440 resultados para Lunar eclipses.


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Variation in the rate at which parasitic gnathiid isopod juveniles emerged from the benthos at Lizard Island, Great Barrier Reef, Australia, was examined (I) every 4 or 8 h throughout the day and night over a 24 h period, (2) over a 12 h period during the day or night, and (3) during different lunar phases (weeks). The number of gnathiids sampled per 4 or 8 h was low, with only 30% of the traps containing gnathiids and the abundance ranging from 0 to 3 gnathiids m(-2). The number of gnathiids that emerged over 12 h, in contrast, ranged from 0 to 36 m(-2). During the third and fifth weeks sampled, more gnathiids emerged during the day than at night. This coincided with the full moon and new moon. Most gnathiids that emerged from the reef during the day (98 %) had not fed, in contrast to those sampled at night (71%). Of the gnathiids with no engorged gut, most (97 %) of those collected during the day were small (II. mm) compared to those collected at night (19%), the latter being mostly >1 mm. Of the gnathiids with an engorged gut, most were sampled at night (83 %) and 97 % were >1 mm in size. These percentages suggest differences in the emergence behaviour among Life stages or species of gnathiids. This study, which shows that gnathiids do emerge during the day and supports other studies showing that gnathiids also attack fishes during the day, has important implications for understanding the role of cleaner fish and their main food source, gnathiids, as it shows there is a constant source of gnathiids emerging from the reef during the day and night in search of hosts.

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The Genius of Erasmus Darwin provides insight into the full extent of Erasmus Darwin's exceptional intellect. He is shown to be a major creative thinker and innovator, one of the minds behind the late eighteenth-century industrial revolution, and one of the first, if not the first, to perceive the living world (including humans) as part of a unified evolutionary scenario. The contributions here provide contextual understandings of Erasmus Darwin's thought, as well as studies of particular works and accounts of the later reception of his writings. In this way it is possible to see why the young Samuel Taylor Coleridge was moved to describe Darwin as 'the first literary character in Europe, and the most original-minded man'. Erasmus Darwin, Charles Darwin's grandfather, was one of the leading intellectuals of eighteenth-century England. He was a man with an extraordinary range of interests and activities: he was a doctor, biologist, inventor, poet, linguist, and botanist. He was also a founding member of the Lunar Society, an intellectual community that included such eminent men as James Watt and Josiah Wedgwood. Contents: Introduction; Setting the scene, Jonathan Powers; Prologue 'Catching up with Erasmus Darwin in the New Century', Desmond King-Hele. Section 1: Medicine: Physicians and physic in 17th and 18th century Lichfield, Dennis Gibbs; Dr Erasmus Darwin MD FRS (1731–1802): England's greatest physician?, Gordon Cook; William Pale (1743–1805) and James Parkinson (1755–1824): two peri-Erasmatic thinkers (and several others), Christopher Gardner-Thorpe; The vertiginous philosophers: Erasmus Darwin and William Charles Wells on vertigo, Nicholas Wade. Section 2: Biology: The Antipodes and Erasmus Darwin: the place of Erasmus Darwin in the heritage of Australian literature and biology, John Pearn; Erasmus Darwin on human reproductive generation: placing heredity within historical and Zoonomian contexts, Philip Wilson; All from fibres: Erasmus Darwin's evolutionary psychobiology, C.U.M. Smith; Two special doctors: Erasmus Darwin and Luigi Galvani, Rafaella Simili. Section 3: Education: But what about the women? The lunar society's attitude to women and science and to the education of girls, Jenny Uglow; The Derbyshire 'Darwinians': the persistence of Erasmus Darwin's influence on a British provincial literary and scientific community, c.1780–1850, Paul Elliot. Section 4: Technology: Designing better steering for carriages (and cars); with a glance at other inventions, Desmond King-Hele; Mama and papa: the ancestors of modern-day speech science, Philip Jackson; Negative and positive images: Erasmus Darwin, Tom Wedgwood and the origins of photography, Alan Barnes; Section 5: Environment: Erasmus Darwin's contributions to the geological sciences, Hugh Torrens; The air man, Desmond King-Hele; Erasmus Darwin, work and health, Tim Carter; Section 6: Literature: The progress of society: Darwin's early drafts for the temple of nature, Martin Priestman; The poet as pathologist: myth and medicine in Erasmus Darwin's epic poetry, Stuart Harris; 'Another and the same': nature and human beings in Erasmus Darwin's doctrines of love and imagination, Maurizio Valsania. Epilogue: 'One great slaughter-house the warring world': living in revolutionary times, David Knight; Coda: Midlands memorabilia, Nick Redman; Appendix: The Creation of the Erasmus Darwin Foundation and Erasmus Darwin House, Tony Barnard; Index.

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In tropical and subtropical estuaries, gradients of primary productivity and salinity are generally invoked to explain patterns in community structure and standing crops of fishes. We documented spatial and temporal patterns in fish community structure and standing crops along salinity and nutrient gradients in two subtropical drainages of Everglades National Park, USA. The Shark River drains into the Gulf of Mexico and experiences diurnal tides carrying relatively nutrient enriched waters, while Taylor River is more hydrologically isolated by the oligohaline Florida Bay and experiences no discernable lunar tides. We hypothesized that the more nutrient enriched system would support higher standing crops of fishes in its mangrove zone. We collected 50 species of fish from January 2000 to April 2004 at six sampling sites spanning fresh to brackish salinities in both the Shark and Taylor River drainages. Contrary to expectations, we observed lower standing crops and density of fishes in the more nutrient rich tidal mangrove forest of the Shark River than in the less nutrient rich mangrove habitats bordering the Taylor River. Tidal mangrove habitats in the Shark River were dominated by salt-tolerant fish and displayed lower species richness than mangrove communities in the Taylor River, which included more freshwater taxa and yielded relatively higher richness. These differences were maintained even after controlling for salinity at the time of sampling. Small-scale topographic relief differs between these two systems, possibly created by tidal action in the Shark River. We propose that this difference in topography limits movement of fishes from upstream marshes into the fringing mangrove forest in the Shark River system, but not the Taylor River system. Understanding the influence of habitat structure, including connectivity, on aquatic communities is important to anticipate effects of construction and operational alternatives associated with restoration of the Everglades ecosystem.

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TYC 3034-0299-1 (CVn) is a magnetically active, contact binary, ROTSE variable. UBVRcIc light curves are presented along with a period study and a simultaneous UBVRI light curve solution. Our light curves show eclipse amplitudes of 0.72 and 0.62 mags (V) in the primary and secondary eclipses. Modeled results include a dark spot region, found at longitude 51°, a 24% Roche lobe fill-out, and a mass ratio of 0.48. A total eclipse is found to occur in the secondary eclipse making TYC 3034-0299-1 a W-type (less massive star is hotter) W UMa variable.

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Analogous to sunspots and solar photospheric faculae, which visibility is modulated by stellar rotation, stellar active regions consist of cool spots and bright faculae caused by the magnetic field of the star. Such starspots are now well established as major tracers used to estimate the stellar rotation period, but their dynamic behavior may also be used to analyze other relevant phenomena such as the presence of magnetic activity and its cycles. To calculate the stellar rotation period, identify the presence of active regions and investigate if the star exhibits or not differential rotation, we apply two methods: a wavelet analysis and a spot model. The wavelet procedure is also applied here to study pulsation in order to identify specific signatures of this particular stellar variability for different types of pulsating variable stars. The wavelet transform has been used as a powerful tool for treating several problems in astrophysics. In this work, we show that the time-frequency analysis of stellar light curves using the wavelet transform is a practical tool for identifying rotation, magnetic activity, and pulsation signatures. We present the wavelet spectral composition and multiscale variations of the time series for four classes of stars: targets dominated by magnetic activity, stars with transiting planets, those with binary transits, and pulsating stars. We applied the Morlet wavelet (6th order), which offers high time and frequency resolution. By applying the wavelet transform to the signal, we obtain the wavelet local and global power spectra. The first is interpreted as energy distribution of the signal in time-frequency space, and the second is obtained by time integration of the local map. Since the wavelet transform is a useful mathematical tool for nonstationary signals, this technique applied to Kepler and CoRoT light curves allows us to clearly identify particular signatures for different phenomena. In particular, patterns were identified for the temporal evolution of the rotation period and other periodicity due to active regions affecting these light curves. In addition, a beat-pattern vii signature in the local wavelet map of pulsating stars over the entire time span was also detected. The second method is based on starspots detection during transits of an extrasolar planet orbiting its host star. As a planet eclipses its parent star, we can detect physical phenomena on the surface of the star. If a dark spot on the disk of the star is partially or totally eclipsed, the integrated stellar luminosity will increase slightly. By analyzing the transit light curve it is possible to infer the physical properties of starspots, such as size, intensity, position and temperature. By detecting the same spot on consecutive transits, it is possible to obtain additional information such as the stellar rotation period in the planetary transit latitude, differential rotation, and magnetic activity cycles. Transit observations of CoRoT-18 and Kepler-17 were used to implement this model.

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While the carnivores are considered regulators and structuring of natural communities are also extremely threatened by human activities. Endangered little-spotted-cat (Leopardus tigrinus) is one of the lesser known species from the Neotropical cats. In this work we investigate the occupancy and the activity pattern of L. tigrinus in Caatinga of Rio Grande do Norte testing: 1) how environmental and anthropogenic factors influence their occupation and 2) how biotic and abiotic factors influence their activity pattern. For this we raised occurrence data of species in 10 priority areas for conservation. We built hierarchical models of occupancy based on maximum likelihood to represent biological hypotheses which were ranked using the Akaike Information Criterion (AIC). According to the results the feline occupancy is more likely away from rural settlements and in areas with a higher proportion of woody vegetation. The opportunistic killing of L. tigrinus and in retaliation for poultry predation close to residential areas can explain this result; as well as more complex vegetation structure can better serve as refuge and ensure more food. Analyzing the records of the species through circular statistics we conclude that the activity pattern is mostly nocturnal, although considerable crepuscular and a small diurnal activity. L. tigrinus activity was directly affected by the availability of small terrestrial mammals, which are essentially nocturnal. In addition, the temperatures recorded in the environment directly and indirectly affect the activity of the little-spotted-cat, as also influence the activity of their potential prey. Generally, the cats were more active when possible prey were active, and this happened at night when lower temperatures are recorded. Moreover, the different lunar phases did not affect the activity pattern. The results improve the understanding of an endangered feline inhabiting the Caatinga biome, and thus can help develop conservation and management strategies, as well as in planning future research in this semi-arid ecosystem.

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Binary systems are key environments to study the fundamental properties of stars. In this work, we analyze 99 binary systems identified by the CoRoT space mission. From the study of the phase diagrams of these systems, our sample is divided into three groups: those whose systems are characterized by the variability relative to the binary eclipses; those presenting strong modulations probably due to the presence of stellar spots on the surface of star; and those whose systems have variability associated with the expansion and contraction of the surface layers. For eclipsing binary stars, phase diagrams are used to estimate the classification in regard to their morphology, based on the study of equipotential surfaces. In this context, to determine the rotation period, and to identify the presence of active regions, and to investigate if the star exhibits or not differential rotation and study stellar pulsation, we apply the wavelet procedure. The wavelet transform has been used as a powerful tool in the treatment of a large number of problems in astrophysics. Through the wavelet transform, one can perform an analysis in time-frequency light curves rich in details that contribute significantly to the study of phenomena associated with the rotation, the magnetic activity and stellar pulsations. In this work, we apply Morlet wavelet (6th order), which offers high time and frequency resolution and obtain local (energy distribution of the signal) and global (time integration of local map) wavelet power spectra. Using the wavelet analysis, we identify thirteen systems with periodicities related to the rotational modulation, besides the beating pattern signature in the local wavelet map of five pulsating stars over the entire time span.

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Binary systems are key environments to study the fundamental properties of stars. In this work, we analyze 99 binary systems identified by the CoRoT space mission. From the study of the phase diagrams of these systems, our sample is divided into three groups: those whose systems are characterized by the variability relative to the binary eclipses; those presenting strong modulations probably due to the presence of stellar spots on the surface of star; and those whose systems have variability associated with the expansion and contraction of the surface layers. For eclipsing binary stars, phase diagrams are used to estimate the classification in regard to their morphology, based on the study of equipotential surfaces. In this context, to determine the rotation period, and to identify the presence of active regions, and to investigate if the star exhibits or not differential rotation and study stellar pulsation, we apply the wavelet procedure. The wavelet transform has been used as a powerful tool in the treatment of a large number of problems in astrophysics. Through the wavelet transform, one can perform an analysis in time-frequency light curves rich in details that contribute significantly to the study of phenomena associated with the rotation, the magnetic activity and stellar pulsations. In this work, we apply Morlet wavelet (6th order), which offers high time and frequency resolution and obtain local (energy distribution of the signal) and global (time integration of local map) wavelet power spectra. Using the wavelet analysis, we identify thirteen systems with periodicities related to the rotational modulation, besides the beating pattern signature in the local wavelet map of five pulsating stars over the entire time span.

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Besnoitia besnoiti es un protozoo apicomplejo formador de quistes responsable de la besnoitiosis bovina, una enfermedad crónica y debilitante que origina importantes pérdidas económicas en el ganado bovino a nivel mundial. En la actualidad, no existen tratamientos ni vacunas disponibles y, por tanto, las medidas de control se deben basar en la detección de animales infectados para reducir la prevalencia en zonas endémicas y evitar la entrada de la enfermedad en zonas libres a través de la compra de animales infectados. Los principales retos en la investigación sobre este parásito son, por un lado, la mejora de las técnicas serológicas para realizar un diagnóstico preciso y, por otro lado, el empleo de las nuevas pruebas diagnósticas desarrolladas para determinar el impacto de la enfermedad mediante estudios de prevalencia e incidencia. Dada la rápida diseminación de la besnoitiosis bovina en Europa, se han desarrollado numerosas técnicas de diagnóstico serológico. Sin embargo, éstas no han sido validadas en estudios comparativos y, por ello, los datos epidemiológicos descritos por los diferentes laboratorios, no son comparables. Además, no se ha establecido una prueba de referencia, lo cual es de vital importancia para el establecimiento de un protocolo de diagnóstico común entre los países afectados. Por otra parte, se ha puesto de manifiesto la necesidad de mejorar la sensibilidad (Se) de las pruebas para detectar a los animales infectados durante la fase aguda, así como los infectados durante la fase crónica que presentan niveles bajos de anticuerpos, los cuales en diversas ocasiones se encuentran por debajo del punto de corte de las técnicas diagnósticas. Además, también es necesario mejorar su especificidad (Esp), ya que las actuales pruebas ELISA, que se emplean de forma rutinaria en el diagnóstico de la infección, pueden dar lugar a un elevado número de resultados falsos-positivos que pueden repercutir de forma negativa en la eficacia de los planes de control...

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Desarrollo de una guía interactiva donde se muestran los ciclos biológicos,imágenes y dibujos de los estadios evolutivos de los principales géneros y especies de parásitos protozoos relevantes en al ámbito veterinario.

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Hydrogenous manganese nodules form on the ocean floor by slow authigenic precipitation (1-6 mm/Ma) of the oxyhydroxides of manganese and iron that continuously scavenge trace elements from the marine environment. Consequently, these nodules represent independent marine deposits useful for the study of the chemical signatures of the paleomarine environments. The results presented are a continuation of a study of the Zetes-3D nodule from the Pacific Ocean. It is a large (24x17x10 cm) hydrogenous nodule whose slow growth rate of 1.3 mm/Ma was detremined using 10Be techniques. A positive cerium anomaly is observed throughout the nodule and its Ir content indicates a sharp spike at 54-62 Ma in fair agreement with the K-T event.

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Justificación: La osteoporosis es causa de fracturas patológicas y pérdida de autonomía y validismo en la mujer post-menopáusica. La identificación de factores de riesgo puede servir en la prevención de la aparición de esta co-morbilidad. Objetivos: Determinar la asociación entre la desmineralización ósea y características demográficas, clínicas y antropométricas selectas de la mujer post-menopásica que puedan asumirse como factores de riesgo. Diseño del estudio: No experimental, transversal, analítico. Serie de estudio: 53 mujeres con edades ≥ 60 años atendidas en el Hospital "San Juan" de Especialidades de Riobamba (Provincia del Chimborazo, República del Ecuador). Material y método: Se determinó la densidad mineral ósea (DMO) en 2 regiones de interés (columna lumbar I fémur) mediante DEXA (DPX-L, Lunar Technologies, EEUU). La desmineralización ósea se estableció ante puntajes "t" < -1,0 desviaciones estándar. La cuantía y calidad de los ingresos de Calcio dietético se estimaron mediante el puntaje pCa que tiene en cuenta la frecuencia de consumo de alimentos tenidos como fuente de calcio y la biodisponibilidad del mineral. Se evaluaron la naturaleza y la fuerza de la asociación entre la desmineralización ósea, por un lado, y los factores presuntivos de riesgo de osteoporosis y el estado del ingreso del calcio dietético, por el otro. Resultados: La desmineralización ósea fue dependiente de la región de interés: Fémur: Osteoporosis: 13,2% + Osteopenia: 50,9%; Columna lumbar: Osteoporosis: 49,1% + Osteopenia: 37,7%. Los mayores ingresos de calcio dietético se concentraron en: Leche y lácteos (pCa = 26,56), Carnes, pescados, mariscos y huevos (pCa = 6,51), Frijoles y otras leguminosas (soja incluida) (pCa = 2,85); y Verduras (pCa = 2,54); respectivamente. El puntaje "t" de DMO se asoció con la edad de la mujer, los antecedentes familiares de fracturas óseas, el Índice de Masa Corporal (IMC), y la grasa corporal (estimada mediante DEXA). Los ingresos de calcio dietético fueron independientes de los factores presuntivos de riesgo de desmineralización ósea, y del puntaje "t" de DMO en las regiones de interés. Las razones de disparidades para las variables asociadas univariadamente con la DMO fueron como sigue: Edad: OR = 2,09 (p < 0,05); IMC: OR = 0,278 (p = 0,059): y Grasa corporal: OR = 0,553 (p > 0,05); respectivamente. Conclusiones: La desmineralización ósea se asocia significativamente con el envejecimiento femenino, y una mayor presencia de la grasa corporal. Los antecedentes familiares de fracturas óseas pueden servir para identificar a la mujer post-menopáusica con un riesgo incrementado de desmineralización ósea. Se deben emprender investigaciones ulteriores para establecer el papel del ejercicio físico y mejores ingresos de calcio dietético como factores protectores de la pérdida de la DMO.

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Bulwer'spetrelsarenocturnalseabirdsthatmostlypreyonmesopelagicfauna.Asaerialforagersand shallowdivers,theirfeedingopportunitiesarelimitedbynear-surfaceavailabilityoftheirprey,whichis highlyvariablebothtemporally(reflectingdiurnalandlunarcycles)andspatially.Herewestudiedhow Bulwer'spetrelscopewiththeseconstraintsbyanalysingtheirat-seadistributionandactivityduringthe incubationperiod.Wetrackedthemovementsof20birdsfromSelvagemGrande(NEAtlantic)duringa completelunarcycle,andrecorded30foragingtripsthatlasted11daysonaverage.Birdswereboth distributedaroundthecolonyandinwatersclosetotheAzoreanarchipelago(mid-Atlantic)located 1700kmaway,andweresignificantlymoreactiveatnight(especiallyjustaftersunsetandbeforesunrise), whenmesopelagicfaunaisalsoclosertotheseasurfaceduetotheirdielverticalmigrations.Bulwer's petrelsspentsignificantlymoretime flyingduringmoonlight,althoughtheeffectofthemoonwasrela- tivelyweak(ca.10–15%differencebetweenmoonlitanddarkperiodsofthenight),andnotobviouswhen birdswereforaginginmid-Atlanticwaters,whichwerealsotargetedmoreoftenduringfull-moon.These resultsrevealkeyadaptationsoftheBulwer'spetreltothehighlydynamicecologyofitsmesopelagicprey.

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Available information on the larval release rhythms of brachyurans is biased to temperate estuarine species and outcomes resulting from some sort of artificial manipulation of ovigerous females. In this study we applied field methods to describe the larval release rhythms of an assemblage of tropical rocky shore crabs. Sampling the broods of ovigerous females of Pachygrapsus transversus at two different shores indicated a spatially consistent semilunar pattern, with larval release maxima around the full and new moon. Yet, synchronism between populations varied considerably, with the pattern obtained at the site exposed to a lower wave action far more apparent. Breeding cohorts at one of the sampled shores apparently belonged to actual age groups composing the ovigerous population. The data suggest that these breeding groups release their larvae in alternate syzygy periods, responding to a lunar cycle instead of the semilunar pattern observed for the whole population. For the description of shorter-term rhythms, temporal series at hour intervals were obtained by sampling the plankton and confinement boxes where ovigerous females were held. Unexpectedly, diurnal release activity prevailed over nocturnal hatching. Yet, only grapsids living higher on the shore exhibited strong preferences over the diel cycle, with P. transversus releasing their larvae during the day and Geograpsus lividus during the night. The pea crab Dissodactylus crinitichelis, the spider crab Epialtus brasiliensis and a suite of xanthoids undertook considerable releasing activity in both periods. Apart from the commensal pea crab D. crinitichelis, all other taxa revealed tide-related rhythms of larval release, with average estimates of the time of maximum hatching always around the time of high tides; usually during the flooding and slack, rather than the ebbing tide. Data obtained for P. transversus females held in confinement boxes indicated that early larval release is mostly due to nocturnal hatching, while zoeal release in diurnal groups took place at the time of high tide. Since nocturnal high tides at the study area occurred late, sometimes close to dusk, early release would allow more time for offshore transport of larvae when the action of potential predators is reduced.