The pet person.

El perro Rex quiere de regalo para su cumpleaños una persona como mascota. Pero sus padres, su tío y sus abuelos le dicen que las personas son horribles, malolientes e imposibles de adiestrar. Rex no está convencido de esto y sale a la calle a buscar su mascota.

Instant PET : ready-to-use tasks and activities.

Libro para la preparación del examen Cambridge PET (Preliminary English Test), para alumnos de nivel intermedio bajo. Está divido en cuatro secciones (lectura, redacción, comprensión auditiva y expresión oral) que se corresponden con los ejercicios de la prueba oficial, y que a su vez se organizan en una serie de sesenta actividades diseñadas en formato de páginas enfrentadas, con una hoja para el profesor con las indicaciones paso a paso, notas explicativas y las soluciones de los ejercicios, y otra que se puede fotocopiar con las tareas para los alumnos.

Demonstrating the validity of three general scores of PET in predicting higher education achievement in Israel

Resumen basado en el de la publicación

A Monte Carlo-Based Fiber Tracking Algorithm using Diffusion Tensor MRI

Diffusion tensor magnetic resonance imaging, which measures directional information of water diffusion in the brain, has emerged as a powerful tool for human brain studies. In this paper, we introduce a new Monte Carlo-based fiber tracking approach to estimate brain connectivity. One of the main characteristics of this approach is that all parameters of the algorithm are automatically determined at each point using the entropy of the eigenvalues of the diffusion tensor. Experimental results show the good performance of the proposed approach

Cats about town: is predation by free-ranging pet cats Felis catus likely to affect urban bird populations?

Even though they are fed daily by their owners, free-ranging pet cats Felis catus may kill wild birds and, given their high densities (typically > 200 cats/km(2)), it has been postulated that cat predation could be a significant negative factor affecting the dynamics of urban bird populations. In this study, we: (1) used questionnaire surveys in 10 sites within the city of Bristol, UK, to estimate cat density; (2) estimated the number of birds killed annually in five sites by asking cat owners to record prey animals returned home; and then (3) compared the number of birds killed with breeding density and productivity to estimate the potential impact of cat predation. In addition, we (4) compared the condition of those birds killed by cats versus those killed in collisions, e.g. window strikes. Mean (+/- sd) cat density was 348 +/- 86 cats/km(2) (n = 10 sites); considering the eight species most commonly taken by cats, the mean ratios of adult birds/cats and juvenile birds/cats across the five sites were 1.17 +/- 0.23 and 3.07 +/- 0.74, respectively. Approximately 60% of the cats studied for up to 1 year at each site never returned any prey home; despite this, the estimated number of birds killed was large relative to their breeding density and productivity in many sites. Across species, cat-killed birds were in significantly poorer condition than those killed following collisions; this is consistent with the notion that cat predation represents a compensatory rather than additive form of mortality. Interpretation of these results is, however, complicated by patterns of body mass regulation in passerines. The predation rates estimated in this study would suggest that cats were likely to have been a major cause of mortality for some species of birds. The effect of cat predation in urban landscapes therefore warrants further investigation. The potential limitations of the current study are discussed, along with suggestions for resolving them.

Structure and biogenesis of the capsular F1 antigen from Yersinia pestis: Preserved folding energy drives fiber formation

Most gram-negative pathogens express fibrous adhesive virulence organelles that mediate targeting to the sites of infection. The F1 capsular antigen from the plague pathogen Yersinia pestis consists of linear fibers of a single subunit (Caf1) and serves as a prototype for nonpilus organelles assembled via the chaperone/usher pathway. Genetic data together with high-resolution X-ray structures corresponding to snapshots of the assembly process reveal the structural basis of fiber formation. Comparison of chaperone bound Caf1 subunit with the subunit in the fiber reveals a novel type of conformational change involving the entire hydrophobic core of the protein. The observed conformational change suggests that the chaperone traps a high-energy folding intermediate of Caf1. A model is proposed in which release of the subunit allows folding to be completed, driving fiber formation.

Streptococcus castoreus sp nov., isolated from a beaver (Castor fiber)

A previously undescribed, Gram-positive, catalase-negative, Streptococcus-like organism originating from a European beaver (Castor fiber) was subjected to a taxonomic study. The organism displayed beta-haemolytic activity and gave a positive reaction with Lancefield group A antisera. Based on the results of biochemical testing, the organism was tentatively identified as a member of the genus Streptococcus, but it did not correspond phenotypically to any recognized species of this genus. Comparative 16S rRNA gene sequencing studies confirmed this assignment, with the bacterium forming a hitherto unknown subline within the genus. Sequence divergence values of greater than 3% from other reference streptococcal species, however, demonstrated that the unidentified coccus-shaped organism represents a hitherto unknown species. Based on phenotypic and molecular phylogenetic evidence, it is therefore proposed that the unknown organism from a beaver be classified as a novel species, Streptococcus castoreus sp. nov. The type strain is M605815/03/2(T) (=CCUG 48115(T) = CIP 108205(T)).

Microglial activation correlates with severity in Huntington disease: a clinical and PET study

Background: Huntington disease ( HD) is characterized by the progressive death of medium spiny dopamine receptor bearing striatal GABAergic neurons. In addition, microglial activation in the areas of neuronal loss has recently been described in postmortem studies. Activated microglia are known to release neurotoxic cytokines, and these may contribute to the pathologic process. Methods: To evaluate in vivo the involvement of microglia activation in HD, the authors studied patients at different stages of the disease using [ C-11]( R)-PK11195 PET, a marker of microglia activation, and [ C-11] raclopride PET, a marker of dopamine D2 receptor binding and hence striatal GABAergic cell function. Results: In HD patients, a significant increase in striatal [ C-11]( R)-PK11195 binding was observed, which significantly correlated with disease severity as reflected by the striatal reduction in [ C-11] raclopride binding, the Unified Huntington's Disease Rating Scale score, and the patients' CAG index. Also detected were significant increases in microglia activation in cortical regions including prefrontal cortex and anterior cingulate. Conclusions: These [ C-11]( R)-PK11195 PET findings show that the level of microglial activation correlates with Huntington disease ( HD) severity. They lend support to the view that microglia contribute to the ongoing neuronal degeneration in HD and indicate that [ C-11]( R)-PK11195 PET provides a valuable marker when monitoring the efficacy of putative neuroprotecting agents in this relentlessly progressive genetic disorder.

Neuromuscular junction morphology, fiber-type proportions, and satellite-cell proliferation rates are altered in MyoD(-/-) mice

Gene compensation by members of the myogenic regulatory factor (MRF) family has been proposed to explain the apparent normal adult phenotype of MyoD(-/-) mice. Nerve and field stimulation were used to investigate contraction properties of muscle from MyoD(-/-) mice, and molecular approaches were used to investigate satellite-cell behavior. We demonstrate that MyoD deletion results in major alterations in the organization of the neuromuscular junction, which have a dramatic influence on the physiological contractile properties of skeletal muscle. Second, we show that the lineage progression of satellite cells (especially initial proliferation) in the absence of MyoD is abnormal and linked to perturbations in the nuclear localization of beta-catenin, a key readout of canonical Wnt signaling. These results show that MyoD has unique functions in both developing and adult skeletal muscle that are not carried out by other members of the MRF family.

Radiometric analysis of the light coupled by optimally cut plastic optical fiber amplitude modulating reflectance displacement sensors

A radiometric analysis of the light coupled by optical fiber amplitude modulating extrinsic-type reflectance displacement sensors is presented. Uncut fiber sensors show the largest range but a smaller responsivity. Single cut fiber sensors exhibit an improvement in responsivity at the expense of range. A further increase in responsivity as well as a reduction in the operational range is obtained when the double cut sensor configuration is implemented. The double cut configuration is particularly suitable in applications where feedback action is applied to the moving reflector surface. © 2000 American Institute of Physics.

Os efeitos de um programa de exercícios domiciliares em pacientes com Paraparesia Espástica Tropical/Mielopatia Associada ao HTLV-1 (PET/MAH)

Introdução e Objetivos: Os efeitos da prática de exercícios sobre a funcionalidade de indivíduos com Paraparesia Espástica Tropical/Mielopatia Associada ao HTLV-1 (PET/MAH) são desconhecidos. O objetivo deste estudo é avaliar os efeitos de um Programa de Exercícios Domiciliares (PED) e a sua taxa de adesão em indivíduos com PET/MAH. Métodos: Vinte e três participantes com o diagnóstico de PET/MAH, marcha preservada e que não praticavam exercícios há pelo menos um mês foram submetidos ao PED de 20 semanas. Os desfechos primários incluíram os escores de força muscular, contração isométrica voluntária máxima (CIVM) e comprimento muscular dos membros inferiores, dor lombar e nos membros inferiores, EDSS, Escala de Incapacidade do IPEC, Índice de Barthel e SF-36. A taxa de adesão e os eventos adversos também foram mensurados e caracterizados. Resultados: No momento da análise os pacientes foram divididos em dois grupos de acordo com o teste Timed Up and Go (TUG) (<20s vs \226520s). O comprimento dos músculos isquiotibiais e plantiflexores, a CIVM dos membros inferiores e o componente \201CAspectos Sociais\201D da SF-36 apresentaram melhora significativa no grupo TUG <20s. Os indivíduos do grupo TUG \226520s melhoraram significativamente o componente \201CCapacidade Funcional\201D da SF-36. A taxa de adesão foi de 90% no total e os eventos adversos, como fadiga, dor muscular e caimbras foram de intensidade leve a moderada Discussão: Foi observada uma boa adesão ao PED, além de melhora significativa da incapacidade e da qualidade de vida dos indivíduos com PET/MAH. É possível que o grupo TUG \226520s apresente um maior componente neurodegenerativo e, portanto, uma menor probabilidade de incremento da funcionalidade. Conclusões: O PED foi eficaz em melhorar algumas incapacidades e a qualidade de vida dos indivíduos com PET/MAH. Tais resultados reforçam a necessidade de estratégias alternativas ao modelo ambulatorial, que ampliem a participação destas pessoas a programas de reabilitação