| 1. |
- Arndt, D. S., et al.
(författare)
-
State of the Climate in 2016
- 2017
-
Ingår i: Bulletin of The American Meteorological Society - (BAMS). - 0003-0007 .- 1520-0477. ; 98:8, s. S1-S280
-
Tidskriftsartikel (refereegranskat)abstract
- In 2016, the dominant greenhouse gases released into Earth's atmosphere-carbon dioxide, methane, and nitrous oxide-continued to increase and reach new record highs. The 3.5 +/- 0.1 ppm rise in global annual mean carbon dioxide from 2015 to 2016 was the largest annual increase observed in the 58-year measurement record. The annual global average carbon dioxide concentration at Earth's surface surpassed 400 ppm (402.9 +/- 0.1 ppm) for the first time in the modern atmospheric measurement record and in ice core records dating back as far as 800000 years. One of the strongest El Nino events since at least 1950 dissipated in spring, and a weak La Nina evolved later in the year. Owing at least in part to the combination of El Nino conditions early in the year and a long-term upward trend, Earth's surface observed record warmth for a third consecutive year, albeit by a much slimmer margin than by which that record was set in 2015. Above Earth's surface, the annual lower troposphere temperature was record high according to all datasets analyzed, while the lower stratospheric temperature was record low according to most of the in situ and satellite datasets. Several countries, including Mexico and India, reported record high annual temperatures while many others observed near-record highs. A week-long heat wave at the end of April over the northern and eastern Indian peninsula, with temperatures surpassing 44 degrees C, contributed to a water crisis for 330 million people and to 300 fatalities. In the Arctic the 2016 land surface temperature was 2.0 degrees C above the 1981-2010 average, breaking the previous record of 2007, 2011, and 2015 by 0.8 degrees C, representing a 3.5 degrees C increase since the record began in 1900. The increasing temperatures have led to decreasing Arctic sea ice extent and thickness. On 24 March, the sea ice extent at the end of the growth season saw its lowest maximum in the 37-year satellite record, tying with 2015 at 7.2% below the 1981-2010 average. The September 2016 Arctic sea ice minimum extent tied with 2007 for the second lowest value on record, 33% lower than the 1981-2010 average. Arctic sea ice cover remains relatively young and thin, making it vulnerable to continued extensive melt. The mass of the Greenland Ice Sheet, which has the capacity to contribute similar to 7 m to sea level rise, reached a record low value. The onset of its surface melt was the second earliest, after 2012, in the 37-year satellite record. Sea surface temperature was record high at the global scale, surpassing the previous record of 2015 by about 0.01 degrees C. The global sea surface temperature trend for the 21st century-to-date of +0.162 degrees C decade(-1) is much higher than the longer term 1950-2016 trend of +0.100 degrees C decade(-1). Global annual mean sea level also reached a new record high, marking the sixth consecutive year of increase. Global annual ocean heat content saw a slight drop compared to the record high in 2015. Alpine glacier retreat continued around the globe, and preliminary data indicate that 2016 is the 37th consecutive year of negative annual mass balance. Across the Northern Hemisphere, snow cover for each month from February to June was among its four least extensive in the 47-year satellite record. Continuing a pattern below the surface, record high temperatures at 20-m depth were measured at all permafrost observatories on the North Slope of Alaska and at the Canadian observatory on northernmost Ellesmere Island. In the Antarctic, record low monthly surface pressures were broken at many stations, with the southern annular mode setting record high index values in March and June. Monthly high surface pressure records for August and November were set at several stations. During this period, record low daily and monthly sea ice extents were observed, with the November mean sea ice extent more than 5 standard deviations below the 1981-2010 average. These record low sea ice values contrast sharply with the record high values observed during 2012-14. Over the region, springtime Antarctic stratospheric ozone depletion was less severe relative to the 1991-2006 average, but ozone levels were still low compared to pre-1990 levels. Closer to the equator, 93 named tropical storms were observed during 2016, above the 1981-2010 average of 82, but fewer than the 101 storms recorded in 2015. Three basins-the North Atlantic, and eastern and western North Pacific-experienced above-normal activity in 2016. The Australian basin recorded its least active season since the beginning of the satellite era in 1970. Overall, four tropical cyclones reached the Saffir-Simpson category 5 intensity level. The strong El Nino at the beginning of the year that transitioned to a weak La Nina contributed to enhanced precipitation variability around the world. Wet conditions were observed throughout the year across southern South America, causing repeated heavy flooding in Argentina, Paraguay, and Uruguay. Wetter-than-usual conditions were also observed for eastern Europe and central Asia, alleviating the drought conditions of 2014 and 2015 in southern Russia. In the United States, California had its first wetter-than-average year since 2012, after being plagued by drought for several years. Even so, the area covered by drought in 2016 at the global scale was among the largest in the post-1950 record. For each month, at least 12% of land surfaces experienced severe drought conditions or worse, the longest such stretch in the record. In northeastern Brazil, drought conditions were observed for the fifth consecutive year, making this the longest drought on record in the region. Dry conditions were also observed in western Bolivia and Peru; it was Bolivia's worst drought in the past 25 years. In May, with abnormally warm and dry conditions already prevailing over western Canada for about a year, the human-induced Fort McMurray wildfire burned nearly 590000 hectares and became the costliest disaster in Canadian history, with $3 billion (U.S. dollars) in insured losses.
|
|
| 2. |
|
|
| 3. |
- Bowman, John L, et al.
(författare)
-
Insights into Land Plant Evolution Garnered from the Marchantia polymorpha Genome
- 2017
-
Ingår i: Cell. - : Elsevier BV. - 0092-8674 .- 1097-4172. ; 171:2, s. 287-304.15
-
Tidskriftsartikel (refereegranskat)abstract
- The evolution of land flora transformed the terrestrial environment. Land plants evolved from an ancestral charophycean alga from which they inherited developmental, biochemical, and cell biological attributes. Additional biochemical and physiological adaptations to land, and a life cycle with an alternation between multicellular haploid and diploid generations that facilitated efficient dispersal of desiccation tolerant spores, evolved in the ancestral land plant. We analyzed the genome of the liverwort Marchantia polymorpha, a member of a basal land plant lineage. Relative to charophycean algae, land plant genomes are characterized by genes encoding novel biochemical pathways, new phytohormone signaling pathways (notably auxin), expanded repertoires of signaling pathways, and increased diversity in some transcription factor families. Compared with other sequenced land plants, M. polymorpha exhibits low genetic redundancy in most regulatory pathways, with this portion of its genome resembling that predicted for the ancestral land plant. PAPERCLIP.
|
|
| 4. |
- Guimarães, Patrícia O, et al.
(författare)
-
Effect of Apixaban on All-Cause Death in Patients with Atrial Fibrillation : a Meta-Analysis Based on Imputed Placebo Effect
- 2017
-
Ingår i: Cardiovascular Drugs and Therapy. - : Springer Science and Business Media LLC. - 0920-3206 .- 1573-7241. ; 31:3, s. 295-301
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Vitamin K antagonists (VKAs) are the standard of care for stroke prevention in patients with atrial fibrillation (AF); therefore, there is not equipoise when comparing newer oral anticoagulants with placebo in this setting.METHODS: To explore the effect of apixaban on mortality in patients with AF, we performed a meta-analysis of apixaban versus placebo using a putative placebo analysis based on randomized controlled clinical trials that compared warfarin, aspirin, and no antithrombotic control. We used data from two prospective randomized controlled trials for our comparison of apixaban versus warfarin (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) and apixaban versus aspirin (Apixaban Versus Acetylsalicylic Acid to Prevent Stroke in Atrial Fibrillation Patients Who Have Failed or Are Unsuitable for Vitamin K Antagonist Treatment). Using meta-analysis approaches, we indirectly compared apixaban with an imputed placebo with respect to the risk of death in patients with AF. We used results from meta-analyses of randomized trials as our reference for the comparison between warfarin and placebo/no treatment, and aspirin and placebo/no treatment.RESULTS: In these meta-analyses, a lower rate of death was seen both with warfarin (odds ratio [OR] 0.74, 95% confidence interval [CI] 0.57-0.97) and aspirin (OR 0.86, 95% CI 0.69-1.07) versus placebo/no treatment. Using data from ARISTOTLE and AVERROES, apixaban reduced the risk of death by 34% (95% CI 12-50%; p = 0.004) and 33% (95% CI 6-52%; p = 0.02), respectively, when compared with an imputed placebo. The pooled reduction in all-cause death with apixaban compared with an imputed placebo was 34% (95% CI 18-47%; p = 0.0002).CONCLUSIONS: In patients with AF, indirect comparisons suggest that apixaban reduces all-cause death by approximately one third compared with an imputed placebo.
|
|
| 5. |
- Marsh, Gary M., et al.
(författare)
-
Mortality Among Hardmetal Production Workers : Pooled Analysis of Cohort Data From an International Investigation
- 2017
-
Ingår i: Journal of Occupational and Environmental Medicine. - Philadelphia, PA, USA : Lippincott Williams & Wilkins. - 1076-2752 .- 1536-5948. ; 59:12, s. e342-e364
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Based on a pooled analysis of data from an international study, evaluate total and cause-specific mortality among hardmetal production workers with emphasis on lung cancer.METHODS: Study members were 32,354 workers from three companies and 17 manufacturing sites in five countries. We computed standardized mortality ratios and evaluated exposure-response via relative risk regression analysis.RESULTS: Among long-term workers, we observed overall deficits or slight excesses in deaths for total mortality, all cancers, and lung cancer and found no evidence of any exposure-response relationships for lung cancer.CONCLUSIONS: We found no evidence that duration, average intensity, or cumulative exposure to tungsten, cobalt, or nickel, at levels experienced by the workers examined, increases lung cancer mortality risks. We also found no evidence that work in these facilities increased mortality risks from any other causes of death.
|
|
| 6. |
- Hou, Song, et al.
(författare)
-
Oxidation of 4-bromo-4'-chlorobiphenyl, model species for forming mixed halogenated aromatic compounds
- 2017
-
Ingår i: International Journal of Environment and Pollution. - : InderScience Publishers. - 0957-4352 .- 1741-5101. ; 61:3-4, s. 243-260
-
Tidskriftsartikel (refereegranskat)abstract
- This contribution reports results from the gas-phase oxidation of 4-bromo-4'-chlorobiphenyl (4,4'-BCB) in order to fathom the formation of toxic species produced during the combustion of mixed halogenated aromatics. In their own right, mixed polybrominated/polychlorinated biphenyls (PXBs) represent a new class of environmental contaminants, recently detected in food and human tissues. Gas chromatography-quadrupole mass spectrometry (GC-QMS), gas chromatography-quadrupole time of flight mass spectrometry (GC-QTOFMS), Fourier transform infrared spectroscopy (FTIR) and ion chromatography (IC) served to analyse the volatile and semi-volatile organic compounds (V/SVOCs), including mixed halogenated dibenzo-p-dioxins and dibenzofurans (PXDD/Fs), and gaseous products including HBr/HCl. The selection of non-ortho substituted PXB as a model species yields a large number of halogenated compounds, including monochloro- and monobromobenzene and higher halogenated benzenes and naphthalenes and derivatives of halogenated benzenes (such as 1-chloro-4-ethynylbenzene). We also detect small amounts of chlorinated and mixed halogenated dibenzofurans. The present study provides insights into the formation of several classes of halogenated and mixed-halogenated pollutants in combustion processes involving both bromine and chlorine sources, such as those of brominated flame retardants and PVC plastics.
|
|
