Monthly Changes in the Composition of Friendship Networks in Early Adolescence

Short-term stability in adolescents’ self-reported friendship networks was examined as a function of (1) participants’ gender, (2) friendship status (best vs. secondary), (3) friendship gender composition (same sex vs. opposite sex), and (4) friendship contexts (school only vs. nonschool only vs. multiple). Adolescents (N = 102) took part in five monthly telephone interviews in which they nominated their friends and provided specific information for each of them. Results indicated that on average, one-third of participants’ nominated friendships in their network were unstable over five months, with girls’ perceived networks being more unstable than boys. Best friendship choices were more stable than secondary ones. Girls’ reports of their opposite-sex friendships were more unstable than boys’, and multicontext friendships (school and nonschool) were more stable than single-context friendships (school only or nonschool only). Results are discussed by highlighting the contribution of short-term assessments in understanding how adolescent networks change over time

Electromagnetic interference of GSM mobile phones with the implantable deep brain stimulator, ITREL-III

BACKGROUND: The purpose was to investigate mobile phone interference with implantable deep brain stimulators by means of 10 different 900 Mega Hertz (MHz) and 10 different 1800 MHz GSM (Global System for Mobile Communications) mobile phones. METHODS: All tests were performed in vitro using a phantom especially developed for testing with deep brain stimulators. The phantom was filled with liquid phantom materials simulating brain and muscle tissue. All examinations were carried out inside an anechoic chamber on two implants of the same type of deep brain stimulator: ITREL-III from Medtronic Inc., USA. RESULTS: Despite a maximum transmitted peak power of mobile phones of 1 Watt (W) at 1800 MHz and 2 W at 900 MHz respectively, no influence on the ITREL-III was found. Neither the shape of the pulse form changed nor did single pulses fail. Tests with increased transmitted power using CW signals and broadband dipoles have shown that inhibition of the ITREL-III occurs at frequency dependent power levels which are below the emissions of GSM mobile phones. The ITREL-III is essentially more sensitive at 1800 MHz than at 900 MHz. Particularly the frequency range around 1500 MHz shows a very low interference threshold. CONCLUSION: These investigations do not indicate a direct risk for ITREL-III patients using the tested GSM phones. Based on the interference levels found with CW signals, which are below the mobile phone emissions, we recommend similar precautions as for patients with cardiac pacemakers: 1. The phone should be used at the ear at the opposite side of the implant and 2. The patient should avoid carrying the phone close to the implant

Inadequate Dissemination of Phase I Trials: A Retrospective Cohort Study

François Chapuis and colleagues examine a cohort of clinical trial protocols approved by French ethics committees, and show that Phase I trials are less frequently published than other types of trials

Algorithme de décodage adaptatif pour codes convolutionnels

Décodage probabiliste des codes convolutionnels -- Variantes des algorithmes de décodage -- Algorithme de Viterbi adaptatif -- Performance de l'algorithme de Viterbi adaptatif

A natural stochastic extension of the sandpile model on a graph

We introduce a new model of a stochastic sandpile on a graph $G$ containing a sink. When unstable, a site sends one grain to each of its neighbours independently with probability $p \in (0,1]$. For $p=1$, this coincides with the standard Abelian sandpile model. In general, for $p\in(0,1)$, the set of recurrent configurations of this sandpile model is different from that of the Abelian sandpile model. We give a characterisation of this set in terms of orientations of the graph $G$. We also define the lacking polynomial $L_G$ as the generating function counting this set according to the number of grains, and show that this polynomial satisfies a recurrence which resembles that of the Tutte polynomial

Synthesis of Macromolecules Containing Phenylalanine and Aliphatic Building Blocks

Aiming at developing efficient interfacial agents for fiber‐reinforced composite materials, macromolecules are designed to have different components able to stick to the fiber and be compatible with the polymer matrix, respectively. Herein, macromolecules are prepared by solid‐phase synthesis considering phenylalanine residues to promote adsorption of the macromolecule on aramid fibers and aliphatic building blocks to interact with a hydrophobic polymer matrix. Using phenylalanine as building block for the preparation of macromolecules by iterative synthesis has been shown to be challenging. Thus, the screening of various parameters for the optimization of the synthesis of these macromolecules is discussed in this communication. A preliminary thermal study by thermal gravimetric analysis is conducted to evaluate their thermal stability

CCD-based imaging and 3D space--time mapping of terahertz fields via Kerr frequency conversion

We investigate the spatially and temporally resolved four-wave mixing of terahertz (THz) fields and optical pulses in large-bandgap dielectrics, such as diamond. We show that it is possible to perform beam profiling and space–time resolved mapping of THz fields by encoding the spatial information into an optical signal, which can then be recorded by a standard CCD camera

Earlier versus later start of antiretroviral therapy in HIV-infected adults with tuberculosis.

Tuberculosis remains an important cause of death among patients infected with the human immunodeficiency virus (HIV). Robust data are lacking with regard to the timing for the initiation of antiretroviral therapy (ART) in relation to the start of antituberculosis therapy

Open-Full-Jaw: An open-access dataset and pipeline for finite element models of human jaw

Developing computational models of the human jaw acquired from cone-beam computed tomography (CBCT) scans is time-consuming and labor-intensive. Besides, a quantitative comparison is not attainable in the literature due to the involved manual tasks and the lack of surface/volumetric meshes. We share an open-access repository of 17 patient-specific finite-element (FE) models of human jaws acquired from CBCT scans and the utilized pipeline for generating them. The proposed pipeline minimizes model generation time and potential errors caused by human interventions. It gets dense surface meshes and provides reduced conformal surface/volumetric meshes suitable for FE analysis. We have quantified the geometrical variations of developed models and assessed models' accuracy from different aspects; (1) the maximum deviations from the input meshes, (2) the mesh quality, and (3) the simulation results. Our results indicate that the developed computational models are precise and have quality meshes suitable for various FE scenarios. Therefore, we believe this dataset will pave the way for future population studies