On the role of impulsivity and decision-making in suicidal behavior

Suicide risk constitutes a complex set of interacting demographic, clinical, psychobiological and environmental variables. Impulsivity is a long-known risk factor for suicide attempts. However, research based on clearer conceptual refinement in this area is imperative. One emerging field of study is that of decision-making. Impulsivity involves a failure of higher-order control, including decision-making. Using standardized operational definitions that take into consideration relevant aspects of impulsivity, including state- and trait-components and a deeper understanding of the process of decision-making in the suicidal mind, we may come a step closer to understanding suicidality and winning the fight in this scourge of human suffering.

Health-related quality of life, anxiety, depression and impulsivity in patients with advanced gastroenteropancreatic neuroendocrine tumours

AIM To compare health-related quality of life(HRQoL),anxiety, depression, and impulsivity scores in patients with and without carcinoid syndrome(CS), and correlated them with serum 5-hydroxyindoleacetic acid(5-HIAA) levels.METHODS Patients with advanced gastroenteropancreatic neuroendocrine tumours(GEPNET), with and without CS completed HRQoL QLQ-C30 and QLQ-GI.NET21, Hospital Anxiety and Depression Scale(HADS) and Barratt Impulsivity Scale(BIS) questionnaires. Twosample Wilcoxon test was applied to assess differences in serum 5-HIAA levels, two-sample Mann-Whitney U test for HRQoL and BIS, and proportion test for HADS, between those with and without CS.RESULTS Fifty patients were included; 25 each with and without CS. Median 5-HIAA in patients with and without CS was 367 nmol/L and 86 nmol/L, respectively(P = 0.003). Scores related to endocrine symptoms were significantly higher amongst patients with CS(P = 0.04) and scores for disease-related worries approached significance in the group without CS, but no other statistically-significant differences were reported between patients with and without CS in responses on QLQ-C30 or QLQ-GI.NET21. Fifteen patients(26%) scored ≥ 8/21 on anxiety scale, and 6(12%) scored ≥ 8/21 on depression scale. There was no difference in median 5-HIAA between those scoring < or ≥ 8/21 on anxiety scale(P = 0.53). There were no statistically significant differences between groups in first or second-order factors(BIS) or total sum(P = 0.23).CONCLUSION Excepting endocrine symptoms, there were no significant differences in HRQoL, anxiety, depression or impulsivity between patients with advanced GEPNET, with or without CS. Over one quarter of patients had high anxiety scores, unrelated to peripheral serotonin metabolism.

Alterations of attention and impulsivity in the rat following a transgenerational decrease in dietary omega-3 fatty acids

Polyunsaturated fatty acids(PUFAs),particularly the omega-3 PUFAs,are thought to be involved in neuronal processes,to play a role in neurodevelopmental disorders and to be important for the integrity of central nervous system functioning.The present study investigated the effects of nutritional omega-3 PUFAs on attentional functions and impulsive behavior in Wistar rats.For this purpose,female Wistar rats were fed an omega-3 deficient diet over several generations,and the dams of the seventh generation were randomly assigned to two diet groups and fed an omega-3 deficient or an omega-3 sufficient diet.In addition,a group of previously untreated dams was fed an omega-3 sufficient diet.The male offspring of these three diet groups were tested using an established paradigm for the assessment of attention and impulsive behavior,i.e.a modified version of the five-choice-serial-reaction-time task(5CSRTT).The present data show that the deficiency of omega-3 PUFAs over generations led to substantial changes in attentional processes and impulsive behaviors.The impairments associated with an omega-3 deficiency were partly corrected by treatment with the omega-3 sufficient diet in the last generation of the omega-3 deficient group which showed substantial improvements in attention parameters.While there were no significant effects of dietary modifications on psychomotor activity levels,there was some evidence for changes in impulsive behavior.In conclusion,transgenerational dietary changes in the availability of omega-3 PUFAs led to changes in attentional processes and impulsive behavior in rats,supporting the hypothesis that omega-3 PUFAs play a role in cognitive and behavioral processes.The present findings offer a promising approach in the investigation of the role of omega-3 PUFAs in a variety of cognitive and behavioral domains.

Variation in the <i>DRD2</i>gene affects impulsivity in intertemporal choice

Introduction: Impulsivity in intertemporal choice has been operationalized as “delay discounting,” referring to the preference for a sooner, smaller reward in neuroeconomics. It is reportedly associated with the dopaminergic systems. Dopamine receptor D2 (DRD2) is the D2 subtype of the dopamine receptor of the G-protein coupled receptor family. The aim of this study was to explore the effect of single nucleotide polymorphisms (SNPs) in DRD2 gene on delay discounting. Methods: The participants consisted of 91 healthy Japanese people (66 males and 25 females with a mean age of 40.9 ± 6.9 years). Each participant completed the Kirby’s monetary choice questionnaire (MCQ) for delayed gain and donated a whole blood sample. Two SNPs (C957T (rs6277) and TaqI A (rs1800497)) in DRD2 were genotyped by using the DigiTag2 assay. SNP linear regression analyses with 100,000 permutations were conducted for the hyperbolic time-discount rate (k). Results: The SNP C957T showed a significant association;participants with more minor alleles (T) were more impulsive in intertemporal choice for delayed gain (multiplicity-corrected P = 0.041 with a small effect size). Conclusion: The variation in the DRD2 gene is associated with impulsive decision-making. This is the first study to demonstrate an association between DRD2 and impulsivity in intertemporal choice with a multiplicity-corrected significance.

Gambling and Impulsivity: An Exploratory Study in a French Adolescent Population

Pathological gambling can be a serious problem, more so to a vulnerable population such as adolescents and youth. This study aims to investigate the links between gambling behaviours and impulsivity through a multidimensional approach in a French adolescent population. A secondary aim of this study is to find out the prevalence of pathological gambling behaviour amongst adolescents who are not meant to have legal access to such games. We administered the UPPS Impulsive behaviour Scale (UPPS-P) and the Canadian Pathological Gambling Index CPGI to 1800 adolescents aged between 11 to 17 years. Our results indicate that 33% of subjects have gambled at least once during the last year and that girls gamble as much as boys (17% and 16% respectively). Scratch games are the most common games played by adolescents (81.4%). We also notice that 1.6% of our population has problematic gambling behaviour. Although we found that many dimensions of impulsivity (Urgency, Positive urgency and Sensation seeking) are correlated to gambling behaviour, only sensation seeking seems to be a good predictor of pathological gambling severity. These results can be taken into account in the development of prevention programs.

Impulsivity Subtypes and Maladaptive Road Performance among Drivers in Germany and Switzerland

Excessive speed and speeding substantially compromise road safety in Germany and Switzerland.Approximately one third of all fatal accidents are caused by maladjusted speed.Recent studies attribute a special importance to the impulsivity construct in the context of maladaptive road behavior.Thus,the effects of impulsivity on risky driving behaviors(speeding violations)were examined in a Swiss-German sample of N=361 car drivers(both on speed affine drivers and putative ordinary drivers).The participants filled in a questionnaire battery consisting of an impulsiveness scale as well as traffic-related attitudes and cognitive appraisal tendencies on the one hand and indicators for maladaptive behaviors at and beyond traffic domain on the other hand.The directions of the observed correlations between the scales were as expected,with impulsivity correlating negatively with age(young drivers scored higher)but not at all with gender or driving experience.To find out more about the functionality of impulsivity,specific personality profiles were carried out via cluster analysis.Three different control types were empirically found(impulsivity subtype,reduced compliance subtype,vulnerability subtype),while high impulsive drivers scored high in impulsivity,low on compliance,high on affective responsiveness and described themselves as affordance-prone.The impulsive type additionally shows more speeding offences stored in the driving license file,overrides speed limits for more than 15 km/h more frequently and even shows deviancy beyond traffic domain.The results are discussed in the light of the impulse control system and conclusions are drawn regarding assessment of driving aptitude and interventions.The theoretical framework including a hierarchical structured model of deviance was confirmed empirically.

The Link between Facets of Impulsivity and Aggression in Extremely Violent Prisoners

Evidence is growing that aggressive behavior and impulsivity have subgroups. The subscales of the Urgency, Premeditation, Perseverance and Sensation seeking (UPPS) impulsivity scale and the Bryant and Smith shortened and refined version of the Aggression Questionnaire were used to describe and compare impulsive and aggressive behavior in extremely violent and aggressive male inmates and non-violent healthy male controls. The Mann-Whitney test showed that there was a significant difference (p < 0. 006) in the total UPPS impulsivity scale scores between the aggressive inmates and the controls. The subscales revealed that this difference was based mainly on the urgency score (p < 0. 003). On the aggression subscales, the inmates scored significantly higher for physical aggression than the controls (p < 0.001), but no significant difference was seen between inmates and controls for verbal aggression, anger and hostility, although the exact p-value was very close to statistical significance at 0.054. Regression analysis revealed a strong relationship between urgency and the aggression subscales hostility (p = 0.0004) and anger (p = 0.003) and that urgency was also linked to symptoms of anxiety (p = 0.008). Finally, a statistically significant link was found between both hostility (p = 0.0003) and anger (p = 0.002) and symptoms of anxiety. The highly selected subgroup of extremely violent criminals in this study were more physically aggressive than non-violent controls, with urgency as the driving feature in their impulsive behavior, and hostility, anger and symptoms of anxiety as underlying traits.

Characterizing motor impulsivity of individuals classified as overweight to obese

Deficits in the impulse control system are an important predictor of energy intake and body weight.Adults classified as overweight to obese may possess these deficits as a general behavioral trait or they may be foodspecific.The present study assessed motor impulsivity(ability to suppress a pre-potent response)when presented with food and neutral(non-food)cues,testing if deficits in motor impulsivity is specific to food cues or a general trait among participants classified as overweight to obese.The proportion of inhibitory failures to no-go targets following food cues(10.8%)was significantly greater than the proportion of inhibitory failures to no-go targets following neutral cues(1.9%,p<0.001).These differences remained when covering for sex and hunger.This indicates deficits in food-specific impulse control(as opposed to general impulse control)are present in those classified as overweight to obese.Understanding the specific aspect of impulse control that is present in this population is needed for the development of future impulse control training interventions that seek to change eating behaviors as a means for weight control.

Analysis and Design of Time-Delay Impulsive Systems Subject to Actuator Saturation

This paper investigates the exponential stability and performance analysis of nonlinear time-delay impulsive systems subject to actuator saturation. When continuous dynamics is unstable, under some conditions, it is shown that the system can be stabilized by a class of saturated delayed-impulses regardless of the length of input delays. Conversely, when the system is originally stable, it is shown that under some conditions, the system is robust with respect to sufficient small delayed-impulses. Moreover, the design problem of the controller with the goal of obtaining a maximized estimate of the domain of attraction is formulated via a convex optimization problem. Three examples are provided to demonstrate the validity of the main results.

PCA-LSTM:An Impulsive Ground-Shaking Identification Method Based on Combined Deep Learning

Near-fault impulsive ground-shaking is highly destructive to engineering structures,so its accurate identification ground-shaking is a top priority in the engineering field.However,due to the lack of a comprehensive consideration of the ground-shaking characteristics in traditional methods,the generalization and accuracy of the identification process are low.To address these problems,an impulsive ground-shaking identification method combined with deep learning named PCA-LSTM is proposed.Firstly,ground-shaking characteristics were analyzed and groundshaking the data was annotated using Baker’smethod.Secondly,the Principal Component Analysis(PCA)method was used to extract the most relevant features related to impulsive ground-shaking.Thirdly,a Long Short-Term Memory network(LSTM)was constructed,and the extracted features were used as the input for training.Finally,the identification results for the Artificial Neural Network(ANN),Convolutional Neural Network(CNN),LSTM,and PCA-LSTMmodels were compared and analyzed.The experimental results showed that the proposed method improved the accuracy of pulsed ground-shaking identification by>8.358%and identification speed by>26.168%,compared to other benchmark models ground-shaking.

Modeling Near-Field Impulsive Waves Generated by Deformable Landslide Using the HBP Model Based on the SPH Method

Landslide-generated impulsive waves(LGWs)in reservoir areas can seriously threaten waterway safety as well as hu-man life and properties around the two side slopes.The risk reduction and mitigation of such a hazard require the accurate prediction of near-field wave characteristics,such as wave amplitude and run-up.However,near-field LGW involves complicated fluid-solid interactions.Furthermore,the wave characteristics are closely related to various aspects,including the geometry and physical features of the slide,river,and body of water.However,the empirical or analytical methods used for rough estimation cannot derive accurate results,especially for deformable landslides,due to their significant geometry changes during the sliding process.In this study,the near-field waves generated by deformable landslides were simulated by smoothed particle hydrodynamics(SPH)based on multi-phase flow.The deformable landslides were generalized as a kind of viscous flow by adopting the Herschel-Bulkley-Papanastasiou(HBP)-based nonNewtonian rheology model.The HBP model is capable of producing deformable landslide dynamics even though the high-speed sliding process is involved.In this study,an idealized experiment case originating from Lituya LGW and a practical case of Gongjiafang LGW were reproduced for verification and demonstration.The simulation results of both cases show satisfactory consistency with the experiment/investigation data in terms of landslide movement and near-field impulsive wave characteristics,thus indicating the applicability and accuracy of the proposed method.Finally,the effects of the HBP model’s rheological parameters on the landslide dynamics and near-field wave characteristics are discussed,providing a parameter calibration method along with sug-gestions for further applications.

Lyapunov Conditions for Finite-Time Input-to-State Stability of Impulsive Switched Systems

Dear Editor,This letter studies finite-time input-to-state stability(FTISS)for impulsive switched systems.A set of Lyapunov-based conditions are established for guaranteeing FTISS property.When constituent modes governing continuous dynamics are FTISS and discrete dynamics involving impulses are destabilizing,the FTISS can be retained if impulsive-switching signals satisfy an average dwell-time(ADT)condition.

Research on the Relationship Between Environmental and Economic Coupling Systems in Bohai Bay Area Based on a Vector Autoregression(VAR)Model

This study analyzed the impact of land-based contaminants and tertiary industrial structure on economic development in the selected Bohai Bay area,China.Based on panel data spanning 2011-2020,a vector autoregressive(VAR)model is used to analyze and forecast the short-run and long-run relationships between three industrial structures,pollutant discharge,and economic development.The results showed that the environmental index had a long-term cointegration relationship with the industrial structure economic index.Per capital chemical oxygen demand(PCOD)and per capita ammonia nitrogen(PNH_(3)N)had a positive impact on delta per capita GDP(dPGDP),while per capita solid waste(PSW),the secondary industry rate(SIR)and delta tertiary industry(dTIR)had a negative impact on dPGDP.The VAR model under this coupling system had stability and credibility.The impulse response results showed that the short-term effect of the coupling system on dPGDP was basically consistent with the Granger causality test results.In addition,variance decomposition was used in this study to predict the long-term impact of the coupling system in the next ten periods(i.e.,ten years).It was found that dTIR had a great impact on dPGDP,with a contribution rate as high as 74.35%in the tenth period,followed by the contribution rate of PCOD up to 3.94%,while the long-term contribution rates of PSW,SIR and PNH3N were all less than 1%.The results show that the government should support the development of the tertiary industry to maintain the vitality of economic development and prevent environmental deterioration.

Experimental and numerical investigation on alternatives to sandy gravel

The NATO agreement STANAG 4569 defines the protection levels for the occupants of logistic and light armored vehicle.The Allied Engineering Publication,AEP-55,Volume 2 document outlines the test conditions for underbelly improvised explosive device(IEDs),which must be buried in water-saturated sandy gravel.The use of sandy gravel has some drawbacks,for instance reproducibility,time consumption,and cost.This paper focuses on the investigation of four alternatives to sandy gravel,which could produce similar specific and cumulative impulses:a concrete pot filled with water,a concrete pot filled with quartz sand,a steel pot without filling and a concrete pot filled with glass spheres(diameter 200μm—300μm)and different water contents.The impulses are measured with a ring technology developed at the Fraunhofer EMI.A numerical soil model based on the work of Marrs,2014 and Fi serov a,2006 and considering the soil moisture was used to simulate the experiments with glass spheres at different water contents,showing much better agreement with the experiments than the classical Laine&Sandvik model,even for high saturation levels.These results can be used to create new test conditions at original scale that are more cost-effective,more reproducible and simpler to manage in comparison to the current tests carried out with STANAG sandy gravel.

Application of ultrasonography-elastography score to suspect porto-sinusoidal vascular disease in patients with portal vein thrombosis

Background:Porto-sinusoidal vascular disease(PSVD)and portal vein thrombosis(PVT)are causes of portal hypertension characterized respectively by an intrahepatic and a pre-hepatic obstacle to the flow in the portal system.As PVT may be a consequence of PSVD,in PVT patients at presentation,a pre-existing PSVD should be suspected.In these patients the identification of an underlying PSVD would have relevant implication regarding follow-up and therapeutic management,but it could be challenging.In this setting ultrasonography may be valuable in differential diagnosis.The aim of the study was to use ultrasonography to identify parameters to discriminate between PSVD and“pure”PVT and then to suspect PVT secondary to a pre-existing PSVD.Methods:Fifty-three patients with histologically proven PSVD and forty-eight patients affected by chronic PVT were enrolled and submitted to abdominal ultrasonography with elastography by acoustic radiation force impulse(ARFI).Results:ARFI was higher and superior mesenteric vein(SMV)diameter was wider in PSVD patients than in PVT patients.Thus,a prognostic score was obtained as linear combinations of the two parameters with a good discrimination capacity between PSVD and PVT(the area under the curve=0.780;95%confidence interval:0.690-0.869).Conclusions:A score based on ARFI and SMV diameter may be useful to suspect an underlying PSVD in patients with PVT and to identify a subgroup of patients to be submitted to liver biopsy.

Localization for mixed near-field and far-field sources under impulsive noise

In order to solve the problem that the performance of traditional localization methods for mixed near-field sources(NFSs)and far-field sources(FFSs)degrades under impulsive noise,a robust and novel localization method is proposed.After eliminating the impacts of impulsive noise by the weighted out-lier filter,the direction of arrivals(DOAs)of FFSs can be estimated by multiple signal classification(MUSIC)spectral peaks search.Based on the DOAs information of FFSs,the separation of mixed sources can be performed.Finally,the estimation of localizing parameters of NFSs can avoid two-dimension spectral peaks search by decomposing steering vectors.The Cramer-Rao bounds(CRB)for the unbiased estimations of DOA and range under impulsive noise have been drawn.Simulation experiments verify that the proposed method has advantages in probability of successful estimation(PSE)and root mean square error(RMSE)compared with existing localization methods.It can be concluded that the proposed method is effective and reliable in the environment with low generalized signal to noise ratio(GSNR),few snapshots,and strong impulse.

ON DE FINETTI'S OPTIMAL IMPULSE DIVIDEND CONTROL PROBLEM UNDER CHAPTER 11 BANKRUPTCY

Motivated by recent advances made in the study of dividend control and risk management problems involving the U.S.bankruptcy code,in this paper we follow[44]to revisit the De Finetti dividend control problem under the reorganization process and the regulator's intervention documented in U.S.Chapter 11 bankruptcy.We do this by further accommodating the fixed transaction costs on dividends to imitate the real-world procedure of dividend payments.Incorporating the fixed transaction costs transforms the targeting optimal dividend problem into an impulse control problem rather than a singular control problem,and hence computations and proofs that are distinct from[44]are needed.To account for the financial stress that is due to the more subtle concept of Chapter 11 bankruptcy,the surplus process after dividends is driven by a piece-wise spectrally negative Lévy process with endogenous regime switching.Some explicit expressions of the expected net present values under a double barrier dividend strategy,new to the literature,are established in terms of scale functions.With the help of these expressions,we are able to characterize the optimal strategy among the set of admissible double barrier dividend strategies.When the tail of the Lévy measure is log-convex,this optimal double barrier dividend strategy is then verified as the optimal dividend strategy,solving our optimal impulse control problem.

Decision-Making and Management of Self-Care in Persons with Traumatic Spinal Cord Injuries: A Preliminary Study

Patients and physicians understand the importance of self-care following spinal cord injury (SCI), yet many individuals with SCI do not adhere to recommended self-care activities despite logistical supports. Neurobehavioral determinants of SCI self-care behavior, such as impulsivity, are not widely studied, yet understanding them could inform efforts to improve SCI self-care. We explored associations between impulsivity and self-care in an observational study of 35 US adults age 18 - 50 who had traumatic SCI with paraplegia at least six months before assessment. The primary outcome measure was self-reported self-care. In LASSO regression models that included all neurobehavioral measures and demographics as predictors of self-care, dispositional measures of greater impulsivity (negative urgency, lack of premeditation, lack of perseverance), and reduced mindfulness were associated with reduced self-care. Outcome (magnitude) sensitivity, a latent decision-making parameter derived from computationally modeling successive choices in a gambling task, was also associated with self-care behavior. These results are preliminary;more research is needed to demonstrate the utility of these findings in clinical settings. Information about associations between impulsivity and poor self-care in people with SCI could guide the development of interventions to improve SCI self-care and help patients with elevated risks related to self-care and secondary health conditions.

Exponential Estimation of the Lyapunov Function for Delay-Coupled Neural Networks with Integral Terms

This paper investigates a class of coupled neural networks with delays and ad-dresses the exponential synchronization problem using delay-compensatory impulsive control. Razumikhin-type inequalities involving some destabilizing delayed impulse gains are proposed, along with a new delay-compensatory concept demonstrating two crucial roles in system stability. Based on the constructed inequalities and the introduced delay-compensatory concept, sufficient stability and synchronization criteria for globally exponential synchronization of coupled neural networks are provided. To address the exponential synchronization problem in coupled neural networks. Utilizing delay-compensatory impulsive control and Razumikhin-type inequalities. The Lyapunov function for coupled neural networks with delays and integral terms exhibits exponential estimates.

Modification of SDOF model for reinforced concrete beams under close-in explosion

In this paper,a modified single-degree-of-freedom(SDOF)model of reinforced concrete(RC)beams under close-in explosion is proposed by developing the specific impulse equivalent method and flexural resistance calculation method.The equivalent uniform specific impulse was obtained based on the local conservation of momentum and global conservation of kinetic energy.Additionally,the influence of load uniformity,boundary condition and complex material behaviors(e.g.strain rate effect,hardening/softening and hoop-confined effect)was considered in the resistance calculation process by establishing a novel relationship between external force,bending moment,curvature and deflection successively.The accuracy of the proposed model was verified by carrying out field explosion tests on four RC beams with the scaled distances of 0.5 m/kg~(1/3)and 0.75 m/kg~(1/3).The test data in other literatures were also used for validation.As a result,the equivalent load implies that the blast load near the mid-span of beams would contribute more to the maximum displacement,which was also observed in the tests.Moreover,both the resistance model and test results declare that when the blast load becomes more concentrated,the ultimate resistance would become lower,and the compressive concrete would be more prone to softening and crushing.Finally,based on the modified SDOF model,the calculated maximum displacements agreed well with the test data in this paper and other literatures.This work fully proves the rationality of the modified SDOF method,which will contribute to a more accurate damage assessment of RC structures under close-in explosion.