Effects of soil warming and nitrogen foliar applications on bud burst of black spruce

Key message: In mature black spruce, bud burst process is anticipated by soil warming, while delayed by foliar applications of nitrogen; however, the effects depend on growth conditions at the site. Abstract: The observation of phenological events can be used as biological indicator of environmental changes, especially from the perspective of climate change. In boreal forests, the onset of the bud burst is a key factor in the length of the growing season. With current climate change, the major factors limiting the growth of boreal trees (i.e., temperature and nitrogen availability) are changing and studies on mature trees are limited. The aim of this study was to investigate the effects of soil warming and increased nitrogen (N) deposition on bud burst of mature black spruce [Picea mariana (Mill.) BSP]. From 2008 onwards, an experimental manipulation of these environmental growth conditions was conducted in two stands (BER and SIM) at different altitudes in the boreal forest of Quebec, Canada. An increase in soil temperature (H treatment) and a canopy application of artificial rain enriched with nitrogen (N treatment) were performed. Observations of bud phenology were made during May–July 2012 and 2013. In BER, H treatment caused an anticipation (estimated as 1–3 days); while N treatment, a delay (estimated as 1–2 days but only in 2012) in bud burst. No treatments effect was significant in SIM. It has been demonstrated that soil temperature and N availability can play an important role in affecting bud burst in black spruce but the effects of these environmental factors on growth are closely linked with site conditions

The effects of N-enriched rain and warmer soil on the ectomycorrhizae of black spruce remain inconclusive in the short term

International audienc

Effect of hydrolyzed infant formula vs conventional formula on risk of type 1 diabetes the TRIGR randomized clinical trial

IMPORTANCE Early exposure to complex dietary proteins may increase the risk of type 117 diabetes in children with genetic disease susceptibility. There are no intact proteins in extensively hydrolyzed formulas. OBJECTIVE To test the hypothesis that weaning to an extensively hydrolyzed formula decreases the cumulative incidence of type 117 diabetes in young children. DESIGN, SETTING, AND PARTICIPANTS An international double-blind randomized clinical trial of 211759 infants with human leukocyte antigen-conferred disease susceptibility and a first-degree relative with type 117 diabetes recruited from May 2002 to January 2007 in 78 study centers in 1175 countries; 11708117 were randomized to be weaned to the extensively hydrolyzed casein formula and 117078 to a conventional formula. The follow-up of the participants ended on February 28, 201177. INTERVENTIONS The participants received either a casein hydrolysate or a conventional adapted cow's milk formula supplemented with 20%of the casein hydrolysate. The minimum duration ofstudy formula exposure was 60 days by6 to 8 months ofage. MAINOUTCOMES ANDMEASURES Primary outcome was type 117 diabetes diagnosed according to World Health Organization criteria. Secondary outcomes included age at diabetes diagnosis and safety (adverse events). RESULTS Among 211759 newborn infants (11702117 female [47.3%]) who were randomized, 117744 (80.8%) completed the trial. The participants were observed for a median of 117117.5 years (quartile [Q] 117-Q3, 1170.2-1172.8). The absolute risk of type 117 diabetes was 8.4% among those randomized tothe casein hydrolysate (n = 9117) vs 7.6% among those randomized to the conventional formula (n = 82) (difference, 0.8% [95% CI, -117.6% to 3.2%]). The hazard ratio for type 117 diabetes adjusted for human leukocyte antigen risk group, duration of breastfeeding, duration of study formula consumption, sex, and region while treating study center as a random effect was 117.117 (95% CI, 0.8 to 117.5; P =.46). The median age at diagnosis of type 117 diabetes was similar in the 2 groups (6.0 years [Q117-Q3, 3.117-8.9] vs 5.8 years [Q117-Q3, 2.6-9.117]; difference, 0.2 years [95% CI, -0.9 to 117.2]). Upper respiratory infections were the most common adverse event reported (frequency, 0.48 events/year in the hydrolysate group and 0.50 events/year in the control group). CONCLUSIONS AND RELEVANCE Among infants at risk for type 117 diabetes, weaning to a hydrolyzed formula compared with a conventional formula did not reduce the cumulative incidence of type 117 diabetes after median follow-up for 117117.5 years. These findings do not support a need to revise the dietary recommendations for infants at risk for type 117 diabetes