| 3. |
- Silvano, Alessandro, et al.
(författare)
-
Observing Antarctic Bottom Water in the Southern Ocean
- 2023
-
Ingår i: Frontiers in Marine Science. - 2296-7745. ; 10
-
Forskningsöversikt (refereegranskat)abstract
- Dense, cold waters formed on Antarctic continental shelves descend along the Antarctic continental margin, where they mix with other Southern Ocean waters to form Antarctic Bottom Water (AABW). AABW then spreads into the deepest parts of all major ocean basins, isolating heat and carbon from the atmosphere for centuries. Despite AABW's key role in regulating Earth's climate on long time scales and in recording Southern Ocean conditions, AABW remains poorly observed. This lack of observational data is mostly due to two factors. First, AABW originates on the Antarctic continental shelf and slope where in situ measurements are limited and ocean observations by satellites are hampered by persistent sea ice cover and long periods of darkness in winter. Second, north of the Antarctic continental slope, AABW is found below approximately 2 km depth, where in situ observations are also scarce and satellites cannot provide direct measurements. Here, we review progress made during the past decades in observing AABW. We describe 1) long-term monitoring obtained by moorings, by ship-based surveys, and beneath ice shelves through bore holes; 2) the recent development of autonomous observing tools in coastal Antarctic and deep ocean systems; and 3) alternative approaches including data assimilation models and satellite-derived proxies. The variety of approaches is beginning to transform our understanding of AABW, including its formation processes, temporal variability, and contribution to the lower limb of the global ocean meridional overturning circulation. In particular, these observations highlight the key role played by winds, sea ice, and the Antarctic Ice Sheet in AABW-related processes. We conclude by discussing future avenues for observing and understanding AABW, impressing the need for a sustained and coordinated observing system.
|
|
| 4. |
- Franklin, Stanley S., et al.
(författare)
-
The Cardiovascular Risk of White-Coat Hypertension
- 2016
-
Ingår i: Journal of the American College of Cardiology. - : Elsevier BV. - 0735-1097 .- 1558-3597. ; 68:19, s. 2033-2043
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND The role of white-coat hypertension (WCH) and the white-coat-effect (WCE) in development of cardiovascular disease (CVD) risk remains poorly understood. OBJECTIVES Using data from the population-based, 11-cohort IDACO (International Database on Ambulatory Blood Pressure Monitoring in Relation to Cardiovascular Outcomes), this study compared daytime ambulatory blood pressure monitoring with conventional blood pressure measurements in 653 untreated subjects with WCH and 653 normotensive control subjects. METHODS European Society Hypertension guidelines were used as a 5-stage risk score. Low risk was defined as 0 to 2 risk factors, and high risk was defined as >= 3 to 5 risk factors, diabetes, and/or history of prior CVD events. Age-and cohort-matching was done between 653 untreated subjects with WCH and 653 normotensive control subjects. RESULTS In a stepwise linear regression model, systolic WCE increased by 3.8 mm Hg (95% confidence interval [CI]: 3.1 to 4.6 mm Hg) per 10-year increase in age, and was similar in low-and high-risk subjects with or without prior CVD events. Over a median 10.6-year follow-up, incidence of new CVD events was higher in 159 high-risk subjects with WCH compared with 159 cohort-and age-matched high-risk normotensive subjects (adjusted hazard ratio [HR]: 2.06; 95% CI: 1.10 to 3.84; p = 0.023). The HR was not significant for 494 participants with low-risk WCH and age-matched low-risk normotensive subjects. Subgroup analysis by age showed that an association between WCH and incident CVD events is limited to older (age >= 60 years) high-risk WCH subjects; the adjusted HR was 2.19 (95% CI: 1.09 to 4.37; p = 0.027) in the older high-risk group and 0.88 (95% CI: 0.51 to 1.53; p = 0.66) in the older low-risk group (p for interaction = 0.044). CONCLUSIONS WCE size is related to aging, not to CVD risk. CVD risk in most persons with WCH is comparable to age-and risk-adjusted normotensive control subjects.
|
|
