Fresh air in the 21st century?

Ozone is an air quality problem today for much of the world's population. Regions can exceed the ozone air quality standards (AQS) through a combination of local emissions, meteorology favoring pollution episodes, and the clean-air baseline levels of ozone upon which pollution builds. The IPCC 2001 assessment studied a range of global emission scenarios and found that all but one projects increases in global tropospheric ozone during the 21st century. By 2030, near-surface increases over much of the northern hemisphere are estimated to be about 5 ppb (+2 to +7 ppb over the range of scenarios). By 2100 the two more extreme scenarios project baseline ozone increases of >20 ppb, while the other four scenarios give changes of -4 to +10 ppb. Even modest increases in the background abundance of tropospheric ozone might defeat current AQS strategies. The larger increases, however, would gravely threaten both urban and rural air quality over most of the northern hemisphere

Projet Termitofuel: les termites et leurs symbiontes pour mieux valoriser la biomasse ligno-cellulosique

L’exploitation actuelle de la biomasse ligno-cellulosique, extrêmement abondante sur Terre, est liée à la production de déchets relativement peu valorisables. C’est pourquoi le projet TERMITOFUEL étudie la digestion du bois chez les termites, grâce à une approche pluridisciplinaire, en vue d’améliorer la production de bioéthanol de seconde génération. Au sein de l’Unité d’Entomologie Fonctionnelle et Evolutive, l’approche protéomique est employée afin d’identifier les micro-organismes présents dans le tube digestif des termites et caractériser les activités enzymatiques

Site-Directed Mutagenesis of the Streptomyces R61 Dd-Peptidase. Catalytic Function of the Conserved Residues around the Active Site and a Comparison with Class-a and Class-C Beta-Lactamases

The importance of various residues in the Streptomyces R61 penicillin-sensitive DD-peptidase has been assessed by site-directed mutagenesis. The replacement of the active Ser62 by a Cys residue yielded an inactive protein which was also unable to recognize penicillin. The activity of the Lys65 → Arg mutant with the peptide and thiol ester substrates was decreased 100-200-fold and the rate of penicillin inactivation was decreased 20 000-fold or more. The mutant thus behaved as a poor, but penicillin-resistant, DD-peptidase. The other studied mutations, the mutations Phe358 → Leu, Tyr90 → Asn, Thr101 → Asn, Phe164 → Ala, Asp225 → Glu and Asp225 → Asn had little influence on the catalytic and penicillin-binding properties. The Asp225 mutants did not exhibit an increased sensitivity to cefotaxime. The Phe164 → Ala mutant was significantly more unstable than the wild-type enzyme

Genomic location of the bovine growth hormone secretagogue receptor (Ghsr) gene and investigation of genetic polymorphism

The growth hormone secretagogue receptor (GHSR) is involved in the regulation of energetic homeostasis and GH secretion. In this study, the bovine GHSR gene was mapped to BTA1 between BL26 and BMS4004. Two different bovine GHSR CDS (GHSR1a and GHSR1b) were sequenced. Six polymorphisms (five SNPs and one 3-bp indel) were also identified, three of them leading to amino acid variations L24V, D194N, and Del R242. These variations are located in the extracellular N-terminal end, the exoloop 2, and the cytoloop 3 of the receptor, respectively

Quinine-Resistant Malaria in Traveler Returning from Senegal, 2007

We describe clinical and parasitologic features of in vivo and in vitro Plasmodium falciparum resistance to quinine in a nonimmune traveler who returned to France from Senegal in 2007 with severe imported malaria. Clinical quinine failure was associated with a 50% inhibitory concentration of 829 nmol/L. Increased vigilance is required during treatment follow-up

In-situ observations using tagged animals

Marine mammals help gather information on some of the harshest environments on the planet, through the use of miniaturized ocean sensors glued on their fur. Since 2004, hundreds of diving marine animals, mainly Antarctic and Arctic seals, have been fitted with a new generation of Argos tags developed by the Sea Mammal Research Unit of the University of St Andrews in Scotland, UK. These tags investigate the at-sea ecology of these animals while simultaneously collecting valuable oceanographic data. Some of the study species travel thousands of kilometres continuously diving to great depths (up to 2100 m). The resulting data are now freely available to the global scientific community at http://www.meop.net. Despite great progress in their reliability and data accuracy, the current generation of loggers while approaching standard ARGO quality specifications have yet to match them. Yet, improvements are underway; they involve updating the technology, implementing a more systematic phase of calibration and taking benefit of the recently acquired knowledge on the dynamical response of sensors. Together these efforts are rapidly transforming animal tagging into one of the most important sources of oceanographic data in polar regions and in many coastal areas.Publisher PDFNon peer reviewe

Ozone-CO Correlations Determined by the TES Satellite Instrument in Continental Outflow Regions

Collocated measurements of tropospheric ozone (O3) and carbon monoxide (CO) from the Tropospheric Emission Spectrometer (TES) aboard the EOS Aura satellite provide information on O3-CO correlations to test our understanding of global anthropogenic influence on O3. We examine the global distribution of TES O3-CO correlations in the middle troposphere (618 hPa) for July 2005 and compare to correlations generated with the GEOS-Chem chemical transport model and with ICARTT aircraft observations over the eastern United States (July 2004). The TES data show significant O3-CO correlations downwind of polluted continents, with dO3/dCO enhancement ratios in the range 0.4–1.0 mol mol−1 and consistent with ICARTT data. The GEOS-Chem model reproduces the O3-CO enhancement ratios observed in continental outflow, but model correlations are stronger and more extensive. We show that the discrepancy can be explained by spectral measurement errors in the TES data. These errors will decrease in future data releases, which should enable TES to provide better information on O3-CO correlations.Earth and Planetary SciencesEngineering and Applied Science

Anti-malarial prescriptions in three health care facilities after the emergence of chloroquine resistance in Niakhar, Senegal (1992–2004)

<p>Abstract</p> <p>Background</p> <p>In the rural zone of Niakhar in Senegal, the first therapeutic failures for chloroquine (CQ) were observed in 1992. In 2003, the national policy regarding first-line treatment of uncomplicated malaria was modified, replacing CQ by a transitory bi-therapy amodiaquine/sulphadoxine-pyrimethamine (AQ/SP), before the implementation of artemisinin-based combination therapy (ACT) in 2006.</p> <p>The aims of the study were to assess the evolution of anti-malarial prescriptions in three health care facilities between 1992 and 2004, in parallel with increasing CQ resistance in the region.</p> <p>Methods</p> <p>The study was conducted in the area of Niakhar, a demographic surveillance site located in a sahelo-sudanese region of Senegal, with mesoendemic and seasonal malaria transmission. Health records of two public health centres and a private catholic dispensary were collected retrospectively to cover the period 1992–2004.</p> <p>Results</p> <p>Records included 110,093 consultations and 292,965 prescribed treatments. Twenty-five percent of treatments were anti-malarials, prescribed to 49% of patients. They were delivered all year long, but especially during the rainy season, and 20% of patients with no clinical malaria diagnosis received anti-malarials. Chloroquine and quinine represented respectively 55.7% and 34.6% of prescribed anti-malarials. Overall, chloroquine prescriptions rose from 1992 to 2000, in parallel with clinical malaria; then the CQ prescription rate decreased from 2000 and was concomitant with the rise of SP and the persistence of quinine use. AQ and SP were mainly used as bi-therapy after 2003, at the time of national treatment policy change.</p> <p>Conclusion</p> <p>The results show the overall level of anti-malarial prescription in the study area for a considerable number of patients over a large period of time. Even though resistance to CQ rapidly increased from 1992 to 2001, no change in CQ prescription was observed until the early 2000s, possibly due to the absence of an obvious decrease in CQ effectiveness, a lack of therapeutic options or a blind follow-up of national guidelines.</p

A full year of aerosol size distribution data from the central Arctic under an extreme positive Arctic Oscillation : insights from the Multidisciplinarydrifting Observatory for the Study of Arctic Climate (MOSAiC) expedition

The Arctic environment is rapidly changing due to accelerated warming in the region. The warming trend is driving a decline in sea ice extent, which thereby enhances feedback loops in the surface energy budget in the Arctic. Arctic aerosols play an important role in the radiative balance and hence the climate response in the region, yet direct observations of aerosols over the Arctic Ocean are limited. In this study, we investigate the annual cycle in the aerosol particle number size distribution (PNSD), particle number concentration (PNC), and black carbon (BC) mass concentration in the central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. This is the first continuous, year-long data set of aerosol PNSD ever collected over the sea ice in the central Arctic Ocean. We use a k-means cluster analysis, FLEXPART simulations, and inverse modeling to evaluate seasonal patterns and the influence of different source regions on the Arctic aerosol population. Furthermore, we compare the aerosol observations to land-based sites across the Arctic, using both long-term measurements and observations during the year of the MOSAiC expedition (2019-2020), to investigate interannual variability and to give context to the aerosol characteristics from within the central Arctic. Our analysis identifies that, overall, the central Arctic exhibits typical seasonal patterns of aerosols, including anthropogenic influence from Arctic haze in winter and secondary aerosol processes in summer. The seasonal pattern corresponds to the global radiation, surface air temperature, and timing of sea ice melting/freezing, which drive changes in transport patterns and secondary aerosol processes. In winter, the Norilsk region in Russia/Siberia was the dominant source of Arctic haze signals in the PNSD and BC observations, which contributed to higher accumulation-mode PNC and BC mass concentrations in the central Arctic than at land-based observatories. We also show that the wintertime Arctic Oscillation (AO) phenomenon, which was reported to achieve a record-breaking positive phase during January-March 2020, explains the unusual timing and magnitude of Arctic haze across the Arctic region compared to longer-term observations. In summer, the aerosol PNCs of the nucleation and Aitken modes are enhanced; however, concentrations were notably lower in the central Arctic over the ice pack than at land-based sites further south. The analysis presented herein provides a current snapshot of Arctic aerosol processes in an environment that is characterized by rapid changes, which will be crucial for improving climate model predictions, understanding linkages between different environmental processes, and investigating the impacts of climate change in future Arctic aerosol studies.Peer reviewe