Doppler-free frequency modulation spectroscopy of atomic erbium in a hollow cathode discharge cell

The erbium atomic system is a promising candidate for an atomic Bose-Einstein condensate of atoms with a non-vanishing orbital angular momentum ($L \neq 0$) of the electronic ground state. In this paper we report on the frequency stabilization of a blue external cavity diode laser system on the 400.91 $nm$ laser cooling transition of atomic erbium. Doppler-free saturation spectroscopy is applied within a hollow cathode discharge tube to the corresponding electronic transition of several of the erbium isotopes. Using the technique of frequency modulation spectroscopy, a zero-crossing error signal is produced to lock the diode laser frequency on the atomic erbium resonance. The latter is taken as a reference laser to which a second main laser system, used for laser cooling of atomic erbium, is frequency stabilized

A rotating three component perfect fluid source and its junction with empty space-time

The Kerr solution for empty space-time is presented in an ellipsoidally symmetric coordinate system and it is used to produce generalised ellipsoidal metrics appropriate for the generation of rotating interior solutions of Einstein's equations. It is shown that these solutions are the familiar static perfect fluid cases commonly derived in curvature coordinates but now endowed with rotation. The resulting solutions are also discussed in the context of T-solutions of Einstein's equations and the vacuum T-solution outside a rotating source is presented. The interior source for these solutions is shown not to be a perfect fluid but rather an anisotropic three component perfect fluid for which the energy momentum tensor is derived. The Schwarzschild interior solution is given as an example of the approach.Comment: 14 page

ICER is requisite for Th17 differentiation.

Inducible cAMP early repressor (ICER) has been described as a transcriptional repressor isoform of the cAMP response element modulator (CREM). Here we report that ICER is predominantly expressed in Th17 cells through the IL-6-STAT3 pathway and binds to the Il17a promoter, where it facilitates the accumulation of the canonical enhancer RORγt. In vitro differentiation from naive ICER/CREM-deficient CD4(+) T cells to Th17 cells is impaired but can be rescued by forced overexpression of ICER. Consistent with a role of Th17 cells in autoimmune and inflammatory diseases, ICER/CREM-deficient B6.lpr mice are protected from developing autoimmunity. Similarly, both anti-glomerular basement membrane-induced glomerulonephritis and experimental encephalomyelitis are attenuated in ICER/CREM-deficient mice compared with their ICER/CREM-sufficient littermates. Importantly, we find ICER overexpressed in CD4(+) T cells from patients with systemic lupus erythematosus. Collectively, our findings identify a unique role for ICER, which affects both organ-specific and systemic autoimmunity in a Th17-dependent manner

Non-destructive, dynamic detectors for Bose-Einstein condensates

We propose and analyze a series of non-destructive, dynamic detectors for Bose-Einstein condensates based on photo-detectors operating at the shot noise limit. These detectors are compatible with real time feedback to the condensate. The signal to noise ratio of different detection schemes are compared subject to the constraint of minimal heating due to photon absorption and spontaneous emission. This constraint leads to different optimal operating points for interference-based schemes. We find the somewhat counter-intuitive result that without the presence of a cavity, interferometry causes as much destruction as absorption for optically thin clouds. For optically thick clouds, cavity-free interferometry is superior to absorption, but it still cannot be made arbitrarily non-destructive . We propose a cavity-based measurement of atomic density which can in principle be made arbitrarily non-destructive for a given signal to noise ratio

Reasons for participation in a child development study: Are cases with developmental diagnoses different from controls?

Background: Current knowledge about parental reasons for allowing child participation in research comes mainly from clinical trials. Fewer data exist on parents’ motivations to enrol children in observational studies. Objectives: Describe reasons parents of preschoolers gave for participating in the Study to Explore Early Development (SEED), a US multi-site study of autism spectrum disorder (ASD) and other developmental delays or disorders (DD), and explore reasons given by child diagnostic and behavioural characteristics at enrolment. Methods: We included families of children, age 2–5 years, participating in SEED (n = 5696) during 2007–2016. We assigned children to groups based on characteristics at enrolment: previously diagnosed ASD; suspected ASD; non-ASD DD; and population controls (POP). During a study interview, we asked parents their reasons for participating. Two coders independently coded responses and resolved discrepancies via consensus. We fit binary mixed-effects models to evaluate associations of each reason with group and demographics, using POP as reference. Results: Participants gave 1–5 reasons for participation (mean = 1.7, SD = 0.7). Altruism (48.3%), ASD research interest (47.4%) and perceived personal benefit (26.9%) were most common. Two novel reasons were knowing someone outside the household with the study conditions (peripheral relationship; 14.1%) and desire to contribute to a specified result (1.4%). Odds of reporting interest in ASD research were higher among diagnosed ASD participants (odds ratio [OR] 2.89, 95% confidence interval [CI] 2.49–3.35). Perceived personal benefit had higher odds among diagnosed (OR 1.92, 95% CI 1.61–2.29) or suspected ASD (OR 3.67, 95% CI 2.99–4.50) and non-ASD DD (OR 1.80, 95% CI 1.50–2.16) participants. Peripheral relationship with ASD/DD had lower odds among all case groups. Conclusions: We identified meaningful differences between groups in parent-reported reasons for participation. Differences demonstrate an opportunity for future studies to tailor recruitment materials and increase the perceived benefit for specific prospective participants

Atomic diffraction from nanostructured optical potentials

We develop a versatile theoretical approach to the study of cold-atom diffractive scattering from light-field gratings by combining calculations of the optical near-field, generated by evanescent waves close to the surface of periodic nanostructured arrays, together with advanced atom wavepacket propagation on this optical potential.Comment: 8 figures, 10 pages, submitted to Phys. Rev.

Maternal Pre-pregnancy Body Mass Index and Gestational Weight Gain in Relation to Autism Spectrum Disorder and other Developmental Disorders in Offspring

Most prior studies examining maternal pre-pregnancy body mass index (BMI) in relation to offspring autism spectrum disorders (ASD) have reported an association, though findings are not uniform and few have also examined gestational weight gain (GWG). Therefore, we examined both in the Study to Explore Early Development, a multi-site case–control study of children born in 2003–2006. Children identified from clinics, schools, and birth certificates were enrolled at ages 2–5 year and using standardized developmental evaluations, classified as: ASD, other developmental delays (DD), or population-based controls. Maternal height, weight, and GWG were self-reported during the telephone interview. Three primary weight risk factors were examined: (a) Pre-pregnancy BMI, classified as underweight to obese, (b) GWG continuous and categorized as quintiles, and (c) Institute of Medicine clinical weight-gain recommendations. Odds ratios adjusted (AOR) for sociodemographic and prenatal factors were calculated among term singletons, comparing the ASD (n = 540) or DD (n = 720) groups to the control group (n = 776). The AOR of ASD and maternal obesity was 1.37 (95%CI 0.98–1.92). Associations with higher GWG were stronger (Quintile5 vs. Quintile3 AOR = 1.58, 95%CI 1.08–2.31), and particularly so among overweight/obese women (AOR = 1.90, 95%CI 0.98–3.68). DD was associated with maternal overweight and obesity (obesity AOR = 1.48, 95%CI 1.08–2.02), but not with total GWG or clinical recommendations. High maternal BMI and GWG are risk factors for other pregnancy and child outcomes, and our results suggest they may also represent modifiable risk factors for neurodevelopmental outcomes. Autism Res 2019, 12: 316–327 © 2018 International Society for Autism Research, Wiley Periodicals, Inc. Lay Summary: In a large, national study, we found that children with autism were more likely than unaffected children to have mothers with higher weight gain during pregnancy; risk of autism may be even stronger if mothers were also overweight before pregnancy. Children with other developmental delays were more likely to have mothers who were overweight or obese before pregnancy, but not who gained more weight during pregnancy. Overweight and weight gain may represent factors that could be modified

Demographic and Operational Factors Predicting Study Completion in a Multisite Case-Control Study of Preschool Children

Participant attrition can limit inferences drawn from study results and inflate research costs. We examined factors associated with completion of the Study to Explore Early Development (2007-2011), a multiple-component, case-control study of risk factors for autism spectrum disorder in preschoolers, conducted in California, Colorado, Georgia, Maryland, North Carolina, and Pennsylvania. Participants (n = 3,769) were asked to complete phone interviews, questionnaires, an in-person evaluation, and biologic sampling. We examined whether participant demographic and administrative factors predicted completion using mixed-effects logistic regression models. Completion of individual key study components was generally 70% or higher. However, 58% of families completed all per-protocol data elements (defined a priori as key study components). Per-protocol completion differed according to mother's age, race, educational level, driving distance to clinic, number of contact attempts to enroll, and number of telephone numbers provided (all P < 0.05). Case status was not associated with completion, despite additional data collection for case-confirmation. Analysis of a subset that completed an early interview revealed no differences in completion by household factors of income, primary language spoken, number of adults, or number of children with chronic conditions. Differences in completion by race and education were notable and need to be carefully considered in developing future recruitment and completion strategies

Early Life Exposure to Air Pollution and Autism Spectrum Disorder: Findings from a Multisite Case-Control Study

BACKGROUND: Epidemiologic studies have reported associations between prenatal and early postnatal air pollution exposure and autism spectrum disorder (ASD); however, findings differ by pollutant and developmental window. OBJECTIVES: We examined associations between early life exposure to particulate matter ≤2.5 µm in diameter (PM2.5) and ozone in association with ASD across multiple US regions. METHODS: Our study participants included 674 children with confirmed ASD and 855 population controls from the Study to Explore Early Development, a multi-site case-control study of children born from 2003 to 2006 in the United States. We used a satellite-based model to assign air pollutant exposure averages during several critical periods of neurodevelopment: 3 months before pregnancy; each trimester of pregnancy; the entire pregnancy; and the first year of life. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for study site, maternal age, maternal education, maternal race/ethnicity, maternal smoking, and month and year of birth. RESULTS: The air pollution-ASD associations appeared to vary by exposure time period. Ozone exposure during the third trimester was associated with ASD, with an OR of 1.2 (95% CI: 1.1, 1.4) per 6.6 ppb increase in ozone. We additionally observed a positive association with PM2.5 exposure during the first year of life (OR = 1.3 [95% CI: 1.0, 1.6] per 1.6 µg/m increase in PM2.5). CONCLUSIONS: Our study corroborates previous findings of a positive association between early life air pollution exposure and ASD, and identifies a potential critical window of exposure during the late prenatal and early postnatal periods