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Institution

University of Iceland

EducationReykjavik, Suðurnes, Iceland
About: University of Iceland is a education organization based out in Reykjavik, Suðurnes, Iceland. It is known for research contribution in the topics: Population & Genome-wide association study. The organization has 5423 authors who have published 16199 publications receiving 694762 citations. The organization is also known as: Háskóli Íslands.


Papers
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Journal ArticleDOI
TL;DR: It is proposed that shock-induced sympatho-adrenal hyperactivation is a critical driver of endothelial cell and glycocalyx damage (endotheliopathy) in acute critical illness, with the overall aim of ensuring organ perfusion through an injured microvasculature.
Abstract: One quarter of patients suffering from acute critical illness such as severe trauma, sepsis, myocardial infarction (MI) or post cardiac arrest syndrome (PCAS) develop severe hemostatic aberrations and coagulopathy, which are associated with excess mortality. Despite the different types of injurious “hit”, acutely critically ill patients share several phenotypic features that may be driven by the shock. This response, mounted by the body to various life-threatening conditions, is relatively homogenous and most likely evolutionarily adapted. We propose that shock-induced sympatho-adrenal hyperactivation is a critical driver of endothelial cell and glycocalyx damage (endotheliopathy) in acute critical illness, with the overall aim of ensuring organ perfusion through an injured microvasculature. We have investigated more than 3000 patients suffering from different types of acute critical illness (severe trauma, sepsis, MI and PCAS) and have found a potential unifying pathologic link between sympatho-adrenal hyperactivation, endotheliopathy, and poor outcome. We entitled this proposed disease entity, shock-induced endotheliopathy (SHINE). Here we review the literature and discuss the pathophysiology of SHINE.

233 citations

Journal Article
TL;DR: The records of a cohort of 11,580 females and 11,366 males participating in an Icelandic cardiovascular risk factor study and the Icelandic Cancer Registry, identifying 1,785 males and 1,490 females who had been registered with neoplastic diseases from 1968 to 1995 show that smoking is the most important risk factor, negative only for endometrium.
Abstract: The records of a cohort of 11,580 females and 11,366 males participating in an Icelandic cardiovascular risk factor study were linked with the Icelandic Cancer Registry, identifying 1,785 males and 1,490 females who had been registered with neoplastic diseases from 1968 to 1995. The interval between the time of measurement of the variables and the diagnosis of the malignancy ranged from 4 to 27 years. The variables consisted of answers from a questionnaire on smoking and the use of hypertensive drugs and anthropometric and biochemical measurements. Cox's regression was applied to analyze the predictive power of the variables on the risk of cancer after the first examination at the Heart Preventive Clinic, Reykjavik. Univariate analyses, adjusted for age, were performed for each variable and each major site. Within each major site, multivariate regression analysis was applied for variables that were found significantly (10% level in univariate analysis) positive or negative as risk factors. The results show that smoking is the most important risk factor, negative only for endometrium. For lung cancer, the risk is twice as strong for females as it is for males, whereas for pancreas, males have a relative risk ratio of 4.5, compared with 2.4 for females. Height is a risk factor for all sites for each sex, for breast in females, and for kidney in males. Several anthropometric risk factors were studied. Some of these can describe positive or negative relative risk ratios for cancer, and their use may shed light on cancer pathogenesis. Serum cholesterol is a negative risk factor for breast cancer in females, but triglycerides are a positive risk factor for cervix cancer in females and for colon or rectum and thyroid cancer in males. Serum glucose is a positive risk factor for prostate cancer and a negative risk factor for lymphomas and leukemias.

232 citations

Journal ArticleDOI
TL;DR: Experimental results on four real HSI datasets demonstrate the superiority of the proposed SBDSM algorithm over several well-known classification approaches in terms of both classification accuracies and computational speed.
Abstract: A novel superpixel-based discriminative sparse model (SBDSM) for spectral–spatial classification of hyperspectral images (HSIs) is proposed. Here, a superpixel in a HSI is considered as a small spatial region whose size and shape can be adaptively adjusted for different spatial structures. In the proposed approach, the SBDSM first clusters the HSI into many superpixels using an efficient oversegmentation method. Then, pixels within each superpixel are jointly represented by a set of common atoms from a dictionary via a joint sparse regularization. The recovered sparse coefficients are utilized to determine the class label of the superpixel. In addition, instead of directly using a large number of sampled pixels as dictionary atoms, the SBDSM applies a discriminative K-SVD learning algorithm to simultaneously train a compact representation dictionary, as well as a discriminative classifier. Furthermore, by utilizing the class label information of training pixels and dictionary atoms, a class-labeled orthogonal matching pursuit is proposed to accelerate the K-SVD algorithm while still enforcing high discriminability on sparse coefficients when training the classifier. Experimental results on four real HSI datasets demonstrate the superiority of the proposed SBDSM algorithm over several well-known classification approaches in terms of both classification accuracies and computational speed.

232 citations

Journal ArticleDOI
15 Jul 2016-Science
TL;DR: It is concluded that interaction between the pressure exerted by the subsiding reservoir roof and the physical properties of the subsurface flow path explain the gradual near-exponential decline of both the collapse rate and the intensity of the 180-day-long eruption of the Bárdarbunga volcano.
Abstract: INTRODUCTION The Bardarbunga caldera volcano in central Iceland collapsed from August 2014 to February 2015 during the largest eruption in Europe since 1784. An ice-filled subsidence bowl, 110 square kilometers (km 2 ) in area and up to 65 meters (m) deep developed, while magma drained laterally for 48 km along a subterranean path and erupted as a major lava flow northeast of the volcano. Our data provide unprecedented insight into the workings of a collapsing caldera. RATIONALE Collapses of caldera volcanoes are, fortunately, not very frequent, because they are often associated with very large volcanic eruptions. On the other hand, the rarity of caldera collapses limits insight into this major geological hazard. Since the formation of Katmai caldera in 1912, during the 20th century’s largest eruption, only five caldera collapses are known to have occurred before that at Bardarbunga. We used aircraft-based altimetry, satellite photogrammetry, radar interferometry, ground-based GPS, evolution of seismicity, radio-echo soundings of ice thickness, ice flow modeling, and geobarometry to describe and analyze the evolving subsidence geometry, its underlying cause, the amount of magma erupted, the geometry of the subsurface caldera ring faults, and the moment tensor solutions of the collapse-related earthquakes. RESULTS After initial lateral withdrawal of magma for some days though a magma-filled fracture propagating through Earth’s upper crust, preexisting ring faults under the volcano were reactivated over the period 20 to 24 August, marking the onset of collapse. On 31 August, the eruption started, and it terminated when the collapse stopped, having produced 1.5 km of basaltic lava. The subsidence of the caldera declined with time in a near-exponential manner, in phase with the lava flow rate. The volume of the subsidence bowl was about 1.8 km 3 . Using radio-echo soundings, we find that the subglacial bedrock surface after the collapse is down-sagged, with no indications of steep fault escarpments. Using geobarometry, we determined the depth of magma reservoir to be ~12 km, and modeling of geodetic observations gives a similar result. High-precision earthquake locations and moment tensor analysis of the remarkable magnitude M 5 earthquake series are consistent with steeply dipping ring faults. Statistical analysis of seismicity reveals communication over tens of kilometers between the caldera and the dike. CONCLUSION We conclude that interaction between the pressure exerted by the subsiding reservoir roof and the physical properties of the subsurface flow path explain the gradual near-exponential decline of both the collapse rate and the intensity of the 180-day-long eruption. By combining our various data sets, we show that the onset of collapse was caused by outflow of magma from underneath the caldera when 12 to 20% of the total magma intruded and erupted had flowed from the magma reservoir. However, the continued subsidence was driven by a feedback between the pressure of the piston-like block overlying the reservoir and the 48-km-long magma outflow path. Our data provide better constraints on caldera mechanisms than previously available, demonstrating what caused the onset and how both the roof overburden and the flow path properties regulate the collapse.

232 citations

Journal ArticleDOI
TL;DR: In this article, high precision iron isotope analyses by MC-ICP-MS were performed on a suite of rock samples representative for the volcanic evolution of the Hekla volcano, Iceland.

232 citations


Authors

Showing all 5561 results

NameH-indexPapersCitations
Albert Hofman2672530321405
Kari Stefansson206794174819
Ronald Klein1941305149140
Eric Boerwinkle1831321170971
Unnur Thorsteinsdottir167444121009
Vilmundur Gudnason159837123802
Hakon Hakonarson152968101604
Bernhard O. Palsson14783185051
Andrew T. Hattersley146768106949
Fernando Rivadeneira14662886582
Rattan Lal140138387691
Jonathan G. Seidman13756389782
Christine E. Seidman13451967895
Augustine Kong13423789818
Timothy M. Frayling133500100344
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202377
2022209
20211,222
20201,118
20191,140
20181,070