In this work a sufficient condition is shown to obtain transitivity in families of piecewise increassing maps with an inevitable discontinuity in x=0. Specifically, it is shown that the characteristics of a large class of transformations of the real line with a discontinuity in x=0 to be transitive (exhibits a dense orbit), they are the following: f has no fixed points, f has a vertical asymptote at x=0 and the preimage of zero is different from empty. In particular, the famous Boole transformation together with some of its parameterizations they exhibit these characteristics. As a particular case, for the family to a parameter of hyperbolas its dynamic behavior is explicitly determined according to the values of the parameter p > 0.

Multiple resistance to antibiotics was determined in bacterial isolates from Thoroughbred horses at the National Race Track «La Rinconada», Caracas, Venezuela. From a population of 128 horses in 2009, 12 did not respond to antibacterial treatment despite being treated for 7 days with gentamicin (6 mg/kg), penicillin (22,000 IU/kg) and ceftiofur (4 mg/kg). Necropsy was conducted and tissue samples were collected from abscesses in septic arthritis (4), abscess in endocardium (1), suppurative esophagitis (2), laryngeal granuloma (1), pneumonia (2), pyelonephritis (1) and dermatitis (1). Samples were placed in Stuart transport medium and cultured. The bacterial isolates were tested for antibiotic susceptibility. E. coli was isolated in 12 cases (75%), Proteus mirabilis in 2 (12.5%), Pseudomonas aeruginosa in 1 (6.25%), and Streptococcus equi subspecies zooepidemicus in 1 (6.25%). The bacte...

Se determinó la resistencia múltiple a los antibióticos en aislados bacteriales de caballos Pura Sangre en el Hipódromo «La Rinconada», Caracas, Venezuela durante el 2009. Se trabajó con una población de 128 caballos, donde 12 no respondieron al tratamiento contra infecciones adquiridas, pese a ser tratados durante 7 días con gentamicina (6 mg/kg), penicilina (22.000 UI/kg) y ceftiofur sódico (4 mg/kg). Se practicó la necropsia y se tomaron muestras de tejido de abscesos en artritis séptica (4), endocarditis con abscesos (1), esofagitis supurada (2), granuloma laríngeo (1), neumonía (2), pielonefritis (1) y dermatitis (1). Las muestras se colocaron en medio de transporte Stuart y fueron cultivadas. Los aislados fueron sometidos a una prueba de susceptibilidad antibacterial. La bacteria E. coli fue aislada en 12 casos (75%), Proteus mirabilis en 2 (12.5%), Pseudomonas aerugi...

A thoroughbred race horses, of 2 years old and male was remited. With history of severe emaciation, rough hair and sporadic chronic diarrhea. Previous stool examinations showed HPG 1850 (eggs per g of feces) of Strongylus spp. The employee was treated with Ivermectin 0.2 mg. kg-1 single dose orally. Necropsy was performed and tissue samples were taken for histopathological study, the same as those processed by conventional methods. Additionally, intestinal contents were sampled for parasitological studies. Macroscopic findings were severe emaciation, rough hair and pale mucous membranes. It was noticed gastric ulcer syndrome, hemorrhagic enteritis in the small intestine with chronic focal presence of parasitic forms of 3-5 cm and type cysts, and hemomelasma ilei. The histological sections showed proliferative enteritis by a lymphocytic infiltrate and few eosinophils. Parasitic cysts were...