Wintertime losses of ozone in high northern latitudes

Total column ozone data over the past 22 to 30 years from ground-based Dobson and filter ozonometer stations between 30 N and 80 N are analyzed for residual trends remaining after allowance for the known geophysical variations corresponding to: (1) the change of seasons; (2) the quasi-biennial oscillation; and (3) the 11-year solar sunspot cycle. Examination of the data from several ground stations between 45 and 55 N indicated a seasonal difference in the long-term ozone series, with statistically significant losses in several winter months. Accordingly, the data from individual stations were analyzed with multiple regression analysis, seeking trends on a monthly basis after allowance for the known geophysical cycles. Previous statistical analyses were conducted as tests of 1-D model calculations which do not show any differences with the seasons, and any trend toward change in ozone concentrations is expressed in a yearly trend without seasonal variation. Such a model is inappropriate for calculations with a data set which exhibits a pronounced tendency toward seasonal differences in the trends. Comparisons with model calculations then require 2-D models into which seasonal and latitudinal differences can easily be programmed

Detection of Earth-like Planets Using Apodized Telescopes

The mission of NASA's Terrestrial Planet Finder (TPF) is to find Earth-like planets orbiting other stars and characterize the atmospheres of these planets using spectroscopy. Because of the enormous brightness ratio between the star and the reflected light from the planet, techniques must be found to reduce the brightness of the star. The current favorite approach to doing this is with interferometry: interfering the light from two or more separated telescopes with a $\pi$ phase shift, nulling out the starlight. While this technique can, in principle, achieve the required dynamic range, building a space interferometer that has the necessary characteristics poses immense technical difficulties. In this paper, we suggest a much simpler approach to achieving the required dynamic range. By simply adjusting the transmissive shape of a telescope aperture, the intensity in large regions around the stellar image can be reduced nearly to zero. This approach could lead to construction of a TPF using conventional technologies, requiring space optics on a much smaller scale than the current TPF approach.Comment: Accepted for publication in ApJ Letters, 9 pages, 6 figure

Plasma Leptin Levels and Incidence of Heart Failure, Cardiovascular Disease, and Total Mortality in Elderly Individuals

OBJECTIVE: Obesity predisposes individuals to congestive heart failure (CHF) and cardiovascular disease (CVD). Leptin regulates energy homeostasis, is elevated in obesity, and influences ventricular and vascular remodeling. We tested the hypothesis that leptin levels are associated with greater risk of CHF, CVD, and mortality in elderly individuals. RESEARCH DESIGN AND METHODS: We evaluated 818 elderly (mean age 79 years, 62% women) Framingham Study participants attending a routine examination at which plasma leptin was assayed. RESULTS: Leptin levels were higher in women and strongly correlated with BMI (P < 0.0001). On follow-up (mean 8.0 years), 129 (of 775 free of CHF) participants developed CHF, 187 (of 532 free of CVD) experienced a first CVD event, and 391 individuals died. In multivariable Cox regression models adjusting for established risk factors, log-leptin was positively associated with incidence of CHF and CVD (hazard ratio [HR] per SD increment 1.26 [95% CI 1.03–1.55] and 1.28 [1.09–1.50], respectively). Additional adjustment for BMI nullified the association with CHF (0.97 [0.75–1.24]) but only modestly attenuated the relation to CVD incidence (1.23 [1.00–1.51], P = 0.052). We observed a nonlinear, U-shaped relation between log-leptin and mortality (P = 0.005 for quadratic term) with greater risk of death evident at both low and high leptin levels. CONCLUSIONS: In our moderate-sized community-based elderly sample, higher circulating leptin levels were associated with a greater risk of CHF and CVD, but leptin did not provide incremental prognostic information beyond BMI. Additional investigations are warranted to elucidate the U-shaped relation of leptin to mortality.National Institutes of Health's National Heart, Lung, and Blood Institute (N01-HC25195, N01-HV28178, K24-HL04334, R01-DK080739

Cryogenic mechanical loss of a single-crystalline GaP coating layer for precision measurement applications

The first direct observations of gravitational waves have been made by the Advanced LIGO detectors. However, the quest to improve the sensitivities of these detectors remains, and epitaxially grown single-crystal coatings show considerable promise as alternatives to the ion-beam sputtered amorphous mirror coatings typically used in these detectors and other such precision optical measurements. The mechanical loss of a 1 μm thick single-crystalline gallium phosphide (GaP) coating, incorporating a buffer layer region necessary for the growth of high quality epitaxial coatings, has been investigated over a broad range of frequencies and with fine temperature resolution. It is shown that at 20 K the mechanical loss of GaP is a factor of 40 less than an undoped tantala film heat-treated to 600 °C and is comparable to the loss of a multilayer GaP/AlGaP coating. This is shown to translate into possible reductions in coating thermal noise of a factor of 2 at 120 K and 5 at 20 K over the current best IBS coatings (alternating stacks of silica and titania-doped tantala). There is also evidence of a thermally activated dissipation process between 50 and 70 K

Transverse and longitudinal characterization of electron beams using interaction with optical near-fields

We demonstrate an experimental technique for both transverse and longitudinal characterization of bunched femtosecond free electron beams. The operation principle is based on monitoring of the current of electrons that obtained an energy gain during the interaction with the synchronized optical near-field wave excited by femtosecond laser pulses. The synchronous accelerating/decelerating fields confined to the surface of a silicon nanostructure are characterized using a highly focused sub-relativistic electron beam. Here the transverse spatial resolution of 450 nm and femtosecond temporal resolution achievable by this technique are demonstrated

The Category of Node-and-Choice Forms, with Subcategories for Choice-Sequence Forms and Choice-Set Forms

The literature specifies extensive-form games in many styles, and eventually I hope to formally translate games across those styles. Toward that end, this paper defines $\mathbf{NCF}$, the category of node-and-choice forms. The category's objects are extensive forms in essentially any style, and the category's isomorphisms are made to accord with the literature's small handful of ad hoc style equivalences. Further, this paper develops two full subcategories: $\mathbf{CsqF}$ for forms whose nodes are choice-sequences, and $\mathbf{CsetF}$ for forms whose nodes are choice-sets. I show that $\mathbf{NCF}$ is "isomorphically enclosed" in $\mathbf{CsqF}$ in the sense that each $\mathbf{NCF}$ form is isomorphic to a $\mathbf{CsqF}$ form. Similarly, I show that $\mathbf{CsqF_{\tilde a}}$ is isomorphically enclosed in $\mathbf{CsetF}$ in the sense that each $\mathbf{CsqF}$ form with no-absentmindedness is isomorphic to a $\mathbf{CsetF}$ form. The converses are found to be almost immediate, and the resulting equivalences unify and simplify two ad hoc style equivalences in Kline and Luckraz 2016 and Streufert 2019. Aside from the larger agenda, this paper already makes three practical contributions. Style equivalences are made easier to derive by [1] a natural concept of isomorphic invariance and [2] the composability of isomorphic enclosures. In addition, [3] some new consequences of equivalence are systematically deduced.Comment: 43 pages, 9 figure

Sulfur isotope fractionation during oxidation of sulfur dioxide: gas-phase oxidation by OH radicals and aqueous oxidation by H2O2, O3 and iron catalysis

The oxidation of SO[subscript 2] to sulfate is a key reaction in determining the role of sulfate in the environment through its effect on aerosol size distribution and composition. Sulfur isotope analysis has been used to investigate sources and chemical processes of sulfur dioxide and sulfate in the atmosphere, however interpretation of measured sulfur isotope ratios is challenging due to a lack of reliable information on the isotopic fractionation involved in major transformation pathways. This paper presents laboratory measurements of the fractionation factors for the major atmospheric oxidation reactions for SO2: Gas-phase oxidation by OH radicals, and aqueous oxidation by H[subscript 2]O[subscript 2], O[subscript 3] and a radical chain reaction initiated by iron. The measured fractionation factor for [superscript 34]S/[superscript 32]S during the gas-phase reaction is α[subscript OH] = (1.0089±0.0007)−((4±5)×10[subscript −5]) T(°C). The measured fractionation factor for [superscript 34]S/[superscript 32]S during aqueous oxidation by H[subscript 2]O[subscript 2] or O[subscript 3] is α[subscript aq] = (1.0167±0.0019)−((8.7±3.5) ×10[superscript −5])T(°C). The observed fractionation during oxidation by H2O2 and O3 appeared to be controlled primarily by protonation and acid-base equilibria of S(IV) in solution, which is the reason that there is no significant difference between the fractionation produced by the two oxidants within the experimental error. The isotopic fractionation factor from a radical chain reaction in solution catalysed by iron is αFe = (0.9894±0.0043) at 19 °C for [superscript 34]S/[superscript 32]S. Fractionation was mass-dependent with regards to 33S/32S for all the reactions investigated. The radical chain reaction mechanism was the only measured reaction that had a faster rate for the light isotopes. The results presented in this study will be particularly useful to determine the importance of the transition metal-catalysed oxidation pathway compared to other oxidation pathways, but other main oxidation pathways can not be distinguished based on stable sulfur isotope measurements alone

The association of adolescent spinal-pain-related absenteeism with early adulthood work absenteeism: A six-year follow-up data from a population-based cohort

Objectives Spinal (ie, back and neck) pain often develops as early as during adolescence and can set a trajectory for later life. However, whether early-life spinal-pain-related behavioral responses of missing school/work are predictive of future work absenteeism is yet unknown. We assessed the association of adolescent spinal-pain-related work or school absenteeism with early adulthood work absenteeism in a prospective population-based cohort. Methods Six year follow-up data from the Western Australian Pregnancy Cohort (Raine) study were used (N=476; with a 54% response rate). At age 17, participants reported spinal pain (using the Nordic questionnaire) and adolescent spinal-pain-related work/school absenteeism (with a single item question). Annual total and health-related work absenteeism was assessed with the Health and Work Performance questionnaire distributed in four quarterly text messages during the 23rd year of age. We modelled the association of adolescent spinal-pain-related absenteeism with work absenteeism during early adulthood, using negative binomial regression adjusting for sex, occupation and comorbidities. Results Participants with adolescent low-back or neck pain with work/school absenteeism reported higher total work absenteeism in early adulthood [148.7, standard deviation (SD) 243.4 hours/year], than those without pain [43.7 (SD 95.2) hours/year); incidence rate ratio 3.4 (95% CI 1.2-9.2)]. Comparable findings were found when considering low-back and neck separately, and when considering health-related absenteeism. Conclusions We found a more than three-fold higher risk of work absenteeism in early adulthood among those with adolescent spinal-pain-related absenteeism, compared to those without. These findings suggest that, to keep a sustainable workforce, pain prevention and management should focus on pain-related behaviors as early as in adolescence

Influence of innate sludge factors and ambient environmental parameters in biosolids storage on indicator bacteria survival: A review

The potential health risks associated with sludge cake application to agricultural land are managed by controlling the levels of Escherichia coli (E. coli) bacteria which indicate the risk of pathogen transfer. Analyses undertaken following post-digestion sludge dewatering have shown unpredictable levels of E. coli increase in stored sludge cake. Presently there is limited understanding on environmental parameters controlling the indicator bacteria density in storage and the contributory effects dewatering may have. This review aims to establish the state of current knowledge on innate and environmental factors influencing E. coli dynamics and survival in biosolids. A key factor identified is the effect of mechanical dewatering processes, which transform the sludge matrix environmental conditions through the increased availability of growth factors (e.g. nutrient and oxygen). Examples of storage practices from the agricultural and food industries are also discussed as successful methods to inhibit bacterial growth and survival, which could be extrapolated to the biosolids sector to regulate E. coli concentrations

Constraints on Type Ia Supernova Progenitor Companions from Early Ultraviolet Observations with Swift

We compare early ultraviolet (UV) observations of Type Ia Supernovae (SNe Ia) with theoretical predictions for the brightness of the shock associated with the collision between SN ejecta and a companion star. Our simple method is independent of the intrinsic flux from the SN and treats the flux observed with the Swift/Ultra-Violet Optical Telescope (UVOT) as conservative upper limits on the shock brightness. Comparing this limit with the predicted flux for various shock models, we constrain the geometry of the SN progenitor-companion system. We find the model of a 1 M_sun red supergiant companion in Roche lobe overflow to be excluded at a 95% confidence level for most individual SNe for all but the most unfavorable viewing angles. For the sample of 12 SNe taken together, the upper limits on the viewing angle are inconsistent with the expected distribution of viewing angles for RG stars as the majority of companions with high confidence. The separation distance constraints do allow MS companions. A better understanding of the UV flux arising from the SN itself as well as continued UV observations of young SNe Ia will further constrain the possible progenitors of SNe Ia.Comment: accepted versio