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Elemental, chemical, and structural analysis of polycrystalline materials at the micron scale is frequently carried out using microfocused synchrotron X-ray beams, sometimes on multiple instruments. The Maia pixelated energy-dispersive X-ray area detector enables the simultaneous collection of X-ray fluorescence (XRF) and diffraction because of the relatively large solid angle and number of pixels when compared with other systems. The large solid angle also permits extraction of surface topography because of changes in self-absorption. This work demonstrates the capability of the Maia detector for simultaneous measurement of XRF and diffraction for mapping the short- and long-range order across the grain structure in a Ni polycrystalline foil.
To determine whether the seasonality of surgical site infections (SSIs) can be explained by changes in temperature.
Retrospective cohort analysis.
The National Inpatient Sample database.
All hospital discharges with a primary diagnosis of SSI from 1998 to 2011 were considered cases. Discharges with a primary or secondary diagnoses of specific surgeries commonly associated with SSIs from the previous and current month served as our “at risk” cohort.
We modeled the national monthly count of SSI cases both nationally and stratified by region, sex, age, and type of institution. We used data from the National Climatic Data Center to estimate the monthly average temperatures for all hospital locations. We modeled the odds of having a primary diagnosis of SSI as a function of demographics, payer, location, patient severity, admission month, year, and the average temperature in the month of admission.
SSI incidence is highly seasonal, with the highest SSI incidence in August and the lowest in January. During the study period, there were 26.5% more cases in August than in January (95% CI, 23.3–29.7). Controlling for demographic and hospital-level characteristics, the odds of a primary SSI admission increased by roughly 2.1% per 2.8°C (5°F) increase in the average monthly temperature. Specifically, the highest temperature group, >32.2°C (>90°F), was associated with an increase in the odds of an SSI admission of 28.9% (95% CI, 20.2–38.3) compared to temperatures <4.4°C (<40°F).
At population level, SSI risk is highly seasonal and is associated with warmer weather.
Prehospital ultrasound (PHUS) assessments by physicians and non-physicians are performed on medical and trauma patients with increasing frequency. Prehospital ultrasound has been shown to be of benefit by supporting interventions.
Which patients may benefit from PHUS has not been clearly identified.
A multi-variable logistic regression analysis was performed on a previously created retrospective dataset of five years of physician- and non-physician-performed ultrasound scans in a Canadian critical care Helicopter Emergency Medical Service (HEMS). For separate medical and trauma patient groups, the a-priori outcome assessed was patient characteristics associated with the outcome variable of “PHUS-supported intervention.”
Both models were assessed (Likelihood Ratio, Score, and Wald) as a good fit. For medical patients, the characteristics of heart rate (HR) and shock index (SI) were found to be most significant for an intervention being supported by PHUS. An extremely low HR was found to be the most significant (OR=15.86 [95% confidence interval (CI), 1.46-171.73]; P=.02). The higher the SI, the more likely that an intervention was supported by PHUS (SI 0.9 to<1.3: OR=9.15 [95% CI, 1.36-61.69]; P=.02; and SI 1.3+: OR=8.37 [95% CI, 0.69-101.66]; P=.09). For trauma patients, the characteristics of Prehospital Index (PHI) and SI were found to be most significant for PHUS support. The greatest effect was PHI, where increasing ORs were seen with increasing PHI (PHI 14-19: OR=13.36 [95% CI, 1.92-92.81]; P=.008; and PHI 20-24: OR=53.10 [95% CI, 4.83-583.86]; P=.001). Shock index was found to be similar, though, with lower impact and significance (SI 0.9 to<1.3: OR=9.11 [95% CI, 1.31-63.32]; P=.025; and SI 1.3+: OR=35.75 [95% CI, 2.51-509.81]; P=.008).
In a critical care HEMS, markers of higher patient acuity in both medical and trauma patients were associated with occurrences when an intervention was supported by PHUS. Prospective study with in-hospital follow-up is required to confirm these hypothesis-generating results.
O’DochartaighD, DoumaM, AlexiuC, RyanS, MacKenzieM. Utilization Criteria for Prehospital Ultrasound in a Canadian Critical Care Helicopter Emergency Medical Service: Determining Who Might Benefit. Prehosp Disaster Med. 2017;32(5):536–540.
The paper reports on the third (2009) season of fieldwork of the Cyrenaican Prehistory Project, and on further results from the analysis of materials collected in the previous (2007 and 2008) fieldwork. Sediments in a 14 m-deep core drilled beside the McBurney trench provide an invaluable overview of the overall stratigraphic sequence, including at depths reached by the 1950s Deep Sounding but not yet investigated by the present project. Sampling of newly-exposed faces of the original excavation trench for dating (14C, ESR, OSL, U-series) and palaeoenvirommental indicators continued. Excavation was begun of sediments assigned to the early Holocene Libyco-Capsian (McBurney's Layer X), and of Pre-Aurignacian layers beside the top of the Deep Sounding. The Libyco-Capsian layers are particularly prolific in lithic debris, shells, and animal bones; preliminary analysis of the lithics suggests a development from Typical to Upper Capsian within the layers excavated in 2009. Geoarchaeological survey along the littoral to the west and east of the Haua Fteah identified complex sequences spanning most of the last interglacial-glacial cycle. Geoarchaeological survey south of the Haua Fteah characterized the major landforms of the Gebel Akhdar mountain and of the pre-desert and desert-edge zones further south, with Late Stone Age (Upper Palaeolithic and Epipalaeolithic) material being found especially on the southern side of the Gebel Akhdar, and Middle Stone Age (Middle Palaeolithic) material in the pre-desert and desert regions. The first suite of 14C dates (from charcoal samples taken in 2007) indicates the use of the Haua Fteah by Oranian hunter-gatherers during the Last Glacial Maximum and in the succeeding millennia, but not in the Younger Dryas cold/dry phase (c. 11,000–10,000 cal. BC), with Libyco-Capsian occupation resuming soon after the beginning of the Holocene c. 9000 cal. BC, suggesting that the cave, and perhaps the Gebel Akhdar in general, have a complex history as refugia for human settlement during the Pleistocene.
The paper reports on the fourth (2010) season of fieldwork of the Cyrenaican Prehistory Project, and on further results of analyses of artefacts and organic materials collected in the 2009 season. Ground-based LiDar has provided both an accurate 3D scan of the Haua Fteah cave and information on the cave's morphometry or origins. The excavations in the cave focussed on Middle Palaeolithic or Middle Stone Age ‘Pre-Aurignacian’ layers below the base of the Middle Trench beside the McBurney Deep Sounding (Trench D) and on Final Palaeolithic ‘Oranian’ layers beside the upper part of the Middle Trench (Trench M). Although McBurney referred to the upper part of the Deep Sounding as more or less sterile, the 2010 excavations found evidence for small-scale but regular human presence in the form of stone artefacts and debitage, though given the sedimentary context the latter are unlikely to represent in situ knapping. The excavations of Trench M extended from the basal Capsian layers investigated in 2009 through Oranian layers to the transition with the Dabban Upper Palaeolithic. Some 17,000 lithic pieces have been studied from the Capsian and Oranian layers excavated in Trench M, in an area measuring less than 2 m by 1 m by 1.1 m deep, along with numerous animal bones, molluscs, and macrobotanical remains, as well as occasional shell beads. Preliminary studies of the lithics, bones, molluscs, and plant remains are revealing the changing character of late Pleistocene (Oranian) and early Holocene (Capsian) occupation in the Haua Fteah. Alongside the work in the Haua Fteah, the project continued its assessment of the Quaternary and archaeological sequences of the Cyrenaican coastland and completed a transect survey of surface lithic materials and their landform contexts from the pre-desert across the Gebel Akhdar to the coast, with a new focus on the al-Marj basin. Significant differences are emerging in patterns of Middle Palaeolithic and later hominin occupation and palaeodemography.
The paper reports on the fifth (2012) season of fieldwork of the Cyrenaican Prehistory Project. The primary focus of the season was the continuation of the excavation of the prehistoric occupation layers in the Haua Fteah cave. A small trench (Trench U) was cut into Holocene (Neolithic) sediments exposed on the south wall of Charles McBurney's Upper Trench. Below this, the excavation of Trench M was continued, on the southern side of McBurney's Middle Trench. In previous seasons we had excavated Oranian ‘Epipalaeolithic’ layers dating to c. 18,000–10,000 BP (years before the present). In 2012 the excavation continued downwards through Dabban ‘Upper Palaeolithic’ occupation layers, one of which was associated with a post-built structure and likely hearths. There are indications of an occupational hiatus separating the oldest Dabban from the youngest Levallois-Mousterian (Middle Palaeolithic or Middle Stone Age) lithic material. The Deep Sounding excavated by Charles McBurney in 1955 was cleared of backfill to its base, and its south-facing wall was recorded in detail and sampled extensively for materials for dating and palaeoenvironmental reconstruction. McBurney believed that he had reached bedrock at the base of the Deep Sounding, but a small sounding (Trench S) cut into the sediments below this level found further, albeit sparse, evidence for human occupation. Whilst the antiquity of ‘Pre-Aurignacian’ human occupation at the site still needs to be resolved, it seems likely to reach back at least to Marine Isotope Stage 5e, the beginning of the last interglacial (c. 130,000–115,000 BP). Important finds from the 2012 excavations in terms of the behavioural complexity of the human groups using the cave include a possible worked bone point from a Pre-Aurignacian layer and a granite rubbing stone in a Dabban layer from a source over 600 km from the cave.
The paper reports on the sixth season of fieldwork of the Cyrenaican Prehistory Project (CPP) undertaken in September 2012. As in the spring 2012 season, work focussed on the Haua Fteah cave and on studies of materials excavated in previous seasons, with no fieldwork undertaken elsewhere in the Gebel Akhdar. An important discovery, in a sounding excavated below the base of McBurney's 1955 Deep Sounding (Trench S), is of a rockfall or roof collapse conceivably dating to the cold climatic regime of Marine Isotope Stage (MIS) 6 (globally dated to c. 190–130 ka) but more likely the result of a seismic event within MIS 5 (globally dated to c. 130–80 ka). The sediments and associated molluscan fauna in Trench S and in Trench D, a trench being cut down the side of the Deep Sounding, indicate that this part of the cave was at least seasonally waterlogged during the accumulation, probably during MIS 5, of the ~6.5 m of sediment cut through by the Deep Sounding. Evidence for human frequentation of the cave in this period is more or less visible depending on how close the trench area was to standing water as it fluctuated through time. Trench M, the trench being cut down the side of McBurney's Middle Trench, has now reached the depth of the latest Middle Stone Age or Middle Palaeolithic (Levalloiso-Mousterian) industries. The preliminary indications from its excavation are that the transition from the Levalloiso-Mousterian to the blade-based Upper Palaeolithic or Late Stone Age Dabban industry was complex and perhaps protracted, at a time when the climate was oscillating between warm-stage stable environmental conditions and colder and more arid environments. The estimated age of the sediments, c. 50–40 ka, places these oscillations within the earlier part of MIS 3 (globally dated to 60–24 ka), when global climates experienced rapid fluctuations as part of an overall trend to increasing aridity and cold.
The paper describes the initial results from renewed investigations at Niah Cave in Sarawak on the island of Borneo, famous for the discovery in 1958 of the c. 40,000–year old ‘Deep Skull’. The archaeological sequences from the West Mouth and the other entrances of the cave complex investigated by Tom and Barbara Harrisson and other researchers have potential implications for three major debates regarding the prehistory of south-east Asia: the timing of initial settlement by anatomically modern humans; the means by which they subsisted in the late Pleistocene and early Holocene; and the timing, nature, and causation of the transition from foraging to farming. The new project is informing on all three debates. The critical importance of the Niah stratigraphies was commonly identified – including by Tom Harrisson himself – as because the site provided a continuous sequence of occupation over the past 40,000 years. The present project indicates that Niah was first used at least 45,000 years ago, and probably earlier; that the subsequent Pleistocene and Holocene occupations were highly variable in intensity and character; and that in some periods, perhaps of significant duration, the caves may have been more or less abandoned. The cultural sequence that is emerging from the new investigations may be more typical of cave use in tropical rainforests in south-east Asia than the Harrisson model.
Cover crop–based organic rotational no-till soybean production has attracted attention from farmers, researchers, and other agricultural professionals because of the ability of this new system to enhance soil conservation, reduce labor requirements, and decrease diesel fuel use compared to traditional organic production. This system is based on the use of cereal rye cover crops that are mechanically terminated with a roller-crimper to create in situ mulch that suppresses weeds and promotes soybean growth. In this paper, we report experiments that were conducted over the past decade in the eastern region of the United States on cover crop–based organic rotational no-till soybean production, and we outline current management strategies and future research needs. Our research has focused on maximizing cereal rye spring ground cover and biomass because of the crucial role this cover crop plays in weed suppression. Soil fertility and cereal rye sowing and termination timing affect biomass production, and these factors can be manipulated to achieve levels greater than 8,000 kg ha−1, a threshold identified for consistent suppression of annual weeds. Manipulating cereal rye seeding rate and seeding method also influences ground cover and weed suppression. In general, weed suppression is species-specific, with early emerging summer annual weeds (e.g., common ragweed), high weed seed bank densities (e.g. > 10,000 seeds m−2), and perennial weeds (e.g., yellow nutsedge) posing the greatest challenges. Due to the challenges with maximizing cereal rye weed suppression potential, we have also found high-residue cultivation to significantly improve weed control. In addition to cover crop and weed management, we have made progress with planting equipment and planting density for establishing soybean into a thick cover crop residue. Our current and future research will focus on integrated multitactic weed management, cultivar selection, insect pest suppression, and nitrogen management as part of a systems approach to advancing this new production system.
Thin native oxide layers can dominate the mechanical properties of metallic thin films. However, to date there has been little quantification of how such overlayers affect yield and fracture during indentation in constrained film systems. To gain insight into such processes, electrical contact resistance was measured in situ during nanoindentation on constrained thin films of epitaxial Cr and polycrystalline Al, both possessing a native oxide overlayer. Measurements during loading of the films show both increases and decreases in current, which can then be used to distinguish between various sources of plasticity. Ex situ measurements of the oxide thickness are used to provide a starting point for elasticity simulations of stress in both systems. The results show that dislocation nucleation in the metal film can be differentiated from oxide fracture during indentation.
Renewable energy can provide a host of benefits to society. In addition to the reduction of carbon dioxide (CO2) emissions, governments have enacted renewable energy (RE) policies to meet a number of objectives including the creation of local environmental and health benefits; facilitation of energy access, particularly for rural areas; advancement of energy security goals by diversifying the portfolio of energy technologies and resources; and improving social and economic development through potential employment opportunities. Energy access and social and economic development have been the primary drivers in developing countries whereas ensuring a secure energy supply and environmental concerns have been most important in developed countries.
An increasing number and variety of RE policies–motivated by a variety of factors–have driven substantial growth of RE technologies in recent years. Government policies have played a crucial role in accelerating the deployment of RE technologies. At the same time, not all RE policies have proven effective and efficient in rapidly or substantially increasing RE deployment. The focus of policies is broadening from a concentration almost entirely on RE electricity to include RE heating and cooling and transportation.
RE policies have promoted an increase in RE capacity installations by helping to overcome various barriers. Barriers specific to RE policymaking (e.g., a lack of information and awareness), to implementation (e.g., a lack of an educated and trained workforce to match developing RE technologies) and to financing (e.g., market failures) may further impede deployment of RE.
The Simulations and Role Play I track conducted a series of engaged discussions regarding what a successful simulation requires and what aspects are customizable, given the wide variety of contexts in which a simulation may be used. Recognizing the presence of significant variance in available time, institutional support (both financial and technical), student demographics, and class size, the track concluded that any successful simulation must include several core components, which can be presented in a variety of ways. Chief among these components are a balance between providing necessary structure and allowing room for engaged student creativity and the need for thorough, reflective debriefing.
The Niah Caves in Sarawak, Borneo, have captured evidence for people and economies of 8000 and 4000 years ago. Although not continuous on this site, these open two windows on to life at the cultural turning point, broadly equivalent to the transition from Mesolithic to Neolithic. They have much in common, inferring that the occupants, perhaps belonging to an older maritime dispersal, had a choosy appetite for the Neolithic package.