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This study presents an investigation into relationships among topographic elevation, surface land cover, and tornado intensity using rapid scan, mobile Doppler radar observations of four tornadoes from the U.S. Central Plains. High spatiotemporal resolution observations of tornadic vortex signatures from the radar’s lowest elevation angle data (in most cases ranging from ~100 to 350 m above ground level) are coupled with digital elevation model (DEM) and 2011 National Land Cover Database (NLCD) data using a geographic information system (GIS). The relationships between 1) tornado intensity and topographic elevation or surface roughness and 2) changes in tornado intensity and changes in topographic elevation or surface roughness are investigated qualitatively, and statistical relationships are quantified and analyzed using a bootstrap permutation method for individual case studies and all cases collectively. Results suggest that there are statistically significant relationships for individual cases, but the relationships defy generalization and are different on a case-by-case basis, which may imply that they are coincidental, indicating a null correlation.

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.

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.

An integrated damage, visual, and radar analysis of the EF5 Moore, Oklahoma, tornado that occurred on 20 May 2013 is presented. Characteristics of the damage path are discussed based on detailed ground and aerial surveys. Tree fall reveals highly convergent surface flow over the majority of the damage path. At times, the convergent flow is observed at radii less than that of the condensation funnel. A photogrammetric analysis of still photos and video shows that the damaging winds extend well beyond the condensation funnel location. The condensation funnel often coincides with the EF1, EF2, and EF3 isopleths. Observations of the tornado debris signature (TDS) by the Twin Lakes (KTLX)–Weather Surveillance Radar-1988 Doppler (WSR-88D) are presented. The TDS is not a good indicator of tornado intensity just after tornadogenesis. The spatial relationship between the TDS, condensation funnel, and damage path is highlighted. An analysis of the area encompassed by the respective EF-scale isopleths is presented t...

Sixty market hogs originating from one producer and finished in a concrete and steel facility were divided into two groups of 30 and housed for approximately 60 h on either straw (control group) or pentachlorophenol (PCP) treated wood shavings (test group). Feed, straw, and shavings were analyzed for PCP residues. Both feed and straw yielded nondetectable levels of PCP residues, while shavings ranged from 0.03 to 12.0 ppm. The hogs were shipped to slaughter without bedding, and liver, fat and muscle (muscle from the test group only) samples were collected postmortem. The mean level of PCP residue in control (straw) hog livers was 0.037 ppm, while that of livers of hogs bedded with contaminated shavings was 0.342 ppm, a highly significant difference. The t-value using Welch's approximation equalled 9.77 using 28.5 degrees of freedom, indicating the mean PCP residue level was higher for the treated than the control group at a 0.01% level of significance.

To the Editor, Ms McMurty’s well-written article surprised me somewhat because I am now removed from observing injections of paediatric (human) patients, especially since my youngest is in her teen years. I had anticipated that the pain of routine immunization or other injections would be managed as I have managed it for years in clinical practice. Clearly, injections hurt. Veterinary patients react honestly, immediately and often quite effectively in terms of stopping the pain (ie, scratching, biting and flying off the table). While in veterinary college in the mid 1980s, I visited a dentist in Hamilton, Ontario, who advised that he would be using a distraction technique while injecting local anesthetic. I advised that I was not nervous and that the distraction would certainly not be necessary. He persisted, or rather his assistant persisted and she proceeded to gently but firmly tap the inside of my wrist while the injection was being undertaken. Frankly I was stunned. While fully cognizant of both the procedure and the rationale for it, I did not feel the pain of the injection at all. I resolved to use such a technique in clinical practice, modifying what any large animal practitioner or farmer knows – if you slap the cow’s hip a couple of times and slip the needle in on the second or third slap when treating with antibiotics, you would not have a lightning fast kick to the abdomen or to other areas. These sorts of friendly slaps on the hip are not uncommon in dairy practice. I practised distraction techniques early on with my daughter who was born in my graduating year (1986), firmly but not painfully squeezing her arm or leg while her immunizations were administered by the nurse or physician. Later in small animal practice, large pats were administered to large dogs, small pats or puffs of air to small dogs and whatever worked for the less predictable felines – sometimes a gentle shaking of the scruff or squeezing of the paws. Often the immunization experience was topped off with an edible treat. Canine patients raised under my care veered toward the building on their daily walks, not away in terror as my dog had done in my youth. Cats, admittedly, still largely found the clinical setting less than satisfactory, but they rarely noticed that their injections were being administered. If controlled studies had been performed, I believe behaviours, overall, would be much more acceptable. On one occasion, as a small animal practitioner not equipped with appropriate equine anesthetic medications, I removed a substantial New Year’s dose of porcupine quills from the face of a friend’s horse with only firm large pats administered while the hemostat held a few quills. Perhaps pain experienced by the practitioner helps the learning process. Pity I never thought to ask the dentist whether he had ever been injured while administering injections. Children deserve this sort of consideration. Needles hurt. For your patients as with mine, it is tough to explain why it is good for them. Gentle distraction techniques do not require medications or take up any additional time; they are simply a modification to longstanding habits.