12 research outputs found
Tusk or Bone? An Example of Ivory Substitute in the Wildlife Trade
Bone carvings (and other ivory substitutes) are common in the modern-day lucrative international ivory trade. Souvenirs for unknowing travelers and market shoppers can be made of non-biological material (plastic "ivory" beads) or skillfully crafted natural objects made to resemble something other than their true origin. Many of these items are received at the U. S. National Fish and Wildlife Forensics Laboratory (NFWFL) for species identification as part of law enforcement investigations. Morphologists at the Lab often receive uniquely carved ivory items that have been imported with little or no documentation. In recent years, analysts examined several purported ivory tusks suspected to be walrus, a protected marine mammal. After examination, the Lab determined their origin as carved leg bones of cattle using principles and methods of zooarchaeology and ancient DNA analysis. The naturally long and straight ungulate metapodials had been cut, carved, filled, stained, and polished to closely resemble unmodified ivory tusks. Morphological species identification of these bones proved to be a challenge since diagnostic characters of the bones had been altered and country of origin was unknown. Genetic analysis showed that the bones originated from cattle. While bone is commonly used as a substitute for ivory, this style of artifact was not previously documented in the wildlife trade prior to our analysis. Archaeological ethnobiologists commonly encounter bone tools and other forms of material culture from prehistoric and historic contexts; in this case bone tools come from a modern context, thus the application of methods common in zooarchaeology are situated in wildlife forensics. In addition, results reported here pertain to cross-cultural ivory trade and conservation science.</p
Author Correction: Non-local effect of impurity states on the exchange coupling mechanism in magnetic topological insulators
A Correction to this paper has been published: https://doi.org/10.1038/s41535-021-00314-
Computational prediction and experimental realisation of earth abundant transparent conducting oxide Ga-doped ZnSb2O6
Transparent conducting oxides have become ubiquitous in modern opto-electronics. However, the number of oxides that are transparent to visible light and have the metallic-like conductivity necessary for applications is limited to a handful of systems that have been known for the past forty years. In this work, we use hybrid density functional theory and defect chemistry analysis to demonstrate that tri-rutile zinc antimonate, ZnSb2O6, is an ideal transparent conducting oxide, and identify gallium as the optimal dopant to yield high conductivity and transparency. To validate our computational predictions, we have synthesised both powder samples and single crystals of Ga-doped ZnSb2O6 which conclusively show behaviour consistent with a degenerate transparent conducting oxide. This study demonstrates the possibility of a family of Sb(V) containing oxides for transparent conducting oxide and power electronics applications
Computational Prediction and Experimental Realization of Earth-Abundant Transparent Conducting Oxide Ga-Doped ZnSb<sub>2</sub>O<sub>6</sub>
[Image: see text] Transparent conducting oxides have become ubiquitous in modern optoelectronics. However, the number of oxides that are transparent to visible light and have the metallic-like conductivity necessary for applications is limited to a handful of systems that have been known for the past 40 years. In this work, we use hybrid density functional theory and defect chemistry analysis to demonstrate that tri-rutile zinc antimonate, ZnSb(2)O(6), is an ideal transparent conducting oxide and to identify gallium as the optimal dopant to yield high conductivity and transparency. To validate our computational predictions, we have synthesized both powder samples and single crystals of Ga-doped ZnSb(2)O(6) which conclusively show behavior consistent with a degenerate transparent conducting oxide. This study demonstrates the possibility of a family of Sb(V)-containing oxides for transparent conducting oxide and power electronics applications
High-Resolution Inelastic X-Ray Scattering I: Context, Spectrometers, Samples, and Superconductors
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Predictors of Outcomes in Patients With Mild Ischemic Stroke Symptoms: MaRISS
Background and Purpose: Although most strokes present with mild symptoms, these have been poorly represented in clinical trials. The objective of this study is to describe multidimensional outcomes, identify predictors of worse outcomes, and explore the effect of thrombolysis in this population. Methods: This prospective observational study included patients with ischemic stroke or transient ischemic attack, a baseline National Institutes of Health Stroke Scale (NIHSS) score 0 to 5, presenting within 4.5 hours from symptom onset. The primary outcome was a 90-day modified Rankin Scale score of 0 to 1; secondary outcomes included good outcomes in the Barthel Index, Stroke Impact Scale-16, and European Quality of Life. Multivariable models were created to determine predictors of outcomes and the effect of alteplase. Results: A total of 1765 participants were included from 100 Get With The Guidelines-Stroke participating hospitals (age, 65±14; 42% women; final diagnosis of ischemic stroke, 90%; transient ischemic attack, 10%; 57% received alteplase). At 90 days, 37% were disabled and 25% not independent. Worse outcomes were noted for older individuals, women, non-Hispanic Blacks and Hispanics, Medicaid recipients, smokers, those with diabetes, atrial fibrillation, prior stroke, higher baseline NIHSS, visual field defects, and extremity weakness. Similar outcomes were noted for the alteplase-treated and untreated groups. Alteplase-treated patients were younger (64±13 versus 67±1.4) with higher NIHSS (2.9±1.4 versus 1.7±1.4). After adjusting for age, sex, race/ethnicity, and baseline NIHSS, we did not identify an effect of alteplase on the primary outcome but did find an association with Stroke Impact Scale-16 in the restricted sample of baseline NIHSS score 3–5. Few symptomatic intracerebral hemorrhages were recorded (<1%). Conclusions: A large proportion of stroke patients presenting with low NIHSS have a disabled outcome. Baseline predictors of worse outcomes are described. An effect of alteplase on outcomes was not identified in the overall cohort, but a suggestion of efficacy was noted in the NIHSS 3–5 subgroup. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02072681