Remote photothermal actuation for calibration of in-phase and quadrature readout in a mechanically amplified Fabry-Pérot accelerometer

A mechanically amplified Fabry-Pérot optical accelerometer is reported in which photothermal actuation is used to calibrate the in-phase and quadrature (I&Q) readout. The Fabry-Pérot interferometer (FPI) is formed between a gold-coated silicon mirror, situated in the middle of a V-beam amplifier, and the end surface of a cleaved optical fiber. On the opposite side of the silicon mirror, a further cleaved optical fiber transmits near-infrared laser light (λ = 785 nm), which is absorbed by the uncoated silicon causing heating. The thermal expansion of the V-beam is translated into an amplified change in cavity length of the FPI, large enough for the 2π-phase variation necessary for I&Q calibration. A simple 1D thermal analysis of the structure has been developed to predict the relationship between laser power and change in cavity length. A device having a V-beam of length 1.8 mm, width 20 μm, and angle 2 ° was found to undergo a cavity length change of 785 nm at 30 mW input power. The device response was approximately linear for input accelerations from 0.01 to 15 g. The noise was measured to be ~ 60 μg/√Hz from 100 Hz to 3.0 kHz, whereas the limit of detection was 47.7 mg from dc to 3.0 kHz

Generation of Basis Vectors for Magnetic Structures and Displacement Modes

Increasing attention is being focused on the use of symmetry-adapted functions to describe magnetic structures, structural distortions, and incommensurate crystallography.Though the calculation of such functions is well developed, significant difficulties can arise such as the generation of too many or too few basis functions to minimally span the linear vector space. We present an elegant solution to these difficulties using the concept of basis sets and discuss previous work in this area using this concept. Further, we highlight the significance of unitary irreducible representations in this method and provide the first validation that the irreducible representations of the crystallographic space groups tabulated by Kovalev are unitary

The validation of acoustic environment simulator to determine the relationship between sound objects and soundscape

An acoustic environment simulator is a system that facilitates acoustic environment composition by controlling the parameters of sound objects (both background and sound events), allowing the user to compose and compare soundscapes against their expectations. By using the acoustic environment simulator, data regarding parameters of sound objects, such as their sound level and selection, can be obtained. Furthermore, these data can be used to understand the relationship between the sound objects and the soundscapes. This paper describes the development and validation of an acoustic environment simulator, which can be used to design a complex acoustic environment in the laboratory according to the expectations of the user. Validation of the simulated soundscape, whether the composed acoustic environment has the same soundscape dimension characteristics as previous in-situ and other laboratory experiments, was conducted by reproducing acoustic environment compositions using a two-dimensional ambisonic system in the laboratory. Listener responses on semantic differential scales were reduced to three reliable soundscape dimensions by principal component analysis: Calmness/Relaxation (40%), Dynamics/Vibrancy (12%), and Communication (11%). These three soundscape dimensions are consistent with a previous study conducted in situ. The results reported here indicate that acoustic environment composition can successfully imitate the soundscape dimensions of an actual acoustic environment

Chaotic root-finding for a small class of polynomials

In this paper we present a new closed-form solution to a chaotic difference equation, $y_{n+1} = a_2 y_{n}^2 + a_1 y_{n} + a_0$ with coefficient $a_0 = (a_1 - 4)(a_1 + 2) / (4 a_2)$, and using this solution, show how corresponding exact roots to a special set of related polynomials of order $2^p, p \in \mathbb{N}$ with two independent parameters can be generated, for any $p$

The effect of sound level on perception of reproduced soundscapes

The aim of this work was to investigate the perception of soundscape reproduced by an ambisonic reproduction system on a horizontal plane, how the experience of space affected the perception of soundscape reproduction, and how the sound level adjustment on soundscape reproduction affected the perception of soundscape compared with actual conditions. There were three experiments conducted: a soundwalk in situ in Manchester (United Kingdom) city centre, listening tests in Salford (United Kingdom), and listening tests in Bandung (Indonesia). The listening tests used material recorded from four locations on the soundwalk route in Manchester. The Salford listening tests were performed at the in-situ measured sound level, and the participants were asked to adjust the sound level to the level that represents actual locations. The listening test in Bandung was conducted to understand the effect of participants who never come to the actual location to the perception of soundscape and the sound level adjustment. The listening tests in Bandung were conducted at the in situ sound level, at 9.5 dB below the in situ sound level (based on the preference sound level from the experiment in Salford), and the participants were also requested to adjust the sound level to the level that represents the actual space (to examine the consistency with the experiment in Salford). In each case, soundscape perception was measured on 19 semantic differential scales. Analysis of the semantic differential results showed that the ambisonic reproduction produced a similar subjective experience to the in situ soundwalk when the reproduction sound level was 9.5 dB lower than the actual sound level in situ. Reproduction at the actual sound level in situ produced a different dimensional space. The study shows that the sound level adjustment of soundscape reproduction in laboratory experiment produces more ecologically valid results compared to the reproduction at the actual sound level in situ

Mass of the B_c Meson in Three-Flavor Lattice QCD

We use lattice QCD to predict the mass of the $B_c$ meson. We use the MILC Collaboration's ensembles of lattice gauge fields, which have a quark sea with two flavors much lighter than a third. Our final result is $m_{B_c}=6304\pm12^{+18}_{- 0} MeV$. The first error bar is a sum in quadrature of statistical and systematic uncertainties, and the second is an estimate of heavy-quark discretization effects.Comment: 4 pages, 3 figures; shorten to fit in PRL; published versio

Increased alternate splicing of Htr2c in a mouse model for Prader-Willi syndrome leads disruption of 5HT(2C) receptor mediated appetite

Alternate splicing of serotonin (5-hydroxytryptamine; 5-HT) 2C receptor (5-HT2CR) pre-RNA is negatively regulated by the small nucleolar RNA, Snord115, loss of which is observed in nearly all individuals with Prader-Willi Syndrome (PWS), a multigenic disorder characterised by hyperphagia and obesity. Given the role of the 5-HT2CR in the regulation of ingestive behaviour we investigated the pathophysiological implications of Snord115 deficiency on 5-HT2CR regulated appetite in a genotypically relevant PWS mouse model (PWS-IC). Specifically, we demonstrate that loss of Snord115 expression is associated with increased levels of hypothalamic truncated 5-HT2CR pre-mRNA. The 5-HT2CR promotes appetite suppression via engagement of the central melanocortin system. Pro-opiomelancortin (Pomc) mRNA levels within the arcuate nucleus of the hypothalamus (ARC) were reduced in PWS-IC mice. We then went on to assess the functional consequences of these molecular changes, demonstrating that PWS-IC mice are unresponsive to an anorectic doses of a 5-HT2CR agonist and that this is associated with attenuated activation of POMC neurons within the ARC. These data provide new insight into the significance of Htr2c pre-mRNA processing to the physiological regulation of appetite and potentially the pathological manifestation of hyperphagia in PWS. Furthermore, these findings have translational relevance for individuals with PWS who may seek to control appetite with another 5-HT2CR agonist, the new obesity treatment lorcaserin

Tunable topological edge modes in Su–Schrieffer–Heeger arrays

A potential weakness of topological waveguides is that they act on a fixed narrow band of frequencies. However, by 3D printing samples from a photo-responsive polymer, we can obtain a device whose operating frequency can be fine-tuned dynamically using laser excitation. This greatly enhances existing static tunability strategies, typically based on modifying the geometry. We use a version of the classical Su–Schrieffer–Heeger model to demonstrate our approach

Development and validation of measures to evaluate adolescents' knowledge about human papillomavirus (HPV), involvement in HPV vaccine decision-making, self-efficacy to receive the vaccine and fear and anxiety

Objectives: We describe the development and validation of measures of human papillomavirus (HPV)/HPV vaccination knowledge, fear/anxiety about vaccination, involvement in HPV vaccine decision-making, and self-efficacy with regard to getting the vaccine, designed to evaluate the efficacy of an intervention to affect these domains (collectively termed the HAVIQ: HPV Adolescent Vaccine Intervention Questionnaire). / Study design: Literature search, cognitive interviews and cross-sectional survey. / Methods: A literature search identified existing items that were modified for the present measures. Experts reviewed draft measures for face and content validity. Cognitive interviews with adolescents were also used to assess content validity. Adolescents completed the measures and an internal reliability analysis of each measure was performed. / Results: The four experts concurred that the measures had face validity. Cognitive interviews identified items requiring refinement. Content validity was examined with ten experts and was deemed acceptable. There were 1800 adolescents who completed the measures; Cronbach's alpha was >0.6 for three of the four measures. The four final measures are brief, comprising 25 items in total. / Conclusions: The measures are robustly developed and validity-tested. The HAVIQ may be used in research settings to evaluate adolescents' knowledge and experiences of the process of HPV vaccination in a school-based vaccination programme