12 research outputs found
Combining TopâDown and BottomâUp Approaches to Evaluate Recent Trends and Seasonal Patterns in UK N2O Emissions
Atmospheric trace gas measurements can be used to independently assess national greenhouse
gas inventories through inverse modeling. Atmospheric nitrous oxide (N2O) measurements made in the United
Kingdom (UK) and Republic of Ireland are used to derive monthly N2O emissions for 2013â2022 using two
different inverse methods. We find mean UK emissions of 90.5 ± 23.0 (1Ï) and 111.7 ± 32.1 (1Ï) Gg N2O yrâ 1
for 2013â2022, and corresponding trends of â 0.68 ± 0.48 (1Ï) Gg N2O yrâ 2 and â 2.10 ± 0.72 (1Ï) Gg N2O
yrâ 2
, respectively, for the two inverse methods. The UK National Atmospheric Emissions Inventory (NAEI)
reported mean N2O emissions of 73.9 ± 1.7 (1Ï) Gg N2O yrâ 1 across this period, which is 22%â51% smaller
than the emissions derived from atmospheric data. We infer a pronounced seasonal cycle in N2O emissions, with
a peak occurring in the spring and a second smaller peak in the late summer for certain years. The springtime
peak has a long seasonal decline that contrasts with the sharp rise and fall of N2O emissions estimated from the
bottomâup UK Emissions Model (UKEM). Bayesian inference is used to minimize the seasonal cycle mismatch
between the average topâdown (atmospheric dataâbased) and bottomâup (process model and inventoryâbased)
seasonal emissions at a subâsector level. Increasing agricultural manure management and decreasing synthetic
fertilizer N2O emissions reduces some of the discrepancy between the average topâdown and bottomâup
seasonal cycles. Other possibilities could also explain these discrepancies, such as missing emissions from NH3
deposition, but these require further investigation
Intraspecies Variation in the Emergence of Hyperinfectious Bacterial Strains in Nature
Salmonella is a principal health concern because of its endemic prevalence in food and water supplies, the rise in incidence of multi-drug resistant strains, and the emergence of new strains associated with increased disease severity. Insights into pathogen emergence have come from animal-passage studies wherein virulence is often increased during infection. However, these studies did not address the prospect that a select subset of strains undergo a pronounced increase in virulence during the infective process- a prospect that has significant implications for human and animal health. Our findings indicate that the capacity to become hypervirulent (100-fold decreased LD50) was much more evident in certain S. enterica strains than others. Hyperinfectious salmonellae were among the most virulent of this species; restricted to certain serotypes; and more capable of killing vaccinated animals. Such strains exhibited rapid (and rapidly reversible) switching to a less-virulent state accompanied by more competitive growth ex vivo that may contribute to maintenance in nature. The hypervirulent phenotype was associated with increased microbial pathogenicity (colonization; cytotoxin production; cytocidal activity), coupled with an altered innate immune cytokine response within infected cells (IFN-ÎČ; IL-1ÎČ; IL-6; IL-10). Gene expression analysis revealed that hyperinfectious strains display altered transcription of genes within the PhoP/PhoQ, PhoR/PhoB and ArgR regulons, conferring changes in the expression of classical virulence functions (e.g., SPI-1; SPI-2 effectors) and those involved in cellular physiology/metabolism (nutrient/acid stress). As hyperinfectious strains pose a potential risk to human and animal health, efforts toward mitigation of these potential food-borne contaminants may avert negative public health impacts and industry-associated losses
Nighttime sleep duration and hedonic eating in childhood
Higher food intake is implicated in the elevated risk of obesity associated with shorter sleep in children, but the mechanisms driving higher intake are uncertain. Research in adults suggests that acute sleep deprivation affects brain reward systems, which increases responsiveness to palatable foods. However, there have been few studies addressing habitual sleep duration, and few in children, among whom the strongest associations with body mass index (BMI) are seen