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1.
Curr Opin Cardiol ; 38(3): 266-274, 2023 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-37016996

RESUMEN

PURPOSE OF REVIEW: This review summarizes recent literature, updated safety data, and major clinical considerations for commonly used medications for arrhythmias, heart failure, hypertension, ischemic heart disease, and anticoagulation during pregnancy and lactation. RECENT FINDINGS: Recent studies have shown a benefit to more aggressive treatment of mild chronic hypertension to a blood pressure goal of <140/90 with oral labetalol and nifedipine remaining first-line agents. Aspirin is now routinely used for preeclampsia prevention, while experience with other antiplatelet agents, such as purinergic receptor P2Y G protein-coupled 12 (P2Y12) inhibitors, continues to grow. Data on statin therapy are rapidly changing and recent studies suggest this class may not be associated with fetal harm and can be continued in select cases. SUMMARY: As data regarding medication safety continues to evolve, a multidisciplinary team is needed for full consideration of maternal and fetal risks and benefits. Ongoing studies are needed to improve and expand our understanding of medication safety during pregnancy and lactation.


Asunto(s)
Fármacos Cardiovasculares , Fármacos Hematológicos , Embarazo , Femenino , Humanos , Antihipertensivos/uso terapéutico , Aspirina/uso terapéutico , Hipertensión/tratamiento farmacológico , Labetalol/uso terapéutico , Inhibidores de Agregación Plaquetaria/uso terapéutico , Preeclampsia/tratamiento farmacológico , Fármacos Cardiovasculares/efectos adversos , Fármacos Cardiovasculares/uso terapéutico , Fármacos Hematológicos/efectos adversos , Fármacos Hematológicos/uso terapéutico
2.
J Environ Manage ; 329: 117029, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36577300

RESUMEN

Field boundaries are important habitat for bats in agricultural landscapes, serving as commuting and foraging areas for many species. The goal of our study was to better understand the drivers of bat activity in agricultural landscapes to inform conservation policy and make specific recommendations for habitat management. We placed sixty-four full spectrum bat detectors at random recording locations, weekly, along field boundaries in North Somerset between July and October 2020. We used an automated classifier to analyse recordings and performed error rate modelling to account for and remove the majority of error in automated classifications. We used generalised additive models to explore bat response to recording location metrics, controlling for spatial-autocorrelation and temporal differences in sampling. We validated our models with k-fold cross-validation and explored the utility of our models for predicting bat activity at new sites. We found that field boundary characteristics better describe bat activity than adjacent field characteristics or measures of local landscape for the majority of species studied. Bat activity was higher along tall, wide, vegetated field boundaries containing trees; there was lower activity at arable recording locations. Still, bat activity was highly variable and predictive error was high. We found a large spatial effect driving activity patterns, meaning models are not able to predict activity beyond the extent of the study area. We recommend management strategies that give incentives to farmers for replacing fences with hedgerows, planting hedgerow trees, and maintaining tall and outgrown field boundaries.


Asunto(s)
Quirópteros , Animales , Quirópteros/fisiología , Ecosistema , Agricultura
3.
Environ Pollut ; 307: 119552, 2022 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-35654252

RESUMEN

Increasing levels of artificial light at night (ALAN) are a major threat to global biodiversity and can have negative impacts on a wide variety of organisms and their ecosystems. Nocturnal species such as bats are highly vulnerable to the detrimental effects of ALAN. A variety of lighting management strategies have been adopted to minimise the impacts of ALAN on wildlife, however relatively little is known about their effectiveness. Using an experimental approach, we provide the first evidence of negative impacts of part-night lighting (PNL) strategies on bats. Feeding activity of Myotis spp. was reduced along rivers exposed to PNL despite no reduction in overall bat activity. We also provide the first evidence of negative effects of PNL on both feeding and activity for Pipistrellus pipistrellus which has previously been recorded feeding under artificial light. Despite having considerable energy-saving benefits, we outline the potential negative impacts of PNL schemes for bats in riparian habitats. PNL are unlikely to provide desired conservation outcomes for bats, and can potentially fragment important foraging habitats leading to a breakdown of functional connectivity across the landscape. We highlight the potential dichotomy for strategies which attempt to simultaneously address climate change and biodiversity loss and recommend alternative management strategies to limit the impacts of ALAN on biodiversity.


Asunto(s)
Quirópteros , Animales , Animales Salvajes , Ecosistema , Ríos
4.
Ecol Evol ; 11(12): 7890-7904, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34188859

RESUMEN

Effective conservation management requires an understanding of the spatiotemporal dynamics driving large carnivore density and resource partitioning. In African ecosystems, reduced prey populations and the loss of competing guild members, most notably lion (Panthera leo), are expected to increase the levels of competition between remaining carnivores. Consequently, intraguild relationships can be altered, potentially increasing the risk of further population decline. Kasungu National Park (KNP), Malawi, is an example of a conservation area that has experienced large-scale reductions in both carnivore and prey populations, leaving a resident large carnivore guild consisting of only leopard (Panthera pardus) and spotted hyena (Crocuta crocuta). Here, we quantify the spatiotemporal dynamics of these two species and their degree of association, using a combination of co-detection modeling, time-to-event analyses, and temporal activity patterns from camera trap data. The detection of leopard and spotted hyena was significantly associated with the detection of preferred prey and competing carnivores, increasing the likelihood of species interaction. Temporal analyses revealed sex-specific differences in temporal activity, with female leopard activity patterns significantly different to those of spotted hyena and male conspecifics. Heightened risk of interaction with interspecific competitors and male conspecifics may have resulted in female leopards adopting temporal avoidance strategies to facilitate coexistence. Female leopard behavioral adaptations increased overall activity levels and diurnal activity rates, with potential consequences for overall fitness and exposure to sources of mortality. As both species are currently found at low densities in KNP, increased risk of competitive interactions, which infer a reduction in fitness, could have significant implications for large carnivore demographics. The protection of remaining prey populations is necessary to mitigate interspecific competition and avoid further alterations to the large carnivore guild.

5.
Animals (Basel) ; 11(3)2021 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-33809265

RESUMEN

COVID-19, caused by SARS-CoV-2, is a world-wide problem for the human population. It is known that some animal species, such as mink, can become infected and transmit the virus. However, the susceptibility of most animals is not known. Here, we review the use of sequence analysis of the proteins which are known to interact with SARS-CoV-2 as a way to estimate an animal's susceptibility. Although most such work concentrates on the angiotensin-converting enzyme 2 receptor (ACE2), here TMPRSS2 (Transmembrane Serine Protease 2), neuropilin-1 and furin are also considered. Polymorphisms, especially ones which are known to alter viral/host interactions are also discussed. Analysis of ACE2 and TMPRSS2 protein sequences across species suggests this approach may be of some utility in predicting susceptibility; however, this analysis fails to highlight some susceptible animals such as mink. However, combined with observational data which emerges over time about which animals actually become infected, this may, in the future, be a useful tool to assist the management of risks associated with human/animal contact and support conservation and animal welfare measures.

6.
PLoS One ; 15(11): e0240434, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33151973

RESUMEN

Increasing urbanisation has led to a greater use of artificial structures by bats as alternative roost sites. Despite the widespread presence of bats, roost availability may restrict their distribution and abundance in urban environments. There is limited quantitative information on the drivers of bat roost selection and roosting preferences, particularly in African bats. We explore the factors influencing roost selection in the Mauritian tomb bat (Taphozous mauritianus), within an urban landscape in Lilongwe city, Malawi. Eight building and five landscape features of roosts were compared with both adjacent and random control buildings throughout the city. Bat occupied buildings were situated closer to woodland (mean 709m) compared to random buildings (mean 1847m) but did not differ in any other landscape features explored. Roosts were situated on buildings with larger areas and taller walls, suggesting bats select features for predator-avoidance and acoustic perception when leaving the roost. Bats preferred buildings with exposed roof beams which may provide refuge from disturbance. Whilst roosts are situated more often on brick walls, this feature was also associated with landscape features, therefore its importance in roost selection is less clear. These results are indicative that T. mauritianus selects roosts at both the building and landscape level. The selectivity of T. mauritianus in relation to its roost sites implies that preferred roosts are a limited resource, and as such, conservation actions should focus on protecting roost sites and the woodland bats rely on.


Asunto(s)
Quirópteros/fisiología , Planificación de Ciudades/métodos , Bosques , Comportamiento de Nidificación/fisiología , Desarrollo Sostenible , Animales , Malaui , Urbanización
7.
Glob Chang Biol ; 24(12): 5909-5918, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-30288876

RESUMEN

The rapid global spread of artificial light at night is causing unprecedented disruption to ecosystems. In otherwise dark environments, street lights restrict the use of major flight routes by some bats, including the threatened lesser horseshoe bat Rhinolophus hipposideros, and may disrupt foraging. Using radio tracking, we examined the response of individual female R. hipposideros to experimental street lights placed on hedgerows used as major flight routes. Hedgerows were illuminated on one side over four nights using lights with different emission spectra, while the opposite side of the hedge was not illuminated. Automated bat detectors were used to examine changes in overall bat activity by R. hipposideros and other bat species present. R. hipposideros activity reduced significantly under all light types, including red light, challenging a previously held assumption that red light is safe for bats. Despite this, R. hipposideros rapidly adapted to the presence of lights by switching their flight paths to the dark side of the hedgerow, enabling them to reach foraging sites without restriction. Red light had no effect on the activity of the other species present. Slow-flying Myotis spp. avoided orange, white and green light, while more agile Pipistrellus spp. were significantly more active at these light types compared to dark controls, most probably in response to accumulations of insect prey. No effect of any light type was found for Nyctalus or Eptesicus spp. Our findings demonstrate that caution must be used when promoting forms of lighting that are thought to be safe for wildlife before they are tested more widely. We argue that it is essential to preserve dark corridors to mitigate the impacts of artificial light at night on bat activity and movements.


Asunto(s)
Quirópteros/fisiología , Oscuridad , Vuelo Animal , Luz , Animales , Animales Salvajes , Ecosistema , Femenino , Estrés Fisiológico
8.
Proc Natl Acad Sci U S A ; 114(3): 528-533, 2017 01 17.
Artículo en Inglés | MEDLINE | ID: mdl-28028225

RESUMEN

Establishing and maintaining protected areas (PAs) are key tools for biodiversity conservation. However, this approach is insufficient for many species, particularly those that are wide-ranging and sparse. The cheetah Acinonyx jubatus exemplifies such a species and faces extreme challenges to its survival. Here, we show that the global population is estimated at ∼7,100 individuals and confined to 9% of its historical distributional range. However, the majority of current range (77%) occurs outside of PAs, where the species faces multiple threats. Scenario modeling shows that, where growth rates are suppressed outside PAs, extinction rates increase rapidly as the proportion of population protected declines. Sensitivity analysis shows that growth rates within PAs have to be high if they are to compensate for declines outside. Susceptibility of cheetah to rapid decline is evidenced by recent rapid contraction in range, supporting an uplisting of the International Union for the Conservation of Nature (IUCN) Red List threat assessment to endangered. Our results are applicable to other protection-reliant species, which may be subject to systematic underestimation of threat when there is insufficient information outside PAs. Ultimately, conserving many of these species necessitates a paradigm shift in conservation toward a holistic approach that incentivizes protection and promotes sustainable human-wildlife coexistence across large multiple-use landscapes.


Asunto(s)
Acinonyx , Conservación de los Recursos Naturales , África , Animales , Asia , Biodiversidad , Simulación por Computador , Extinción Biológica , Modelos Biológicos , Dinámica Poblacional/tendencias , Factores de Riesgo
9.
Ecol Evol ; 6(22): 8028-8036, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27878075

RESUMEN

LED lighting is predicted to constitute 70% of the outdoor and residential lighting markets by 2020. While the use of LEDs promotes energy and cost savings relative to traditional lighting technologies, little is known about the effects these broad-spectrum "white" lights will have on wildlife, human health, animal welfare, and disease transmission. We conducted field experiments to compare the relative attractiveness of four commercially available "domestic" lights, one traditional (tungsten filament) and three modern (compact fluorescent, "cool-white" LED and "warm-white" LED), to aerial insects, particularly Diptera. We found that LEDs attracted significantly fewer insects than other light sources, but found no significant difference in attraction between the "cool-" and "warm-white" LEDs. Fewer flies were attracted to LEDs than alternate light sources, including fewer Culicoides midges (Diptera: Ceratopogonidae). Use of LEDs has the potential to mitigate disturbances to wildlife and occurrences of insect-borne diseases relative to competing lighting technologies. However, we discuss the risks associated with broad-spectrum lighting and net increases in lighting resulting from reduced costs of LED technology.

11.
PLoS One ; 11(1): e0146782, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26771548

RESUMEN

Bats frequently roost in historic churches, and these colonies are of considerable conservation value. Inside churches, bat droppings and urine can cause damage to the historic fabric of the building and to items of cultural significance. In extreme cases, large quantities of droppings can restrict the use of a church for worship and/or other community functions. In the United Kingdom, bats and their roosts are protected by law, and striking a balance between conserving the natural and cultural heritage can be a significant challenge. We investigated mitigation strategies that could be employed in churches and other historic buildings to alleviate problems caused by bats without adversely affecting their welfare or conservation status. We used a combination of artificial roost provision and deterrence at churches in Norfolk, England, where significant maternity colonies of Natterer's bats Myotis nattereri damage church features. Radio-tracking data and population modelling showed that excluding M. nattereri from churches is likely to have a negative impact on their welfare and conservation status, but that judicious use of deterrents, especially high intensity ultrasound, can mitigate problems caused by bats. We show that deterrence can be used to move bats humanely from specific roosting sites within a church and limit the spread of droppings and urine so that problems to congregations and damage to cultural heritage can be much reduced. In addition, construction of bespoke roost spaces within churches can allow bats to continue to roost within the fabric of the building without flying in the church interior. We highlight that deterrence has the potential to cause serious harm to M. nattereri populations if not used judiciously, and so the effects of deterrents will need careful monitoring, and their use needs strict regulation.


Asunto(s)
Quirópteros/fisiología , Control de Plagas , Animales , Arquitectura , Conducta Animal/fisiología , Vivienda para Animales , Reino Unido
12.
R Soc Open Sci ; 2(8): 150291, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26361558

RESUMEN

The light-emitting diode (LED) street light market is expanding globally, and it is important to understand how LED lights affect wildlife populations. We compared evasive flight responses of moths to bat echolocation calls experimentally under LED-lit and -unlit conditions. Significantly, fewer moths performed 'powerdive' flight manoeuvres in response to bat calls (feeding buzz sequences from Nyctalus spp.) under an LED street light than in the dark. LED street lights reduce the anti-predator behaviour of moths, shifting the balance in favour of their predators, aerial hawking bats.

13.
PLoS One ; 10(8): e0131825, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26244667

RESUMEN

Conflict can arise when bats roost in human dwellings and householders are affected adversely by their presence. In the United Kingdom, the exclusion of bats from roosts can be licensed under exceptional circumstances to alleviate conflict, but the fate of excluded bats and the impact on their survival and reproduction is not well understood. Using radio-tracking, we investigated the effects of exclusion on the soprano pipistrelle Pipistrellus pygmaeus, a species that commonly roosts in buildings in Europe. Exclusions were performed under licence at five roosts in England in spring, when females were in the early stages of pregnancy. Following exclusion, all bats found alternative roosts and colonies congregated in nearby known roosts that had been used by radio-tagged bats prior to exclusion. We found no difference in roosting behaviour before and after exclusion. Both the frequency of roost switching and the type of roosts used by bats remained unchanged. We also found no change in foraging behaviour. Bats foraged in the same areas, travelled similar distances to reach foraging areas and showed similar patterns of habitat selection before and after exclusion. Population modelling suggested that any reduction in survival following exclusion could have a negative impact on population growth, whereas a reduction in productivity would have less effect. While the number of soprano pipistrelle exclusions currently licensed each year is likely to have little effect on local populations, the cumulative impacts of licensing the destruction of large numbers of roosts may be of concern.


Asunto(s)
Conducta Animal/fisiología , Quirópteros/fisiología , Ecosistema , Vivienda para Animales , Animales , Inglaterra , Humanos , Estaciones del Año
14.
Philos Trans R Soc Lond B Biol Sci ; 370(1667)2015 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-25780239

RESUMEN

Artificial light at night is a major feature of anthropogenic global change and is increasingly recognized as affecting biodiversity, often negatively. On a global scale, newer technology white lights are replacing orange sodium lights to reduce energy waste. In 2009, Cornwall County Council (UK) commenced replacement of existing low-pressure sodium (LPS) high intensity discharge (HID) street lights with new Phillips CosmoPolis white ceramic metal halide street lights to reduce energy wastage. This changeover provided a unique collaborative opportunity to implement a before-after-control-impact field experiment to investigate the ecological effects of newly installed broad spectrum light technologies. Activity of the bat species Pipistrellus pipistrellus, P. pygmaeus and Nyctalus/Eptesicus spp. was significantly higher at metal halide than LPS lights, as found in other studies of bat activity at old technology (i.e. mercury vapour) white light types. No significant difference was found in feeding attempts per bat pass between light types, though more passes overall were recorded at metal halide lights. Species-specific attraction of bats to the metal halide lights could have cascading effects at lower trophic levels. We highlight the need for further research on possible ecosystem-level effects of light technologies before they are installed on a wide scale.


Asunto(s)
Quirópteros/fisiología , Conducta Alimentaria/efectos de la radiación , Insectos/efectos de la radiación , Iluminación/instrumentación , Animales , Monitoreo del Ambiente , Contaminación Ambiental , Insectos/fisiología , Especificidad de la Especie
15.
Conserv Biol ; 27(6): 1324-34, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24112694

RESUMEN

The Convention on Biological Diversity has catalyzed worldwide awareness of threats to biological diversity and stimulated global conservation strategies. These have led to national and international legislation and have generated debate about the most effective conservation actions. Under the EU Habitats Directive, all member states are obliged to establish a system for strict protection of species listed in Annex IV(a), which includes all bats. In England, this obligation has resulted in legislation that allows for derogation from strict protection under license, provided activities are undertaken to mitigate any potential negative effects on bat numbers. We used an evidence-based approach to assess the cost-effectiveness of mitigation strategies and the English bat-derogation licensing process as a whole. We analyzed data from 389 bat derogation licenses issued in England from 2003 to 2005 relating to 1776 roosts and 15 species to determine the nature and extent of development and mitigation activities and their effects on bats. Overall the effects of licensed activities on roosts were negative. Despite the level of protection afforded to bats, the majority (68%) of roosts for which derogation licenses were issued were destroyed. There were species-specific differences in the probability of roosts being destroyed, and impacts on roosts did not reflect a species' conservation status. Information provided by licensees was inadequate and inconsistent. Most licensees (67%) failed to submit postdevelopment reports, and postdevelopment monitoring was conducted at only 19% of sites. Despite a minimum of £4.13 million spent on mitigation structures for bats from 2003 to 2005, it was unclear whether the licensing process meets EU obligations. On the basis of our results, we believe there is a need to overhaul the licensing process, to establish a comprehensive, standardized postdevelopment monitoring system, and to demonstrate that mitigation is commensurate with Britain's legal obligations. Mitigando el Efecto del Desarrollo sobre los Murciélagos en Inglaterra con Licencias de Derogación.


Asunto(s)
Conducta Animal , Quirópteros/fisiología , Conservación de los Recursos Naturales/legislación & jurisprudencia , Animales , Especies en Peligro de Extinción , Inglaterra , Especificidad de la Especie
16.
Philos Trans A Math Phys Eng Sci ; 371(2001): 20130097, 2013 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-24043870

RESUMEN

A Community Climate System Model, Version 3 (CCSM3) simulation for 125 ka during the Last Interglacial (LIG) is compared to two recent proxy reconstructions to evaluate surface temperature changes from modern times. The dominant forcing change from modern, the orbital forcing, modified the incoming solar insolation at the top of the atmosphere, resulting in large positive anomalies in boreal summer. Greenhouse gas concentrations are similar to those of the pre-industrial (PI) Holocene. CCSM3 simulates an enhanced seasonal cycle over the Northern Hemisphere continents with warming most developed during boreal summer. In addition, year-round warming over the North Atlantic is associated with a seasonal memory of sea ice retreat in CCSM3, which extends the effects of positive summer insolation anomalies on the high-latitude oceans to winter months. The simulated Arctic terrestrial annual warming, though, is much less than the observational evidence, suggesting either missing feedbacks in the simulation and/or interpretation of the proxies. Over Antarctica, CCSM3 cannot reproduce the large LIG warming recorded by the Antarctic ice cores, even with simulations designed to consider observed evidence of early LIG warmth in Southern Ocean and Antarctica records and the possible disintegration of the West Antarctic Ice Sheet. Comparisons with a HadCM3 simulation indicate that sea ice is important for understanding model polar responses. Overall, the models simulate little global annual surface temperature change, while the proxy reconstructions suggest a global annual warming at LIG (as compared to the PI Holocene) of approximately 1(°)C, though with possible spatial sampling biases. The CCSM3 SRES B1 (low scenario) future projections suggest high-latitude warmth similar to that reconstructed for the LIG may be exceeded before the end of this century.

17.
Curr Biol ; 19(13): 1123-7, 2009 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-19540116

RESUMEN

Anthropogenic disturbance is a major cause of worldwide declines in biodiversity. Understanding the implications of this disturbance for species and populations is crucial for conservation biologists wishing to mitigate negative effects. Anthropogenic light pollution is an increasing global problem, affecting ecological interactions across a range of taxa and impacting negatively upon critical animal behaviors including foraging, reproduction, and communication (for review see). Almost all bats are nocturnal, making them ideal subjects for testing the effects of light pollution. Previous studies have shown that bat species adapted to foraging in open environments feed on insects attracted to mercury vapor lamps. Here, we use an experimental approach to provide the first evidence of a negative effect of artificial light pollution on the commuting behavior of a threatened bat species. We installed high-pressure sodium lights that mimic the intensity and light spectra of streetlights along commuting routes of lesser horseshoe bats (Rhinolophus hipposideros). Bat activity was reduced dramatically and the onset of commuting behavior was delayed in the presence of lighting, with no evidence of habituation. These results demonstrate that light pollution may have significant negative impacts upon the selection of flight routes by bats.


Asunto(s)
Conducta Animal/fisiología , Quirópteros , Ciudades , Vuelo Animal , Luz , Transportes , Animales , Conservación de los Recursos Naturales , Ecolocación , Ecosistema , Humanos , Distribución Aleatoria , Vocalización Animal
18.
Philos Trans A Math Phys Eng Sci ; 367(1886): 49-67, 2009 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-18852094

RESUMEN

The Mid-Pliocene (ca 3Myr ago) was a relatively warm period, with increased atmospheric CO2 relative to pre-industrial. It has therefore been highlighted as a possible palaeo-analogue for the future. However, changed vegetation patterns, orography and smaller ice sheets also influenced the Mid-Pliocene climate. Here, using a general circulation model and ice-sheet model, we determine the relative contribution of vegetation and soils, orography and ice, and CO2 to the Mid-Pliocene Arctic climate and cryosphere. Compared with pre-industrial, we find that increased Mid-Pliocene CO2 contributes 35 per cent, lower orography and ice-sheet feedbacks contribute 42 per cent, and vegetation changes contribute 23 per cent of Arctic temperature change. The simulated Mid-Pliocene Greenland ice sheet is substantially smaller than that of modern, mostly due to the higher CO2. However, our simulations of future climate change indicate that the same increase in CO2 is not sufficient to melt the modern ice sheet substantially. We conclude that, although the Mid-Pliocene resembles the future in some respects, care must be taken when interpreting it as an exact analogue due to vegetation and ice-sheet feedbacks. These act to intensify Mid-Pliocene Arctic climate change, and act on a longer time scale than the century scale usually addressed in future climate prediction.

19.
Nature ; 454(7208): 1102-5, 2008 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-18756254

RESUMEN

It is thought that the Northern Hemisphere experienced only ephemeral glaciations from the Late Eocene to the Early Pliocene epochs (about 38 to 4 million years ago), and that the onset of extensive glaciations did not occur until about 3 million years ago. Several hypotheses have been proposed to explain this increase in Northern Hemisphere glaciation during the Late Pliocene. Here we use a fully coupled atmosphere-ocean general circulation model and an ice-sheet model to assess the impact of the proposed driving mechanisms for glaciation and the influence of orbital variations on the development of the Greenland ice sheet in particular. We find that Greenland glaciation is mainly controlled by a decrease in atmospheric carbon dioxide during the Late Pliocene. By contrast, our model results suggest that climatic shifts associated with the tectonically driven closure of the Panama seaway, with the termination of a permanent El Niño state or with tectonic uplift are not large enough to contribute significantly to the growth of the Greenland ice sheet; moreover, we find that none of these processes acted as a priming mechanism for glacial inception triggered by variations in the Earth's orbit.


Asunto(s)
Atmósfera/química , Dióxido de Carbono/metabolismo , Cubierta de Hielo , Dióxido de Carbono/análisis , Clima , Groenlandia , Historia Antigua , América del Norte , Lluvia , Factores de Tiempo
20.
AIDS ; 16(15): 2043-7, 2002 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-12370503

RESUMEN

OBJECTIVE: To further elucidate the immunopathogenesis of immune restoration diseases (IRD) in HIV patients responding to antiretroviral therapy and determine whether IRD associated with different opportunistic pathogens involve distinct immunopathological mechanisms. DESIGN: DNA samples from patients with a range of IRD were typed for polymorphic loci in genes encoding immune-mediators. METHODS: PCR-restriction fragment length polymorphism assays were used to type loci in the and genes. Alleles of a microsatellite in the CD30 promoter were determined by capillary electrophoresis. RESULTS: Only 8% of patients with IRD associated with a herpesvirus infection carried IL12B-3'UTR*2, compared with 42-54% of patients with other or no IRD. Patients with IRD arising from mycobacterial infection rarely carried IL6-174*C (36% versus 61-71%) and never carried TNFA-308*2 (0% versus 23-52%). TNFA-308*2 was carried by 52% of patients who experienced IRD associated with a herpesvirus infection, as several patients with exacerbations of cytomegalovirus retinitis carried this as part of a HLA-A2,B44 haplotype. Polymorphisms in and showed no distinct patterns. CONCLUSIONS: Distinct cytokine-mediated mechanisms contribute to IRD initiated by herpesvirus and mycobacterial infections.


Asunto(s)
Infecciones Oportunistas Relacionadas con el SIDA/genética , Citocinas/genética , Retinitis por Citomegalovirus/genética , Predisposición Genética a la Enfermedad , Infección por Mycobacterium avium-intracellulare/genética , Polimorfismo Genético , Infecciones Oportunistas Relacionadas con el SIDA/inmunología , Adulto , Terapia Antirretroviral Altamente Activa , Retinitis por Citomegalovirus/inmunología , Encefalomielitis/genética , Encefalomielitis/inmunología , Infecciones por VIH/complicaciones , VIH-1 , Humanos , Sistema Inmunológico , Infección por Mycobacterium avium-intracellulare/inmunología
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