117,427 research outputs found
RELATIVISTIC POINT INTERACTION
No full textA four-parameter family of all self-adjoint operators corresponding to the one-dimensional Dirac Hamiltonian with point interaction is characterized in terms of boundary conditions. The spectrum
and eigenvectors, and the scattering parameters are calculated. It is shown that the nonrelativisticlimit
reproduces (in the norm resolvent sense) the four-parameterfamily of Schrodinger operators with point interaction, their eigenvaluesand scattering parameters
The use of click beetle pheromone traps to optimize the risk assessment of wireworm (Coleoptera: Elateridae) maize damage
Get PDFMaize seeds are routinely coated with insecticide to target Agriotes spp. larvae (wireworms). However, in order to find fields where pest control is actually needed, it might be useful to estimate the adult Agriotes population levels and thus the pressure they exert, with a low-cost risk assessment tool, such as YATLORf (Yf) sex pheromone traps. A database containing 17 consecutive years (1998–2014) of field monitoring was analyzed, with information including both pheromone-trap catches of adults and maize-plant damage by wireworms. Significant associations were discovered between seasonal adult catches in-field, subsequent wireworm populations, and plant damage/yield reduction. When each trap contained over 1,100 A. sordidus adults and over 210 A. brevis adults one year prior (Y-1), the risk of 15%-plus plant damage in Year 0 (Y0) increased by 6 times and 37 times respectively when compared with lower numbers. More than 1,000 A. brevis adults/trap two years prior (Y-2) increased the risk of 15%-plus plant damage in Y0 by 13 times when compared with lower numbers. Cumulative thresholds were also found in Y-1 and Y-2 at the same site. Yf threshold values allowed us to detect fields with a negligible crop-damage risk and thus to reduce the use of insecticides
Integrated Pest Meadow-ploughing timing as an integrated pest management tactic to prevent soil-pest damage to maize
No full textThe management of soil-pests still largely relies on conventional chemical insecticides despite the provisions of Integrated Pest Management (IPM). Long-term research was carried out in north-eastern Italy to assess the potential of meadow ploughing just before maize sowing to prevent wireworm damage. The research was based on the observation that no serious wireworm damage occurred in 20 years when meadows were ploughed just before maize sowing. The research hypothesis was that soil-incorporated fresh meadow turf would be a more attractive wireworm food source than seeds, emerging seedlings and young plants. Meadow plots with a sufficiently homogeneous wireworm density were alternately ploughed the previous autumn and a few days before maize sowing. The same conditions were simulated in pots into which known numbers of cage-reared wireworms had been introduced. Results showed very consistently that plant damage in plots ploughed just before maize sowing was much lower than the damage in plots ploughed in autumn-winter, and always below the economic risk threshold (15% of damaged plants). In controlled conditions, plant damage in pots with soil-incorporated fresh meadow turf was significantly lower than that observed in pots without. In both field and controlled conditions, this major effect on plant protection is likely to be caused by the incorporation of meadow turf living plant parts into the soil. Therefore, the ploughing timing of meadows in rotation may be a viable alternative to chemical insecticides when rotation includes meadow
EFFICACIA DELLA LOTTA INTEGRATA ALLA PIRALIDE DEL MAIS
No full textPer difendersi in modo sostenibile dalla piralide è essenziale trattare nel momento ottimale, che va individuato sulla base del monitoraggio territoriale, dei modelli previsionali e dei riscontri locali. I risultati dimostrano che nel biennio 2011-2012 in un solo caso su quattro l' intervento è risultato economicamente convenient
Role of transient elastography to stage fontan-associated liver disease (Fald) in adults with single ventricle congenital heart disease correction
Get PDFFontan-associated liver disease (FALD) is an arising clinical entity that can occur long after a successful Fontan operation for correction of single ventricle (SV) congenital heart disease (CHD). Occurrence of FALD is characterized by liver cirrhosis and other hepatic complications, and deter-minates an increased morbidity and mortality. Currently, there is no consensus on how to stage FALD. We report here our experience by an observational study in 52 patients with SV-CHD after Fontan operation that were recruited through a period of 36 ± 9.3 months. All cases underwent lab tests and liver and cardiac imaging evaluation, including liver stiffness (LS) measurement by transient elastography (TE) (FibroScan®). According to selective criteria for liver disease, we identified 23/43 (53.5%) cases with advanced FALD that showed: older age (p < 0.05), larger hepatic and cava veins diameter (p < 0.05), worsened NYHA class (p < 0.05), abnormal lymphocytes (p < 0.01), platelet count (p < 0.05), and GGT, prothrombin time (INR), albumin and cystatin C levels (p < 0.05), with respect to cases without advanced FALD. LS values were significantly increased in cases with advanced FALD, at cut-off values higher than 22 kPa (p < 0.001). LS, and its combined score with spleen diameter and platelet count (LSPS) successfully helped to detect 100% of cases with portal hyper-tension (p < 0.001). In conclusion, LS can be effective to stage FALD and to uncover cases with severe risk of complications, avoiding higher morbidity and mortality related to advanced FALD
La ricerca di un vaccino antimalarico tra sfide e parziali successi
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