528 research outputs found
First lattice evidence for a non-trivial renormalization of the Higgs condensate
General arguments related to ``triviality'' predict that, in the broken phase
of theory, the condensate re-scales by a factor
$Z_{\phi}$ different from the conventional wavefunction-renormalization factor,
$Z_{prop}$. Using a lattice simulation in the Ising limit we measure
$Z_{\phi}=m^2 \chi$ from the physical mass and susceptibility and $Z_{prop}$
from the residue of the shifted-field propagator. We find that the two $Z$'s
differ, with the difference increasing rapidly as the continuum limit is
approached. Since $Z_{\phi}$ affects the relation of to the Fermi
constant it can sizeably affect the present bounds on the Higgs mass.Comment: 10 pages, 3 figures, 1 table, Latex2
Influence of microphone housing on the directional response of piezoelectric mems microphones inspired by Ormia ochracea
The influence of custom microphone housings on the acoustic directionality and frequency response of a multiband bio-inspired MEMS microphone is presented. The 3.2 mm by 1.7 mm piezoelectric MEMS microphone, fabricated by a cost-effective multi-user process, has four frequency bands of operation below 10 kHz, with a desired first-order directionality for all four bands. 7×7×2.5 mm3 3-D-printed bespoke housings with varying acoustic access to the backside of the microphone membrane are investigated through simulation and experiment with respect to their influence on the directionality and frequency response to sound stimulus. Results show a clear link between directionality and acoustic access to the back cavity of the microphone. Furthermore, there was a change in direction of the first-order directionality with reduced height in this back cavity acoustic access. The required configuration for creating an identical directionality for all four frequency bands is investigated along with the influence of reducing the symmetry of the acoustic back cavity access. This paper highlights the overall requirement of considering housing geometries and their influence on acoustic behavior for bio-inspired directional microphones
A low frequency dual-band operational microphone mimicking the hearing property of Ormia ochracea
This paper introduces a directional MEMS microphone designed for hearing aid applications appropriate to low frequency hearing impairment, inspired by the hearing mechanism of a fly, the female Ormia ochracea. It uses both piezoelectric and capacitive sensing schemes. In order to obtain a high sensitivity at low frequency bands, the presented microphone is designed to have two resonance frequencies below the threshold of low frequency hearing loss at approximately 2 kHz. One is around 500 Hz and the other is slightly above 2 kHz. The novel dual sensing mechanism allows for optimization of the microphone sensitivity at both frequencies, with a maximum open-circuit (excluding pre-amplification) acoustic response captured via differential piezoelectric sensing at approximately – 46 dB (V) ref. 94 dB (SPL) at the resonance frequencies. The corresponding minimum detectable sound pressure level is just below -12 dB. The comb finger capacitive sensing was employed due to a lower electrical response generated from a ground referenced single-ended output by the piezoelectric sensing at the first resonance frequency compared to the second resonance frequency. The capacitive sensing mechanism, connected to a charge amplifier, generates a -28.4 dB (V) ref. 94 dB (SPL) acoustic response when the device is excited at either of the two resonance frequencies. Due to the asymmetric geometry and the 400 µm thick substrate, the device is predicted to perform as a bi-directional microphone below 3 kHz, which is shown by the measured directional polar patterns
A MEMS microphone inspired by Ormia for spatial sound detection
This work introduces a MEMS microphone with two pairs of orthogonal and joined sensor membranes, with independent acoustic directionality responses, leading to a 3D sound localization potential. This single microphone can thus be regarded as two individual bi-directional microphones. Combining this architecture with the fly Ormia ochracea’s tympana mechanism, this microphone is also the first biomimetic MEMS microphone with piezoelectric sensing, designed for 2D sound localization
Housing influence on multi-band directional MEMS microphones inspired by Ormia ochracea
A new bio-inspired multi-band directional MEMS microphone based on the hearing properties of the fly Ormia ochracea is presented, together with the behavioral influence of 3D-printed housings. The multi-user foundry fabricated microphone operates on four frequency bands, all below 10 kHz and acts as a pressure gradient directional microphone with figure of eight polar pattern, or as an omni-directional microphone depending on the housing. The influence of an open or closed backside housing on the frequency response and directionality is shown, leading to the loss of directionality with no acoustic access to the backside of the fly-ear inspired microphone membrane
Free energy for parameterized Polyakov loops in SU(2) and SU(3) lattice gauge theory
We present a study of the free energy of parameterized Polyakov loops P in
SU(2) and SU(3) lattice gauge theory as a function of the parameters that
characterize P. We explore temperatures below and above the deconfinement
transition, and for our highest temperatures T > 5 T_c we compare the free
energy to perturbative results.Comment: Minor changes. Final version to appear in JHE
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Cognitive Change in a Diverse Group of Individuals Aged 90+: The LifeAfter90 Study
Abstract:
Background:
The oldest‐old are the fastest growing segment of the elderly population but very little is known about cognition in this age group; particularly in diverse populations. Our goal was to evaluate if domain specific cognitive change was different across different ethnoracial groups in those aged 90+.
Method:
LifeAfter90 (LA90) is an ongoing cohort of participants aged 90+ who are long‐term members of Kaiser Permanente Northern California participants. Participants (n = 984) were interviewed every 6 months for up to 3.5 years (1‐7 visits). Executive Function (EF) and Verbal Episodic Memory (VEM) were measured every six months using z‐standardized Spanish English Neuropsychological Assessment Scale. Racial/ethnic identify (Asian, Black, Latino, or White participants) was used in linear mixed models with random slopes and intercepts adjusting for baseline age, gender, education, interview mode, and practice effects.
Result:
Participants were 20% Latino, 23% Black, 24% Asian, 27% White, and 7% other individuals with a mean age of 92.4 (SD = 2.3) and a mean follow up time 1.1 years (Table 1). 39% of the cohort were men, 35% were college educated, and 29% were high school or less educated. Average annual change in EF was ‐0.06 (95% CI: ‐0.12, ‐0.00). Stratified models with Latino as the reference group showed White participants had significantly greater decline in EF (β = ‐0.13; 95%CI:‐0.20,‐0.06), followed by Asian participants (β = ‐0.09; 95%CI:‐0.17,‐0.01). EF scores among Black participants and participants who identified as other declined at a similar rate as Latino participants (β = ‐0.03; 95%CI:‐0.11,‐0.05; β = 0.00; 95%CI:‐0.10, 0.11; respectively) (Table 2: model 2). VEM had an annual change of ‐0.26 (95%CI: ‐0.40, ‐0.13), but there were no significant differences across ethnoracial groups in rate of decline.
Conclusion:
In this population of individuals aged 90+, decline in EF over the study period varied across ethnoracial group with White participants experiencing the fastest decline and Black, Latino, and other participants experiencing the slowest decline. Continued follow up will identify if there are differences in risk of cognitive impairment in this diverse population of oldest‐old. The results suggest the disparities in cognitive aging for those aged 90+ don’t mirror disparities seen in younger‐elderly ages
Influence of microphone housing on the directional response of piezoelectric MEMS microphones inspired by Ormia ochracea
The influence of custom microphone housings on the acoustic directionality and frequency response of a multi-band bio-inspired MEMS microphone is presented. The 3.2mm by 1.7mm piezoelectric MEMS microphone, fabricated by a cost-effective multi-user process, has four frequency bands of operation below 10 kHz, with a desired first order directionality for all four bands. 7x7x2.5 mm3 3D-printed bespoke housings with varying acoustic access to the backside of the microphone membrane are investigated through simulation and experiment with respect to their influence on the directionality and frequency response to sound stimulus. Results show a clear link between directionality and acoustic access to the back cavity of the microphone. Further, there was a change in direction of the first order directionality with reduced height in this back cavity acoustic access. The required configuration for creating an identical directionality for all four frequency bands is investigated along with the influence of reducing the symmetry of the acoustic back cavity access. This work highlights the overall requirement of considering housing geometries and their influence on acoustic behavior for bio-inspired directional microphones
Habitat continuity and geographic distance predict population genetic differentiation in giant kelp
Isolation by distance (IBD) models are widely used to predict levels of genetic connectivity as a function of Euclidean distance, and although recent studies have used GIS-landscape ecological approaches to improve the predictability of spatial genetic structure, few if any have addressed the effect of habitat continuity on gene flow. Landscape effects on genetic connectivity are even less understood in marine populations, where habitat mapping is particularly challenging. In this study, we model spatial genetic structure of a habitat-structuring species, the giant kelp Macrocystis pyrifera, using highly variable microsatellite markers. GIS mapping was used to characterize habitat continuity and distance between sampling sites along the mainland coast of the Santa Barbara Channel, and their roles as predictors of genetic differentiation were evaluated. Mean dispersal distance (σ) and effective population size (Ne) were estimated by comparing our IBD slope with those from simulations incorporating habitat continuity and spore dispersal characteristics of the study area. We found an allelic richness of 7–50 alleles/locus, which to our knowledge is the highest reported for macroalgae. The best regression model relating genetic distance to habitat variables included both geographic distance and habitat continuity, which were respectively, positively and negatively related to genetic distance. Our results provide strong support for a dependence of gene flow on both distance and habitat continuity and elucidate the combination of Ne and σ that explained genetic differentiation
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Life course financial mobility and later-life memory function and decline by gender, and race and ethnicity: an intersectional analysis of the US KHANDLE and STAR cohort studies
BackgroundIntersectionality has rarely been considered in research studies of cognitive ageing. We investigated whether life-course financial mobility is differentially associated with later-life memory function and decline across intersectional identities defined by gender, and race and ethnicity.MethodsData were from two harmonised multiethnic cohorts (the Kaiser Healthy Aging and Diverse Life Experiences cohort and the Study of Healthy Aging in African Americans cohort) in northern California, USA (n=2340). Life-course financial mobility, measured using a combination of self-reported financial capital measures in childhood (from birth to age 16 years) and later adulthood (at the cohort baseline) was defined as consistently high, upwardly mobile, downwardly mobile, or consistently low. We clustered individuals into 32 strata representing intersectional identities defined by life-course financial mobility combined with gender, and race and ethnicity. Verbal episodic memory was assessed using the Spanish and English Neuropsychological Assessment Scales over four waves from 2017 to 2023. Adjusted mixed-effects linear regression models were estimated with and without fixed effects of gender, race and ethnicity, and financial mobility, to evaluate whether the random effects of the intersectional identity strata contributed variance to memory beyond individual fixed effects.FindingsMean age was 73·6 years (SD 8·1). Of 2340 individuals, 1460 (62·4%) were women, 880 (37·6%) were men, 388 (16·6%) were Asian, 1136 (48·5%) were Black, 334 (14·3%) were Latinx, and 482 (20·6%) were White. Consistently low and downwardly mobile financial capital were strongly negatively associated with later-life memory at baseline (-0·162 SD units [95% CI -0·273 to -0·051] for consistently low and -0·171 [-0·250 to -0·092] for downwardly mobile), but not rate of change over time. Intersectional identities contributed 0·2% of memory variance after accounting for the fixed effects of gender, race and ethnicity, and financial mobility.InterpretationConsistently low and downward life-course financial mobility are associated with lower later-life memory function. Intersectional identities defined by financial mobility in addition to gender, and race and ethnicity, contribute negligible additional variance to later-life memory in this study setting.FundingUS National Institute on Aging, US National Institutes of Health
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