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DIALNET OAI Articles (558,108 recursos)
Dialnet (Difusión de Alertas en la Red) es una plataforma de recursos y servicios documentales, cuyo objetivo fundamental se centra en mejorar la visibilidad y el acceso a la literatura científica hispana a través de Internet.

Ciencias biológicas

Mostrando recursos 1 - 20 de 15,780

1. Problemas clínicos en micología médica: problema número 46 - Negroni, Ricardo; Arechavala, Alicia; Santiso, Gabriela; Bonvehí, Pablo
A 49 year old-man, without known previous diseases, who suffered an acute lung infection, is presented. He was a smoker and belonged to a high socioeconomic class. He suddenly presented high fever, dry cough and legs� pain. Thorax X-ray and CT scan showed two excavated pneumonic in?ltrates in the lower part of the right lung. He was treated with antibacterial antibiotics without clinical response. A transparietal ?ne needle lung biopsy was performedandthehistopathologyandcytological studies revealedanepithelioidgranulomawithcapsulatedyeasts.Cryptococcusneoformansantigenemia was positive 1/128, and brain MR, as well as CSF studies, allowed to rule out a central nervous system compromise. The patient was successfully treated with itraconazole by oral route at...

2. Phaeohyphomycosis caused by Cladophialophora bantiana - Martínez Lamas, Lucía; Álvarez Fernández, Maximiliano; Llovo Taboada, José; Gené Díaz, Josepa; Cano Lira, José Francisco
Cladophialophora bantiana is the most frequent cause of central nervous system phaeohyphomycosis. Aims We report a case of phaeohyphomycosis by C. bantiana in a patient with underlying lung disease on steroid therapy. Methods An 81-year-old male was admitted in August 2011 with a history of difficulty speaking and deflection of the oral commeasure to the left side with a brain abscess. Brain tissue was cultured on Sabouraud media and sequence analysis of the internal transcribed spacer region of the ribosomal DNA was done for identification purposes. Susceptibility testing to various antifungal agents was performed using the microdilution test. Results Histopathological examination of the brain tissue ruled...

3. Feohifomicosis cerebral: descripción de un caso y revisión de la literatura - Frasquet Artés, Juan S.; Pemán García, Javier; Blanes Juliá, Marino; Hernández Porto, M.; Cano, Josep; Jiménez, Enrique; López Hontangas, José Luis
Cladophialophora bantiana is the most frequent cause of central nervous system phaeohyphomycosis. Aims We report a case of phaeohyphomycosis by C. bantiana in a patient with underlying lung disease on steroid therapy. Methods An 81-year-old male was admitted in August 2011 with a history of difficulty speaking and deflection of the oral commeasure to the left side with a brain abscess. Brain tissue was cultured on Sabouraud media and sequence analysis of the internal transcribed spacer region of the ribosomal DNA was done for identification purposes. Susceptibility testing to various antifungal agents was performed using the microdilution test. Results Histopathological examination of the brain tissue ruled...

4. Molecular characterization of Cryptococcus gattii genotype AFLP6/VGII isolated from woody debris of divi-divi (Caesalpinia coriaria), Bonaire, Dutch Caribbean - Hagen, Ferry; Chowdhary, Anuradha; Prakash, Anupam; Yntema, Jan-Bart; Meis, J. F. G. M.
The basidiomycetous yeast Cryptococcus gattii is an emerging and primary pathogen. There is a lack of information about its environmental spread outside outbreak regions in Mediterranean Europe, North and South America. Environmental sampling for C. gattii and molecular characterization of the obtained isolates will provide an insight into the global spread of the various genotypes. Methods Woody debris of native divi-divi (Caesalpinia coriaria) trees were sampled across Bonaire, Dutch Caribbean. Colonies suspected for Cryptococcus species were subjected to standard mycology investigations and identification by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Isolates identified as C. gattii were subjected to amplified fragment...

5. Native trees of the Northeast Argentine: Natural hosts of the Cryptococcus neoformans-Cryptococcus gattii species complex - Cattana, Maria; Sosa, Maria de los Angeles; Fernández, Mariana Soledad; Rojas, Florencia; Mangiaterra, Magdalena; Giusiano, Gustavo
In Argentina, information about epidemiology and environmental distribution of Cryptococcus is scarce. The city of Resistencia borders with Brazil and Paraguay where this fungus is endemic. All these supported the need to investigate the ecology of the genus and the epidemiology of cryptococcosis in this area. Aims The aim was to investigate the presence of species of Cryptococcus neoformans�Cryptococcus gattii complex and their genotypes in trees of the city of Resistencia. Methods One hundred and five trees were sampled by swabbing technique. The isolates were identified using conventional and commercial methods and genotyped by PCR-RFLP (Restriction Fragment Length Polymorphism). Results Cryptococcus was found in 7 out...

6. Caracterización de la micobiota aérea de dos depósitos del Archivo Nacional de la República de Cuba - Borrego Alonso, S.; Perdomo Amistad, Ivette
Background: The high relative humidity and temperatures in tropical countries create favorable conditions for development of fungi that are not only a risk to human health but they can also colonize documentary support. Aims: To study the concentrationofthe airborne fungiintwo repositories oftheNationalArchives ofthe Republic of Cuba, the mycobiota deposited on different photographic supports and maps preserved in these repositories, and to determine the taxonomic characterization ofthe fungi isolated. Methods: The air sampling was performed using a sedimentation method, and the supports (6 pictures and 7 maps) were analyzed using moistened sterile swabs. Results: The Cladosporium genus was predominant, followed by Aspergillus and Penicillium genera. Filamentousfungiwereisolatedinallthephotosandmaps,andyeastswereonlyisolatedfromaphotographic supports and a...

7. Especies de Aspergillus en ambientes hospitalarios con pacientes pediátricos en estado crítico - Cattana, Maria; Rojas, Florencia; Sosa, Maria de los Angeles; Aguirre Caballero, Clarisa; Vergara, Felisa Marta; Giusiano, Gustavo; Fernández, Mariana Soledad
Background: Aspergillus is a group of opportunistic fungithat cause infections, with highmorbimortality in immunosuppressed patients. Aspergillus fumigatus is the most frequent species in these infections, although the incidence of other species has increased in the lastfew years. Aims: To evaluate the air fungal load and the diversity of Aspergillus species in hospitals with pediatric patients in critical condition. Methods: The Intensive Care Unit and Burns Unit of a pediatric hospital were sampled every 15 days during the autumn and spring seasons. The air samples were collected with SAS Super 100® and the surface samples were collected by swab method. Results: TheUFC/m3 counts foundexceededthe acceptable levels.TheUFC/m3 andthediversityofAspergillus species found in the...

8. EPICO 2.0 project. Development of educational therapeutic recommendations using the DELPHI technique on invasive candidiasis in critically il adult patients in special situations - Ferrer Roca, R.; Zaragoza Crespo, R.; Maseda, Emilio; Llinares Modejar, Pedro; Rodríguez, A.
Background Although there has been an improved management of invasive candidiasis in the last decade, still controversial issues remain, especially in different therapeutic critical care scenarios. Aims We sought to identify the core clinical knowledge and to achieve high agreement recommendations required to care for critically ill adult patients with invasive candidiasis for antifungal treatment in special situations and different scenarios. Methods Second prospective Spanish survey reaching consensus by the DELPHI technique, conducted anonymously by electronic e-mail in the first phase to 23 national multidisciplinary experts in invasive fungal infections from five national scientific societies including intensivists, anesthesiologists, microbiologists, pharmacologists and infectious disease specialists, answering...

9. Methods for investigating parameter redundancy - Gimenez, Olivier; Viallefont, Anne; Catchpole, Edward A.; Choquet, Rémi; Morgan, Byron J. T.
Methods for investigating parameter redundancy.� The quantitative study of marked individuals relies mainly on the use of meaningful biological models. Classical inference is then conducted based on the model likelihood, parameterized by parameters such as survival, recovery, transition and recapture probabilities. In classical statistics, we seek parameter estimates by maximising the likelihood. However, models are often overparameterized and, as a consequence, some parameters cannot be estimated separately. Identifying how many and which (functions of) parameters are estimable is thus crucial not only for proper model selection based upon likelihood ratio tests or information criteria but also for the interpretation of the estimates obtained. In this paper, we provide...

10. Exploring mark-resighting-recovery models to study savannah tree demographics - Lahoreau, G.; Gignoux, J.; Julliard, R.
Exploring mark�resighting�recovery models to study savannah tree demographics.� Despite their sessile nature, juvenile trees in savannah ecosystems are not always easy to encounter. Here, we evaluate the applicability to plants of the remedy of choice in animal studies: capture�recapture modelling. The plant equivalents, tagging and resighting, were caried outnin 7 censuses, involving 4,145 juvenile trees of 8 dominant savannah species. Using models with joint analysis of live and dead encounters, the resighting probabilities averaged 0.88 ± 0.15 and 0.92 ± 0.10 for seedlings and resprouts respectively; while dead recovery probabilities averaged 0.71 ± 0.25 for all age�classes. An ad hoc method that did not take into account encounter probabilities yielded...

11. Estimating true age-dependence in survival when only adults can be observed: an example with Black-legged Kittiwakes - Frederiksen, Morten; Wanless, Sarah; Harris, Michael P.
Estimating true age�dependence in survival when only adults can be observed: an example with Black� legged Kittiwakes .� In long�lived birds, pre�breeders are often difficult or impossible to observe, and even though a proportion of marked adults may be of known age, the estimation of age�specific survival is complicated by the absence of observations during the first years of life. New developments in MARK now allow use of an updated individual covariate. We used this powerful approach to model age�dependence in survival of Black�legged Kittiwakes ( Rissa tridactyla ) at a North Sea colony. Although only 69 marked breeders were of known age, there was strong evidence for a...

12. Dispersal and survival rates of adult and juvenile Red-tailed tropicbirds (Phaethon rubricauda) exposed to potential contaminants - Schreiber, E. A.; Doherty, P. F.; Schenk, G. A.
Dispersal and survival rates of adult and juvenile Red¿tailed tropicbirds (Phaethon rubricauda) exposed to potential contaminants .¿ Annual survival and dispersal rates of adult and juvenile red¿tailed tropicbirds were examined in connection with exposure to heavy metals. From 1990¿2000 the incineration of a U.S. stockpile of chemical weapons stored at Johnston Atoll exposed nesting tropicbirds to increased levels of human disturbance, smoke stack emissions and potential leaks. Using a multi¿state mark¿recapture modeling approach, birds nesting in this site (downwind of the plant) were compared to those nesting in a reference site (upwind of the plant) with less human disturbance, no exposure to smoke stack emissions or other...

13. A Bayesian approach to combining animal abundance and demographic data - Brooks, S. P.; King, R.; Morgan, B. J. T.
A Bayesian approach to combining animal abundance and demographic data. � In studies of wild animals, one frequently encounters both count and mark�recapture�recovery data. Here, we consider an integrated Bayesian analysis of ring�recovery and count data using a state�space model. We then impose a Leslie� matrix�based model on the true population counts describing the natural birth�death and age transition processes. We focus upon the analysis of both count and recovery data collected on British lapwings ( Vanellus vanellus ) combined with records of the number of frost days each winter. We demonstrate how the combined analysis of these data provides a more robust inferential framework and discuss how the Bayesian...

14. Population models for Greater Snow Geese: a comparison of different approaches to assess potential impacts of harvest - Gauthier, Gilles; Lebreton, Jean�Dominique
Population models for Greater Snow Geese: a comparison of different approaches to assess potential impacts of harvest .¿ Demographic models, which are a natural extension of capture¿recapture (CR) methodology, are a powerful tool to guide decisions when managing wildlife populations. We compare three different modelling approaches to evaluate the effect of increased harvest on the population growth of Greater Snow Geese (Chen caerulescens atlantica). Our first approach is a traditional matrix model where survival was reduced to simulate increased harvest. We included environmental stochasticity in the matrix projection model by simulating good, average, and bad years to account for the large inter¿annual variation in fecundity and first¿year survival,...

15. Estimating components of variance in demographic parameters of Tawny Owls, Strix aluco - Francis, Charles M.; Saurola, Pertti
Estimating components of variance in demographic parameters of Tawny Owls, Strix aluco.¿ Survival rates of Tawny Owls (Strix aluco) were estimated using recapture and recovery data from approximately 20,000 nestling and adult owls ringed between 1980 and 1999 in southern Finland. Survival rates averaged 33% in the first year of life, 64% in the second, and 73% in subsequent years, but varied dramatically among years. Approximately 50% of annual variation in survival could be explained by stage of the vole cycle and severity of winter weather. Capture probabilities, an index of breeding propensity, varied dramatically among years, and could almost entirely be explained by the vole cycle,...

16. Beyond survival estimation: mark-recapture, matrix population models, and population dynamics - Caswell, Hal; Fujiwara, Masami
Beyond survival estimation: mark�recapture, matrix population models, and population dynamics .� Survival probability is of interest primarily as a component of population dynamics. Only when survival estimates are included in a demographic model are their population implications apparent. Survival describes the transition between living and dead. Biologically important as this transition is, it is only one of many transitions in the life cycle. Others include transitions between immature and mature, unmated and mated, breeding and non� breeding, larva and adult, small and large, and location x and location y . The demographic consequences of these transitions can be captured by matrix population models, and such models provide a natural link connecting multi�stage...

17. Population dynamics - Cooch, Evan G.; Dhond, André A.

18. Occupancy as a surrogate for abundance estimation - MacKenzie, Darryl I.; Nichols, James D.
Occupancy as a surrogate for abundance estimation .� In many monitoring programmes it may be prohibitively expensive to estimate the actual abundance of a bird species in a defined area, particularly at large spatial scales, or where birds occur at very low densities. Often it may be appropriate to consider the proportion of area occupied by the species as an alternative state variable. However, as with abundance estimation, issues of detectability must be taken into account in order to make accurate inferences: the non�detection of the species does not imply the species is genuinely absent. Here we review some recent modelling developments that permit unbiased estimation of...

19. Components of population growth rate for White-winged Scoters in Saskatchewan, Canada - Alisauskas, Ray T.; Traylor, Joshua J.; Swoboda, Cindy J.; Kehoe, F. Patrick
Components of population growth rate for White�winged Scoters in Saskatchewan, Canada .� Breeding range and abundance of White�winged Scoters ( Melanitta fusca deglandi ) have declined in northwestern North America. Hypotheses proposed to account for this trend are that survival and/or recruitment of females had declined. Thus, we used a reverse�time capture�recapture approach to directly estimate survival, seniority and capture probabilities for females of breeding age at Redberry Lake, Saskatchewan, Canada for 1975�1980 and 2000�2003. We also estimated population size of breeding females for 1975�1985 and 2000�2003 using capture�recapture data. Initially, this local population was in serious decline [95% CL ( ) = 0.89 ± 0.09], but has since...

20. Abundance estimation and Conservation Biology - Nichols, James D.; MacKenzie, Darryl I.

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