1,647 research outputs found
Coupled ocean-atmosphere dynamics of the 2017 extreme coastal El Niño.
In March 2017, sea surface temperatures off Peru rose above 28 °C, causing torrential rains that affected the lives of millions of people. This coastal warming is highly unusual in that it took place with a weak La Niña state. Observations and ocean model experiments show that the downwelling Kelvin waves caused by strong westerly wind events over the equatorial Pacific, together with anomalous northerly coastal winds, are important. Atmospheric model experiments further show the anomalous coastal winds are forced by the coastal warming. Taken together, these results indicate a positive feedback off Peru between the coastal warming, atmospheric deep convection, and the coastal winds. These coupled processes provide predictability. Indeed, initialized on as early as 1 February 2017, seasonal prediction models captured the extreme rainfall event. Climate model projections indicate that the frequency of extreme coastal El Niño will increase under global warming
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Pollinator limitation causes sexual reproductive failure in ex situ populations of self-compatible Iris ensata
Ozone and haze pollution weakens net primary productivity in China
Atmospheric pollutants have both beneficial and detrimental effects on carbon uptake by land ecosystems. Surface ozone (O3) damages leaf photosynthesis by oxidizing plant cells, while aerosols promote carbon uptake by increasing diffuse radiation and exert additional influences through concomitant perturbations to meteorology and hydrology. China is currently the world’s largest emitter of both carbon dioxide and short-lived air pollutants. The land ecosystems of China are estimated to provide a carbon sink, but it remains unclear whether air pollution acts to inhibit or promote carbon uptake. Here, we employ Earth system modeling and multiple measurement datasets to assess the separate and combined effects of anthropogenic O3 and aerosol pollution on net primary productivity (NPP) in China. In the present day, O3 reduces annual NPP by 0.6 Pg C (14 %) with a range from 0.4 Pg C (low O3 sensitivity) to 0.8 Pg C (high O3 sensitivity). In contrast, aerosol direct effects increase NPP by 0.2 Pg C (5 %) through the combination of diffuse radiation fertilization, reduced canopy temperatures, and reduced evaporation leading to higher soil moisture. Consequently, the net effects of O3 and aerosols decrease NPP by 0.4 Pg C (9 %) with a range from 0.2 Pg C (low O3 sensitivity) to 0.6 Pg C (high O3 sensitivity). However, precipitation inhibition from combined aerosol direct and indirect effects reduces annual NPP by 0.2 Pg C (4 %), leading to a net air pollution suppression of 0.8 Pg C (16 %) with a range from 0.6 Pg C (low O3 sensitivity) to 1.0 Pg C (high O3 sensitivity). Our results reveal strong dampening effects of air pollution on the land carbon uptake in China today. Following the current legislation emission scenario, this suppression will be further increased by the year 2030, mainly due to a continuing increase in surface O3. However, the maximum technically feasible reduction scenario could drastically relieve the current level of NPP damage by 70 % in 2030, offering protection of this critical ecosystem service and the mitigation of long-term global warming
Whole Grain Food Standard System Construction Status and Development Direction
Existing studies have clearly demonstrated that people eating more whole grains have reduced risks of many chronic metabolic diseases compared to those eating less. In the past 20 years, the whole grain industry has developed so rapidly in major developed countries and regions. In recent years, whole grains have also attracted extensive attention in our country. The research and development efforts of the whole grain standards in China have been strengthened. This paper introduced the progress of the global definition consensus of whole grain and whole grain food, summarized the international development status of whole grain raw materials and whole grain food related standards in many countries and institutions, such as the Working Group of ISO Whole Grain, the United States, Canada, the Netherlands, Codex Alimentarius Commission, and so on. This paper also reviewed the present situation of definition of the whole grain and whole grain food related standards in China. More than 20 relevant raw materials, food related standards and production technical regulations and the publishment situation of other whole grain standards in China, including national standards and industry standards and local standards and group standards, were summarized, and some whole grain related standards under formulation were also introduced. Finally, the paper puts forward the development direction and suggestions for the construction of whole grain standard system in China, including fully combining with the actual production situation of China’s whole grain food industry, integrating with international standards, and combining standard testing and certification. On the whole, the gradual improvement of the standard system of the whole grain food industry will help guide and regulate the high-quality and healthy development of the whole grain industry in China, and promote the creation of a diversified and healthy grain food ecology, and provide a technical basis for the development of the whole grain industry
Bright 22 m Excess Candidates from WISE All-Sky Catalog and Hipparcos Main Catalog
In this paper we present a catalog which includes 141 bright candidates
( mag, V band) showing the infrared (IR) excess at 22 m. Of
which, 38 stars are known IR excess stars or disk, 23 stars are double or
multiple stars and 4 are Be stars. While the remaining more than 70 stars are
identified as the 22 m excess candidates in our work. The criterion of
selecting candidates is . All these candidates are selected
from \emph{WISE} All-sky data cross-correlated with \emph{Hipparcos} Main
Catalog and the likelihood-ratio technique is employed. Considering the effect
of background, we introduce the \emph{IRAS} 100 m level to exclude the
high background. We also estimated the coincidence probability of these
sources. In addition, we presented the optical to mid-infrared SEDs and optical
images of all the candidates, and gave the observed optical spectra of 6 stars
with NAOC's 2.16-m telescope. To measure for the dust amount around each star,
the fractional luminosity is also provided. We also test whether our method of
selecting IR excess stars can be used to search for extra-solar planets, we
cross-matched our catalog with known IR-excess stars having planets but none is
matched. Finally, we give the fraction of stars showing IR-excess for different
spectral type of main-sequence stars.Comment: 45 pages, 16 figures, 4 tables. Accepted for publication in ApJ
Hexakis(1-benzyl-1H-imidazole-κN 3)manganese(II) bis(perchlorate)
In the title compound, [Mn(C10H10N2)6](ClO4)2, the MnII ion, located on an inversion center, is coordinated by six N atoms from three pairs of symmetry-related 1-benzyl-1H-imidazole ligands in a distorted octahedral geometry. In the crystal, weak intermolecular C—H⋯O hydrogen bonds link the complex cations and perchlorate anions
1,1′-[1,4-Phenylenebis(methylene)]bis(2-methyl-1H-imidazol-3-ium) 2,4-dicarboxybenzene-1,5-dicarboxylate monohydrate
In the dication of the title compound, C16H20N4
2+·C10H4O8
2−·H2O, the dihedral angles formed by mean planes of the imidazolium rings and the benzene ring are 69.05 (18) and 89.1 (2)°. In the crystal, the components are linked into a three-dimensional network by intermolecular N—H⋯O and O—H⋯O hydrogen bonds
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