Calibration and validation of physical behaviour cut-points using wrist-worn ActiGraphs for children and adolescents: A systematic review.

OBJECTIVES: To review cut-points calibrated and independently validated from wrist-worn ActiGraph accelerometers to measure moderate to vigorous physical activity (MVPA) and time spent sedentary (SED) in children and adolescents. DESIGN: Systematic literature review. METHODS: Five databases were searched for relevant cut-point calibration and independent validation studies relating to wrist worn ActiGraphs in children and adolescents from inception through 30 April 2022. Extracted data included: country of publication; study name; population; device model; wear location; sampling frequency; epoch length; activity protocol; criterion method and definitions used to classify PA intensity; statistical methods for calibration; statistical methods for validation/cross-validation; and MVPA and SED outcome. RESULTS: Fourteen calibration studies and seven independent validation studies were identified. Calibrated cut-points for MVPA vector magnitude counts ranged from 7065 to 9204 counts per minute (cpm) and 63.5 to 201 milli-gravitational units (mg). For SED, calibrated cut-points ranged from <2556 cpm to 4350 cpm and 30.8 to 48.1 mg. Classification accuracy values determined by independent validation studies varied, with kappa values ranging from 0.31 to 0.60 and area under the curve statistics ranging from 0.51 to 0.84 for MVPA and kappa values ranging from 0.31 to 0.44 and area under the curve statistics ranging from 0.70 to 0.85 for SED. CONCLUSIONS: The results of this systematic literature review support the use of the Crouter and colleagues cut-points for the measurement of MVPA and SED for children and adolescents aged 6-12 years. Further work is required to independently validate cut-points developed in younger children and older adolescents.

Real-time reconstruction of high energy, ultrafast laser pulses using deep learning.

We report a method for the phase reconstruction of an ultrashort laser pulse based on the deep learning of the nonlinear spectral changes induce by self-phase modulation. The neural networks were trained on simulated pulses with random initial phases and spectra, with pulse durations between 8.5 and 65 fs. The reconstruction is valid with moderate spectral resolution, and is robust to noise. The method was validated on experimental data produced from an ultrafast laser system, where near real-time phase reconstructions were performed. This method can be used in systems with known linear and nonlinear responses, even when the fluence is not known, making this method ideal for difficult to measure beams such as the high energy, large aperture beams produced in petawatt systems.

"A Person I Cared About Was Involved": Exploring Bystander Motivation to Help in Incidents of Potential Sexual Assault and Dating Violence.

The purpose of the present study was to examine what motivates college students to put themselves in harm's way and help their peers in risky situations involving sexual assault and dating violence. College students reported on the frequency of witnessing a wide range of potentially dangerous incidents, whether or not they intervened, why they chose to intervene, what their relationship was to the victim, and reactions to their intervention. A sample of 182 (59.5% female) college students (Mage = 19.3 years) participated. We coded and analyzed narrative responses to the question regarding what influenced their decision to get involved. For female students, relationship to the victim, and, for males, the severity of the situation, were key motivational factors for bystander involvement. Some students reported positive feelings while others reported negative feelings directly related to their involvement. Tapping into the motivations underlying college students' helping behavior will be particularly informative for those designing and implementing bystander intervention programs on college campuses. A better understanding of bystander behavior will not only improve bystander intervention programs but it will also put students in the best position to make informed and responsible choices when faced with a difficult situation.

Transoral vertebral augmentation with polymethylmethacrylate in the treatment of a patient with a dens fracture nonunion and subarticular vertebral body fracture of C2.

The injection of polymethylmethacrylate (PMMA) is a minimally invasive, image-guided procedure used to treat vertebral fractures due to osteoporosis, metastatic lesions, multiple myeloma, and benign but destabilizing bone tumors. The injection of PMMA into the C2 vertebral body using the transoral technique has been reported in three separate patients for treatment of benign tumors (a vertebral hemangioma and an aneurysmal bone cyst) and for multiple myeloma in the third patient. Although the injection of PMMA into the vertebral body is most commonly performed to treat benign vertebral compression fractures, a transoral C2 approach has not been reported in the English literature as a treatment for a benign fracture of C2. We report the treatment of a fracture and nonunion of the base of the dens and a subarticular fracture of the vertebral body of C2 using a bilateral transoral approach.