Testing the SOC hypothesis for the magnetosphere

As noted by Chang, the hypothesis of Self-Organised Criticality provides a theoretical framework in which the low dimensionality seen in magnetospheric indices can be combined with the scaling seen in their power spectra and the recently-observed plasma bursty bulk flows. As such, it has considerable appeal, describing the aspects of the magnetospheric fuelling:storage:release cycle which are generic to slowly-driven, interaction-dominated, thresholded systems rather than unique to the magnetosphere. In consequence, several recent numerical "sandpile" algorithms have been used with a view to comparison with magnetospheric observables. However, demonstration of SOC in the magnetosphere will require further work in the definition of a set of observable properties which are the unique "fingerprint" of SOC. This is because, for example, a scale-free power spectrum admits several possible explanations other than SOC. A more subtle problem is important for both simulations and data analysis when dealing with multiscale and hence broadband phenomena such as SOC. This is that finite length systems such as the magnetosphere or magnetotail will by definition give information over a small range of orders of magnitude, and so scaling will tend to be narrowband. Here we develop a simple framework in which previous descriptions of magnetospheric dynamics can be described and contrasted. We then review existing observations which are indicative of SOC, and ask if they are sufficient to demonstrate it unambiguously, and if not, what new observations need to be made?Comment: 29 pages, 0 figures. Based on invited talk at Spring American Geophysical Union Meeting, 1999. Journal of Atmospheric and Solar Terrestrial Physics, in pres

Which jobs are done from home? Evidence from the American Time Use Survey?

Which jobs are more likely to be affected by mobility restrictions due to the Covid-19 pandemic? This paper uses American Time Use Survey data to measure the share of the work hours that are spent at home for different job categories. We compute and provide home-working shares by occupation (US census classification, SOC and international ISCO classification), and by industry (US census classification, NAICS and international ISIC classification)

Estrogen priming GnRH antagonist regimen is an efficient protocol in poor responders

International-Federation-of-Fertility-Societies 21st World Congress on Fertility and Sterility / 69th Annual Meeting of the American-Society-for-Reproductive-Medicine -- OCT 12-17, 2013 -- Boston, MAInt Federat Fertil Soc, Amer Soc Reprod Me

Semidefinite Relaxations for Stochastic Optimal Control Policies

Recent results in the study of the Hamilton Jacobi Bellman (HJB) equation have led to the discovery of a formulation of the value function as a linear Partial Differential Equation (PDE) for stochastic nonlinear systems with a mild constraint on their disturbances. This has yielded promising directions for research in the planning and control of nonlinear systems. This work proposes a new method obtaining approximate solutions to these linear stochastic optimal control (SOC) problems. A candidate polynomial with variable coefficients is proposed as the solution to the SOC problem. A Sum of Squares (SOS) relaxation is then taken to the partial differential constraints, leading to a hierarchy of semidefinite relaxations with improving sub-optimality gap. The resulting approximate solutions are shown to be guaranteed over- and under-approximations for the optimal value function.Comment: Preprint. Accepted to American Controls Conference (ACC) 2014 in Portland, Oregon. 7 pages, colo

Light pollution at high zenith angles, as measured at Cerro Tololo Inter-American Observatory

On the basis of measurements of the V-band sky brightness obtained at Cerro Tololo Inter-American Observatory in December 2006 and December 2008 we confirm the functional form of the basic model of Garstang (1989, 1991). At high zenith angles we measure an enhancement of a factor of two over Garstang's later model when there is no marine cloud layer over La Serena/Coquimbo. No corresponding enhancement is found in the B-band.Comment: 12 pages, 4 figures, to be published in the March, 2010, issue of Publs. of the Astron. Soc. of the Pacifi

The Football Factor: Shaping Community on Campus

Many American universities continue to invest in expensive intercollegiate football programs, and specifically cite the sport’s ability to foster a sense of community (SOC) as justification for the cost. This study sought to assess the importance of SOC and the influence of football on the cultivation thereof. A pre-post test design utilizing an online survey compared SOC levels for students (N = 886) before and after the implementation of Division I football on a large university campus. No significant differences were found in SOC levels before and after the football season (regardless of attendance). Post-test SOC perceptions differed based on game attendance (i.e., moderate and loyal attendees reported the highest levels). Finally, SOC had a moderate to strong positive influence on four outcome variables: Satisfaction, Retention, Current Support of Athletics, and Future Support for Athletics. This study suggests that while SOC is very important to students, at least in the short term the introduction of a football program does not foster a greater SOC for all students

Soil organic carbon development and turnover in natural and disturbed salt marsh environments

Author Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 48(2), (2021): e2020GL090287, https://doi.org/10.1029/2020GL090287.Salt marsh survival with sea‐level rise (SLR) increasingly relies on soil organic carbon (SOC) accumulation and preservation. Using a novel combination of geochemical approaches, we characterized fine SOC (≤1 mm) supporting marsh elevation maintenance. Overlaying thermal reactivity, source (δ13C), and age (F14C) information demonstrates several processes contributing to soil development: marsh grass production, redeposition of eroded material, and microbial reworking. Redeposition of old carbon, likely from creekbanks, represented ∼9%–17% of shallow SOC (≤26 cm). Soils stored marsh grass‐derived compounds with a range of reactivities that were reworked over centuries‐to‐millennia. Decomposition decreases SOC thermal reactivity throughout the soil column while the decades‐long disturbance of ponding accelerated this shift in surface horizons. Empirically derived estimates of SOC turnover based on geochemical composition spanned a wide range (640–9,951 years) and have the potential to inform predictions of marsh ecosystem evolution.This work was supported by NSF (OCE1233678) and NOAA (NA14OAR4170104 and NA14NOS4190145) grants to ACS, USGS Coastal & Marine Geology Program, and PIE‐LTER (NSF OCE1238212 and OCE1637630).2021-06-1

The Football Factor: Shaping Community on Campus

Many American universities continue to invest in expensive intercollegiate football programs, and specifically cite the sport’s ability to foster a sense of community (SOC) as justification for the cost. This study sought to assess the importance of SOC and the influence of football on the cultivation thereof. A pre-post test design utilizing an online survey compared SOC levels for students (N = 886) before and after the implementation of Division I football on a large university campus. No significant differences were found in SOC levels before and after the football season (regardless of attendance). Post-test SOC perceptions differed based on game attendance (i.e., moderate and loyal attendees reported the highest levels). Finally, SOC had a moderate to strong positive influence on four outcome variables: Satisfaction, Retention, Current Support of Athletics, and Future Support for Athletics. This study suggests that while SOC is very important to students, at least in the short term the introduction of a football program does not foster a greater SOC for all students

Vulnerability of high latitude soil organic carbon in North America to disturbance

This synthesis addresses the vulnerability of the North American high-latitude soil organic carbon (SOC) pool to climate change. Disturbances caused by climate warming in arctic, subarctic, and boreal environments can result in significant redistribution of C among major reservoirs with potential global impacts. We divide the current northern high-latitude SOC pools into (1) near-surface soils where SOC is affected by seasonal freeze-thaw processes and changes in moisture status, and (2) deeper permafrost and peatland strata down to several tens of meters depth where SOC is usually not affected by short-term changes. We address key factors (permafrost, vegetation, hydrology, paleoenvironmental history) and processes (C input, storage, decomposition, and output) responsible for the formation of the large high-latitude SOC pool in North America and highlight how climate-related disturbances could alter this pool\u27s character and size. Press disturbances of relatively slow but persistent nature such as top-down thawing of permafrost, and changes in hydrology, microbiological communities, pedological processes, and vegetation types, as well as pulse disturbances of relatively rapid and local nature such as wildfires and thermokarst, could substantially impact SOC stocks. Ongoing climate warming in the North American high-latitude region could result in crossing environmental thresholds, thereby accelerating press disturbances and increasingly triggering pulse disturbances and eventually affecting the C source/sink net character of northern high-latitude soils. Finally, we assess postdisturbance feedbacks, models, and predictions for the northern high-latitude SOC pool, and discuss data and research gaps to be addressed by future research

Impact of a stage-matched weight loss intervention on stage of change progression in predominantly African-American female primary care patients

Obesity is associated with several chronic medical conditions. Certain individuals are at higher risk for obesity including low-income African American females. Despite the many benefits to weight loss, many individuals do not seek treatment. Individuals are likely to attend primary care appointments where obesity can be targeted. Although stage matched interventions based on the Transtheoretical Model (TM) have been used successfully to aid in health behavior change, few studies have examined the use of stage matched weight loss interventions in African American females. There is also a paucity of research examining the effects of stage matched weight loss interventions on TM related constructs, such as perceived stage of change (SOC), decisional balance (the perceived pros and cons of weight loss) and self-efficacy (confidence in ability to lose weight). This study examined the impact of a 6-month physician directed, stage matched weight-loss intervention on SOC, decision balance, and self-efficacy for weight loss in 158 low-income African Americans selected from primary care medical clinics. No differences in SOC, decisional balance, and self-efficacy from baseline to end of active treatment were found for the intervention group. Similarly, no differences in SOC were found between the intervention group and the usual care control (UC) group. Attempts to detect differences in SOC were greatly attenuated by the finding that 87% of participants indicated they were already in an advanced SOC prior to the start of treatment. Self-efficacy was found to be higher in the action SOC than the maintenance SOC, which was inconsistent with past research. These results suggest that stage-matched interventions work differently in this population and may not add any additional benefit to weight loss interventions. More research is needed comparing these interventions to more general weight loss techniques in primary care samples of low-income African Americans