Decremental Processes Research Articles

Cascadic failure and preferential decay via pruning mediated percolation on interdependent networks: implications for schizophrenia

IntroductionDuring adolescence the brain is dynamically changing. Destabilization and acceleration of the normal adolescent synaptic pruning process is likely a contributing factor to the neuropathology of schizophrenia. Details on whether normal pruning effects weaker synapses more or uniformly all synapses with different strengths, needs to be further evaluated. Widespread impairment in structural connectivity in schizophrenic patients involving several cortical and subcortical areas, has been previously described. In this computational study, we investigated a stochastic percolation process in interdependent networks, motivated by pathological synaptic pruning. We examined preferential decay in the connectivity decremental process, as well as differential pruning in interconnected subnetworks. Finally, the speed of the percolation process, as well as the potential for pharmacological interventions of percolation in random networks was explored. Statistical structural properties of decaying networks pinpointed several network attributes which the disintegration and phase transitions qualitatively depended on.ObjectivesThe following objectives were explored: 1.) Apart from a random percolation process, we investigated preferential decay of the connections. We introduced different percolation rules for various connection types. 2.) Based on previous experimental results, we assumed that different interconnected neural subpopulations prune differently, therefore we explored differential pruning process in the subnetworks. 3.) The speed of the percolation was studied and the pharmacological synaptic connectivity change was also analyzed.MethodsWe considered two inter-connected randomly connected networks, where the connections were removed during the percolation process. Simulations were partially performed using Octave on a Lenovo Thinkpad running the Linux operating system and partially performed on a supercomputer at UPPMAX (NAISS Small Compute 2023 Dnr: NAISS 2023/22-102).ResultsWe found that the coupled network system shows rich percolation behaviors with phase transitions for various coupling strength and coupling patterns. The phase transitions of both layers are altered qualitatively between discontinuous, mixed and continuous. Recursively developing percolation in interdependent networks can cause complete fragmentation of these networks, resulting in cascadic failure which might be related to schizophrenia symptoms.Conclusions This computational study analyzes the pruning-mediated percolation in interdependent neural networks. Consequences of the pathological overpruning were related to the attributes of the interdependent network properties. Implications for schizophrenia development and predictions for compensatorial iatrogenic percolation was also pinpointed and discussed.Disclosure of InterestNone Declared

Online Feature Selection Using Sparse Gradient

Feature Selection (FS) is an important preprocessing step in data analytics. It is used to select a subset of the original feature set such that the selected subset does not affect the classification performance significantly. Its objective is to remove irrelevant and redundant features from the original dataset. FS can be done either in offline mode or in online mode. The basic assumption in the former mode is that the entire dataset has been available for the FS algorithm; and the FS algorithm takes multiple epochs to select optimal feature subset that gives good accuracy. In contrast, the FS algorithms in online mode take input data one instance at a time and accumulate knowledge by learning each one of them. In online mode each instance of the original dataset is considered as training and testing sample as well. The offline FS algorithms require long time periods, if the data to be processed is large such as Big data. Whereas online FS algorithms will take only one epoch to learn the entire data and can produce the results swiftly which is highly desirable in the case of Big data. This paper deals with the online FS problem and provides a novel Feature Selection algorithm which uses the Sparse Gradient method to build a sparse classifier. In this proposed method, an online classifier is built and maintained throughout the learning process and feature weights, which are limited to a particular boundary limit, are reduced in a step by step decrement process. This method creates sparsity in the classifier. Effectively, the built classifier is used to select optimal feature subset from the incoming data. As this method reduces the weights in the classifier in step by step manner, only those important features which have value higher than the boundary survive from this repeated decrement process. The resultant optimal feature subset is formed using these non-zero weighted features. Most significantly, this particular method can be used with any learning algorithm. To show its applicability with different learning algorithms, various online feature selection models have been built using Learning Vector Quantization, Radial Basis Function Networks and Adaptive Resonance Theory MAP. In all these models, the proposed Sparse Gradient method is used. The encouraging results shows the effectiveness of the proposed method with different learning algorithms in medium and large sized benchmark datasets.

Adsorption thermodynamics of CO2 on nitrogen‐doped biochar synthesized with moderate temperature ionic liquid

AbstractThe purpose of this work was to investigate the thermodynamic characteristics of carbon dioxide (CO2) adsorption on a promising nitrogen‐doped biochar at constant temperature and isopiestic pressure. The biochar was prepared as a CO2 adsorbent based on catalytic pyrolysis of pristine coconut shells using urea as the nitrogen source and moderate temperature ionic liquid as a catalyst. The results showed that CO2 adsorption on the biochar was a spontaneous, dominantly physical, exothermic, and entropy decrement process that could be well described by the slip model and the dual‐site Langmuir model. Those thermodynamic parameters, including interface potential, exhibited a series of interesting tendencies with the changes in adsorption temperature and pressure. Under the conditions of 273 K and 100 kPa, the adsorption capacity and the interface potential were 4.6 mmol/g and −16.7 J/g, respectively. And the site energy ranged from 2.57 to 5.13 kJ/mol in the test conditions, which became narrow with increasing temperature. The temperature exhibited positive effects on interface potential, enthalpy change, entropy change, enthalpy change, internal energy change but negative effects on adsorption capacity, Gibbs free energy change, and Helmholtz free energy change. Interestingly, the pressure exhibited the opposite effect trends. The peak pressure with maximum temperature effect at a given temperature and the peak temperature with maximum pressure effect at a given pressure were found to exist for some thermodynamic parameters. These exhibited a different but significantly beneficial perspective to understand the mass and energy transfer during CO2 adsorption on the biochar at constant temperature and isopiestic pressure, which have rarely been reported before.

Weighted Incremental–Decremental Support Vector Machines for concept drift with shifting window

We study the problem of learning the data samples’ distribution as it changes in time. This change, known as concept drift, complicates the task of training a model, as the predictions become less and less accurate. It is known that Support Vector Machines (SVMs) can learn weighted input instances and that they can also be trained online (incremental–decremental learning). Combining these two SVM properties, the open problem is to define an online SVM concept drift model with shifting weighted window. The classic SVM model should be retrained from scratch after each window shift. We introduce the Weighted Incremental–Decremental SVM (WIDSVM), a generalization of the incremental–decremental SVM for shifting windows. WIDSVM is capable of learning from data streams with concept drift, using the weighted shifting window technique. The soft margin constrained optimization problem imposed on the shifting window is reduced to an incremental–decremental SVM. At each window shift, we determine the exact conditions for vector migration during the incremental–decremental process. We perform experiments on artificial and real-world concept drift datasets; they show that the classification accuracy of WIDSVM significantly improves compared to a SVM with no shifting window. The WIDSVM training phase is fast, since it does not retrain from scratch after each window shift.

Structural and optical properties of BaTiO3 modified cadmium alkali borate glasses

Borate glasses Na2B4O7–CdO–CuO–BaTiO3 have been manufactured by the traditional melt quenching method. The increment of BaTiO3 affects strictly the density and the molar volume of the glass samples. The spectroscopic investigations by FTIR and Raman spectra show that the glass network consists of different structural units of [BO3] and [BO4] along with [TiO4]. The elaborated investigations assume the glass former role of TiO2. These arguments depend on the transformation of [BO3] into [BO4] units, which result in a decrement in the magnitude of disorder in the glass structure. The compositional dependence on BaTiO3 reveals that the behavior of Urbach energy confirms the increment of the disorder and the trend of the optical band gap shows a decrement process with a priority to direct transitions. Moreover, EPR spectra revealed that the Cu2+ ions occupy the positions of elongated octahedral positions with tetragonal distortions.

Exploration of the Damping Characteristics of Basalt Hybrid Composites Reinforced with Natural Fibers and Epoxy Resin

The article examines the unprecedented characteristics of bi-directional basalt lamina such as damping and vibration, reinforced with twill-weaved, untreated natural fibers (basalt fiber and banana fiber) and epoxy resins as the paramount factor in the development of materials for aerospace and material industries were considered to be weight reduction and destruction tolerance. Experimentally, when the material is subjected to impulse or force excitation in the frequency field, the dynamic features of the composite laminates could be determined using dynamic modal analysis which provides different mode shapes and it also provides the area or region to be damped to minimize vibration, and as a result the outcomes of hybrid configuration indicate a distribution between dedicated basalt composites and basalt/natural fiber composites which is been carried in this research work. The damping properties were remained restrained using a vibration response envelope curve using the logarithmic decrement process. The findings disclose that, the reinforcement of natural fibers in composite laminates improves the damping characteristics of laminates when they are combined with polymeric resins, due to the boundless basic structural rigidity and strength of natural fibers. In addition, research on the mechanical properties of polymeric fiber composites are compared with natural reinforced hybrid basalt composites which have a negative hybrid effect on the tensile properties and positive hybrid effect on the compressive and flexural properties. The result suggests that, the applications which require good sound, vibration, low load bearing and temperature properties could deploy natural fiber-reinforced composites as a pertinent material.

Thermodynamics of CO2 adsorption on cellulose‐derived biochar prepared in ionic liquid

AbstractThis work focused on thermodynamic analysis of carbon dioxide (CO2) adsorption on a promising biochar as a CO2 adsorbent. The biochar was prepared by catalytic pyrolysis of cellulose material in ionic liquid at moderate temperature. The adsorption characteristics, such as adsorption capacity, interfacial potential, Gibbs free energy change, enthalpy change, entropy change, and internal energy change, influenced by adsorption temperature and gas pressure, were systematically investigated. The results indicated that CO2 adsorption on cellulose‐derived biochar was a spontaneous, physical, exothermic, and entropic decrement process, accompanied by adsorption capacity of 5.2 mmol/g and interfacial potential of −18.2 J/g at 273 K and 100 kPa. The process could be well described by adsorption potential theory. Then a quasi‐Gaussian distribution of site energy was verified for CO2 adsorption. The interfacial potential was found to be a monotropic function of the amount of CO2 adsorbed, and the latter was actually a differential of the former via adsorption potential. The positive temperature effect and negative pressure effect on negative Gibbs free energy change indicated that reducing adsorption temperature and increasing gas pressure were beneficial to CO2 uptake, accompanied by the increase of adsorption capacity and the reduction of interfacial energy, entropy, enthalpy, and internal energy. The strongest temperature effects on entropy change, enthalpy change, and internal energy change existed at given pressure or temperature. The pressure effect was stronger and more sensitive to pressure at lower adsorption pressure. More interestingly, the peak pressure or peak temperature with the strongest pressure effect possibly existed during CO2 adsorption.

Degradation reliability modeling of stabilized base course materials based on a modulus decrement process

The dynamic elastic modulus of stabilized base course materials is crucial to the design and evaluation of pavement, which has a great effect on the life-cycle performance of pavement. In this study, the fatigue performance of commonly used stabilized base course materials was investigated. A general framework of degradation-based reliability was developed. To accurately characterize the degradation process of dynamic elastic modulus, a degradation index was proposed and its failure threshold values were defined. A degradation model to describe the evolution of degradation index was established and validated. A new approach to calculate reliability was established using Monte Carlo simulation. The corresponding degradation-based reliability was conducted on the fatigue test data. Results show that the value of critical degradation index is significantly influenced by the properties. The proposed degradation model is capable of predicting the degradation index with high degree of accuracy. The developed degradation-based reliability approach is able to capture the more real-degradation behavior of stabilized base course materials. The degradation-based reliability includes three phases, which correspond to different degree of cracking. The mean value of fatigue life corresponds to reliability decreasing phase.

All-Trance Retinoid Acid (ATRA) Makes Refractory Immune Thrombocytopenia (RITP) Less Refractory: A Retrospective Study of Ritp Patients Treated with Combination Therapies Including ATRA

Abstract 3338 Background:Refractory immune thrombocytopenia (RITP) is a severe bleeding disorder with a high mortality rate of 10% to 30%, which is resulted from the toxicities associated with therapies, as well as from life-threatening bleedings. Up to now, treatments for RITP patients are still limited and no consensus has been reached about the standard treatment protocol, therefore, it remains a great problem and challenge for hematologists to think out ways to treat RITP, that is to say, new therapies should be explored to maintain a relatively stable and safe platelet counts with minimum toxicities, so as to improve patients' quality of life and reduce mortalities related to severe bleedings and therapies. ITP is an autoimmune disorder ascribed not only to increased PLT destruction, but also to reduced PLT production, which appears to be related to impaired megakaryocytes (MKs) maturation. ATRA belongs to a class of retinoids, which exerts immunomodulatory and differentiation inducing capacities, and has been included in clinical trails about autoimmune diseases and has been successfully applied in clinic to cure APL by inducing the differentiation of cancer cells. Design and Methods:In this study, we retrospectively reviewed the medical charts of 35 RITP patients who took ATRA as part of the combination therapy from February 2008 to August 2012. We made phone calls for some other detailed medically relevant information not recorded, including previous ITP history, bleeding episodes and etc. All the patients fulfilled the primary ITP criteria as described. They had a median ITP duration of 29 months (range, 6–129 months), with a diagnosed RITP duration of 11months (range, 2–79 months). All the patients have received a median of 6 therapies (range, 3–8) prior to taking ATRA, including steroids, IVIG, CSA, azathioprine, danazol and etc. The median lowest PLT number in the course of their disease was 12×109/L (range, 1–27×109/L), and the median PLT count before starting take ATRA was 11×109/L (range, 1–23×109/L). Patients were treated with ATRA (10mg 3times/day), in combination with any one of methylprednisolone, danazol and CSA or nothing not randomly. When patients were severely thrombocytopenia or present with bleeding sings or symptoms, transfusion of PLT or injection of thrombopoietin were applied. Patients were monitored every 1 to 3 days at the first two weeks and every 1to 4 weeks afterwards for PLT counts, and were monitored every 1 month for transaminitis and other side effects. Results:Of the 35 patients, 25 responded to our treatments in a median of 8 weeks (range, 3–16 weeks), with PLT increased to greater than 30*109/L, and remained in remission in a median of 24 months, after which, 10 patients relapsed and 8 patients regained remission with the addition of other drugs. The other 15 patients remained in remission after 24 months during the maintenance therapy process and the following drugs decrement process. 5 patients had a relatively stable and safe PLT count (median 58×109/L, rang 38–225×109/L) after discontinuation of all the medications and the other 10 continued the therapy with a low dose for relapsing after the medicine discontinuation. The median peak PLT count after starting the ATRA therapy was 94×109/L (rang 57–225×109/L), and it is after a median of 3 month (range, 1.5–8 months) before the median PLT count reached to peak level. During the treatment process, no severe adverse events and bleedings happened. Patients refractory to previous conventional first-line therapies and combined therapies responded to the combination of ATRA with any one of methylprednisolone, danazol or CSA, which implies that ATRA has the potential of making RITP less refractory and even curing RITP. Given to the limited samples size and nonrandomization of our study, no prognostic factors were found in our study, including sex, age, ITP duration, the lowest PLT count, previous therapy numbers, previous bleeding episodes, the combined drug and etc. Conclusion:ATRA may have the potential to help RITP patients gain remission and maintain remission combined with one of the conventional first-line therapies, which requires to be verified by more large-sized, prospective, randomized, and controlled clinical trials, and the mechanism of ATRA in treating RITP also needs to be further investigated. Disclosures:No relevant conflicts of interest to declare.

A dual association model for the extinction of animal conditioning

Reversal of synaptic plasticity has been the prevalent theory for extinction of animal conditioning. Phenomena like faster reacquisition after extinction are explained via residual synaptic plasticity in the relevant neural circuits. However, this account cannot explain many recent behavioral findings. This includes phenomena like savings in extinction, reinstatement, spontaneous recovery and renewal. These phenomena point to the possibility that extinction is not a mere reversal of the associations formed during acquisition. It instead involves the superimposition of some separate decremental process that works to inhibit the previously learned responses. We have explored this dual-pathway account using a neurocomputational model of conditioning. In our model, associations related to acquisition and extinction are maintained side by side as a result of the interaction between general neural learning processes and the presence of lateral inhibition between neurons. The model captures most of the relevant behavioral phenomena that prompted the hypothesis of separate acquisition and extinction pathways. It also shows how seemingly complex behavior can emerge out of relatively simple underlying neural mechanisms.

Kenaf Nanofiber/Polylactic Acid (PLA) Nanocomposite

Kenaf fiber was treated with alkaline to reduce lignin content and tested under Fourier transform infrared spectroscopy (FTIR). FTIR result showed that peak at 1146 cm-1 which is acetyl group of lignin was reduced in treated fiber while disappearing of carbonyl group in treated kenaf fiber at 1750cm-1 was significantly shown compared to untreated kenaf fiber. Treated fiber undergoes mechanical size decrement process by high pressure homogenizer with 500bar pressure and 60 passes. Transmission Electron microscopy (TEM) was used to determine size and distribution of fiber. Moreover, morphology of nanofiber was observed under scanning electron microscope (SEM). Nanofiber (3%, 5%, 8% and 10%) was mixed with PLA using internal mixer and then compressed with hot pressed to produce specimen for tensile test. Tensile strength and tensile modulus of nanocomposite with 10% of nanofiber increased by 30% and 85% respectively compared to pure PLA.

Motivational variables and the sensitization and habituation of aggression in the convict cichlid (Cichlasoma nigrofasciatum).

Four experiments using territorial Convict Cichlids investigated motivational factors involved in the incremental and decremental processes associated with aggression resulting from exposure to conspecifics intruded into the territory. The first three experiments varied some single aspect of the experimental situation (temperature, distance from the nest or size of the intruder). The fourth experiment combined those factors which resulted in faster habituation (small intruder, far from the nest, in cool water) and compared the response to factors which resulted in slower habituation or an increase in response rate (large intruder, close to the nest in warm water). While a combination of higher intensity stimuli did result in slower habituation than the combination of lower intensity stimuli, response rate was not a simple algebraic summation of the factors. Results are discussed in relation to multi-factor theory of habituation and the nature of "drive".

Preparation and characteristics of large-area and high-filling Ag nanowire arrays in OPAA template

Highly ordered porous anodic aluminum oxide (OPAA) on aluminum substrate with an ultrathin barrier layer was prepared by a two-step aluminum anodic oxidation plus a step-by-step voltage decrement process. Ag nanowire arrays have been successfully electrodeposited into the OPAA template through constant current technique. The morphology, composition and structure of the nanowire arrays were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that Ag nanowires possess smooth surface and high aspect ratio up to 330 with a diameter of 70–80 nm. Nearly 100% of the pores were filled by Ag nanowires, which have face center cubic structure and (111) preferential orientation. The branch of originally straight pores at the formation front was demonstrated and the branched pores favor the formation of several nucleation sites in each pore at the beginning of the electrodeposition.

Spontaneous recovery after reversal and partial reinforcement

Six experiments used magazine approach in rat subjects to explore changes with time in responding for stimuli brought to a common moderate level of performance through acquisition or extinction. They found no evidence for increases with time in behavior during stimuli given simple acquisition. However, stimuli brought to that same level by reversal learning, repeated reversal, or partial reinforcement all showed increases in responding with time. These results suggest that the decremental process established by nonreinforcement endures through subsequent reinforcement and is especially sensitive to the passage of time.

放射光を用いた銀電極によるフェライト格子歪の評価

The lattice constant of the NiZnCu ferrite was evaluated by X-ray diffraction using the synchrotron radiation source. In the experiment of the powder X-ray diffraction under pressure, the lattice constant shows the different values between the increment process and the decrement process. The behavior is similar to the change of the inductance under pressure. On the other hand, in the experiment of the mapping on the simplified multilayer chip inductor, the lattice constant depends on the sintering temperature and the location in the device. Moreover, Ag particles diffused from the Ag-conductor are found on the sample sintered at 920°C by Electron Probe Micro-Analysis. These results suggest that the lattice distortion of the NiZnCu ferrite caused by the stress from Ag-conductor and Ag-diffusion affects the magnetic permeability.

Resistance to extinction: contingency termination and generalization decrement

We present an algebraic model of resistance to extinction that is consistent with research on resistance to change. The model assumes that response strength is a power function of reinforcer rate and that extinction involves two additive, decremental processes: (1) the termination of the reinforcement contingency and (2) generalization decrement resulting from reinforcer omission. The model was supported by three experiments. In Experiment 1, 4 pigeons were trained on two-component multiple variable-interval (VI) 60-sec, VI 240-sec schedules. In two conditions, resistance to change was tested by terminating the response-reinforcer contingency and presenting response-independent reinforcers at the same rate as in training. In two further conditions, resistance to change was tested by prefeeding and by extinction. In Experiment 2, 6 pigeons were trained on two-component multiple VI 150-sec schedules with 8-sec or 2-sec reinforcers, and resistance to change was tested by terminating the response-reinforcer contingency in three conditions. In two of those conditions, brief delays were interposed between responses and response-independent reinforcers. In both Experiments 1 and 2, response rate was more resistant to change in the richer component, except for extinction in Experiment 1. In Experiment 3, 8 pigeons were trained on multiple VI 30-sec, VI 120-sec schedules. During extinction, half of the presentations of each component were accompanied by a novel stimulus to produce generalization decrement. The extinction data of Experiments 1 and 3 were well described by our model. The value of the exponent relating response strength and reinforcement was similar in all three experiments.

Retraining of extinguished Pavlovian stimuli.

Five Pavlovian magazine approach experiments with rat subjects examined the mechanisms by which reconditioning restores extinguished responding. Experiments 1, 2, and 3 found that retraining did not destroy the spontaneous recovery with the passage of time that is characteristic of extinguished stimuli. Experiments 4 and 5 found evidence that retaining after extinction enhanced the strength of the originally trained associations. Together these results suggest that, just as extinction does not destroy original acquisition but superimposes some decremental process, so retraining does not destroy that decremental process but instead superimposes further associative learning.

Spontaneous recovery after training with multiple outcomes

Four experiments explored the increase in an instrumental response (R) with time after it had been subjected either to extinction or to training with a second outcome (O). Experiment 1 found less performance of an extinguished response immediately after extinction than after a 7-day delay (spontaneous recovery). Experiments 2–4 found a similar difference when training with a second outcome replaced extinction, despite the failure of that replacement to itself undermine performance. Similar results did not occur when the second outcome was identical to that used in initial training. These results suggest that training with a novel outcome generates a decremental process that is not directly observable but that dissipates with time.

Decrement and the Illusions of the Mueller-Lyer Figure

Decrement, a time-related decrease in the magnitude of the Mueller-Lyer illusion, was measured separately for the wings-out and the wings-in variants of the Mueller-Lyer figure. There were significant reductions of wings-out illusion magnitude during the decrement period. Observers viewing the wings-in segment showed a non-significant decrement pattern. Analyses of individual decrement patterns showed that illusion magnitude did not decrease for a number of observers even when there were significant time-related trends at the group level. Data for 80 observers imply that the mechanisms of perceptual learning proposed by previous models of Mueller-Lyer illusion decrement are not sufficient explanations of the decrement process.

Elicitation and habituation of the electrodermal orienting response in a short interstimulus interval paradigm

The present experiment was carried out to investigate elicitation and habituation of the electrodermal Orienting Response with stimulus trains utilising a short interstimulus interval (ISI) of 1.1 s. We sought evidence for within-train response decrement to repeated stimulus presentation, response recovery to a change stimulus and dishabituation following the change stimulus — the three properties necessary to unequivocally identify a decremental process as habituation. No autonomic study could be found using such a short ISI. Autonomic studies on this time scale are necessary if these measures are to be integrated with central event-related potential (ERP) measures of electrical brain function. Overcoming this paradigm gap required the development of novel measurement procedures to estimate the small electrodermal responses obtained, usually occurring on the recovery slope of the response to the previous stimulus in the train. With our novel measurement procedures, evidence was found indicating that electrodermal activity in such a paradigm exhibited the three classic criteria of habituation.