Laboratory measurements of the physics of auroral electron acceleration by Alfvén waves.

While the aurora has attracted attention for millennia, important questions remain unanswered. Foremost is how auroral electrons are accelerated before colliding with the ionosphere and producing auroral light. Powerful Alfvén waves are often found traveling Earthward above auroras with sufficient energy to generate auroras, but there has been no direct measurement of the processes by which Alfvén waves transfer their energy to auroral electrons. Here, we show laboratory measurements of the resonant transfer of energy from Alfvén waves to electrons under conditions relevant to the auroral zone. Experiments are performed by launching Alfvén waves and simultaneously recording the electron velocity distribution. Numerical simulations and analytical theory support that the measured energy transfer process produces accelerated electrons capable of reaching auroral energies. The experiments, theory, and simulations demonstrate a clear causal relationship between Alfvén waves and accelerated electrons that directly cause auroras.

Screening and Confirmatory Analyses of Flunixin in Tissues and Bodily Fluids after Intravenous or Intramuscular Administration to Cull Dairy Cows with or without Lipopolysaccharide Challenge.

Twenty cull dairy cows (645 ± 83 kg) were treated with 2.2 mg/kg bw flunixin by intravenous (IV) or intramuscular (IM) administration with, or without, exposure to lipopolysaccharide in a two factor balanced design. The usefulness of screening assays to identify violative flunixin levels in a variety of easily accessible ante-mortem fluids in cattle was explored. Two animals with violative flunixin liver residue and/or violative 5-hydroxy flunixin milk residues were correctly identified by a flunixin liver ELISA screen. Oral fluid did not produce anticipated flunixin concentration profiles using ELISA determination. One cow that had liver and milk violative residues, and one cow that had a milk violation at the prescribed withdrawal period were correctly identified by flunixin milk lateral flow analyses. The ratio of urinary flunixin and 5-hydroxy flunixin may be useful for predicting disruption of metabolism caused by disease or other factors potentially leading to violative liver flunixin residues.

Excretory, Secretory, and Tissue Residues after Label and Extra-label Administration of Flunixin Meglumine to Saline- or Lipopolysaccharide-Exposed Dairy Cows.

Twenty lactating dairy cattle were intravenously infused with either lipopolysaccharide (LPS) (n = 10) or sterile saline (n = 10). Five cattle in each group received three doses of flunixin meglumine administered by either intravenous infusion or intramuscular injection at 24 h intervals. Milk, urine, and tissues were collected. Thirty-six hours after the last flunixin administration, milk from six cows contained 5-hydroxyflunixin (5OHF) levels greater than the milk tolerance of 2 ng/mL; by 48 h, milk from two cows, a saline and a LPS-treated animal, had violative milk concentrations of 5OHF. A single animal treated with LPS and intramuscular flunixin contained violative flunixin residues in liver. The ratio of urinary flunixin/5OHF was correlated (P < 0.01; R(2) = 0.946) with liver flunixin residues in LPS-treated animals, but not (P = 0.96; R(2) = 0.003) in cows treated with saline in lieu of LPS. Violative residues of flunixin in dairy cattle may be related to LPS inhibition of flunixin metabolism.

Two cases of elevated tryptase in abdominal aortic aneurysm.

INTRODUCTION: From the literature, patients with a history of anaphylaxis to hymenoptera venom and positive specific IgE have shown a correlation between elevated tryptase levels and two clinical situations: systemic mastocytosis and an increased risk of reactions to venom immunotherapy or hymenoptera sting. Other clinical scenarios could explain elevated tryptase levels. MATERIAL AND METHODS: A 67 year old male (P1) and a 77 year old male (P2) were evaluated for previous severe anaphylaxis to hymenoptera sting. They underwent standard diagnostic work-up for hymenoptera venom allergy. Having found elevated tryptase levels, these were followed by a bone marrow biopsy to rule out systemic mastocytosis. RESULTS: P1: specific IgE and skin tests were positive for Vespula species; tryptase 52.8 ng/ml; P2: specific IgE and skin tests were positive for Vespa cabro and tryptase 153 ng/ml. Bone marrow biopsy results were negative for mastocytosis. We carried out magnetic resonance imaging, in P1 to better characterize the severe osteoporosis and in P2 because during physical examination a pulsating mass had been identified in the mesogastrium, and an aneurysm of the abdominal aorta which required surgical intervention in both patients was detected. Eight months after surgery, tryptase levels had diminished significantly (P1: 11.6 ng/ml and P2: 14.5 ng/ml). DISCUSSION: The elevated tryptase levels were correlated to abdominal aneurysm in both patients. In fact, post-surgery tryptase levels dramatically decreased. These two cases demonstrate that high tryptase levels in subjects with a history of hymenoptera venom anaphylaxis can be associated to undiagnosed aneurysmatic disease.

Effect of flaxseed physical form on digestibility of lactation diets fed to Holstein steers.

Four multicannulated (rumen, duodenum, and ileum) Holstein steers (459.7±46.4kg of initial body weight) were used in a 4×4 Latin square design to determine the effect of flaxseed processing method on ruminal fermentation and digestibility. Treatments were based on inclusion of (1) 7.5% linseed meal (control), (2) 10% whole flaxseed, (3) 10% rolled flaxseed, or (4) 10% ground flaxseed on a dry matter (DM) basis, and were formulated to mimic typical high-producing dairy cow lactation diets. The control diet contained linseed meal in a proportion to provide crude protein (CP) equal to the amount of CP contributed by the flaxseed in the other treatments. Diets were fed for ad libitum intake and contained 30% corn silage, 17% chopped alfalfa hay, 6% sugar beet pulp, and 47% concentrate (comprising ground corn, supplemental protein, trace minerals and vitamins, and either flaxseed or linseed meal (DM basis). Diets were formulated to contain 17% CP, 34% neutral detergent fiber, 21% acid detergent fiber, and 4% fatty acid (DM basis). Periods were 14 d long and consisted of 7 d of adaptation and 7 d of sample collection. Dry matter intake (as a % of body weight) was similar (2.41±0.17) for all treatments. The inclusion of flaxseed, regardless of processing method, tended to decrease total-tract organic matter digestibility relative to the linseed control, but no differences in CP intake, duodenal CP flow (bacterial, apparent feed, or total), ileal CP flow, fecal CP output, microbial efficiency, or CP digestibility (apparent ruminal, true ruminal, small intestine, large intestine, or total tract) were observed between treatments. Method of processing did not alter ruminal pH, ammonia, or volatile fatty acids production. The ground flaxseed treatment had the fastest rate of in situ DM degradation (11.25%/h), followed by the control (7.46%/h), rolled flaxseed (4.53%/h), and whole flaxseed (0.57%/h) treatments. Degradability of CP and fat followed the same pattern as DM degradability for processed flaxseed. In situ degradation rates of alfalfa hay neutral detergent fiber and acid detergent fiber tended to be fastest for the ground flaxseed treatment. Taken together, the digestibility, fermentation, and in situ data indicate that rolling and grinding are both acceptable methods of processing flaxseed. The in situ data strongly support the need for processing flaxseed before inclusion in lactation diets.

Effect of feeding rolled flaxseed on milk fatty acid profiles and reproductive performance of dairy cows.

The objectives were to study the effects of feeding rolled flaxseed (FLX) to early-lactation dairy cows on milk yield, milk components, and milk fatty acid profiles as well as on measures of cow reproduction. Lactating Holstein cows, on 3 commercial dairies, were fed either an early-lactation ration (CON) or a ration that was similar in protein, energy, and fat content but that included FLX (0.85 kg of DM/cow per day). Within each dairy, cows were allocated alternately to breeding pens upon leaving the fresh pen (approximately 10 ± 5 d postpartum). Pens (n = 4 to 5 pens/dairy) were randomized to treatment (n = 2 to 3 pens/treatment per dairy). Pen (CON, n = 6; FLX, n = 7) was considered the experimental unit and data were analyzed as a split plot with pen as the whole-plot error term. Cows fed FLX had greater (P ≤ 0.06) proportions of cis-9, trans-11 C18:2, C18:3n-3, and C20:0 fatty acids in milk fat and a lesser (P = 0.03) proportion of C20:3n-6 fatty acid when compared with cows fed the CON diet. Treatment did not affect (P ≥ 0.24) milk yield, milk protein, protein yield, milk fat, or milk fat yield. No interactions (P ≥ 0.52) were found between treatment and season of the year or parity, or between treatment and days open, pregnancies per AI at first or second service, or pregnancy loss. In conclusion, feeding FLX at 0.85 kg/cow per day (DM basis) altered the fatty acid profile of milk, but milk yield, milk composition, and reproductive performance of dairy cows were not affected.

Altering the fatty acids in milk fat by including canola seed in dairy cattle diets.

The objective was to evaluate the effects of feeding ground canola seed on the fatty acid profile, yield, and composition of milk from dairy cows. Twenty-four multiparous Holstein cows (548.3 +/- 11.9 kg body weight and 28 +/- 9 d in lactation) were randomly assigned to 1 of 2 treatments: Control (CON) or ground canola seed treatment (GCS) with 14% [of diet dry matter (DM)] of the total ration as ground canola seed containing 34% lipid. Diets contained 20% crude protein, but varied in net energy as a result of fat content differences of 2.5% and 6.4% (DM) for CON and GCS, respectively. Diets were composed of corn, corn silage, alfalfa (50:50 ground hay and haylage, DM basis), soybean and blood meal, and vitamins and minerals. Mechanically extruded canola meal was used in the CON diet to adjust for the protein from canola seed in the GCS diet. Cows were housed in tie-stalls and fed and milked twice daily for 10 wk. The inclusion of ground canola seed did not alter DM intake, weight gain, or body condition score of cows. Milk fat from GCS cows had greater proportions of long-chain fatty acids (> or = 18 carbons) and a lower ratio of n-6 to n-3 fatty acids. Feeding GCS reduced the proportion of short- and medium-chain fatty acids. Milk fat from cows fed GCS had a greater proportion of vaccenic acid and tended to have a higher proportion of cis-9,trans-11 conjugated linoleic acid. Actual and 3.5% fat-corrected milk yields were similar between treatments. The milk fat and protein percentages were lower for GCS cows, but total yield of these components was similar between treatments. Milk urea nitrogen was lower and serum urea nitrogen tended to be lower in cows fed canola seed. Serum glucose, insulin, and nonesterified fatty acids were not altered, but serum triglycerides were higher in GCS cows. Ammonia and total volatile fatty acids tended to be lower in ruminal fluid from GCS cows; rumen pH was unchanged. Feeding canola seed to lactating dairy cows resulted in milk fat with higher proportions of healthful fatty acids without affecting milk yield or composition of milk.

Optimizing the level of wet corn gluten feed in the diet of lactating dairy cows.

Twenty-four multiparous Holstein cows averaging 566 +/- 43 kg of body weight and 83 +/- 49 d in lactation were assigned to treatments stratified by age, days in milk, and milk yield to evaluate the effects of feeding increasing levels of wet corn gluten feed (WCGF) on lactational performance and milk composition. Complete diets containing 0, 15, 30, or 45% of the total ration dry matter (DM) as WCGF were formulated to be 17.2% crude protein and 1.72 Mcal of NE(L) per kilogram of DM, and fed twice daily to individual cows in Calan gates for 15 wk. All diets had a positive metabolizable protein balance. WCGF did not alter DM intake, but feed intake variance tended to be more consistent among cows fed 15 and 30% WCGF (DM basis). Weight gain was numerically greatest for those cows receiving 45% WCGF. Efficiency of energy and protein utilization was not different among treatments. Milk components of fat, protein, and casein were not different among treatments. Milk urea nitrogen was greater for cows on WCGF. Serum urea nitrogen was greatest in cows fed diets containing 15 and 45% WCGF. Serum insulin was lowest in the groups receiving 30 and 45% WCGF, but serum glucose and total protein were unaffected. The concentration of the ruminal volatile fatty acid, valerate, was greater in cows on the WCGF diet and highest in cows fed 30% WCGF. Ruminal ammonia was greatest in cows receiving 30% WCGF. It was estimated that 18.6% of the dietary DM fed as WCGF as a replacement for both portions of the concentrate and the forage in similar diets would have maximized milk yield without negatively affecting milk composition or feed efficiency.

What are the primary concerns of recently graduated surgeons and how do they differ from those of the residency training years?

HYPOTHESIS: Graduated surgeons have differences in concerns when comparisons are made between fellows and practicing surgeons, practicing surgeons and residents, and male and female surgeons. DESIGN AND SETTING: A survey was distributed to surgeons who graduated from 17 New England residency programs from 1993 to 1996, consisting of 9 demographic questions and 33 items coded on a Likert-type scale (with scores from 1 [least concerning] to 5 [most concerning]). PARTICIPANTS: Surgical fellows and practicing surgeons recently graduated from general surgical residency programs in New England who had participated in a previous study as residents. INTERVENTION: Distribution and completion of the survey. MAIN OUTCOME MEASURE: Personal and career-oriented concerns of recently graduated surgical residents. RESULTS: Personal issues continue to rank high for graduated residents, but the areas of greatest concern became more financially and career oriented. The top concerns of fellows were personal finances (mean score, 3.2), child rearing (mean score, 3.1), salary (mean score, 3.1), postponing family plans (mean score, 3.0), availability of role models (mean score, 2.9), and number of work hours (mean score, 2.8). The top concerns of practicing surgeons were salary (mean score, 3.2), personal finances (mean score, 3.1), number of referrals (mean score, 3.0), support for research (mean score, 2.7), child rearing (mean score, 2.7), and availability of role models (mean score, 2.7). Differences existed between men and women for child rearing, initiating personal relationships, maintaining personal relationships, maternity leave, and promotional advancement. Women were more concerned than men. CONCLUSIONS: Assistance with career planning and job selection during the residency years should be enhanced to diminish the concerns about financial issues and the availability of role models after graduation. Many of the concerns among male and female graduates are still reflective of larger societal expectations, but some, such as promotional advancement, may be attenuated through guidance and mentoring of residents before job selection.