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- Ameen, Carly, et al.
(author)
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Specialized sledge dogs accompanied Inuit dispersal across the North American Arctic
- 2019
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In: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 286:1916
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Journal article (peer-reviewed)abstract
- Domestic dogs have been central to life in the North American Arctic for millennia. The ancestors of the Inuit were the first to introduce the widespread usage of dog sledge transportation technology to the Americas, but whether the Inuit adopted local Palaeo-Inuit dogs or introduced a new dog population to the region remains unknown. To test these hypotheses, we generated mitochondrial DNA and geometric morphometric data of skull and dental elements from a total of 922 North American Arctic dogs and wolves spanning over 4500 years. Our analyses revealed that dogs from Inuit sites dating from 2000 BP possess morphological and genetic signatures that distinguish them from earlier Palaeo-Inuit dogs, and identified a novel mitochondrial clade in eastern Siberia and Alaska. The genetic legacy of these Inuit dogs survives today in modern Arctic sledge dogs despite phenotypic differences between archaeological and modern Arctic dogs. Together, our data reveal that Inuit dogs derive from a secondary pre-contact migration of dogs distinct from Palaeo-Inuit dogs, and probably aided the Inuit expansion across the North American Arctic beginning around 1000 BP.
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| 2. |
- Bentzer, Peter, et al.
(author)
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Will this hemodynamically unstable patient respond to a bolus of intravenous fluids?
- 2016
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In: JAMA: The Journal of the American Medical Association. - : American Medical Association (AMA). - 0098-7484. ; 316:12, s. 1298-1309
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Journal article (peer-reviewed)abstract
- IMPORTANCE Fluid overload occurring as a consequence of overly aggressive fluid resuscitation may adversely affect outcome in hemodynamically unstable critically ill patients. Therefore, following the initial fluid resuscitation, it is important to identify which patients will benefit from further fluid administration. OBJECTIVE To identify predictors of fluid responsiveness in hemodynamically unstable patients with signs of inadequate organ perfusion. DATA SOURCES AND STUDY SELECTION Search of MEDLINE and EMBASE (1966 to June 2016) and reference lists from retrieved articles, previous reviews, and physical examination textbooks for studies that evaluated the diagnostic accuracy of tests to predict fluid responsiveness in hemodynamically unstable adult patients who were defined as having refractory hypotension, signs of organ hypoperfusion, or both. Fluid responsiveness was defined as an increase in cardiac output following intravenous fluid administration. DATA EXTRACTION Two authors independently abstracted data (sensitivity, specificity, and likelihood ratios [LRs]) and assessed methodological quality. A bivariate mixed-effects binary regression model was used to pool the sensitivities, specificities, and LRs across studies. RESULTS A total of 50 studies (N = 2260 patients) were analyzed. In all studies, indices were measured before assessment of fluid responsiveness. The mean prevalence of fluid responsiveness was 50% (95%CI, 42%-56%). Findings on physical examination were not predictive of fluid responsiveness with LRs and 95%CIs for each finding crossing 1.0. A low central venous pressure (CVP) (mean threshold 8mmHg) was associated with fluid responsiveness (positive LR, 2.6 [95%CI, 1.4-4.6]; pooled specificity, 76%), but a CVP greater than the threshold made fluid responsiveness less likely (negative LR, 0.50 [95%CI, 0.39-0.65]; pooled sensitivity, 62%). Respiratory variation in vena cava diameter measured by ultrasound (distensibility index >15%) predicted fluid responsiveness in a subgroup of patients without spontaneous respiratory efforts (positive LR, 5.3 [95%CI, 1.1-27]; pooled specificity, 85%). Patients with less vena cava distensibility were not as likely to be fluid responsive (negative LR, 0.27 [95%CI, 0.08-0.87]; pooled sensitivity, 77%). Augmentation of cardiac output or related parameters following passive leg raising predicted fluid responsiveness (positive LR, 11 [95%CI, 7.6-17]; pooled specificity, 92%). Conversely, the lack of an increase in cardiac output with passive leg raising identified patients unlikely to be fluid responsive (negative LR, 0.13 [95%CI, 0.07-0.22]; pooled sensitivity, 88%). CONCLUSIONS AND RELEVANCE Passive leg raising followed by measurement of cardiac output or related parameters may be the most useful test for predicting fluid responsiveness in hemodynamically unstable adults. The usefulness of respiratory variation in the vena cava requires confirmatory studies.
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| 4. |
- Suggitt, Andrew J., et al.
(author)
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Extinction risk from climate change is reduced by microclimatic buffering
- 2018
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In: Nature Climate Change. - : Springer Science and Business Media LLC. - 1758-678X .- 1758-6798. ; 8:8, s. 713-
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Journal article (peer-reviewed)abstract
- Protecting biodiversity against the impacts of climate change requires effective conservation strategies that safeguard species at risk of extinction(1). Microrefugia allowed populations to survive adverse climatic conditions in the past(2,3), but their potential to reduce extinction risk from anthropogenic warming is poorly understood(3-5), hindering our capacity to develop robust in situ measures to adapt conservation to climate change(6). Here, we show that microclimatic heterogeneity has strongly buffered species against regional extirpations linked to recent climate change. Using more than five million distribution records for 430 climate-threatened and range-declining species, population losses across England are found to be reduced in areas where topography generated greater variation in the microclimate. The buffering effect of topographic microclimates was strongest for those species adversely affected by warming and in areas that experienced the highest levels of warming: in such conditions, extirpation risk was reduced by 22% for plants and by 9% for insects. Our results indicate the critical role of topographic variation in creating microrefugia, and provide empirical evidence that microclimatic heterogeneity can substantially reduce extinction risk from climate change.
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