Tight basis cycle representatives for persistent homology of large biological data sets.

Persistent homology (PH) is a popular tool for topological data analysis that has found applications across diverse areas of research. It provides a rigorous method to compute robust topological features in discrete experimental observations that often contain various sources of uncertainties. Although powerful in theory, PH suffers from high computation cost that precludes its application to large data sets. Additionally, most analyses using PH are limited to computing the existence of nontrivial features. Precise localization of these features is not generally attempted because, by definition, localized representations are not unique and because of even higher computation cost. Such a precise location is a sine qua non for determining functional significance, especially in biological applications. Here, we provide a strategy and algorithms to compute tight representative boundaries around nontrivial robust features in large data sets. To showcase the efficiency of our algorithms and the precision of computed boundaries, we analyze the human genome and protein crystal structures. In the human genome, we found a surprising effect of the impairment of chromatin loop formation on loops through chromosome 13 and the sex chromosomes. We also found loops with long-range interactions between functionally related genes. In protein homologs with significantly different topology, we found voids attributable to ligand-interaction, mutation, and differences between species.