Determining the Role of Point-of-Care Hemoglobin Testing in the Resuscitation of Acutely Hemorrhaging Patients

Point-of-care hemoglobin (Hb) testing has not been evaluated in the resuscitation of acutely hemorrhaging patients to guide transfusion therapy. This study assessed the correlation of Hb values determined by point-of-care (EPOC) and traditional laboratory (CBC) methods in patients undergoing massive transfusion. All patients transfused per the massive transfusion protocol (MTP) between February 2013 and October 2017 were identified. The EPOC result was most often within 1 g/dL of the CBC result when EPOC resulted in a Hb between 7-10 g/dL and when drawn within 15 minutes of the CBC specimen. In patients on MTP with an EPOC Hb between 7-10 g/dL, intensivists should feel comfortable making decisions related to transfusion therapy without waiting for the CBC result

Galactic annihilation emission from nucleosynthesis positrons

The Galaxy hosts a widespread population of low-energy positrons revealed by successive generations of gamma-ray telescopes through a bright annihilation emission from the bulge region, with a fainter contribution from the inner disk. The exact origin of these particles remains currently unknown. We estimate the contribution to the annihilation signal of positrons generated in the decay of radioactive 26Al, 56Ni and 44Ti. We adapted the GALPROP propagation code to simulate the transport and annihilation of radioactivity positrons in a model of our Galaxy. Using plausible source spatial distributions, we explored several possible propagation scenarios to account for the large uncertainties on the transport of ~1MeV positrons in the interstellar medium. We then compared the predicted intensity distributions to the INTEGRAL/SPI observations. We obtain similar intensity distributions with small bulge-to-disk ratios, even for extreme large-scale transport prescriptions. At least half of the positrons annihilate close to their sources, even when they are allowed to travel far away. In the high-diffusion, ballistic case, up to 40% of them escape the Galaxy. In proportion, this affects bulge positrons more than disk positrons because they are injected further off the plane in a tenuous medium, while disk positrons are mostly injected in the dense molecular ring. The predicted intensity distributions are fully consistent with the observed longitudinally-extended disk-like emission, but the transport scenario cannot be strongly constrained by the current data. Nucleosynthesis positrons alone cannot account for the observed annihilation emission in the frame of our model. An additional component is needed to explain the strong bulge contribution, and the latter is very likely concentrated in the central regions if positrons have initial energies in the 100keV-1MeV range.Comment: 16 pages, 7 figures, accepted for publication in A&

Using Spaced Learning Principles to Translate Knowledge into Behavior: Evidence from Investigative Interviews of Alleged Child Abuse Victims

The present study assessed the progress of 13 investigative interviewers (child protection workers and police officers) before, during, and after an intensive training program (n = 132 interviews). Training began with a 2-day workshop covering the principles of child development and child-friendly interviewing. Interviewers then submitted interviews on a bi-weekly basis to which they received written and verbal feedback over an 8-month period. A refresher session took place two months into training. Interestingly, improvements were observed only after the refresher session. Interviews conducted post-refresher training contained proportionally more open-ended questions, more child details in response to open-ended questions, and proportionally fewer closed questions than interviews conducted prior to training and in the first half of the training program. The need for ‘spaced learning’ may underlie why so many training programs have had little effect on practice

Algebra of chiral currents on the physical surface

Using a particular structure for the Lagrangian action in a one-dimensional Thirring model and performing the Dirac's procedure, we are able to obtain the algebra for chiral currents which is entirely defied on the constraint surface in the corresponding hamiltonian description of the theory.Comment: 10 page

An ecological-physiology perspective on seabird responses to contemporary and historic environmental change

Thesis (Ph.D.) University of Alaska Fairbanks, 2017The chapters included in this dissertation implement an ecological-physiology approach to understanding how long-lived marine organisms, using seabirds as a model, respond to changes in the environment. Many seabird populations are governed by bottom-up processes, yet efforts to connect prey dynamics and parameters such as breeding performance often yield mixed results. Here I examined how individual foraging behavior and nutritional status change at the inter-annual, decadal, and multi-decadal scale. I validated that the concentration of the avian stress hormone in seabird feathers is indicative of their exposure to nutritional stress. I then used this technique to show that young seabirds (Rhinoceros auklets, Cerorhinca monocerata) that experience variable foraging conditions during their prolonged nestling period incurred higher nutritional stress when provisioned with prey that was relatively low in energy content. On the other hand, when examining adult foraging behavior, a signal of environmental variability was lost in the noise of changing diets. Foraging behavior of adults appeared to be highly flexible and less informative in regard to detecting an environmental change. I used stable isotope analysis to re-construct the isotopic niche dynamics (where and at what trophic level seabirds were obtaining prey) and partitioning of food resources for three abundant seabirds (common and thick-billed murres, Uria aalge, and U. lomvia, respectively; and black-legged kittiwakes, Rissa tridactyla) breeding in the southeastern Bering Sea under cold and warm states of the ecosystem. Access to diverse habitat reversed how seabirds partitioned prey during food shortages: seabirds with access to multiple habitats contracted their isotopic niche during food-limited conditions in contrast to the expansion of the isotopic niche observed for seabirds with access to only one type of habitat. Finally, I measured nutritional stress and stable isotope signatures (carbon and nitrogen) in contemporary and historic red-legged kittiwake (Rissa brevirostris) feather samples to examine how birds breeding on St. George Island have responded to changes in summer and winter conditions in the Bering Sea over time. Red-legged kittiwakes were less nutritionally stressed during warm summers and winters. It is not clear, however, whether all seabirds would do well if the Bering Sea were to break with its pattern of oscillating between warm and cold conditions. Prey for these birds may either be negatively affected by continuously warm conditions (murres and black-legged kittiwakes feeding on juvenile pollock, Gadus chalcogrammus) or the conditions that are most beneficial to the prey are not known (red-legged kittiwakes feeding on myctophids). With this work I suggest that measuring nutritional stress in feathers and using stable isotope analysis to characterize foraging niches may document more dynamic responses to changes in the environment than population level parameters such as breeding performance. To do so, however, requires a better understanding of the relationship between these individual-level responses and fitness.General Introduction -- Chapter 2: Feather Corticosterone Reveals Stress Associated with Dietary Changes in a Breeding Seabird -- Chapter 3: Variability in Trophic Level and Habitat Use in Response to Environmental Forcing: Isotopic Niche Dynamics of Breeding Seabirds in the Southeastern Bering Sea -- Chapter 4: Red-legged Kittiwake Feathers Link Food Availability to Environmental Changes in the Bering Sea Basin Over a 100 Year Period -- General Conclusion -- Appendices