Adolescent Boys are at Risk for Body Image Dissatisfaction and Muscle Dysmorphia

Background and Purpose: Muscle Dysmorphia (MD) is characterized by extreme body dissatisfaction and a drive for muscularity that leads to compulsive behaviors to attain an ideal body shape. The primary purpose of this study was to assess the level of body image dissatisfaction (BID) among male adolescents (N = 149, mean age = 15.01 + 1.85 y and mean BMI = 23.26 + 5.01 kg/m2 ) and whether or not BID was correlated with behaviors associated with MD. A secondary purpose was to examine if a difference exists between athletes and non-athletes. Methods: The Eating Attitude Survey (EAS) was used to assess attitudes toward body weight and shape while the Muscle Dysmorphia Inventory (MDI) was used to assess the behavioral and psychological characteristics of MD. Results: This sample of male adolescents indicate some level of BID, which is also associated with overall higher scores for all subscales of the MDI, but especially the subscales relating to muscularity. Athletes in particular showed higher levels of BID and higher scores on the MDI. Conclusion: Individuals who work with adolescent boys should be aware that they can develop body dissatisfaction and may participate in compensatory behaviors that may be harmful to their overall health and development

Morse theory of the moment map for representations of quivers

The results of this paper concern the Morse theory of the norm-square of the moment map on the space of representations of a quiver. We show that the gradient flow of this function converges, and that the Morse stratification induced by the gradient flow co-incides with the Harder-Narasimhan stratification from algebraic geometry. Moreover, the limit of the gradient flow is isomorphic to the graded object of the Harder-Narasimhan-Jordan-H\"older filtration associated to the initial conditions for the flow. With a view towards applications to Nakajima quiver varieties we construct explicit local co-ordinates around the Morse strata and (under a technical hypothesis on the stability parameter) describe the negative normal space to the critical sets. Finally, we observe that the usual Kirwan surjectivity theorems in rational cohomology and integral K-theory carry over to this non-compact setting, and that these theorems generalize to certain equivariant contexts.Comment: 48 pages, small revisions from previous version based on referee's comments. To appear in Geometriae Dedicat

Tailor-made nanostructures bridging chaos and order for highly efficient white organic light-emitting diodes

Organic light-emitting diodes (OLEDs) suffer from notorious light trapping, resulting in only moderate external quantum efficiencies. Here, we report a facile, scalable, lithography-free method to generate controllable nanostructures with directional randomness and dimensional order, significantly boosting the efficiency of white OLEDs. Mechanical deformations form on the surface of poly(dimethylsiloxane) in response to compressive stress release, initialized by reactive ions etching with periodicity and depth distribution ranging from dozens of nanometers to micrometers. We demonstrate the possibility of independently tuning the average depth and the dominant periodicity. Integrating these nanostructures into a two-unit tandem white organic light-emitting diode, a maximum external quantum efficiency of 76.3% and a luminous efficacy of 95.7 lm W−1 are achieved with extracted substrate modes. The enhancement factor of 1.53 ± 0.12 at 10,000 cd m−2 is obtained. An optical model is built by considering the dipole orientation, emitting wavelength, and the dipole position on the sinusoidal nanotexture

Briquets from wood waste

Revised September 1960

Wood fuel combustion practice

Information reviewed and reaffirmed May 1961

Volume loss from inaccurate sawing

This report originally published in Southern Lumberman, Sept. 15, 1954