Projections of climate change impacts on crop yields are inherently uncertain1. Uncertainty is often quantified when projecting future greenhouse gas emissions and their influence on climate2. ...However, multi-model uncertainty analysis of crop responses to climate change is rare because systematic and objective comparisons among process-based crop simulation models1, 3 are difficult4. Here we present the largest standardized model intercomparison for climate change impacts so far. We found that individual crop models are able to simulate measured wheat grain yields accurately under a range of environments, particularly if the input information is sufficient. However, simulated climate change impacts vary across models owing to differences in model structures and parameter values. A greater proportion of the uncertainty in climate change impact projections was due to variations among crop models than to variations among downscaled general circulation models. Uncertainties in simulated impacts increased with CO2 concentrations and associated warming. These impact uncertainties can be reduced by improving temperature and CO2 relationships in models and better quantified through use of multi-model ensembles. Less uncertainty in describing how climate change may affect agricultural productivity will aid adaptation strategy development and policymaking.
Carbon footprints of Indian food items Pathak, H.; Jain, N.; Bhatia, A. ...
Agriculture, ecosystems & environment,
10/2010, Letnik:
139, Številka:
1
Journal Article
Recenzirano
Carbon emission occurs during various stages of life cycle of food products. Greenhouse gases (GHG) emission from 24 Indian food items showed that animal food products (meat and milk) and rice ...cultivation mostly contributed to methane (CH
4) emission, while food products from crops contributed to emission of nitrous oxide (N
2O). Emission of CO
2 occurred during farm operations, production of farm inputs, transport, processing and preparation of food. The GHG emission during the life cycle of cooked rice was 2.8 times the GHG emission during the life cycle of chapatti, a product of wheat flour. Mutton emitted 11.9 times as much GHG as milk, 12.1 times fish, 12.9 times rice and 36.5 times chapatti. As Indians mostly consume fresh foods produced locally, 87% emission came from food production followed by preparation (10%), processing (2%) and transportation (1%). For a balanced diet (vegetarian) an adult Indian man consumed 1165
g food and emitted 723.7
g
CO
2
eq.
GHG
d
−1. A non-vegetarian meal with mutton emitted GHG 1.8 times of a vegetarian meal, 1.5 times of a non-vegetarian meal with chicken and an ovo-vegetarian meal and 1.4 times a lacto-vegetarian meal. Change in food habit thus could offer a possibility for GHG mitigation.
The COVID-19 pandemic has emphasised the need to rapidly assess infection risks for healthcare workers within the hospital environment. Using data from the first year of the pandemic, we investigated ...whether an individual's COVID-19 test result was associated with behavioural markers derived from routinely collected hospital data two weeks prior to a test. The temporal and spatial context of behaviours were important, with the highest risks of infection during the first wave, for staff in contact with a greater number of patients and those with greater levels of activity on floors handling the majority of COVID-19 patients. Infection risks were higher for BAME staff and individuals working more shifts. Night shifts presented higher risks of infection between waves of COVID-19 patients. Our results demonstrate the epidemiological relevance of deriving markers of staff behaviour from electronic records, which extend beyond COVID-19 with applications for other communicable diseases and in supporting pandemic preparedness.
Take your new partner by the hand: Chiral secondary and tertiary alkyl trifluoroborate salts undergo rhodium‐catalyzed 1,2‐addition to aldehydes with complete stereoretention (handedness) in all ...cases, enabling the creation of quaternary stereogenic centers with essentially perfect enantioselectivity (see scheme; cod=cycloocta‐1,5‐diene).
We report the first enantioselective Rh-catalyzed Markovnikov hydroboration of unactivated terminal alkenes. Using a novel sp2–sp3 hybridized diboron reagent and water as a proton source, a broad ...range of alkenes undergo hydroboration to provide secondary boronic esters with high regio- and enantiocontrol.
The addition of an aryllithium reagent to a secondary boronic ester leads to an intermediate boron-ate complex that behaves as a chiral nucleophile, reacting with a broad range of electrophiles with ...inversion of stereochemistry. Depending on the electrophile, the C–B bond can be converted into C–I, C–Br, C–Cl, C–N, C–O, and C–C, all with very high levels of stereocontrol. This discovery now adds a new, readily available, configurationally stable, chiral organometallic-type reagent to the arsenal of methods for use in asymmetric organic synthesis.
3,3‐Disubstituted allylic boronic esters are not sufficiently reactive to react with ketones and imines. However, they can be converted into the corresponding borinic esters by the sequential ...addition of nBuLi and TFAA. These reactive intermediates possess the perfect balance between reactivity and configurational stability. Their enhanced reactivity allows the highly selective allylation of both ketones and ketimines, and facile access to adjacent quaternary stereocenters with full stereocontrol. The versatility of the methodology is demonstrated in the construction of all possible stereoisomers of a quaternary‐quaternary motif and by the allylation of the heterocycles, dihydroisoquinoline and indole.
Goldilocks reactivity: 3,3‐Disubstituted allylic borinic esters possess the perfect balance between reactivity and configurational stability to react with both ketones and ketimines, allowing facile access to adjacent quaternary stereocenters with full stereocontrol. Synthesis of all possible stereoisomers of a quaternary‐quaternary motif is demonstrated. TFAA=trifluoroacetic anhydride.
The size of the transcriptional program of long non-coding RNAs in the mammalian genome has engendered discussions about their biological roles
, particularly the promoter antisense (PAS) transcripts
.... Here we report the development of an assay-referred to as chromatin isolation by RNA-Cas13a complex-to quantitatively detect the distribution of RNA in the genome. The assay revealed that PAS RNAs serve as a key gatekeeper of a broad transcriptional pause release program, based on decommissioning the 7SK small nuclear RNA-dependent inhibitory P-TEFb complex. Induction of PAS RNAs by liganded ERα led to a significant loss of H3K9me3 and the release of basally recruited HP1α and KAP1 on activated target gene promoters. This release was due to PAS RNA-dependent recruitment of H3K9me3 demethylases, which required interactions with a compact stem-loop structure in the PAS RNAs, an apparent feature of similarly regulated PAS RNAs. Activation of the ERα-bound MegaTrans enhancer, which is essential for robust pause release, required the recruitment of phosphorylated KAP1, with its transfer to the cognate promoters permitting 17β-oestradiol-induced pause release and activation of the target gene. This study reveals a mechanism, based on RNA structure, that mediates the function of PAS RNAs in gene regulation.
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