Localized vibrations of disordered multi-span beams - Theory and experiment

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76120/1/AIAA-1986-934-814.pd

Lattice mechanical study of the structure of dodecasil-3C

A recently developed partial charge potential model for SiO2 polymorphs, derived from quantum chem. calcns., was applied to the calcn. of the lattice energy-minimized structure and phys. properties of the low-d. SiO2 crystal Dodecasil-3C. Calcns. were performed using Ewald summations and without symmetry constraints. Results are compared with calcns. using the shell model of Sanders et al. (1983). Best agreement between exptl. and theor. predicted elastic consts. is achieved assuming a triclinic structure. To establish lattice stability, the vibrational frequency spectrum was calcd. For structures with imaginary frequencies, the corresponding at. displacements are used to deform the quasi-stationary geometry. On lattice energy minimization, the deformed structure transforms to a stable energy min. The large anisotropic temp. factors obsd. exptl. are mainly due to static disorder in at. position

High-Q nested resonator in an actively stabilized optomechanical cavity

Experiments involving micro- and nanomechanical resonators need to be carefully designed to reduce mechanical environmental noise. A small scale on-chip approach is to add an additional resonator to the system as a mechanical low-pass filter. Unfortunately, the inherent low frequency of the low-pass filter causes the system to be easily excited mechanically. Fixating the additional resonator ensures that the resonator itself can not be excited by the environment. This, however, negates the purpose of the low-pass filter. We solve this apparent paradox by applying active feedback to the resonator, thereby minimizing the motion with respect the front mirror of an optomechanical cavity. Not only does this method actively stabilize the cavity length, but it also retains the on-chip vibration isolation.Comment: Minor adjustments mad

LIGHT AND ELECTRON MICROSCOPIC RADIOAUTOGRAPHY OF HEPATIC CELL NUCLEOLI IN MICE TREATED WITH ACTINOMYCIN D

Nucleolar partition induced by actinomycin D was used to demonstrate some aspects of nucleolar RNA synthesis and release in mouse hepatic cells, with light and electron microscopic radioautography. The effect of the drug on RNA synthesis and nucleolar morphology was studied when actinomycin D treatment preceded labeling with tritiated orotic acid. Nucleolar partition, consisting of a segegration into granular and fibrillar parts was visible if a dosage of 25 µg of actinomycin D was used, but nucleolar RNA was still synthesized. After a dosage of 400 µg of actinomycin D, nucleolar RNA synthesis was completely stopped If labeling with tritiated orotic acid preceded treatment with 400 µg of actinomycin D, labeled nucleolar RNA was present 15 min after actinomycin D treatment while high resolution radioautography showed an association of silver grains with the granular component. At 30 min after actinomicyn D treatment all labeling was lost. Since labeling was associated with the granular component the progressive loss of label as a result of actinomycin D treatment indicated a release of nucleolar granules. The correlation between this release and the loss of 28S RNA from actinomycin D treated nucleoli as described in the literature is discussed

Development of a high-sensitivity torsion balance to investigate the thermal Casimir force

We report development of a high-sensitivity torsion balance to measure the thermal Casimir force. Special emphasis is placed on experimental investigations of a possible surface electric force originating from surface patch potentials that have been recently noticed by several experimental groups. By gaining a proper understanding of the actual contribution of the surface electric force in real materials, we aim to undertake precision force measurements to resolve the Casimir force at finite temperature in real metals, as well as in other semiconducting materials, such as graphene.Comment: Proceedings of the 10th International Conference "Quantum Field Theory Under the Influence of External Conditions"; 11 pages and 4 figure

Risk inventory water playground Zuiderpret, The Hague

De gemeente Den Haag heeft het RIVM gevraagd om adviezen te geven om de waterkwaliteit van waterspeelplaats Zuiderpret in Den Haag in de toekomst goed te houden en oplossingen aan te reiken voor eventuele problemen. Zuiderpret is een natuurspeelplaats in het Zuiderpark waar kinderen in een stromende beek met water kunnen spelen. Aanleiding voor de adviesaanvraag waren de problemen met de waterkwaliteit tussen 2012 en 2015. De gemeente Den Haag heeft in 2015 zelf maatregelen getroffen waardoor de waterkwaliteit aanzienlijk is verbeterd. Zo is een hek geplaatst om ganzen tegen te houden zodat het water minder wordt verontreinigd door hun uitwerpselen. Ook is de waterloop aangepast waardoor doorlopend vers water uit het Zuiderpark door de beek stroomt. Na een veldbezoek aan de waterspeelplaats adviseert het RIVM te zorgen voor een goede doorstroming van het water door regelmatig planten en algengroei te verwijderen, de hygiëne rondom de beek te bewaken en de waterkwaliteit te blijven toetsen. Ook is duidelijke communicatie richting de bezoekers van de waterspeelplaats van belang, bijvoorbeeld door met borden aan te geven dat het water in de beek geen drinkwater is. Verder blijkt dat gebruikers van de waterspeelplaats tot op heden geen gezondheidsklachten bij GGD Haaglanden hebben gemeld door vervuiling van de beek als gevolg van ontlasting van dier of mens. Problemen met zwemmersjeuk en blauwalgen zijn niet te verwachten doordat het water in de beek continu in beweging is. De gemeente Den Haag en GGD Haaglanden streven ernaar de waterkwaliteit in waterspeelplaats Zuiderpret volledig te laten voldoen aan de eisen die de Europese Zwemwaterrichtlijn stelt aan officiële zwemlocaties. Officieel hoeven waterspeelplaatsen niet aan deze eisen te voldoen omdat ze niet door de provincie als officiële zwemlocaties zijn aangewezenThe municipality of The Hague has asked RIVM to advice on ways to maintain good water quality in water playground Zuiderpret in The Hague in the future, and to provide solutions to any problems that may occur. Zuiderpret is a nature playground in the Zuiderpark where children can play with water in a flowing stream. Reason for the advisory application was the problems with water quality between 2012 and 2015. The municipality of The Hague implemented measures in 2015 that considerably improved water quality. A fence was placed to stop geese resulting in less pollution of the water by goose feces. The watercourse in the stream has been adapted such that there is a continuous flow of fresh water from the Zuiderpark. After a field visit to the water playground, RIVM recommends ensuring a proper water flow by regularly removing plants and algal growth, monitoring the hygiene around the stream, and continued testing of the water quality. Clear communication to the visitors of the water playground is also important, for example by means of warning signs indicating that the water in the stream is no drinking water. It appears that thus far users of the water playground have not reported any health complaints at GGD Haaglanden due to contamination of the stream resulting from animal or human feces. Problems with swimmers' itch and cyanobacteria are not to be expected because the water in the stream is continuously in motion. The municipality of The Hague and GGD Haaglanden strive to full compliance of the water quality in water playground Zuiderpret to the requirements of the European Bathing Water Directive for official bathing sites. Officially, water playgrounds do not have to meet these requirements because they are not designated as official bathing sites by the provinceGemeente Den Haa

Exploring the Psychosocial Needs of Adolescents Whose Parent Is Diagnosed With Breast Cancer

Purpose: Cancer has a major impact on the individual patient and their family, especially children. However, little is known about the needs of adolescents (10–19 years) whose parent is diagnosed with cancer, especially breast cancer. Insights into psychosocial needs are important to develop appropriate guidance and support for these adolescents. The aim of this study is to explore the psychosocial needs of adolescents whose parent is diagnosed with breast cancer to improve the support for these adolescents. Data sources: This is an exploratory, qualitative study. In-depth interviews were conducted, and an interview guide was designed with the following topics: experiences, needs, and support. Participants were selected purposively and approached via the parent(s) after consultation. Interviews were audiotaped, transcribed, and thematically analyzed by using the software program NVivo. Conclusion: Fourteen adolescents (12–19 years) were interviewed, which resulted in five themes: distraction, support, being able to talk about it, information, and continuing a normal life. Adolescents whose parent is diagnosed with breast cancer need the best possible preservation of their normal lives. It is important for them to be able to share their story and find support from someone close to them. Implication for Nursing Practice: The route to the adolescent is always through the parent. Healthcare professionals can discuss the well-being of the adolescent during regular consultation with the parent. If there are concerns, healthcare professionals can advise the parent about the possible needs of the adolescent and could coach the parent in supporting the adolescent to discuss their needs.</p