Orbital angular momentum control of strong-field ionization in atoms and molecules.

Tunnel ionization, the fundamental process in strong field physics and attosecond science, along with the subsequent electron dynamics are typically governed by the polarization and carrier envelope phase of the incident laser pulse. Moreover, most light-matter interactions involve Gaussian beams and rely primarily on dipole-active transitions. In this article, we reveal that Orbital Angular Momentum (OAM) carrying beams enable to control tunnel ionization in atoms and molecules.

Femtosecond Laser Assisted Chemical Ionization Mass Spectrometry: Toward Sub-ppq Detection Limits for Organic Molecules.

Ultrasensitive analysis of organic molecules is crucial for various fundamental research and applications. State-of-the-art techniques for this purpose can achieve detection limits of several hundred ppq (parts-per-quadrillion), while a higher sensitivity is pursued constantly. To achieve this goal, we develop femtosecond laser assisted chemical ionization for mass spectrometry.

The Association Between the Impact of COVID-19 and Internalizing Problems Among Children and Adolescents with ADHD: The Moderating Role of Parental Anxiety.

Previous research has identified an increase in internalizing problems during the COVID-19 pandemic in children and adolescents with attention-deficit/hyperactivity disorder (ADHD). Additionally, it has been observed that parents of children with ADHD had elevated levels of anxiety during the pandemic. The current study aimed to longitudinally assess whether the impact of COVID-19 was associated with internalizing problems in children and adolescents with ADHD during the middle (Time 1-Spring 2021 [T1]) and end (Time 2-Fall/Winter 2022 [T2]) of the pandemic, and whether parental anxiety moderated this relationship over time.

Usability of an eHealth sleep education intervention for university students.

Background: It has been estimated that more than one-third of university students suffer from insomnia. Few accessible eHealth sleep education programmes exist for university students and of the ones that do exist, fewer were developed using a user-centred approach, which allows for student input to be systematically collected and utilized to provide students with a programme that they consider to be easy to use and implement and to be effective. () is a four-session eHealth sleep education programme designed for youth but previously only evaluated in younger adolescents (ages 14-18 years).

Examining the role of the visuospatial sketchpad in children's math calculation skills using Baddeley and Hitch's model of working memory.

Math difficulties (MDs) occur in about 3-7 % of children and have been associated with academic, health, and occupational challenges. To date, findings about the role of working memory in MDs have been conflicting. The Automated Working Memory Assessment Battery (AWMA), which assesses all components of Baddeley and Hitch's model of working memory, was used to investigate which component of the model was most related to math calculation skills in elementary-school children.

Understanding the unique and common perspectives of partners engaged in knowledge mobilization activities within pediatric pain management: a mixed methods study.

Background: Knowledge mobilization (KM) is essential to close the longstanding evidence to practice gap in pediatric pain management. Engaging various partners (i.e.

Intrinsic dichroism in amorphous and crystalline solids with helical light.

Amorphous solids do not exhibit long-range order due to the disordered arrangement of atoms. They lack translational and rotational symmetry on a macroscopic scale and are therefore isotropic. As a result, differential absorption of polarized light, called dichroism, is not known to exist in amorphous solids.

Propagation effects in polarization-gated attosecond soft-X-ray pulse generation.

Accurate estimation of the duration of soft-x-ray pulses from high-harmonic generation (HHG) remains challenging given their higher photon energies and broad spectral bandwidth. The carrier-envelope-phase (CEP) dependence of generated soft-x-ray spectra is indicative of attosecond pulse generation, but advanced simulations are needed to infer the pulse duration from such data. Here, we employ macroscopic propagation simulations to reproduce experimental polarization-gated CEP-dependent soft-x-ray spectra.

Quantum control of flying doughnut terahertz pulses.

The ability to manipulate the multiple properties of light diversifies light-matter interaction and light-driven applications. Here, using quantum control, we introduce an approach that enables the amplitude, sign, and even configuration of the generated light fields to be manipulated in an all-optical manner. Following this approach, we demonstrate the generation of "flying doughnut" terahertz (THz) pulses.

Focus Groups to Inform User-Centered Development of an eHealth Sleep Intervention for Adolescents: Perspectives of Youth with Insomnia Symptoms, with and without Pain.

Introduction: Adolescence is a developmental stage that often coincides with increasing sleep problems. Focus groups were conducted to inform development of an adolescent eHealth sleep intervention by exploring opinions about (1) healthy sleep practices, and (2) using an eHealth intervention.

Methods: Adolescents 14-18 years old experiencing symptoms of insomnia based on the Insomnia Sleep Index, with and without recurrent pain, and associated stakeholders (i.

An eHealth Program for Insomnia in Children With Neurodevelopmental Disorders (Better Nights, Better Days): Protocol for an Economic Evaluation of a Randomized Controlled Trial.

Background: Children with neurodevelopmental disorders have a high risk of sleep disturbances, with insomnia being the most common sleep disorder (ie, chronic and frequent difficulties with going and staying asleep). Insomnia adversely affects the well-being of these children and their caregivers. Pediatric sleep experts recommend behavioral interventions as the first-line treatment option for children.

Associations of active and passive smartphone use with measures of youth mental health during the COVID-19 pandemic.

Smartphone use provides a significant amount of screen-time for youth, and there have been growing concerns regarding its impact on their mental health. While time spent in a passive manner on the device is frequently considered deleterious, more active engagement with the phone might be protective for mental health. Recent developments in mobile sensing technology provide a unique opportunity to examine behaviour in a naturalistic manner.

D formation through photoionization of the molecular D-D dimer.

The H-H molecular dimer is of fundamental importance in the study of chemical interactions because of its unique bonding properties and its ability to model more complex systems. The trihydrogen cation H is also a key intermediate in a range of chemical processes in interstellar environments, such as the formation of various organic molecules and early stars. However, the unexpected high abundance of H in molecular clouds remains challenging to explain.

Sleep Architecture and EEG Power Spectrum Following Cumulative Sleep Restriction: A Comparison between Typically Developing Children and Children with ADHD.

No studies have looked at the effects of cumulative sleep restriction (CSR) on sleep architecture or the power spectrum of sleep EEG (electroencephalogram) in school-age children, as recorded by PSG (polysomnography). This is true for both typically developing (TD) children and children with ADHD (attention deficit/hyperactivity disorder), who are known to have more sleep difficulties. Participants were children (ages 6-12 years), including 18 TD and 18 ADHD, who were age- and sex-matched.

Acceptability of an online intervention for insomnia in children with neurodevelopmental disorders.

Background: Most children with neurodevelopmental disorders (NDDs) experience insomnia. Online interventions may provide a way to reduce barriers to treatment access.

Aims: We explored whether parents of children with NDDs and their health care professionals (HCPs) perceived an online insomnia intervention as acceptable and the perceived pros and cons of this intervention delivery method.

Division of Labour and Parental Mental Health and Relationship Well-Being during COVID-19 Pandemic-Mandated Homeschooling.

While the COVID-19 pandemic has impacted the way parents partition tasks between one another, it is not clear how these division of labour arrangements affect well-being. Pre-pandemic research offers two hypotheses: economic theory argues optimal outcomes result from partners specialising in different tasks, whereas psychological theory argues for a more equitable division of labour. The question of which approach optimizes well-being is more pressing in recent times, with COVID-19 school closures leaving many couples with the burden of homeschooling.

Blister formation in dynamic release mirror structures using femtosecond laser pulses.

Blister formation occurs when a laser pulse interacts with the underside of a polymer film on a glass substrate and is fundamental in Laser-Induced Forward Transfer (LIFT). We present a novel method of controlling blister formation using a thin metal film situated between two thin polymer films. This enables a wide range of laser pulse energies by limiting the laser penetration in the film, which allows us to exploit nonlinear interactions without transmitting high intensities that may destroy a transfer material.

Parental Perceptions of the Impact of the COVID-19 Pandemic on the Sleep of Children With Neurodevelopmental Disorders.

Introduction: Little is known about the impact of the COVID-19 pandemic on sleep in schoolaged children with neurodevelopmental disorders. This study aimed to (1) determine and describe the impact of the COVID-19 pandemic, and (2) identify and describe contributing factors.

Method: Parents of children with neurodevelopmental disorders and insomnia symptoms (n = 100) were surveyed to determine if their child's sleep had changed because of the COVID-19 pandemic.

The Contributions of Cognitive Abilities to the Relationship between ADHD Symptoms and Academic Achievement.

The main objective of this study was to examine whether increased levels of inattentive (INA) and hyperactive/impulsive (H/I) behaviours were associated with lower scores on standardized tests of achievement in basic reading, spelling, and math skills, after accounting for certain known background risk factors and cognitive processes. Clinical assessment data from a rigorously diagnosed, stimulant-medication-naïve sample of 354 elementary school-aged children experiencing academic difficulties and behavioural symptoms of inattention and/or hyperactivity/impulsivity were analyzed. Although higher scores of INA were significantly associated with lower scores in reading, spelling, and math, these associations did not persist when cognitive variables were added to the models.

Reconfigurable terahertz metasurfaces coherently controlled by wavelength-scale-structured light.

Structuring light-matter interaction at a deeply subwavelength scale is fundamental to optical metamaterials and metasurfaces. Conventionally, the operation of a metasurface is determined by the collective electric polarization response of its lithographically defined structures. The inseparability of electric polarization and current density provides the opportunity to construct metasurfaces from current elements instead of nanostructures.

Few-cycle Yb laser source at 20 kHz using multidimensional solitary states in hollow-core fibers.

We demonstrate ultrashort pulse compression from 300 fs down to 17 fs at a repetition rate of 20 kHz and 160-µJ output pulse energy (3.2 W of average power) using multidimensional solitary states (MDSS) in a 1-meter hollow-core fiber (HCF) filled with NO. Under static pressure, thermal limitations at this repetition rate annihilate the MDSS with suppression of spectral broadening.

Energy deposition and incubation effects of nonlinear absorption of ultrashort laser pulses in dielectrics.

Although ultrashort laser has been widely employed in micromachining thanks to its excellent processing precision, one of the main challenges it faces when applied to 3D modification inside dielectrics is its processing efficiency. Many applications require multiple pulses to achieve significant modification to create structure such as microlenses. We report incubation experiments on energy deposition and the control of material modification in fused silica.

Healthy sleep for healthy schools: A pilot study of a sleep education resource to improve adolescent sleep.

Issue Addressed: Insufficient sleep and unhealthy sleep practices in adolescents are associated with significant health risks. Sleep education programs in schools aim to improve sleep behaviour. A new eLearning sleep education program, Healthy Sleep for Healthy Schools (HS4HS), was developed focused on these goals and is distinguishable from other sleep education programs because it is delivered by teachers, making it more sustainable and adaptable for schools.

A Transdiagnostic Self-management Web-Based App for Sleep Disturbance in Adolescents and Young Adults: Feasibility and Acceptability Study.

Background: Sleep disturbance and its daytime sequelae, which comprise complex, transdiagnostic sleep problems, are pervasive problems in adolescents and young adults (AYAs) and are associated with negative outcomes. Effective interventions must be both evidence based and individually tailored. Some AYAs prefer self-management and digital approaches.

Generation of structured coherent extreme ultraviolet beams from an MgO crystal.

Short wavelength high-harmonic sources are undergoing intense development for applications in spectroscopy and microscopy. Despite recent progress in peak and average power, spatial control over coherent extreme ultraviolet (XUV) beams remains a formidable challenge due to the lack of suitable optical elements for beam shaping and control. Here we demonstrate a robust and precise approach that structures XUV high-order harmonics in space as they are emitted from a nanostructured MgO crystal.