Computational fluid dynamics as a tool for urban drainage system analysis: a review of applications and best practice

Computational Fluid Dynamics (CFD) can be applied to gain insights into most fluid processes and associated phenomena and so presents potential to add value in the analysis of urban drainage systems. This paper presents a review of CFD studies carried out in this field, with the objective of developing an appreciation of how and where it can be applied. Existing work has tended to focus around the analysis of four types of urban drainage structure, including Combined Sewer Overflows (CSOs), storage and attenuation systems, stormwater sediment interceptors and sewerage conveyance structures. Within the respective studies, the prediction of flowfields, particulate behaviour, water surface profiles and Residence Time Distributions (RTDs) are found to form the main focus, and as such, these are considered in most detail in the paper. It is concluded that CFD presents a number of opportunities in urban drainage system analysis, and that the scope of this opportunity will further develop as both computational hardware and software resources become more advanced

Reduction of the Three Dimensional Schrodinger Equation for Multilayered Films

In this paper, we present a method for reducing the three dimensional Schrodinger equation to study confined metallic states, such as quantum well states, in a multilayer film geometry. While discussing some approximations that are employed when dealing with the three dimensionality of the problem, we derive a one dimensional equation suitable for studying such states using an envelope function approach. Some applications to the Cu/Co multilayer system with regard to spin tunneling/rotations and angle resolved photoemission are discussed.Comment: 14 pages, 1 figur

Radiative charge transfer lifetime of the excited state of (NaCa)+^+

New experiments were proposed recently to investigate the regime of cold atomic and molecular ion-atom collision processes in a special hybrid neutral-atom--ion trap under high vacuum conditions. The collisional cooling of laser pre-cooled Ca$^+$ ions by ultracold Na atoms is being studied. Modeling this process requires knowledge of the radiative lifetime of the excited singlet A$^1\Sigma^+$ state of the (NaCa)$^+$ molecular system. We calculate the rate coefficient for radiative charge transfer using a semiclassical approach. The dipole radial matrix elements between the ground and the excited states, and the potential curves were calculated using Complete Active Space Self-Consistent field and M\"oller-Plesset second order perturbation theory (CASSCF/MP2) with an extended Gaussian basis, 6-311+G(3df). The semiclassical charge transfer rate coefficient was averaged over a thermal Maxwellian distribution. In addition we also present elastic collision cross sections and the spin-exchange cross section. The rate coefficient for charge transfer was found to be $2.3\times 10^{-16}$ cm$^3$/sec, while those for the elastic and spin-exchange cross sections were found to be several orders of magnitude higher ($1.1\times 10^{-8}$ cm$^3$/sec and $2.3\times 10^{-9}$ cm$^3$/sec, respectively). This confirms our assumption that the milli-Kelvin regime of collisional cooling of calcium ions by sodium atoms is favorable with the respect to low loss of calcium ions due to the charge transfer.Comment: 4 pages, 5 figures; v.2 - conceptual change

Fourier Analysis of Gapped Time Series: Improved Estimates of Solar and Stellar Oscillation Parameters

Quantitative helio- and asteroseismology require very precise measurements of the frequencies, amplitudes, and lifetimes of the global modes of stellar oscillation. It is common knowledge that the precision of these measurements depends on the total length (T), quality, and completeness of the observations. Except in a few simple cases, the effect of gaps in the data on measurement precision is poorly understood, in particular in Fourier space where the convolution of the observable with the observation window introduces correlations between different frequencies. Here we describe and implement a rather general method to retrieve maximum likelihood estimates of the oscillation parameters, taking into account the proper statistics of the observations. Our fitting method applies in complex Fourier space and exploits the phase information. We consider both solar-like stochastic oscillations and long-lived harmonic oscillations, plus random noise. Using numerical simulations, we demonstrate the existence of cases for which our improved fitting method is less biased and has a greater precision than when the frequency correlations are ignored. This is especially true of low signal-to-noise solar-like oscillations. For example, we discuss a case where the precision on the mode frequency estimate is increased by a factor of five, for a duty cycle of 15%. In the case of long-lived sinusoidal oscillations, a proper treatment of the frequency correlations does not provide any significant improvement; nevertheless we confirm that the mode frequency can be measured from gapped data at a much better precision than the 1/T Rayleigh resolution.Comment: Accepted for publication in Solar Physics Topical Issue "Helioseismology, Asteroseismology, and MHD Connections

The prototypes of tobacco users scale (Potus) for cigarette smoking and e-cigarette use: Development and validation

Endorsing prototypes of cigarette smokers predicts cigarette smoking, but less is known about prototypes of users of other tobacco products. Our study sought to establish the reliability and validity of a measure of prototypes of smokers and e-cigarette users. Participants were from a national survey of smokers and non-smokers (n = 1414), a randomized clinical trial (RCT) of adult smokers (n = 2149), and adolescent children of adults in the trial (n = 112). The Prototypes of Tobacco Users Scale (POTUS) has four positive adjectives (cool, sexy, smart, and healthy) and four negative adjectives (disgusting, unattractive, immature, and inconsiderate) describing cigarette smokers and e-cigarette users. Confirmatory factor analyses identified a two-factor solution. The POTUS demonstrated strong internal consistency reliability in all three samples (median α = 0.85) and good test–retest reliability among adults in the RCT (median r = 0.61, 1–4 weeks follow-up). In the RCT, smokers more often agreed with negative prototypes for smokers than for e-cigarette users (mean = 2.03 vs. 1.67, p < 0.05); negative prototypes at baseline were also associated with more forgoing of cigarettes and making a quit attempt at the end of the trial (Week 4 follow-up). The POTUS may be useful to public health researchers seeking to design interventions that reduce tobacco initiation or cessation through the manipulation of tobacco user prototypes

Characterization of the variability and repeatability of gonadotropin-releasing hormone–induced luteinizing hormone responses in dairy cows within a synchronized ovulation protocol

peer-reviewedThe primary objective was to determine the variability and repeatability of GnRH-induced LH responses. The secondary objective was to evaluate the associations among plasma LH, FSH, estradiol (E2), and progesterone (P4) concentrations. One hundred lactating Holstein cows (35 primiparous, 65 multiparous) were initially subjected to a presynchronization protocol (d 0, PGF2α; d 3, GnRH) followed 7 d later by Ovsynch (d 10, GnRH; d 17, PGF2α; 56 h later, GnRH) and timed artificial insemination 16 h after the last GnRH. Blood samples were collected immediately before the GnRH injection of presynchronization and the second GnRH of Ovsynch to determine plasma concentrations of LH, FSH, and P4. A second blood sample was collected 2 h after each of the above GnRH injections to determine GnRH-induced LH and FSH concentrations. Plasma concentrations of E2 were also determined in samples collected immediately before the second GnRH of Ovsynch. Cows that (1) had higher LH concentrations at 0 h than at 2 h after GnRH, (2) showed an ongoing spontaneous LH surge, (3) did not respond to GnRH, and (4) had P4 ≥ 0.5 ng/mL at GnRH of presynchronization and the second GnRH of Ovsynch were excluded from the analysis. The variability (coefficient of variation) and repeatability [between animal variance/(within animal variance + between animal variance)] of GnRH-induced LH response were determined from samples collected 2 h after the GnRH of presynchronization and the second GnRH of Ovsynch. The associations among plasma LH, FSH, E2, and P4 were determined at the second GnRH of Ovsynch. Mean (±SEM) LH concentrations before GnRH were 0.5 ± 0.04 and 0.6 ± 0.03 ng/mL, whereas mean LH concentrations 2 h after GnRH were 9.8 ± 1.0 and 12.1 ± 0.8 ng/mL at GnRH of presynchronization and the second GnRH of Ovsynch, respectively. The variability of GnRH-induced LH was 76.1 and 52.1% at GnRH of presynchronization and the second GnRH of Ovsynch, respectively. The repeatability estimate for GnRH-induced LH concentration between GnRH of presynchronization and Ovsynch assessments was 0.10. Plasma concentrations of LH were positively associated with FSH and E2 (r = 0.61 and 0.30, respectively) and negatively associated with P4 (r = −0.46) at the second GnRH of Ovsynch. In summary, GnRH-induced LH responses were highly variable and unrepeatable, and LH concentrations were positively associated with FSH and E2 and negatively associated with P4

The relationship between anogenital distance and fertility, and genome-wide associations for anogenital distance in Irish Holstein-Friesian cows

peer-reviewedThe evaluation of anogenital distance (AGD), the distance from the center of the anus to base of the clitoris, as a potential fertility trait for genetic selection in dairy cows has generated recent interest. The objectives of this cross-sectional observational study were to (1) characterize the distribution and variability of AGD, (2) determine factors associated with AGD, (3) estimate heritability for AGD, (4) identify single nucleotide polymorphisms (SNP) associated with phenotypic variation of AGD, and (5) validate the relationship between categories of AGD and fertility in Irish Holstein-Friesian cows. Anogenital distance was measured using digital calipers in 1,180 Holstein cows (mean ± standard deviation: 225 ± 79 d in milk) from 10 dairy herds located in Munster, Ireland. In addition, age (yr), weight (kg), height at hip (cm), and body condition score (BCS) at the time of AGD measurement were determined in a subset of 281 cows. Genotype information available from 908 cows was subsequently imputed to the Illumina Bovine High Density BeadChip (Illumina Inc., San Diego, CA) for genome-wide association analysis of phenotypic variation in AGD. Overall, AGD had a normal distribution and high variability (mean ± standard deviation; 119.2 ± 11.6 mm). Anogenital distance was weakly but positively associated with cow age, hip height, and body weight, and negatively associated with BCS; the phenotypic variation in AGD that was explainable by these variables was small (coefficient of determination; R2 = 0.09, 0.06, 0.10, and 0.02, respectively). The estimated heritability for AGD was 0.37 (standard error of mean ± 0.08). Six SNP of suggestive significance were identified on Bos taurus autosomes 6, 15, 20, and 26; however, none of these SNP was related to previously identified candidate genes for fertility. Cows were categorized into quartiles (Q1; 86 to 111 mm; n = 311, Q2; 112 to 120 mm; n = 330; Q3; 121 to 127 mm; n = 265, and Q4; 128 to 160 mm; n = 274) based on AGD and the association with reproductive outcomes examined (21-d submission rate, pregnancy to first AI, pregnancy rate within 21, 42 and 84-d after the farm mating start date, and number of times bred). None of the reproductive variables differed significantly between AGD categories. In summary, despite identification of high variability and moderate heritability for AGD in Irish Holstein-Friesian cows, reproductive outcomes did not differ between categories of AGD. This latter result differs from our previous finding of an inverse relationship between AGD and pregnancy outcomes in first- and second-parity Canadian Holstein cows, emphasizing the need to test and validate this new phenotype in diverse cow populations

Effectiveness of Prenatal Tetanus, Diphtheria, Acellular Pertussis Vaccination in the Prevention of Infant Pertussis in the U.S.

Introduction: It is recommended that all pregnant women in the U.S. receive tetanus, diphtheria, acellular pertussis (Tdap) immunization to prevent infant pertussis. This study's objective was to examine the clinical effectiveness of prenatal Tdap, and whether effectiveness varies by gestational age at immunization. Methods: A nationwide cohort study of pregnant women with deliveries in 2010–2014 and their infants was performed. Commercial insurance claims data were analyzed in 2016–2017 to identify Tdap receipt by the pregnant women, and hospitalizations and outpatient visits for pertussis in their infants until the infants reached 18 months of age. Pertussis occurrence was compared between infants of mothers who received prenatal Tdap (overall and stratified by gestational age at administration) and infants of unvaccinated mothers. Results: There were 675,167 mother–infant pairs in the cohort. Among infants whose mothers received prenatal Tdap, the rate of pertussis was 43% lower (hazard ratio=0.57, 95% CI=0.35, 0.92) than infants whose mothers did not receive prenatal or postpartum Tdap; this reduction was consistent across pertussis definitions (hazard ratio for inpatient-only pertussis=0.32, 95% CI=0.11, 0.91). Pertussis rates were also lower for infants whose mothers received Tdap during the third trimester. Infants whose mothers received Tdap at <27 weeks of gestation did not experience reductions in pertussis rates (hazard ratio for pertussis=1.10, 95% CI=0.54, 2.25). Conclusions: Infants of mothers who received prenatal Tdap experienced half the rate of pertussis as compared with infants of unimmunized mothers. These results do not provide evidence to support changing the currently recommended timing of Tdap administration in pregnancy