Five-thousand years of hydroclimate variability on Adak Island, Alaska inferred from δD of n-alkanoic acids

Hydrogen isotope ratios (δD) in various types of leaf waxes, including n-alkanoic acids, extracted from lacustrine sediments are becoming increasingly popular for understanding past climate changes. Leaf-wax δD values track precipitation δD, and provided that controls on precipitation δD are known, changes in leaf wax δD can be used to reconstruct these changes in the past. Seventy-six sediment samples from Andrew Lake, Adak Island, Alaska, extending to 4800 years ago (4.8 ka) were analyzed for δD of n-alkanoic acids. δD values of isolated C28 n-alkanoic acids show a strong inverse correlation with October-May storminess (days with >19 mm of precipitation) over the meteorological record (r2 = 0.58, p < 0.02), and a similarly strong correlation with total precipitation amount. This implies that isotopes in precipitation on Adak Island are strongly influenced by the amount effect. Shifts in precipitation amount and storminess are associated with shifts in the North Pacific hydroclimate, which is driven by the Aleutian Low during fall and winter. Low δD values indicate high precipitation amount/storminess on Adak Island, which correlates well to a weak or westward Aleutian Low as inferred from other sites, while high δD values indicate lower precipitation amount and generally correlate with a stronger or more eastward Aleutian Low. Results from Adak Island were combined with evidence from previously published paleoclimate studies from southern Alaska and the Yukon to reveal a more complete spatial picture of hydroclimatological changes for the last 5000 years. Variability in δD since 3.5 ka is related to changes in North Pacific atmospheric circulation patterns including the Aleutian Low. High precipitation amount/storminess during the Medieval Climate Anomaly (∼850 to 1050 AD) on Adak Island is consistent with evidence from other studies that suggest a weakened Aleutian Low. Evidence of decrease precipitation during the early Little Ice Age (∼1200 to 1500 AD) gave way to wetter conditions during the latter half (∼1500 to 1900 AD). A wet late LIA is consistent with the results from coastal studies in southern Alaska, suggesting another period of a weakened Aleutian Low. This study is part of a multi-proxy investigation involving two lakes on Adak Island including analyses of pollen, biogenic silica, chironomids, isotopes in diatoms, and other proxies to help increase our knowledge about past hydroclimate in the North Pacific

Pain Assessment and Narcotic Abuse in Veterans

Narcotic substance abuse is resulting from previously deployed veterans suffering from pain, which contributes to the overall opioid crisis in America. Our research question is, in veterans, what is the effect of pain on narcotic abuse? This topic has been widely discussed and is gaining research; however, many facilities lack the knowledge and resources to adequately assess pain in veterans. A study found that 32% of veterans had at least one opioid prescribed for pain management. We obtained our information through a systematic review of literature. More education on pain relief alternatives should be taught to health care providers to prevent the prolonged suffering of veterans. We created a protocol that that will be useful in helping nurses to determine when opioid use is appropriate and when to use alternative options

A mild Little Ice Age and unprecedented warmth in an 1800 year record from Svalbard

The Arctic region is subject to a great amplitude of climate variability and is currently undergoing large-scale changes due in part to anthropogenic global warming. Accurate projections of future change depend on anticipating the response of the Arctic climate system to forcing, and understanding how the response to human forcing will interact with natural climate variations. The Svalbard Archipelago occupies an important location for studying patterns and causes of Arctic climate variability; however, available paleoclimate records from Svalbard are of restricted use due to limitations of existing climate proxies. Here we present a sub-decadal- to multidecadal-scale record of summer temperature for the past 1800 yr from lake sediments of Kongressvatnet on West Spitsbergen, Svalbard, based on the fi rst instrumental calibration of the alkenone paleothermometer. The age model for the High Arctic lake sediments is based on 210Pb, plutonium activity, and the first application of tephrochronology to lake sediments in this region. We fi nd that the summer warmth of the past 50 yr recorded in both the instrumental and alkenone records was unmatched in West Spitsbergen in the course of the past 1800 yr, including during the Medieval Climate Anomaly, and that summers during the Little Ice Age (LIA) of the 18th and 19th centuries on Svalbard were not particularly cold, even though glaciers occupied their maximum Holocene extent. Our results suggest that increased wintertime precipitation, rather than cold temperatures, was responsible for LIA glaciations on Svalbard and that increased heat transport into the Arctic via the West Spitsbergen Current began ca. A.D. 1600