Photogrammetric Analysis of the 2013 El Reno Tornado Combined with Mobile X-Band Polarimetric Radar Data

Abstract This study presents rapid-scanning X-band polarimetric radar data combined with photogrammetry of the El Reno tornado of 31 May 2013. The relationship between the hook echo, weak-echo hole (WEH), weak-echo column (WEC), and the rotational couplet with the visual characteristics of the tornado are shown. For the first time, cross-correlation coefficient (ρhv) and differential reflectivity (ZDR) data are included in the photogrammetric analyses. The tornado was accompanied by a large tornadic debris signature (TDS) with a diameter ~2 km wide during the analysis time. The center of the TDS was not collocated with the WEH and the rotational couplet. Instead, the TDS was displaced ~1 km to the north and within the weak-echo notch of the hook echo. A “debris overhang” was identified in vertical cross sections of the ρhv fields. The overhang was located in a weak-echo trench and a notch of high ρhv, consistent with the position of the tornado updraft. The updraft was hypothesized to be carrying small debris particles to heights that produced the overhang signature. A U-shaped band of high ρhv and ZDR was resolved in a vertical cross section and positioned at the periphery of the WEC during one of the analysis times. It was proposed that the band formed as a result of hydrometeors encircling the WEC while being surrounded on all sides by relatively hydrometeor-free air. The characteristics of the scatterers within the WEC were resolved and believed to be composed of a low concentration of very small, randomly oriented, debris particles, even in the presence of strong centrifuging, and a general absence of hydrometeors

Testing fluvial erosion models using the transient response of bedrock rivers to tectonic forcing in the Apennines, Italy

The transient response of bedrock rivers to a drop in base level can be used to discriminate between competing fluvial erosion models. However, some recent studies of bedrock erosion conclude that transient river long profiles can be approximately characterized by a transport‐limited erosion model, while other authors suggest that a detachment‐limited model best explains their field data. The difference is thought to be due to the relative volume of sediment being fluxed through the fluvial system. Using a pragmatic approach, we address this debate by testing the ability of end‐member fluvial erosion models to reproduce the well‐documented evolution of three catchments in the central Apennines (Italy) which have been perturbed to various extents by an independently constrained increase in relative uplift rate. The transport‐limited model is unable to account for the catchments’response to the increase in uplift rate, consistent with the observed low rates of sediment supply to the channels. Instead, a detachment‐limited model with a threshold corresponding to the field‐derived median grain size of the sediment plus a slope‐dependent channel width satisfactorily reproduces the overall convex long profiles along the studied rivers. Importantly, we find that the prefactor in the hydraulic scaling relationship is uplift dependent, leading to landscapes responding faster the higher the uplift rate, consistent with field observations. We conclude that a slope‐ dependent channel width and an entrainment/erosion threshold are necessary ingredients when modeling landscape evolution or mapping the distribution of fluvial erosion rates in areas where the rate of sediment supply to channels is low

Aerial Damage Survey of the 2013 El Reno Tornado Combined with Mobile Radar Data

A detailed damage survey of the El Reno, Oklahoma, tornado of 31 May 2013 combined with rapid-scanning data recorded from two mobile radars is presented. One of the radars was equipped with polarimetric capability. The relationship between several suction vortices visually identified in pictures with the high-resolution Doppler velocity data and swath marks in fields is discussed. The suction vortices were associated with small shear features in Doppler velocity and a partial ringlike feature of high spectral width. For the first time, a suction vortex that created a swath mark in a field was visually identified in photographs and high-definition video while the rotational couplet was tracked by radar. A dual-Doppler wind synthesis of the tornadic circulation at low levels near the location of several storm chaser fatalities resolved ground-relative wind speeds in excess of 90 m s−1, greater than the minimum speed for EF5 damage. The vertical vorticity analysis revealed a rapid transition from a single tornadic vortex centered on the weak-echo hole (WEH) to suction vortices surrounding the WEH and collocated with the ring of enhanced radar reflectivities. Several bands/zones of enhanced convergence were resolved in the wind syntheses. One of the bands was associated with an internal or secondary rear-flank gust front. An inner band of convergence appeared to be a result of the positive bias in tornado-relative radial velocity owing to centrifuging of large lofted debris swirling within the tornado. An outer band of convergence formed at the northern edge of a region of strong inflow that was lofting small debris and dust into the storm

Basins of attraction on random topography

We investigate the consequences of fluid flowing on a continuous surface upon the geometric and statistical distribution of the flow. We find that the ability of a surface to collect water by its mere geometrical shape is proportional to the curvature of the contour line divided by the local slope. Consequently, rivers tend to lie in locations of high curvature and flat slopes. Gaussian surfaces are introduced as a model of random topography. For Gaussian surfaces the relation between convergence and slope is obtained analytically. The convergence of flow lines correlates positively with drainage area, so that lower slopes are associated with larger basins. As a consequence, we explain the observed relation between the local slope of a landscape and the area of the drainage basin geometrically. To some extent, the slope-area relation comes about not because of fluvial erosion of the landscape, but because of the way rivers choose their path. Our results are supported by numerically generated surfaces as well as by real landscapes

Characteristics of Internet Addiction/Pathological Internet Use in U.S. University Students: A Qualitative-Method Investigation

Studies have identified high rates and severe consequences of Internet Addiction/Pathological Internet Use (IA/PIU) in university students. However, most research concerning IA/PIU in U.S. university students has been conducted within a quantitative research paradigm, and frequently fails to contextualize the problem of IA/PIU. To address this gap, we conducted an exploratory qualitative study using the focus group approach and examined 27 U.S. university students who self-identified as intensive Internet users, spent more than 25 hours/week on the Internet for non-school or non-work-related activities and who reported Internet-associated health and/or psychosocial problems. Students completed two IA/PIU measures (Young’s Diagnostic Questionnaire and the Compulsive Internet Use Scale) and participated in focus groups exploring the natural history of their Internet use; preferred online activities; emotional, interpersonal, and situational triggers for intensive Internet use; and health and/or psychosocial consequences of their Internet overuse. Students’ self-reports of Internet overuse problems were consistent with results of standardized measures. Students first accessed the Internet at an average age of 9 (SD = 2.7), and first had a problem with Internet overuse at an average age of 16 (SD = 4.3). Sadness and depression, boredom, and stress were common triggers of intensive Internet use. Social media use was nearly universal and pervasive in participants’ lives. Sleep deprivation, academic under-achievement, failure to exercise and to engage in face-to-face social activities, negative affective states, and decreased ability to concentrate were frequently reported consequences of intensive Internet use/Internet overuse. IA/PIU may be an underappreciated problem among U.S. university students and warrants additional research

The Effect of U.S. University Students' Problematic Internet Use on Family Relationships: A Mixed-Methods Investigation

This is the first study to investigate how college students in the U.S. with problematic Internet use perceive the role the Internet plays within their families of origin. The sample included 27 U.S. university students who self-identified as excessive Internet users. Participants reported spending more than 25 hours a week on the Internet on non-school or non-work-related activities and reported Internet-associated health and/or psychosocial problems. This study provides descriptive statistics from participants' completion of two problematic Internet use measures (i.e., Young's Diagnostic Questionnaire and the Compulsive Internet Use Scale) and reports findings from four focus groups. Three themes emerged from the focus groups: (1) family connectedness, (2) family conflict/family disconnection, and (3) family Internet overuse. The findings of this study are a first step toward the design of effective interventions for problematic Internet use among U.S. college students and serve to inform clinical practice and health policy in this area

College Students’ Responses to Antismoking Messages: Denial, Defiance, and Other Boomerang Effects

Despite the success of antismoking campaigns that aim to prevent young teens from smoking, this qualitative study provides strong evidence that different initiatives are needed for college students, particularly those who already smoke. When asked for responses to current antismoking messages, nonsmokers generally championed the cause; however, smokers often responded with anger, defiance, denial, and other negative responses. Consumers who respond in this manner are not well served by existing strategies, and money used for such campaigns could be better spent. New strategies are offered in hopes that antismoking campaigns can communicate more effectively with one high-risk group—college student smokers

Diurnal secretion of growth hormone, cortisol, and dehydroepiandrosterone in pre- and perimenopausal women with active rheumatoid arthritis: a pilot case-control study

Rheumatoid arthritis (RA) is associated with neuroendocrine and immunologic dysfunction leading to rheumatoid cachexia. Although excess proinflammatory cytokines can decrease somatotropic axis activity, little is known about the effects of RA on growth hormone/insulin-like growth factor-1 (GH/IGF-I) axis function. We tested the hypothesis that patients with active RA exhibit decreased GH/IGF-I axis activity. To do so, we conducted a pilot case-control study at a clinical research center in 7 pre- and perimenopausal women with active RA and 10 age- and body mass index-matched healthy women. Participants underwent blood sampling every 20 minutes for 24 hours (8 a.m. to 8 a.m.), and sera were assayed for GH, cortisol, and dehydroepiandrosterone (DHEA). Sera obtained after overnight fasting were assayed for IGF-I, IGF-binding protein (IGFBP)-1, IGFBP-3, C-reactive protein (CRP), interleukin-6 (IL-6), glucose, insulin, and lipids. Body composition and bone mineral density were evaluated by DEXA (dual emission x-ray absorptiometry) scans. In patients with RA, mean disease duration was 7.6 ± 6.8 years, and erythrocyte sedimentation rate, CRP, and IL-6 were elevated. GH half-life was shorter than in control subjects (p = 0.0037), with no other significant group differences in GH deconvolution parameters or approximate entropy scores. IGF-I (p = 0.05) and IGFBP-3 (p = 0.058) were lower, whereas IGFBP-1 tended to be higher (p = 0.066), in patients with RA, with nonsignificantly increased 24-hour total GH production rates. There were no significant group differences in cortisol or DHEA secretion. Lean body mass was lower in patients with RA (p = 0.019), particularly in the legs (p = 0.01). Women with active RA exhibit a trend toward GH insensitivity and relatively diminished diurnal cortisol and DHEA secretion for their state of inflammation. Whether these changes contribute to rheumatoid cachexia remains to be determined

Ordinary morality does not imply atheism

Many theist as well as many atheist philosophers have maintained that if God exists, then every instance of undeserved, unwanted suffering ultimately benefits the sufferer. Recently, several authors have argued that this implication of theism conflicts with ordinary morality. I show that these arguments all rest on a common mistake. Defenders of these arguments overlook the role of merely potential instances of suffering in determining our moral obligations toward suffering