North atlantic oscillation dynamics recorded in greenland ice cores

Carefully selected ice core data from Greenland can be used to reconstruct an annual proxy North Atlantic oscillation (NAO) index. This index for the past 350 years indicates that the NAO is an intermittent climate oscillation with temporally active (coherent) and passive (incoherent) phases. No indication for a single, persistent, multiannual NAO frequency is found. In active phases, most of the energy is located in the frequency band with periods less than about 15 years. In addition, variability on time scales of 80 to 90 years has been observed since the mid-19th century.     

Predicting eruptions at mount st. Helens, june 1980 through december 1982

Thirteen eruptions of Mount St. Helens between June 1980 and December 1982 were predicted tens of minutes to, more generally, a few hours in advance. The last seven of these eruptions, starting with that of mid-April 1981, were predicted between 3 days and 3 weeks in advance. Precursory seismicity, deformation of the crater floor and the lava dome, and, to a lesser extent, gas emissions provided telltale evidence of forthcoming eruptions. The newly developed capability for prediction reduced risk to life and property and influenced land-use decisions.     

Fascioliasis in cattle in Louisiana: development of a system to predict disease risk by climate, using the Thornthwaite water budget

A system correlating climate with the annual risk of fascioliasis in cattle in central Louisiana was developed, using the Thornthwaite water budget and a 6-year data base that included records on herd prevalence rates, transmission to fluke-free sentinel calves, and snail population dynamics. The system developed was compared with modifications of the wet-day and Mt forecasting systems previously developed for use in the oceanic climate zone of western Europe. The wet-day system correlated poorly with transmission data, whereas the Mt and Thornthwaite water budget-derived systems correctly ranked 5 of the 6 years in terms of annual numbers of flukes transmitted to sentinel calves. Compared with the Mt system, the water budget-based system more closely correlated with transmission data, on the basis of statistical regression analysis. The water budget system was calculated by use of a microcomputer software program, and provided a means of measuring the effect of moisture stress and flooding in snail habitats that serve as foci of transmission of Fasciola hepatica to cattle on pastures.     

Influence of solar heating and precipitation scavenging on the simulated lifetime of post--nuclear war smoke

The behavior of smoke injected into the atmosphere by massive fires that might follow a nuclear war was simulated. Studies with a three-dimensional global atmospheric circulation model showed that heating of the smoke by sunlight would be important and might produce several effects that would decrease the efficiency with which precipitation removes smoke from the atmosphere. The heating gives rise to vertical motions that carry smoke well above the original injection height. Heating of the smoke also causes the tropopause, which is initially above the smoke, to reform below the heated smoke layer. Smoke above the tropopause is physically isolated from precipitation below. Consequently, the atmospheric residence time of the remaining smoke is greatly increased over the prescribed residence times used in previous models of nuclear winter.     

Experience and confidence of final year veterinary students in performing desexing surgeries

AIMS: To describe the level of experience and confidence of veterinary students in performing canine and feline desexing procedures at the end of their final clinical year.

METHOD: A cross-sectional survey was conducted with veterinary students at Massey University in November 2017 after completion of their final clinical year. The questions included career plans after graduation, number of assisted and unassisted desexing procedures performed, approximate time to complete desexing surgeries, level of confidence with different aspects of desexing surgeries, what aspects of their desexing surgery training were most helpful, and what could be done to improve training in desexing surgical skills in veterinary school.

RESULTS: The survey was completed by 70/95 (74%) students in their final clinical year. Among respondents, 55/70 (70%) had performed >2 unassisted feline neuters before graduation. However 38/70 (54%) students had never performed an unassisted feline spay, 31/70 (44%) had never performed an unassisted canine neuter, and 44/70 (63%) students had never performed an unassisted canine spay. The median reported times to complete a feline neuter, feline spay, canine neuter, and canine spay were 9, 40, 30 and 60 minutes, respectively. The median level of confidence for these procedures were 9, 6, 7 and 5 (on a scale from 1=least confident to 10=most confident), respectively. The reported time to complete procedures and the confidence in performing procedures did not change markedly with increasing total number of procedures performed. Students were most concerned about their ability to perform the desexing procedures in a reasonable amount of time and to prevent post-operative bleeding from occurring. Students were least concerned with their ability to manage post-operative pain in patients and to select the appropriate suture material. Free-text comments revealed that 62/70 (89%) students wanted more hands-on surgical experience prior to graduation.

CONCLUSION AND CLINICAL RELEVENCE: Many students are currently completing veterinary school with limited experience and low confidence with performing routine canine and feline desexing procedures. Further research is needed to identify the most effective ways for addressing this issue within the constraints of the veterinary curriculum and teaching hospital resources.     

SPLENIC SEQUESTRATION SCINTIGRAPHY IN THE DOG: A COMPARISON OF DENATURING TECHNIQUES

Five mixed-breed dogs underwent splenic sequestration scintigraphy following intravenous injection of 647.5 to 740 MBq (17.5–20 mCi) of ^99mTechnetium labeled autologous red blood cells (RBCs) that had been chemically denatured using two μg of stannous chloride. Left lateral dynamic images were obtained for 20 minutes after injection. Regions of interest (ROI) were drawn around the splenic body and ventral extremity, ventral liver and caudal abdominal great vessels and time activity curves created. Count density information was obtained and uptake ratios were calculated for the spleen ROI/vessel ROI, liver ROI/vessel ROI and spleen ROI/liver ROI at 1, 2.5, 5, 10, 15 and 20 minutes after injection. Two additional studies using different RBC denaturing procedures were done in four of the five dogs. In the second study, the stannous chloride level was doubled to 4.0 μg, while in the third study, the RBCs were denatured by addition of 2.0 μg of stannous chloride and heating at 49°C for 15 minutes. Progressive splenic uptake of denatured RBCs was seen in all dogs during the first 15 to 20 minutes of each study, no matter which denaturing technique was utilized. Significant increases in the spleen ROI:/vessel ROI and spleen ROI:liver ROI ratios were obtained at 5, 10, 15 and 20 minutes when compared to the 1 minute values for each of the labeling techniques. A significant difference was not identified between the three ratios at 15 minutes between the three labeling techniques. There was a trend of increasing values for each ratio where 2.0 μg of stannous chloride technique being the lowest, 4.0 μg of stannous chloride having an intermediate value and the heated technique had the highest values. The heating technique resulted in higher liver activity and increased variability of the mean liver ROI/vessel ROI ratios at all times (1, 2.5, 5,10, and 15 minutes). Using a non-linear least squares regression analysis, a double exponential equation fit the spleen ROI/vessel ROI and spleen ROI/liver ROI ratios for all three labeling techniques. Imaging of the spleen using all three techniques was acceptable, and a persistent blood pool image would allow for vascular imaging and cardiac gated studies 30 minutes after injection of the denatured, labeled autologous red blood cells. Veterinary Radiology & Ultrasound, Vol. 36, No. I, 1995, pp 57–63.     

Simulated N management effects on corn yield and tile-drainage nitrate loss

Thoroughly tested simulation models are needed to help quantify the long-term effects of agriculture. We evaluated the Root Zone Water Quality Model (RZWQM) response to different N management strategies and then used the tested model with observed weather data from 1961-2003 to quantify long-term effects on corn (Zea mays L.) yield and flow weighted nitrate-N concentration in subsurface “tile” drainage water (Nconc). Fourteen years (1990-2003) of field data from 30, 0.4 ha plots in northeast Iowa were available for model testing. Annual crop yield, nitrate-N loss to subsurface “tile” drainage water (Nloss), Nconc, and subsurface “tile” drainage amount (drain) for various management scenarios were averaged over plots and years to create five chemical fertilizer and five swine manure treatments. Predicted corn yield and Nconc for the 10 treatments were significantly correlated with observed data (R² > 0.83). The Root Mean Square Errors (RMSE) were 15% and 18% of its observed average Nconc for chemical fertilizer and manure treatments, respectively. Corresponding RMSEs for corn yields were 8% and 10% of its observed average corn yields for chemical fertilizer and manure treatments. The long-term simulations indicate that average corn yield plateaus and Nloss accelerates as quadratic functions of increasing spring UAN-N rates from 100 to 200 kg N/ha. Winter wheat (Triticum aestivum L.) sowed after corn and soybean [Glycine max (L.) Merr.] harvest was predicted to reduce long-term Nloss by 5 to 6 kg N/ha, which appears consistent with published field studies and may be a treatment to ameliorate agricultural management with potential for elevated Nloss such as swine manure application to soybean. The results suggest that after calibration and thorough testing, RZWQM can be used to quantify the relative effects of corn production and Nconc under several alternative management practices.     

Evaluation of substance P as a neurotransmitter in equine jejunum

OBJECTIVE: To determine whether substance P (SP) functions as a neurotransmitter in equine jejunum. SAMPLE POPULATION: Samples of jejunum obtained from horses that did not have lesions in the gastrointestinal tract. PROCEDURE: Jejunal smooth muscle strips, oriented in the plane of the circular or longitudinal muscle, were suspended isometrically in muscle baths. Neurotransmitter release was induced by electrical field stimulation (EFS) delivered at 2 intensities (30 and 70 V) and various frequencies on muscle strips that were maintained at low tension or were under contraction. A neurokinin-1 receptor blocker (CP-96,345) was added to baths prior to EFS to interrupt SP neurotransmission. Additionally, direct effects of SP on muscle strips were evaluated, and SP-like immunoreactivity was localized in intestinal tissues, using indirect immunofluorescence testing. RESULTS: Substance P contracted circularly and longitudinally oriented muscle strips. Prior treatment with CP-96,345 altered muscle responses to SP and EFS, suggesting that SP was released from depolarized myenteric neurons. Depending on orientation of muscle strips and stimulation variables used, CP-96,345 increased or decreased the contractile response to EFS. Substance P-like immunoreactivity was detected in the myenteric plexus and circular muscle layers. CONCLUSIONS AND CLINICAL RELEVANCE: Substance P appears to function as a neurotransmitter in equine jejunum. It apparently modulates smooth muscle contractility, depending on preexisting conditions. Effects of SP may be altered in some forms of intestinal dysfunction. Altering SP neurotransmission in the jejunum may provide a therapeutic option for motility disorders of horses that are unresponsive to adrenergic and cholinergic drugs.     

Comparison of two immunochromatographic assays and the indirect immunofluorscence antibody test for diagnosis of Trypanosoma cruzi infection in dogs in south central Louisiana

Two rapid tests evaluated in dogs considered to be of high risk of infection with the Chagas parasite Trypanosoma cruzi using two immunochromatographic assays: Trypanosoma Detect™ for canine, InBios, Seattle, WA and CHAGAS STAT-PAK™ assay, Chembio Diagnostic Systems, Medford, NY, in south central Louisiana. For this purpose a serological survey was carried out in a total of 122 dogs and a serum bank was created. These 122 animals were first tested by IFAT that was used as the standard test. From the serum bank 50 samples were tested using the two rapid Chagas assays and results compared to the standard test IFAT. The serological survey using IFAT showed a prevalence of T. cruzi infection in 22.1% of the tested dogs. In the immunochromatographic assays, 13 and 11 animals were positive on rapid assay: Trypanosoma Detect™ for canine, InBios and CHAGAS STAT-PAK™, Chembio Diagnostic Systems, respectively compared to 11 positive by IFAT. These two immunochromatographic tests have shown high susceptibility and specificity compared to our standard method IFAT. The rapid, easy and accurate screening assays used in conjunction with confirmatory tests, would be an excellent tool for veterinarians to diagnose T. cruzi infection. Early detection of T. cruzi infection may prevent complications through an effective treatment. Greater awareness by veterinarians of the risk, clinical findings, history along with diagnostic methods will contribute greatly to an understanding of the true prevalence of Chagas disease in dogs in Louisiana.     

Point mutations including a novel Pro-197-Phe mutation confer cross-resistance to acetolactate synthase (ALS) inhibiting herbicides in Lactuca serriola in Australia

BACKGROUND

Control of prickly lettuce has become increasingly difficult for lentil growers in southern Australia because of widespread resistance to common herbicides, a lack of alternative herbicide options and the prolific production of highly mobile seed. This study aimed to quantify acetolactate synthase (ALS)-inhibiting herbicide resistance in the Mid North (MN) and Yorke Peninsula (YP) of South Australia, characterize the resistance mutations present and investigate population structure and gene flow in this species.

RESULTS

Resistance was identified in all populations tested, with average survival of 92% to chlorsulfuron and 95% to imazamox + imazapyr. Five different amino acid substitutions were identified at proline 197 of the ALS gene. There was no significant difference in the median lethal dose (LD₅₀) between plants with these five different substitutions when treated with metsulfuron-methyl; however, the imidazolinone resistance level was higher in plants with a phenylalanine substitution and lower in plants with a serine. Population structure based on 701 single nucleotide polymorphisms and 271 individuals provided evidence for both independent evolution of the same mutation in different populations, as well as frequent short- to medium-distance dispersal accompanied by occasional long-distance dispersal events. The overall inbreeding coefficient (F_IS) was calculated at 0.5174, indicating an intermediate level of outcrossing despite the cross-pollination experiment showing only low outcrossing. In the structure analyses, most individuals from YP were assigned to a single cluster, whereas most individuals from MN were assigned 50% to each of two clusters, indicating some genetic differences between these two regions, but also evidence for dispersal between them.

CONCLUSIONS

Use of imidazolinone herbicides has selected for mutations conferring higher levels of resistance, such as the Pro-197-Phe mutation, and resulted in further spread of resistance in this species. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.