Aridity and hominin environments.

Aridification is often considered a major driver of long-term ecological change and hominin evolution in eastern Africa during the Plio-Pleistocene; however, this hypothesis remains inadequately tested owing to difficulties in reconstructing terrestrial paleoclimate. We present a revised aridity index for quantifying water deficit (WD) in terrestrial environments using tooth enamel δ18O values, and use this approach to address paleoaridity over the past 4.4 million years in eastern Africa. We find no long-term trend in WD, consistent with other terrestrial climate indicators in the Omo-Turkana Basin, and no relationship between paleoaridity and herbivore paleodiet structure among fossil collections meeting the criteria for WD estimation. Thus, we suggest that changes in the abundance of C4 grass and grazing herbivores in eastern Africa during the Pliocene and Pleistocene may have been decoupled from aridity. As in modern African ecosystems, other factors, such as rainfall seasonality or ecological interactions among plants and mammals, may be important for understanding the evolution of C4 grass- and grazer-dominated biomes.

Succinylcholine Use and Dantrolene Availability for Malignant Hyperthermia Treatment: Database Analyses and Systematic Review.

BACKGROUND: Although dantrolene effectively treats malignant hyperthermia (MH), discrepant recommendations exist concerning dantrolene availability. Whereas Malignant Hyperthermia Association of the United States guidelines state dantrolene must be available within 10 min of the decision to treat MH wherever volatile anesthetics or succinylcholine are administered, a Society for Ambulatory Anesthesia protocol permits Class B ambulatory facilities to stock succinylcholine for airway rescue without dantrolene. The authors investigated (1) succinylcholine use rates, including for airway rescue, in anesthetizing/sedating locations; (2) whether succinylcholine without volatile anesthetics triggers MH warranting dantrolene; and (3) the relationship between dantrolene administration and MH morbidity/mortality. METHODS: The authors performed focused analyses of the Multicenter Perioperative Outcomes Group (2005 through 2016), North American MH Registry (2013 through 2016), and Anesthesia Closed Claims Project (1970 through 2014) databases, as well as a systematic literature review (1987 through 2017). The authors used difficult mask ventilation (grades III and IV) as a surrogate for airway rescue. MH experts judged dantrolene treatment. For MH morbidity/mortality analyses, the authors included U.S. and Canadian cases that were fulminant or scored 20 or higher on the clinical grading scale and in which volatile anesthetics or succinylcholine were given. RESULTS: Among 6,368,356 queried outcomes cases, 246,904 (3.9%) received succinylcholine without volatile agents. Succinylcholine was used in 46% (n = 710) of grade IV mask ventilation cases (median dose, 100 mg, 1.2 mg/kg). Succinylcholine without volatile anesthetics triggered 24 MH cases, 13 requiring dantrolene. Among 310 anesthetic-triggered MH cases, morbidity was 20 to 37%. Treatment delay increased complications every 10 min, reaching 100% with a 50-min delay. Overall mortality was 1 to 10%; 15 U.S. patients died, including 4 after anesthetics in freestanding facilities. CONCLUSIONS: Providers use succinylcholine commonly, including during difficult mask ventilation. Succinylcholine administered without volatile anesthetics may trigger MH events requiring dantrolene. Delayed dantrolene treatment increases the likelihood of MH complications. The data reported herein support stocking dantrolene wherever succinylcholine or volatile anesthetics may be used.

Macroscopic Freestanding Nanosheets with Exceptionally High Modulus.

Macroscopic single-wall carbon nanotube (SWCNT) films of nanoscale thickness have significant potential for an array of applications that demand thin, transparent, conductive coatings. Using macroscopic micrometer thick polystyrene sheets as a reference, we characterize the elastic response of freestanding multifunctional SWCNT nanosheets possessing both exceptionally high Young's modulus and good durability. Thin SWCNT films (20-200 nm thick) asymmetrically "doped" with dilute concentrations of superparamagnetic colloids were suspended in ethanol as freestanding nanosheets. Through repeated and controlled deformation in an external magnetic field, we measure the temporal relaxation of nanosheet curvature back to equilibrium. From the relaxation time and its dependence on nanosheet thickness and length, we extract the SWCNT nanosheet modulus through a simple viscoelastic model. Our results are consistent with nearly ideal SWCNT rigidity percolation with moduli approaching 200 GPa and limited plasticity for sufficiently thick sheets, which we attribute to the screening of van der Waals interactions by the surrounding solvent and the macroscopic nature of the deformation.

Dietary changes of large herbivores in the Turkana Basin, Kenya from 4 to 1 Ma.

A large stable isotope dataset from East and Central Africa from ca. 30 regional collection sites that range from forest to grassland shows that most extant East and Central African large herbivore taxa have diets dominated by C4 grazing or C3 browsing. Comparison with the fossil record shows that faunal assemblages from ca. 4.1-2.35 Ma in the Turkana Basin had a greater diversity of C3-C4 mixed feeding taxa than is presently found in modern East and Central African environments. In contrast, the period from 2.35 to 1.0 Ma had more C4-grazing taxa, especially nonruminant C4-grazing taxa, than are found in modern environments in East and Central Africa. Many nonbovid C4 grazers became extinct in Africa, notably the suid Notochoerus, the hipparion equid Eurygnathohippus, the giraffid Sivatherium, and the elephantid Elephas. Other important nonruminant C4-grazing taxa switched to browsing, including suids in the lineage Kolpochoerus-Hylochoerus and the elephant Loxodonta. Many modern herbivore taxa in Africa have diets that differ significantly from their fossil relatives. Elephants and tragelaphin bovids are two groups often used for paleoecological insight, yet their fossil diets were very different from their modern closest relatives; therefore, their taxonomic presence in a fossil assemblage does not indicate they had a similar ecological function in the past as they do at present. Overall, we find ecological assemblages of C3-browsing, C3-C4-mixed feeding, and C4-grazing taxa in the Turkana Basin fossil record that are different from any modern ecosystem in East or Central Africa.

Orchestrating ACO success: how top performers achieve shared savings.

Leaders of the top-performing accountable care organizations in the Medicare Shared Savings Program attribute the success of their organizations in large part to seven strategies: Seek action-oriented leadership. Transform primary care physician practices. Keep patients out of the emergency department. Ensure all transitions are smooth. Make effective use of available data. Share information on physician performance. Keep patients engaged.

Purifying colloidal nanoparticles through ultracentrifugation with implications for interfaces and materials.

Liquid-phase processing and colloidal self-assembly will be critical to the successful implementation of nanotechnology in the next generation of materials and devices. A key hurdle to realizing this will be the development of efficient methods to purify nanomaterials composed of a variety of shapes, including nanocrystals, nanotubes, and nanoplates. Although density-gradient ultracentrifugation (DGU) has long been appreciated as a valuable tool for separating biological macromolecules and components, the method has recently emerged as an effective way to purify colloidal nanoparticles by size and optical and electronic properties. In this feature article, we review our recent contributions to this growing field, with an emphasis on some of the implications that our results have for interfaces and materials. Through transient or isopycnic DGU performed in both aqueous and organic environments, we demonstrate some explicit examples of how the mechanical, electronic, and optical properties of thin films assembled from two specific colloidal nanomaterials--single-walled carbon nanotubes and silicon nanocrystals--can be modified in response to fractionation.

Wrinkling and folding of nanotube-polymer bilayers.

The influence of a polymer capping layer on the deformation of purified single-wall carbon nanotube (SWCNT) networks is analyzed through the wrinkling of compressed SWCNT-polymer bilayers on polydimethylsiloxane. The films exhibit both wrinkling and folding under compression and we extract the elastoplastic response using conventional two-plate buckling schemes. The formation of a diffuse interpenetrating nanotube-polymer interface has a dramatic effect on the nanotube layer modulus for both metallic and semiconducting species. In contrast to the usual percolation exhibited by the pure SWCNT films, the capped films show a crossover from "composite" behavior (the modulus of the SWCNT film is enhanced by the polymer) to "plasticized" behavior (the modulus of the SWCNT film is reduced by the polymer) as the SWCNT film thickness increases. For almost all thicknesses, however, the polymer enhances the yield strain of the nanotube network. Conductivity measurements on identical films suggest that the polymer has a modest effect on charge transport, which we interpret as a strain-induced polymer penetration of interfacial nanotube contacts. We use scaling, Flory-Huggins theory, and independently determined nanotube-nanotube and nanotube-polymer Hamaker constants to model the response.

Late Miocene to Pliocene carbon isotope record of differential diet change among East African herbivores.

Stable isotope and molecular data suggest that C(4) grasses first appeared globally in the Oligocene. In East Africa, stable isotope data from pedogenic carbonate and fossil tooth enamel suggest a first appearance between 15-10 Ma and subsequent expansion during the Plio-Pleistocene. The fossil enamel record has the potential to provide detailed information about the rates of dietary adaptation to this new resource among different herbivore lineages. We present carbon isotope data from 452 fossil teeth that record differential rates of diet change from C(3) to mixed C(3)/C(4) or C(4) diets among East African herbivore families at seven different time periods during the Late Miocene to the Pliocene (9.9-3.2 Ma). Significant amounts of C(4) grasses were present in equid diets beginning at 9.9 Ma and in rhinocerotid diets by 9.6 Ma, although there is no isotopic evidence for expansive C(4) grasslands in this part of the Late Miocene. Bovids and hippopotamids followed suit with individuals that had C(4)-dominated (>65%) diets by 7.4 Ma. Suids adopted C(4)-dominated diets between 6.5 and 4.2 Ma. Gomphotheriids and elephantids had mostly C(3)-dominated diets through 9.3 Ma, but became dedicated C(4) grazers by 6.5 Ma. Deinotheriids and giraffids maintained a predominantly C(3) diet throughout the record. The sequence of differential diet change among herbivore lineages provides ecological insight into a key period of hominid evolution and valuable information for future studies that focus on morphological changes associated with diet change.

The Union Army's Surgical Handbook and the Positive Story of Civil War Surgery.

Western armies have relied on surgical field manuals to help physicians deal with unfamiliar combat medical conditions from the Napoleonic wars to the present day, but there has been little discussion of whether these handbooks have been used or improved outcomes. Recent research shows that the Union Army's American Civil War (1861-1865) surgical case fatality rates improved as the war progressed, much like the US Army's experience in later wars, and were generally superior to comparable European results. These positive Civil War outcomes have been attributed to field experience, adoption of best practices, and enhanced communication, without consideration of New York surgeon Stephen Smith's widely-used Hand-Book of Surgical Operations. The Army of the Potomac added Smith's pocket-sized Hand-Book to its supply table in 1862. Northern medical journals applauded it, and Smith's contemporaries documented its wide use. Smith's handbook explained and demonstrated surgical techniques that were adopted as the war progressed, such as the use of general anesthesia and limb-sparing resection (debridement) of gunshot wounds. It offered pithy, well-documented advice from recognized experts along with numerous illustrations, which allowed untrained physicians to visualize anatomical relationships and see contemporary best practices in a way that no other wartime publication provided, making it an exemplar of a mass-media surgical improvement change agent.

The Public Health Leader Who Brought Antisepsis to William Halsted.

William Halsted wrote to aging surgeon, Stephen Smith, in 1919, that he remembered the lessons Smith had taught him, "when I walked with you through the wards of Bellevue Hospital." Smith was an early advocate of Joseph Lister's antiseptic method, and because of his public health work, he was also an early advocate of environmental hygiene and microbial control based on the unproved germ theory. While Lister's work at the time emphasized germ-killing around the operative site with carbolic acid (antisepsis), Smith adopted and encouraged surgical practices at Bellevue that would be hallmarks of the germ-preventing (asepsis) surgical approach that fully developed after German bacteriologic discoveries in the mid-1880s, and with which Halsted is historically identified. Some physicians and historians have emphasized temporal and conceptual differences between Lister's antisepsis and German asepsis, but Smith and Halsted's experiences argue that surgical asepsis was the evolutionary outcome of germ theory-based surgical changes that began well before scientific proof arrived.

The transition to emerging revenue models.

A financial assessment aimed at gauging the true impact of the healthcare industry's new value-based payment models for a health system should begin with separate analyses of the following: The direct contract results, The impact of volume changes on net income, The impact of operational improvements, Net income at risk from competitor actions. The results of these four analyses then should be evaluated in combination to identify the ultimate impact of the new revenue models on the health system's bottom line.

Glacial trees from the La Brea tar pits show physiological constraints of low CO2.

• While studies of modern plants indicate negative responses to low [CO2] that occurred during the last glacial period, studies with glacial plant material that incorporate evolutionary responses are rare. In this study, physiological responses to changing [CO2] were compared between glacial (La Brea tar pits) and modern Juniperus trees from southern California. • Carbon isotopes were measured on annual rings of glacial and modern Juniperus. The intercellular:atmospheric [CO2] ratio (c(i) /c(a) ) and intercellular [CO2] (c(i) ) were then calculated on an annual basis and compared through geologic time. • Juniperus showed constant mean c(i) /c(a) between the last glacial period and modern times, spanning 50,000 yr. Interannual variation in physiology was greatly dampened during the last glacial period relative to the present, indicating constraints of low [CO2] that reduced responses to other climatic factors. Furthermore, glacial Juniperus exhibited low c(i) that rarely occurs in modern trees, further suggesting limiting [CO2] in glacial plants. • This study provides some of the first direct evidence that glacial plants remained near their lower carbon limit until the beginning of the glacial-interglacial transition. Our results also suggest that environmental factors that dominate carbon-uptake physiology vary across geologic time, resulting in major alterations in physiological response patterns through time.

Rampage violence requires a new type of research.

Tragedies such as school shootings and the assault on Congresswoman Gabrielle Giffords share features that define them as acts of "rampage violence." These types of events can lead to despair about their inevitability and unpredictability. To understand and prevent rampage violence, we need to acknowledge that current discipline-based violence research is not well suited to this specific challenge. There are numerous important, unanswered research questions that can inform policies designed to prevent rampage violence. It is time to develop alternative research approaches to reduce the risk of rampage violence. Such approaches should incorporate transdisciplinary research models; flexible, outcomes-focused organizational structures similar to those used to investigate other catastrophic events; and an expanded inventory of analytic tools.

Emily Blackwell's Medical School Betrayal: "Duplicity and Double Dealing Somewhere".

Elizabeth Blackwell's younger sister, Emily (1826-1910), was the third woman to graduate from a regular U.S. medical college in 1854. Unlike the experience of the two women who preceded her, the Chicago medical school that accepted Emily refused to allow her to complete her studies and graduate, forcing her to hastily find an alternative. There was no explanation at the time and the Chicago Tribune, which investigated the incident, could only speculate about the source of such a dishonorable act: "It is very evident there is duplicity and double dealing somewhere. Who is guilty?" Generations of historians have attributed it to Illinois Medical Society pressure against Rush Medical College, but there was no contemporary evidence of such pressure. A closer examination of Blackwell's journal and historical records suggests that Rush founder, president, and professor of surgery, Daniel Brainard engineered her dismissal. One possible motive was a misplaced romantic approach by Brainard. Rush's actions had the paradoxical result of temporarily opening the doors of the Cleveland Medical College (now Case Western Reserve) to four more women medical students.

The Medicare bundled payment pilot program participation considerations.

The Medicare bundled payment pilot program is scheduled to begin in January 2013 and will run for five years. The program holds the promise of increased alignment between hospitals and physicians, presenting opportunities for hospital cost reduction and improvements in quality. Nonetheless, the program carries fixed costs and assumption of risks that hospitals need to evaluate as they deliberate over whether to seek to participate in the program.

Solving the ACO conundrum.

Hospitals contemplating developing an accountable care organization (ACO) will be rewarded for improving quality and reducing waste, but a chief strategic concern is the fear of losing volume. Hospital financial leaders considering an ACO should conduct a detailed financial analysis that examines the net impact of both shared ACO savings and hospital volume changes. A key part of this analysis should be an assessment of the organization's prospects for using the ACO to increase market share.

Access to capital: implications for hospital consolidation.

Recent economic challenges have left many independent hospitals and their boards concerned about long-term viability of their organizations as stand-alone facilities. The CFO's role should be to facilitate a candid, objective assessment of the organization's ability to continue to go it alone. Key indicators that should be considered in such an assessment include patient volume, degree of physician alignment, profitability, current debt burden, cash, available capital versus capital requirements, and credit rating changes.

Reply to Van Valkenburgh et al.

DeSantis et al. respond to the concerns raised by Van Valkenburgh et al. on their original study.