Relative adrenal insufficiency in dogs with sepsis

BACKGROUND: A syndrome of relative adrenal insufficiency has been identified in septic humans, and is associated with hypotension and death. Relative adrenal insufficiency is generally associated with basal serum cortisol concentration within or above the reference range and a blunted cortisol response to adrenocorticotropic hormone administration. It is unknown whether relative adrenal insufficiency occurs in septic dogs. HYPOTHESIS: That relative adrenal insufficiency occurs in septic dogs, and that relative adrenal insufficiency is associated with hypotension and mortality. ANIMALS: Thirty-three septic dogs admitted to a small animal intensive care unit. METHODS: Dogs were included in the study if they had a known or suspected infectious disease and had systemic inflammatory response syndrome. Dogs were excluded if they had disease or medication history expected to affect the hypothalamic-pituitary-adrenal axis. Serum cortisol and endogenous plasma adrenocorticotropic hormone concentrations were measured before, and serum cortisol concentration measured 1 hour after, intramuscular administration of 250 microg of cosyntropin/dog. The change in cortisol concentration (delta-cortisol) before and after cosyntropin administration was determined in each dog. RESULTS: Hypotension was associated with lower delta-cortisol values (OR 1.3; CI 1.0-1.9; P = .029). delta-Cortisol cutoff of 3.0 microg/dL was most accurate for predicting hypotension, survival to discharge, and 28-day survival. The rate of death in dogs with delta-cortisol < or = 3 microg/dL was 4.1 times that of dogs with delta-cortisol > 3 microg/dL (RR 4.1; CI 1.5-12.3; P = .01). CONCLUSIONS AND CLINICAL RELEVANCE: Delta-cortisol < or = 3 microg/dL after adrenocorticotropic hormone administration is associated with systemic hypotension and decreased survival in septic dogs.     

铅锌尾矿中砷代谢功能基因的多样性

Microbial activities impact arsenic (As) transformation in mine tailings substantially,yet little is understood on the functional diversity of As metabolism genes.This study explored this issue using a metagenomic approach coupled by a local BLASTN procedure established in our recent studies.An assembled metagenome,recovered from hypersaline and sulfidic mine tailings,was screened for As metabolism genes aioA,arrA,arsC and arsM.This was done using a local BLASTN procedure against databases of the As metabolism genes built in this study.Putative As metabolism genes detected in the assembled metagenome included 11 arsM,20 arsC and 1 arrA full-length sequences.Together with the rRNA-based phylogenetic profiling results,a picture depicting microbial As cycling in the tailings to the genus level was obtained.It was found that most of the dominant genera in the tailings potentially harboured the genes for As reduction and/or methylation.In particular,a typical pyrite-eater present in the tailings,Thioalkalivibrio sp.,was found to harbour not only arsC and arsM,but also arrA.These results highlight the unexpected diversity of As metabolism genes in the tailings,especially considering the extremely low species diversity therein.The microbial As cycling picture established here has potential use for guiding the purposeful manipulation of As biogeochemistry in the tailings.     

A quantitative method for measuring regional economic resilience to the great recession

Regional economic resilience can be defined as an economy’s ability to withstand and recover quickly from shocks. The ability to measure resilience is necessary to developing our understanding of what influences resilience. In this paper, we develop a new, two‐dimensional quantitative measure of resilience using observed differences between expected and actual employment in a region following a shock and distinguish the response to the shock from random variation. We demonstrate one application of this metric to US county‐level employment data to compare county responses to the 2007–2009 national recession and discuss how different regions of the United States responded to the shock of the Great Recession in terms of resilience.     

Forest succession and climate variability interacted to control fire activity over the last four centuries in an Alaskan boreal landscape

Context

The boreal forest is globally important for its influence on Earth’s energy balance, and its sensitivity to climate change. Ecosystem functioning in boreal forests is shaped by fire activity, so anticipating the impacts of climate change requires understanding the precedence for, and consequences of, climatically induced changes in fire regimes. Long-term records of climate, fire, and vegetation are critical for gaining this understanding.

Objectives

We investigated the relative importance of climate and landscape flammability as drivers of fire activity in boreal forests by developing high-resolution records of fire history, and characterizing their centennial-scale relationships to temperature and vegetation dynamics.

Methods

We reconstructed the timing of fire activity in interior Alaska, USA, using seven lake-sediment charcoal records spanning CE 1550–2015. We developed individual and composite records of fire activity, and used correlations and qualitative comparisons to assess relationships with existing records of vegetation and climate.

Results

Our records document a dynamic relationship between climate and fire. Fire activity and temperature showed stronger coupling after ca. 1900 than in the preceding 350 yr. Biomass burning and temperatures increased concurrently during the second half of the twentieth century, to their highest point in the record. Fire activity followed pulses in black spruce establishment.

Conclusions

Fire activity was facilitated by warm temperatures and landscape-scale dominance of highly flammable mature black spruce, with a notable increase in temperature and fire activity during the twenty-first century. The results suggest that widespread burning at landscape scales is controlled by a combination of climate and vegetation dynamics that together drive flammability.