658 research outputs found

    Livestock Drugs and Disease: The Fatal Combination behind Breeding Failure in Endangered Bearded Vultures

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    There is increasing concern about the impact of veterinary drugs and livestock pathogens as factors damaging wildlife health, especially of threatened avian scavengers feeding upon medicated livestock carcasses. We conducted a comprehensive study of failed eggs and dead nestlings in bearded vultures (Gypaetus barbatus) to attempt to elucidate the proximate causes of breeding failure behind the recent decline in productivity in the Spanish Pyrenees. We found high concentrations of multiple veterinary drugs, primarily fluoroquinolones, in most failed eggs and nestlings, associated with multiple internal organ damage and livestock pathogens causing disease, especially septicaemia by swine pathogens and infectious bursal disease. The combined impact of drugs and disease as stochastic factors may result in potentially devastating effects exacerbating an already high risk of extinction and should be considered in current conservation programs for bearded vultures and other scavenger species, especially in regards to dangerous veterinary drugs and highly pathogenic poultry viruses

    Resolución de problemas de matemáticas y evaluación: aspectos afectivos y cognitivos

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    Asumiendo que la evaluación debe estar integrada en el proceso de enseñanza-aprendizaje, estamos desarrollando una investigación con profesores de matemáticas de secundaria en Bogotá (Colombia), para analizar sus concepciones y prácticas acerca de la evaluación sobre la resolución de problemas en matemáticas. Partimos de un cuestionario que indaga sobre la importancia que se da a diferentes aspectos cognitivos y afectivos, y al hecho de evaluarlos. Se identifica que en la evaluación de la resolución de problemas se continúa priorizando la evaluación de aspectos del dominio cognitivo, sobre el afectivo. Y en el dominio cognitivo se hace un mayor énfasis sobre los aspectos propios del conocimiento matemático que sobre las estrategias heurísticas

    Aprender a enseñar geometría en primaria. Una experiencia en formación inicial de maestros

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    Es nuestra intención, con la publicación que tienes entre tus manos, presentar una pro- puesta metodológica basada en una experiencia desarrollada durante algunos años en un aula de formación inicial de maestros. Por ello, la estructura de la primera parte sigue el desarrollo de las actividades del aula, con observaciones sobre el proceso de interacción profesor-estu- diantes para Maestros (EM) y entre los estudiantes, así como reflexiones que surgen en el aula, que tienen su fundamento en experiencias anteriores o en aportaciones de diferentes autores. Además, el lenguaje utilizado es coloquial y reflejo del trabajo desarrollado en el aula

    Aprender a enseñar geometría en primaria. Una experiencia en formación inicial de maestros

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    Es nuestra intención, con la publicación que tienes entre tus manos, presentar una propuesta metodológica basada en una experiencia desarrollada durante algunos años en un aula de formación inicial de profesores. Por ello, el formato de la primera parte sigue el desarrollo de las actividades del aula, con observaciones sobre el proceso de interacción profesor-estudiantes para Maestros (EM) y entre los estudiantes, así como reflexiones que surgen en el aula, que tienen su fundamento en experiencias anteriores o en aportaciones de diferentes autores. Por ello, además, el lenguaje utilizado es coloquial y reflejo del trabajo desarrollado en el aula. Trabajando sobre “la clasificación de los cuadriláteros” e iniciando “la simetría axial” queremos mostrar una secuencia metodológica que podría ser desarrollada de forma similar, en el aula de Primaria. De esta manera, seguimos las recomendaciones que nos sugieren un cierto paralelismo entre la enseñanza recibida por los estudiantes para profesores y la que posteriormente queramos que desarrollen en los Centros de Enseñanza Obligatoria, que se complementan con reflexiones sobre la enseñanza y aprendizaje (E/A) de la Geometría escolar que serán, posteriormente, fundamentadas en aportaciones teóricas. Ello posibilitará la generación de un metaconocimiento sobre la enseñanza de las Matemáticas y que los EM doten de significado a las actividades que se desarrollen. Además, mostramos los diferentes aspectos que hay que considerar en la construcción de los dos contenidos señalados. Finalmente, y dado que el contexto es un aula de formación inicial mostramos las dificultades que, los Estudiantes para Maestro tienen cuando afrontan la tarea y algunas aportaciones de autores que han trabajado sobre la E/A de la Geometría escolar

    Serotypes, virulence genes, and PFGE patterns of enteropathogenic Escherichia coli isolated from Cuban pigs with diarrhea

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    Thirty-six enteropathogenic Escherichia coli strains isolated from Cuban pigs with diarrhea were serotyped and screened by PCR for the presence of virulence genes. The 36 isolates belonged to 11 O serogroups and 14 O:H serotypes, with 53% of the isolates belonging to only two serotypes: O141:H– (13 isolates) and O157:H19 (6 isolates). Genes coding for STb, STa, VT2e, and LT toxins were identified in 69, 61, 53, and 6% of the isolates, respectively. The most prevalent fimbrial adhesin was F18, detected in 22 (61%) isolates. The gene encoding F6 (P987) colonization factor was identified in three (8%) isolates. None of the 36 isolates assayed contained genes encoding F4 (K88), F5 (K99), or F41. The seropathotype O141:H–:STa/STb/VT2e/F18 (13 isolates) was the most frequently detected, followed by O157:H19:VT2e/F18 (5 isolates). A genetic diversity study, carried out by pulsed-field gel electrophoresis (PFGE) of 24 representative isolates, revealed 21 distinct restriction patterns clustered in 18 groups (I–XVIII). Isolates of the same serotype were placed together in a dendrogram, but isolates of serotype O157:H19 showed a high degree of polymorphism. The results of this study demonstrate the presence in Cuba of different clusters among one of the most prevalent serotypes isolated from pigs with diarrhea. Further experiments are needed to determine whether some of these clusters have appeared recently; if so, their evolution, as well as their possible association with pathogenicity in farms should be studied. [Int Microbiol 2006; 9(1):53-60

    The PHA Test Reflects Acquired T-Cell Mediated Immunocompetence in Birds

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    cological immunology requires techniques to reliably measure immunocompetence in wild vertebrates. The PHA-skin test, involving subcutaneous injection of a mitogen (phytohemagglutinin, PHA) and measurement of subsequent swelling as a surrogate of T-cell mediated immunocompetence, has been the test of choice due to its practicality and ease of use in the field. However, mechanisms involved in local immunological and inflammatory processes provoked by PHA are poorly known, and its use and interpretation as an acquired immune response is currently debated.) and plasma proteins circulating in the bloodstream, potentially involved in the immunological and inflammatory processes, through flow cytometry and electrophoresis.Our results showed stronger responses after a second PHA injection, independent of species, time elapsed and changes in body mass of birds between first and second injections, thus supporting the adaptive nature of this immune response. Furthermore, the concomitant changes in the plasma concentrations of T-lymphocyte subsets and globulins indicate a causal link between the activation of the T-cell mediated immune system and local tissue swelling.These findings justify the widespread use of the PHA-skin test as a reliable evaluator of acquired T-cell mediated immunocompetence in diverse biological disciplines. Further experimental research should be aimed at evaluating the relative role of innate immunocompetence in wild conditions, where the access to dietary proteins varies more than in captivity, and to ascertain how PHA responses relate to particular host-parasite interactions

    Espectroscopía NIR como método no destructivo de determinación de parámetros de calidad del fruto en melocotón tardío de Calandra y en Miraflores

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    1 copia .pdf (a-3) de póster original presentado. 3 Figs.El melocotonero tardío de Calanda (Prunus persica (L.) Batsch.) es una variedad población de melocotonero (Prunus persica (L.) Batsch.) de gran importancia económica por su alto valor añadido. La espectroscopía NIR es una técnica cuyo principal interés radica en la posibilidad de estimación, por métodos no destructivos, de parámetros de calidad del fruto.Trabajo financiado por los proyectos “PET2007-09-COS-02 (INIA) y PM005/2006 (Gobierno de Aragón). El equipo de Investigación de Aula Dei está integrado en el Grupo Consolidado “Alimentos de Origen Vegetal”, reconocido por el Gobierno de Aragón.Peer reviewe

    Necrotoxigenic Escherichia coli from sheep and goats produce a new type of cytotoxic necrotizing factor (CNF3) associated with the eae and ehxA genes

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    Fecal samples from sheep and goats were screened by tissue-culture assays and PCR for the presence of necrotoxigenic Escherichia coli (NTEC) producing cytotoxic necrotizing factors (CNFs). Of the 18 NTEC strains assayed, four were positive for the cnf1 gene while 14 strains were negative for the cnf1 and cnf2 genes. All of the NTEC strains had the eae gene and most of them also carried the ehxA gene. Moreover, all the cnf1– cnf2– NTEC strains were negative for several virulence markers associated with CNF1+ or CNF2+ strains. The cnf gene present in one of these strains was sequenced and analysis of the gene product revealed a new type of CNF, which was named CNF3 (and the coding gene cnf3). Oligonucleotide primers were designed to PCR-amplify a fragment of cnf3. The results showed that all strains examined in this study, except one cnf1+strain, were cnf3+. The association of cnf3 with eae and ehxA suggests that cnf3+ NTEC strains might be pathogenic for humans. [Int Microbiol 2007; 10(1):47-55

    Identification of two new intimin types in atypical enteropathogenic Escherichia coli

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    Stool specimens of patients with diarrhea or other gastrointestinal alterations who were admitted to Xeral-Calde Hospital (Lugo, Spain) were analyzed for the prevalence of typical and atypical enteropathogenic Escherichia coli (EPEC). Atypical EPEC strains (eae+ bfp–) were detected in 105 (5.2%) of 2015 patients, whereas typical EPEC strains (eae+ bfp+) were identified in only five (0.2%) patients. Atypical EPEC strains were (after Salmonella) the second most frequently recovered enteropathogenic bacteria. In this study, 110 EPEC strains were characterized. The strains belonged to 43 O serogroups and 69 O:H serotypes, including 44 new serotypes not previously reported among human EPEC. However, 29% were of one of three serogroups (O26, O51, and O145) and 33% belonged to eight serotypes (O10:H–, O26:H11, O26:H–, O51:H49, O123:H19, O128:H2, O145:H28, and O145:H–). Only 14 (13%) could be assigned to classical EPEC serotypes. Fifteen intimin types, namely, α1 (6 strains), α2 (4 strains), β1 (34 strains), ξR/β2 (6 strains), γ1 (13 strains), γ2/θ (16 strains), δ/k (5 strains), ε1 (9 strains), νR/ε2 (5 strains), ζ (6 strains), ι1 (1 strain), μR/ι2 (1 strain), νB (1 strain), ξB (1 strain), and ο (2 strains), were detected among the 110 EPEC strains, but none of the strains was positive for intimin types μ1, μ2, λ, or μB. In addition, in atypical EPEC strains of serotypes O10:H–, O84:H–, and O129:H–, two new intimin genes (eae-νB and eae-ο) were identified. These genes showed less than 95% nucleotide sequence identity with existing intimin types. Phylogenetic analysis revealed six groups of closely related intimin genes: (i) α1, α2, ζ, νB, and ο; (ii) ι1 and μR/ι2; (iii) β1, ξR/β2B, δ/β2O, and κ; (iv) ε1, ξB, η1,η2, and νR/ε2; (v) γ1, μB, γ2, and θ; and (vi) λ. These results indicate that atypical EPEC strains belonging to large number of serotypes and with different intimin types might be frequently isolated from human clinical stool samples in Spain. [Int Microbiol 2006; 9(2):103-110

    Serotypes, virulence genes, and PFGE profiles of Escherichia coli isolated from pigs with postweaning diarrhoea in Slovakia

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    BACKGROUND: Postweaning diarrhoea (PWD) in pigs is usually the main infectious problem of large-scale farms and is responsible for significant losses worldwide. The disease is caused mainly by enterotoxigenic E. coli (ETEC) and Shiga-toxin producing E. coli (STEC). In this study a total of 101 E. coli isolated from pigs with PWD in Slovakia were characterized using phenotypic and genotypic methods. RESULTS: These 101 isolates belonged to 40 O:H serotypes. However, 57% of the isolates belonged to only six serotypes (O9:H51, O147:H-, O149:H10, O163:H-, ONT:H-, and ONT:H4), including two new serotypes (O163:H- and ONT:H4) not previously found among porcine ETEC and STEC isolated in other countries. Genes for EAST1, STb, STa, LT and Stx2e toxins were identified in 64%, 46%, 26%, 20%, and 5% of isolates, respectively. PCR showed that 35% of isolates carried genes for F18 colonization factor, and further analyzed by restriction endonuclease revealed that all of them were F18ac. Genes for F4 (K88), F6 (P987), F17, F5 (K99), F41, and intimin (eae gene) adhesins were detected in 19 %, 5%, 3%, 0.9%, 0.9%, and 0.9% of the isolates, respectively. The study of genetic diversity, carried out by PFGE of 46 representative ETEC and STEC isolates, revealed 36 distinct restriction profiles clustered in eight groups. Isolates of the same serotype were placed together in the dendrogram, but high degree of polymorphism among certain serotypes was detected. CONCLUSION: Seropathotype O149:H10 LT/STb/EAST1/F4 (14 isolates) was the most commonly detected followed by O163:H- EAST1/F18 (six isolates), and ONT:H4 STa/STb/Stx2e/F18 (five isolates). Interestingly, this study shows that two new serotypes (O163:H- and ONT:H4) have emerged as pig pathogens in Slovakia. Furthermore, our results show that there is a high genetic variation mainly among ETEC of O149:H10 serotype
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