An experimental study of wall-injected flows in a rectangular cylinder

An experimental investigation of the flow inside a rectangular cylinder with air injected continuously along the wall is performed. This kind of flow is a two-dimensional approximation of what happens inside a solid rocket motor, where the lateral grain burns expelling exhaust gas or in processes with air filtration or devices to attain uniform flows. We propose a brief derivation of some analytical solutions and a comparison between these solutions and experimental data, which are obtained using the Particle Image Velocimetry (PIV) technique, in order to provide a global reconstruction of the flowfield. The flow, which enters orthogonal to the injecting wall, turns suddenly its direction being pushed towards the exit of the chamber. Under the incompressible and inviscid flow hypothesis, two analytical solutions are reported and compared. The first one, known as Hart-McClure solution, is irrotational and the injection velocity is non-perpendicular to the injecting wall. The other one, due to Taylor and Culick, has non-zero vorticity and constant, vertical injection velocity. The comparison with laminar solutions is useful to assess whether transition to turbulence is reached and how the disturbance thrown in by the porous injection influences and modifies those solutions

First-Order Regular and Degenerate Identification Differential Problems

We are concerned with both regular and degenerate first-order identification problems related to systems of differential equations of weakly parabolic type in Banach spaces. Several applications to partial differential equations and systems will be given in a subsequent paper to show the fullness of our abstract results

Linear Sobolev Type Equations with Relatively -Sectorial Operators in Space of "Noises"

The concept of "white noise," initially established in finite-dimensional spaces, is transferred to infinite-dimensional case. The goal of this transition is to develop the theory of stochastic Sobolev type equations and to elaborate applications of practical interest. To reach this goal the Nelson-Gliklikh derivative is introduced and the spaces of "noises" are developed. The Sobolev type equations with relatively sectorial operators are considered in the spaces of differentiable "noises." The existence and uniqueness of classical solutions are proved. The stochastic Dzektser equation in a bounded domain with homogeneous boundary condition and the weakened Showalter-Sidorov initial condition is considered as an application

Steady states in a structured epidemic model with Wentzell boundary condition

We introduce a nonlinear structured population model with diffusion in the state space. Individuals are structured with respect to a continuous variable which represents a pathogen load. The class of uninfected individuals constitutes a special compartment that carries mass, hence the model is equipped with generalized Wentzell (or dynamic) boundary conditions. Our model is intended to describe the spread of infection of a vertically transmitted disease, for example Wolbachia in a mosquito population. Therefore the (infinite dimensional) nonlinearity arises in the recruitment term. First we establish global existence of solutions and the Principle of Linearised Stability for our model. Then, in our main result, we formulate simple conditions, which guarantee the existence of non-trivial steady states of the model. Our method utilizes an operator theoretic framework combined with a fixed point approach. Finally, in the last section we establish a sufficient condition for the local asymptotic stability of the positive steady state

Nonsymmetric elliptic operators with wentzell boundary conditions in general domains

We study nonsymmetric second order elliptic operators with Wentzell boundary conditions in general domains with sufficiently smooth boundary. The ambient space is a space of Lp-type, 1 ≤ p ≤ ∞. We prove the existence of analytic quasicontractive (C0)-semigroups generated by the closures of such operators, for any 1 ≤ p ≤ ∞. Moreover, we extend a previous result concerning the continuous dependence of these semigroups on the coefficients of the boundary condition. We also specify precisely the domains of the generators explicitly in the case of bounded domains and 1 ≤ p ≤ ∞, when all the ingredients of the problem, including the boundary of the domain, the coefficients, and the initial condition, are of class C∞

Bullying and cyberbullying: Do personality profiles matter in adolescence?

Bullying and cyberbullying represent pervasive issues in adolescence because they are very common situations with significant implications for concurrent and later adjustment. It is crucial to investigate the extent to which youths’ personality characteristics may represent a vulnerability to becoming (cyber)bullies or (cyber)victims. However, research mostly has focused on associations with single personality dimensions rather than overall functioning patterns, studies on personality profiles in relation to bullying are limited and under-examined, and no evidence for cyberbullying is available. Within Latent Profile Analysis (i.e., LPA), the present study aimed to identify personality profiles in a sample of 426 Italian early adolescents (Mage = 12; 51 % female), according to the Big Five Model (i.e., Extraversion-E, Agreeableness-A, Conscientiousness-C, Emotional Stability-ES, Openness-O), in connection with traditional bullying and cyberbullying roles (i.e., uninvolved, victims, bullies, bullies/victims). Three profiles emerged with specific associations with (cyber)bullying roles: (1) Resilient (with high scores in all traits) which tended to be uninvolved; (2) Undercontrolled (with low C, average-to-high E, and average-to-low ES, and O), which was more likely to be both bullies and victims, both offline and online; and (3) Overcontrolled (with very low E, average C, and average-to-low ES and O), which was more likely to be associated with traditional (but not online) victimization. The results fill a research gap, demonstrating that specific youths’ personality configurations may be associated with different roles in traditional and online bullying

Facing the Pandemic in Italy: Personality Profiles and Their Associations With Adaptive and Maladaptive Outcomes

The negative impact of the COVID-19 pandemic on individuals’ psychosocial functioning was widely attested during the last year. However, the extent to which individual differences are associated with adaptive and maladaptive outcomes during quarantine in Italy remains largely unexplored. Using a person-oriented approach, the present study explored the association of personality profiles, based on three broad individual dispositions (i.e., positivity, irritability, and hostile rumination) and two self-efficacy beliefs in the emotional area (i.e., expressing positive emotions and regulating anger emotion), with adaptive and maladaptive outcomes during the first Italian lockdown (March–June 2020). In doing so, we focused also on how different age groups (i.e., young adults and adults) differently faced the pandemic. The study was conducted through an online survey from May to June 2020 and included 1341 participants living in Italy, divided into two groups: 737 young adults aged 18–35 and 604 adults aged 36–60 years old. Latent Profile Analysis identified three personality profiles: resilient, vulnerable, and moderate. A subsequent path analysis model showed that the resilient profile was positively associated with prosocial behavior as an indicator of adaptive outcome, and negatively associated with three maladaptive outcomes: interpersonal aggression, depressive symptoms, and anxiety problems. Contrarily, the vulnerable profile resulted negatively associated with prosocial behavior and positively associated with the three maladaptive outcomes. Finally, regarding age group differences, young adults belonging to the vulnerable profile showed a greater association especially with interpersonal aggression, depression, and anxiety problems, as compared to adults belonging to the same profile. Overall, the results of the present study highlighted the importance to analyze individual functioning during an isolation period by using a person-oriented approach. Findings evidenced the existence of three different profiles (i.e., Resilient, Vulnerable, and Moderate) and subsequent path analysis revealed, especially for the vulnerable profile and young adults, a greater maladaptive consequence of the quarantine. The practical implications will be discussed

Smartphone and social network addiction in early adolescents: The role of self-regulatory self-efficacy in a pilot school-based intervention

Background: Youths' online problematic behaviors, such as smartphone or social network sites (SNS) addiction, gained increasing attention nowadays, due to their impact on concurrent and later adjustment, such as emotional and/or behavioral problems, academic impairments, or relational issues. Aims: This study aims to evaluate the effectiveness of a pilot school-based intervention to contrast online addictive behaviors while fostering adolescents' self-regulative abilities. Materials & Methods: The intervention started in January 2022 in an Italian junior high school located in Rome, and consisted of four meetings with students. A total sample of 462 15-year-old adolescents (Mage = 15.2; SD = 0.50; 41% females; Ncontrol = 214; Nintervention = 248) was considered. Within the latent difference score framework, we examined short-term changes from the pre-to-the-postintervention levels of SNS and smartphone addiction, and self-regulatory self-efficacy (SRSE) beliefs as a possible booster of the intervention's effectiveness. Results: Results showed a significant decrease in both online addictions (SNS and smartphone addiction), controlling for age, gender, sexual orientation, and socioeconomic status, because of the short-term efficacy of the project. The buffering effect of SRSE beliefs was further supported. Conclusion: These findings emphasized the usefulness of promoting youths' self-regulative beliefs to contrast problematic tendencies, according to a Positive Youth Development perspective which focused on resources rather than only on the prevention of negative outcomes for youths' adjustment

Biallelic BIRC3 inactivation in chronic lymphocytic leukaemia patients with 11q deletion identifies a subgroup with very aggressive disease.

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Exploring the protective function of positivity and regulatory emotional self-efficacy in time of pandemic covid-19

Despite several empirical studies on the 2019 coronavirus disease (COVID-19) pandemic that have highlighted its detrimental effect on individuals’ mental health, the identification of psychological factors that may moderate its impact on individuals’ behavior and well-being remains partly unexplored. The present study was conceived to examine the mediation role of regulatory emotional self-efficacy in the relationship between positivity and anxiety, depression, and perceived self-efficacy in complying with the containment measures to contrast the COVID-19 spread. Furthermore, the moderation role of age was tested. A sample of 1258 participants (64.2% women; Mage = 42.09, SD = 13.62) enrolled from the Italian general population answered an online survey aimed at investigating the role of individual differences in facing the COVID-19 pandemic. We opted for a snowball recruiting procedure to find participants. The online survey was disseminated through email invitation and using social media platforms (i.e., Facebook, Instagram). A multi-group path analysis model was performed using Mplus 8.4 to explore the hypothesized relations among variables. The following criteria were employed to evaluate the goodness of fit: χ2 likelihood ratio statistic, CFI and TLI > 0.95, RMSEA < 0.06 and SRMR < 0.08. The findings corroborated the protective role of both positivity and regulatory emotional self-efficacy in reducing individuals’ anxiety and depressive symptoms, as well as in fostering individuals’ capabilities in complying with the containment measures imposed by the government to reduce the risk of illness and to contain the spread of the virus COVID-19. Specifically, regulatory emotional self-efficacy beliefs partially mediated the relations between positivity and anxiety and depressive symptoms and fully mediated the effect of positivity on perceived self-efficacy beliefs in complying with the containment measures. These paths were equal across ages. The results of the present study appear relevant to implementing psychological interventions aimed to reduce the deleterious effects of the COVID-19 pandemic on mental health through the promotion of individuals’ optimistic orientation and emotion regulation