Model granularity and related concepts

Models are integral to engineering design and basis for many decisions. Therefore, it is necessary to comprehend how a model’s properties might influence its behaviour. Model granularity is an important property but has so far only received limited attention. The terminology used to describe granularity and related phenomena varies and pertinent concepts are distributed across communities. This article positions granularity in the theoretical background of models, collects formal definitions for relevant terms from a range of communities and discusses the implications for engineering design

Role of Hemin and Growth Media on the Autofluorescence of Streptococcus mutans

poster abstractAbstract Carious lesions fluoresce under blue light. The primary cariogenic bacterium Streptococcus mutans has been shown previously to fluoresce within blue light wavelengths. In this study we wanted to determine the role of hemin and various growth media on the fluorescing properties of S. mutans under planktonic (total biomass) and biofilm (biofilm mass) growth conditions. UA159 was grown for 24 h at 37ºC in Tryptic Soy Broth (TSB), Brain Heart Infusion (BHI) and Todd Hewitt broth (THB) with and without hemin in 5% CO2. Biofilm was grown for 24 h in a 96 well sterile microplate in the above described media with and without hemin. A stock solution of Protoporphyrin –IX was prepared and diluted to concentrations ranging from 1.6-3.1×10-4 g/ml. A SpectraMax (M3) was used to determine the fluorescence from UA159. RFU of total biomass and biofilm mass was assessed by exciting at fixed wavelengths of 385 and 405 nm at a spectral band width of 10 nm. Emission spectra at 770 nm were observed with 385 nm and an emission of 800 and 810 nm with 405 nm. ANOVA on the ranks of the measurements was used, with four different factors including wavelength (770, 800 and 810 nm); total biomass or biofilm mass; various growth media (TSB, BHI, THB) and the presence/absence of hemin and interactions among the factors. The analysis allowed each media-hemin combination to have different variances. Hemin decreased the amount of fluorescence; regardless of the levels of the other factors (p≤0.0001). Without hemin, BHI had more fluorescence than THB (p≤0.0003) and TSB (p≤0.0001). However with hemin, THB had more fluorescence than BHI (p≤0.0001) and TSB (p≤0.0001). The role of hemin and porphyrin-related compounds in the metabolism of S. mutans should be elucidated

High rate production of polarized 3He with meta-stability exchange method

Keywords: polarized 3He, meta-stability exchange, infrared laserComment: 4 figures, submitted to J. Phys. Soc. Jpn

Mechanical environment change in root, periodontal ligament, and alveolar bone in response to two canine retraction treatment strategies

OBJECTIVE: To investigate the initial mechanical environment (ME) changes in root surface, periodontal ligament (PDL), and alveolar bone due to two treatment strategies, low or high moment-to-force ratio (M/F). SETTING AND SAMPLE POPULATION: Indiana University-Purdue University Indianapolis. Eighteen patients who underwent maxillary bilateral canine retraction. MATERIAL AND METHOD: Finite element models of the maxillary canines from the patients were built based on their cone beam computed tomography scans. For each patient, the canine on one side had a specially designed T-loop spring with the M/F higher than the other side. Four stress invariants (1st principal/dilatational/3rd principal/von Mises stress) in the tissues were calculated. The stresses were compared with the bone mineral density (BMD) changes reported previously for linking the ME change to bone modeling/remodeling activities. The correlation was tested by the mixed-model anova. RESULTS: The alveolar bone in the direction of tooth movement is primarily in tension, while the PDL is in compression; the stresses in the opposite direction have a reversed pattern. The M/F primarily affects the stress in root. Three stress invariants (1st principal/3rd principal/dilatational stress) in the tooth movement direction have moderate correlations with BMD loss. CONCLUSIONS: The stress invariants may be used to characterize what the osteocytes sense when ME changes. Their distributions in the tissues are significantly different, meaning the cells experience different stimuli. The higher bone activities along the direction of tooth movement may be related to the initial volumetric increase and decrease in the alveolar bone

Eyewear for rugby union: wearer characteristics and experience with rugby goggles

YesUnlike many other sports, Rugby Union has not permitted players to wear spectacles or eye protection. With an industrial partner, World Rugby developed goggles suitable for use while playing rugby for the purposes of growing participation amongst those that need to wear corrective lenses. This study reports on the profile and experiences of goggle wearers. 387 players received the goggles. Data were obtained from 188 (49 %) using an online, 75-item questionnaire. 87 % “strongly agreed/agreed” that goggles are beneficial and 75 % are happy with goggle performance. Common problems reported by 49.7 and 32.6 % of respondents were issues with fogging-up and getting dirty. 15 (8 %) players stopped wearing the goggles because of fogging-up, limits to peripheral vision and poor comfort/fit. Injuries were reported in 3 % of respondents. In none of these cases did the player stop wearing the goggles. From the positive experience of players in the trial, the goggles were adopted into the Laws of the game on July 1, 2019. As the need to correct vision with spectacles is common, and contact lenses are not worn by 80 % + of spectacle wearers, the new Rugby goggles will widen participation for those that need to wear refractive correction, or have an existing/increased risk of uniocular visual impairment

Tuning Heavy Fermion Systems into Quantum Criticality by Magnetic Field

We discuss a series of thermodynamic, magnetic and electrical transport experiments on the two heavy fermion compounds CeNi2Ge2 and YbRh2Si2 in which magnetic fields, B, are used to tune the systems from a Non-Fermi liquid (NFL) into a field-induced FL state. Upon approaching the quantum-critical points from the FL side by reducing B we analyze the heavy quasiparticle (QP) mass and QP-QP scattering cross sections. For CeNi2Ge2 the observed behavior agrees well with the predictions of the spin-density wave (SDW) scenario for three-dimensional (3D) critical spin-fluctuations. By contrast, the observed singularity in YbRh2Si2 cannot be explained by the itinerant SDW theory for neither 3D nor 2D critical spinfluctuations. Furthermore, we investigate the magnetization M(B) at high magnetic fields. For CeNi2Ge2 a metamagnetic transition is observed at 43 T, whereas for YbRh2Si2 a kink-like anomaly occurs at 10 T in M vs B (applied along the easy basal plane) above which the heavy fermion state is completely suppressed.Comment: 15 pages, 8 figures, submitted to Journal of Low Temperature Physics, special Series on "High Magnetic Field Facilities