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1.
Nature ; 522(7555): 197-201, 2015 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-26062511

RESUMEN

Our current understanding of ocean-atmosphere-cryosphere interactions at ice-age terminations relies largely on assessments of the most recent (last) glacial-interglacial transition, Termination I (T-I). But the extent to which T-I is representative of previous terminations remains unclear. Testing the consistency of termination processes requires comparison of time series of critical climate parameters with detailed absolute and relative age control. However, such age control has been lacking for even the penultimate glacial termination (T-II), which culminated in a sea-level highstand during the last interglacial period that was several metres above present. Here we show that Heinrich Stadial 11 (HS11), a prominent North Atlantic cold episode, occurred between 135 ± 1 and 130 ± 2 thousand years ago and was linked with rapid sea-level rise during T-II. Our conclusions are based on new and existing data for T-II and the last interglacial that we collate onto a single, radiometrically constrained chronology. The HS11 cold episode punctuated T-II and coincided directly with a major deglacial meltwater pulse, which predominantly entered the North Atlantic Ocean and accounted for about 70 per cent of the glacial-interglacial sea-level rise. We conclude that, possibly in response to stronger insolation and CO2 forcing earlier in T-II, the relationship between climate and ice-volume changes differed fundamentally from that of T-I. In T-I, the major sea-level rise clearly post-dates Heinrich Stadial 1. We also find that HS11 coincided with sustained Antarctic warming, probably through a bipolar seesaw temperature response, and propose that this heat gain at high southern latitudes promoted Antarctic ice-sheet melting that fuelled the last interglacial sea-level peak.


Asunto(s)
Cubierta de Hielo , Agua de Mar/análisis , Regiones Antárticas , Organismos Acuáticos/metabolismo , Océano Atlántico , Clima , Foraminíferos/metabolismo , Historia Antigua , Región Mediterránea , Mar Mediterráneo , Plancton/metabolismo , Temperatura
2.
Nature ; 491(7426): 744-7, 2012 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-23151478

RESUMEN

Current global warming necessitates a detailed understanding of the relationships between climate and global ice volume. Highly resolved and continuous sea-level records are essential for quantifying ice-volume changes. However, an unbiased study of the timing of past ice-volume changes, relative to polar climate change, has so far been impossible because available sea-level records either were dated by using orbital tuning or ice-core timescales, or were discontinuous in time. Here we present an independent dating of a continuous, high-resolution sea-level record in millennial-scale detail throughout the past 150,000 years. We find that the timing of ice-volume fluctuations agrees well with that of variations in Antarctic climate and especially Greenland climate. Amplitudes of ice-volume fluctuations more closely match Antarctic (rather than Greenland) climate changes. Polar climate and ice-volume changes, and their rates of change, are found to covary within centennial response times. Finally, rates of sea-level rise reached at least 1.2 m per century during all major episodes of ice-volume reduction.


Asunto(s)
Cambio Climático/historia , Clima , Cubierta de Hielo , Temperatura , Animales , Regiones Antárticas , Antozoos , Cambio Climático/estadística & datos numéricos , Retroalimentación , Foraminíferos/aislamiento & purificación , Sedimentos Geológicos/análisis , Groenlandia , Historia Antigua , Cubierta de Hielo/química , Océano Índico , Mar Mediterráneo , Plancton/aislamiento & purificación , Agua de Mar/análisis , Agua de Mar/química , Factores de Tiempo
3.
Climacteric ; 8(3): 251-62, 2005 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16390757

RESUMEN

OBJECTIVES: To assess the efficacy and tolerability of risedronate, a pyridinyl bisphosphonate, in preventing loss of bone mineral density (BMD) of the lumbar spine and proximal femur in early postmenopausal women. METHODS: A total of 383 patients were randomly assigned to receive risedronate 2.5 or 5 mg or placebo once daily for 24 months. All patients received 1 g elemental calcium daily. BMD was measured by dual X-ray absorptiometry at baseline and at 3, 6, 12, 18, and 24 months. RESULTS: Risedronate 5 mg significantly increased BMD at the lumbar spine and femoral neck and trochanter in early postmenopausal women. Significant results were observed as early as 3 months. In the control calcium-supplemented group, BMD decreased steadily at each site throughout the study. The mean percentage change from baseline in BMD in the risedronate 5 mg group was significantly different from that in the control group at each determination at each site. At 24 months, the differences were 4.5 +/- 0.45% at the lumbar spine, 3.3 +/- 0.49% at the femoral neck, and 4.3 +/- 0.67% at the femoral trochanter. Risedronate 2.5 mg maintained BMD at each site, although the effect was less pronounced than that of risedronate 5 mg. Risedronate was well tolerated and was not associated with an increased incidence of overall or upper gastrointestinal adverse events. CONCLUSIONS: Risedronate 5 mg prevents bone loss in early postmenopausal women, is well tolerated, and represents an effective choice to maintain bone mass and prevent osteoporosis.


Asunto(s)
Conservadores de la Densidad Ósea/uso terapéutico , Ácido Etidrónico/análogos & derivados , Osteoporosis Posmenopáusica/prevención & control , Absorciometría de Fotón , Adulto , Aminoácidos/sangre , Biomarcadores/sangre , Creatinina/sangre , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Ácido Etidrónico/uso terapéutico , Femenino , Fémur , Humanos , Vértebras Lumbares , Persona de Mediana Edad , Estudios Prospectivos , Ácido Risedrónico , Resultado del Tratamiento
4.
Int J STD AIDS ; 3(1): 49-51, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-1543768

RESUMEN

A single dose of ciprofloxacin, 250 mg by mouth, was used in an open study to treat pharyngeal or rectal gonorrhoea or both in 64 patients (32 men and 32 women). The study also included 151 men with urethral gonorrhoea and 53 women with cervical or urethral gonorrhoea. Ciprofloxacin cured 63 (98%) patients with pharyngeal or rectal gonorrhoea (including 5 patients with penicillinase-producing Neisseria gonorrhoeae; PPNG), 147 (97%) men with urethral gonorrhoea (including 8 with PPNG) and 52 (98%) women with cervical or urethral gonorrhoea. All the isolates of N. gonorrhoeae were sensitive to 0.03 mg/l of ciprofloxacin. Five of the 6 patients with treatment failure were subsequently cured by a single oral dose of ciprofloxacin 250 mg. None of the patients reported an adverse reaction. Ciprofloxacin 250 mg as a single oral dose is effective and safe in treating patients with pharyngeal or rectal gonorrhoea, including those with PPNG strains.


Asunto(s)
Enfermedades del Ano/tratamiento farmacológico , Ciprofloxacina/uso terapéutico , Enfermedades Urogenitales Femeninas/tratamiento farmacológico , Gonorrea/tratamiento farmacológico , Enfermedades Urogenitales Masculinas , Enfermedades Faríngeas/tratamiento farmacológico , Enfermedades del Ano/epidemiología , Enfermedades del Ano/microbiología , Ciprofloxacina/administración & dosificación , Femenino , Enfermedades Urogenitales Femeninas/epidemiología , Enfermedades Urogenitales Femeninas/microbiología , Estudios de Seguimiento , Gonorrea/epidemiología , Gonorrea/microbiología , Humanos , Londres/epidemiología , Masculino , Pruebas de Sensibilidad Microbiana , Servicio Ambulatorio en Hospital , Enfermedades Faríngeas/epidemiología , Enfermedades Faríngeas/microbiología , Recurrencia , Resultado del Tratamiento
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