Short distance singularities and automatic O(aa) improvement: the cases of the chiral condensate and the topological susceptibility

Short-distance singularities in lattice correlators can modify their Symanzik expansion by leading to additional O($a$) lattice artifacts. At the example of the chiral condensate and the topological susceptibility, we show how to account for these lattice artifacts for Wilson twisted mass fermions and show that the property of automatic O($a$) improvement is preserved at maximal twist.Comment: 12 pages, corrected proof for topological susceptibility, version published in JHE

Topological susceptibility from twisted mass fermions using spectral projectors

We discuss the computation of the topological susceptibility using the method of spectral projectors and dynamical twisted mass fermions. We present our analysis concerning the O(a)-improvement of the topological susceptibility and we show numerical results for Nf=2 and Nf=2+1+1 flavours, performing a study of the quark mass dependence in terms of leading order chiral perturbation theory.Comment: 7 pages, 3 figures; presented at the 31st International Symposium on Lattice Field Theory (Lattice 2013), 29 July - 3 August 2013, Mainz, German

Computation of the chiral condensate using Nf=2N_f=2 and Nf=2+1+1N_f=2+1+1 dynamical flavors of twisted mass fermions

We apply the spectral projector method, recently introduced by Giusti and L\"uscher, to compute the chiral condensate using $N_f=2$ and $N_f=2+1+1$ dynamical flavors of maximally twisted mass fermions. We present our results for several quark masses at three different lattice spacings which allows us to perform the chiral and continuum extrapolations. In addition we report our analysis on the $O(a)$ improvement of the chiral condensate for twisted mass fermions. We also study the effect of the dynamical strange and charm quarks by comparing our results for $N_f=2$ and $N_f=2+1+1$ dynamical flavors.Comment: 7 pages, 3 figures; presented at the 31st International Symposium on Lattice Field Theory (Lattice 2013), 29 July - 3 August 2013, Mainz, German

Testing the Witten-Veneziano Formula on the Lattice

In this proceeding contribution we report on a test of the famous Witten-Veneziano formula using lattice techniques. We perform dedicated quenched simulations and apply the spectral projector method to determine the topological susceptibility in pure Yang-Mills theory. In order to compute the relevant meson masses and the flavor singlet decay constant we employ lattice QCD with $N_f=2+1+1$ dynamical Wilson twisted mass fermions. Taking the continuum and the $SU(2)$ chiral limits we find good agreement within uncertainties for both sides of the formula.Comment: 7 pages, 4 figures, presented at the 33rd International Symposium on Lattice Field Theory, 14 -18 July 2015, Kobe International Conference Center, Kobe, Japa

A Security Risk Assessment Method for Distributed Ledger Technology (DLT) based Applications: Three Industry Case Studies

Distributed ledger technologies have gained significant attention and adoption in recent years. Despite various security features distributed ledger technology provides, they are vulnerable to different and new malicious attacks, such as selfish mining and Sybil attacks. While such vulnerabilities have been investigated, detecting and discovering appropriate countermeasures still need to be reported. Cybersecurity knowledge is limited and fragmented in this domain, while distributed ledger technology usage grows daily. Thus, research focusing on overcoming potential attacks on distributed ledgers is required. This study aims to raise awareness of the cybersecurity of distributed ledger technology by designing a security risk assessment method for distributed ledger technology applications. We have developed a database with possible security threats and known attacks on distributed ledger technologies to accompany the method, including sets of countermeasures. We employed a semi-systematic literature review combined with method engineering to develop a method that organizations can use to assess their cybersecurity risk for distributed ledger applications. The method has subsequently been evaluated in three case studies, which show that the method helps to effectively conduct security risk assessments for distributed ledger applications in these organizations

Benchmarking the vulnerability detection capabilities of software analysis tools

Code cloning and copy-pasting code fragments is common practice in software engineering. If security vulnerabilities exist in a cloned code segment, those vulnerabilities may spread in the related software, potentially leading to security incidents. Code similarity is one effective approach to detect vulnerabilities hidden in software projects. However, due to the complexity, size, and diversity of source code, current methods suffer from low accuracy, and poor performance. Moreover, most existing clone detection techniques focus on a limited set of programming languages in the detection process. We propose to solve these problems using SearchSECO, a software analysis tool that detects vulnerabilities in multiple programming languages

Hunger in Vulnerable Families in Southeastern Europe: Associations With Mental Health and Violence

Background: Hunger can influence healthy development of children and has been shown to be associated with other determinants of child health, such as violence within the family and maternal (mental) health problems. Whilst the majority of research has been conducted in high-income countries with vulnerable populations, less is known about the circumstances in low-and-middle-income countries. This study explored the experience of hunger in vulnerable families in three Southeastern European countries, and simultaneously examined relationships with four sets of risk factors—lack of financial, mental, familial, and social resources. Methods: Families (N = 140) were recruited for a parenting intervention targeting child behavioral problems. Baseline data was collected on hunger, socioeconomic characteristics, mental health and wellbeing, family violence (i.e., child maltreatment and intimate partner violence), and social and emotional support. Univariate and multivariable risk factors of hunger were examined cross-sectionally with regression models. Results: Overall, 31% of families experienced at least one form of hunger in the last month. Worse family functioning, current intimate partner violence, and more instances of child neglect showed univariate associations with family hunger. In hierarchical analysis, five risk factors remained significantly associated with the experience of hunger: lower adult educational, literacy level, emotional support, more children in the household and higher scores on parental depression, anxiety, and stress. Conclusions: Hunger in Southeastern European families, among families with children showing elevated behavioral problems, was associated with more family violence, but specifically poorer mental health and less emotional support above and beyond socio-structural strains. Adapting parenting interventions to support the primary caregiver in getting more access to emotional support may potentially also change hunger and its association with health and violence. However, this hypothetical pathway of change needs explicit testing

Screen use: Its association with caregiver mental health, parenting, and children's ADHD symptoms

Objective: The aim was to examine the relationship between caregiver's mental health (parental psychological distress, and parenting stress), dysfunctional parenting (lax or overreactive parenting), and the screen media use in understanding attention-deficit/hyperactivity disorder (ADHD) symptoms of children within an integrated model framework. Background: Familial factors and screen use have shown to be significantly related to ADHD in children. However, theoretical models of the role of family environment, screen use, and ADHD have rarely been tested jointly, and little is known about these associations in southeastern European middle-income countries (MICs). Method: Data from 835 primary caregivers (92% biological mother, 4% biological father, 3% grandmother or grandfather, 1% other) of children (2 to 9 years) from three MICs were analyzed using path analyses, and models were tested for generalizability across education levels and marital status using multigroup analyses. ADHD-related symptoms were assessed with a structured clinical interview (Mini International Neuropsychiatric Interview for Children and Adolescents–Parent Version [MINI-KID-P]) and the Child Behavioral Checklist (CBCL). Results: Whereas screen use was directly associated with ADHD symptoms across measures, a significant indirect effect of lax parenting on attentional problems via screen use was found only for the CBCL parent report. The final models were tested using multigroup analyses across education levels and marital status with no significant differences. Conclusion: Investments in resource and capacity building for children's primary caregivers that target lax parenting and limiting of screen use may impact children's attentional problems across educational levels and married and nonmarried caregivers

A Feature Model of Consensus Algorithms in Distributed Ledger Technology

A distributed ledger is a database distributed across multiple systems, with each system holding a synchronized copy of the data. Distributed ledger technology has applications in various healthcare, finance, and cybersecurity domains. However, the intricacies of the features of consensus algorithms, which ensure consistency across different ledgers, remain challenging, as the relevant knowledge is scattered across a wide range of literature or in the form of tacit knowledge of software practitioners. This study presents a systematic data collection comprising an extensive literature review and a set of expert interviews to provide insights into designing and evaluating of consensus algorithms for web3 applications. The usability and usefulness of the extracted knowledge were evaluated by seven experienced practitioners in web3 development companies, resulting in an overview of 13 consensus algorithms, their features, and their impacts on quality models. With this comprehensive knowledge, web3 developers can expedite evaluating, selecting, and implementing consensus algorithms for distributed ledgers