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In situ elemental imaging of planetary surface regolith at a spatial resolution of 100s to 1000s of microns can provide evidence of the provenance of rocks or sediments and their habitability, and can identify post-depositional diagenetic alteration affecting preservation. We use high-resolution elemental maps and XRF spectra from MapX, a flight prototype in situ X-ray imaging instrument, to demonstrate this technology in rock types relevant to astrobiology. Examples are given for various petrologies and depositional/diagenetic environments, including ultramafic/mafic rocks, serpentinites, hydrothermal carbonates, evaporites, stromatolitic cherts and diagenetic concretions.
Radiocarbon (14C) dating of sediment deposition around Antarctica is often challenging due to heterogeneity in sources and ages of organic carbon in the sediment. Chemical and thermochemical techniques have been used to separate organic carbon when microfossils are not present. These techniques generally improve on bulk sediment dates, but they necessitate assumptions about the age spectra of specific molecules or compound classes and about the chemical heterogeneity of thermochemical separations. To address this, the Rafter Radiocarbon Laboratory has established parallel ramped pyrolysis oxidation (RPO) and ramped pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) systems to thermochemically separate distinct carbon fractions, diagnose the chemical composition of each fraction, and target suitable RPO fractions for radiocarbon dating. Three case studies of sediment taken from locations around Antarctica are presented to demonstrate the implementation of combined RPO-AMS and Py-GC-MS to provide more robust age determination in detrital sediment stratigraphy. These three depositional environments are good examples of analytical and interpretive challenges related to oceanographic conditions, carbon sources, and other factors. Using parallel RPO-AMS and Py-GC-MS analyses, we reduce the number of radiocarbon measurements required, minimize run times, provide context for unexpected 14C ages, and better support interpretations of radiocarbon measurements in the context of environmental reconstruction.
Controlling weeds is a critically important task in sugarcane production systems. Weeds compete for light, nutrients, and water, and if they are not managed properly can negatively impact sugarcane yields. Accurate detection of weeds versus desired plants was assessed using hyperspectral and pigment analyses. Leaf samples were collected from four commercial Louisiana sugarcane varieties, and nine weed species commonly found in sugarcane fields. Hyperspectral leaf reflectance data (350 to 850 nm) were collected from all samples. Plant pigment (chlorophylls and carotenoids) levels were also determined using high-performance liquid chromatography, and concentrations were determined using authentic standards and leaf area. In all cases, leaf reflectance data successfully differentiated sugarcane from weeds using canonical discrimination analysis. Linear discriminant analysis showed that the accuracy of the classification varied from 67% to 100% for individual sugarcane varieties and weed species. In all cases, sugarcane was not misclassified as a weed. Plant pigment levels exhibited marked differences between sugarcane varieties and weed species with differences in chlorophyll and carotenoid explaining much of the observed variation in reflectance. The ratio of chlorophyll a to chlorophyll b showed significant differences between sugarcane and all weed species. The successful implementation of this technology as either an airborne system to scout and map weeds or a tractor-based system to identify and spray weeds in real-time would offer sugarcane growers a valuable tool for managing their crops. By accurately targeting weeds in sugarcane fields that are emerged and growing, the total amount of herbicide applied could be decreased, resulting in cost savings for the grower and reduced environmental impacts.
Heintz & Scott-Phillips's account of human expression leaves a number of central issues unclear – not least, whether the lack of expression in nonhuman species is attributable to their lack of the relevant metarepresentational abilities, an absence of trust, or a consequence of other factors. In place of their view, we propose a gradualistic account of the origins of human expression.
In this Introductory chapter to “Amending America’s Unwritten Constitution,” the editors invite readers to consider the puzzle presented in the book: How to amend America’s unwritten constitution? The editors undertake a systemic inquiry into each of the major themes raised by the puzzle: What is a “constitution,” what is “America’s” constitution, what does it mean to “amend” a constitution, and how might we identify an amendment to an “unwritten” constitution, specifically the unwritten constitution of the United States. As the editors set out to answer these questions, they survey the existing literature in the field to lay the foundation for the chapters to follow. They introduce the chapters as well as how each of them illuminates the answer to the major thematic questions raised and explored in the book. What results is ultimately both a proper introduction to this book and also an important scholarly resource to understand constitutional change in the United States.
It is well known that the US Constitution has been amended twenty-seven times since its creation in 1787, but that number does not reflect the true extent of constitutional change in America. Although the Constitution is globally recognized as a written text, it consists also of unwritten rules and principles that are just as important, such as precedents, customs, traditions, norms, presuppositions, and more. These, too, have been amended, but how does that process work? In this book, leading scholars of law, history, philosophy, and political science consider the many theoretical, conceptual, and practical dimensions of what it means to amend America's 'unwritten Constitution': how to change the rules, who may legitimately do it, why leaders may find it politically expedient to enact written instead of unwritten amendments, and whether anything is lost by changing the constitution without a codified constitutional amendment.
Co-twin comparisons address familial confounding by controlling for genetic and environmental influences that twin siblings share. We applied the co-twin comparison design to investigate associations of adolescent factors with alcohol dependence (AD) symptoms. Participants were 1286 individuals (581 complete twin pairs; 42% monozygotic; and 54% female) from the FinnTwin12 study. Predictors included adolescent academic achievement, substance use, externalizing problems, internalizing problems, executive functioning, peer environment, physical health, relationship with parents, alcohol expectancies, life events, and pubertal development. The outcome was lifetime AD clinical criterion count, as measured in young adulthood. We examined associations of each adolescent domain with AD symptoms in individual-level and co-twin comparison analyses. In individual-level analyses, adolescents with higher levels of substance use, teacher-reported externalizing problems at age 12, externalizing problems at age 14, self- and co-twin-reported internalizing problems, peer deviance, and perceived difficulty of life events reported more symptoms of AD in young adulthood (ps < .044). Conversely, individuals with higher academic achievement, social adjustment, self-rated health, and parent–child relationship quality met fewer AD clinical criteria (ps < .024). Associations between adolescent substance use, teacher-reported externalizing problems, co-twin-reported internalizing problems, peer deviance, self-rated health, and AD symptoms were of a similar magnitude in co-twin comparisons. We replicated many well-known adolescent correlates of later alcohol problems, including academic achievement, substance use, externalizing and internalizing problems, self-rated health, and features of the peer environment and parent–child relationship. Furthermore, we demonstrate the utility of co-twin comparisons for understanding pathways to AD. Effect sizes corresponding to the associations between adolescent substance use, teacher-reported externalizing problems, co-twin-reported internalizing problems, peer deviance, and self-rated health were not significantly attenuated (p value threshold = .05) after controlling for genetic and environmental influences that twin siblings share, highlighting these factors as candidates for further research.
Decisions on the use of nature reflect the values and rights of individuals, communities and society at large. The values of nature are expressed through cultural norms, rules and legislation, and they can be elicited using a wide range of tools, including those of economics. None of the approaches to elicit peoples’ values are neutral. Unequal power relations influence valuation and decision-making and are at the core of most environmental conflicts. As actors in sustainability thinking, environmental scientists and practitioners are becoming more aware of their own posture, normative stance, responsibility and relative power in society. Based on a transdisciplinary workshop, our perspective paper provides a normative basis for this new community of scientists and practitioners engaged in the plural valuation of nature.
Optimal stroke care requires access to resources such as neuroimaging, acute revascularization, rehabilitation, and stroke prevention services, which may not be available in rural areas. We aimed to determine geographic access to stroke care for residents of rural communities in the province of Ontario, Canada.
Methods:
We used the Ontario Road Network File database linked with the 2016 Ontario Acute Stroke Care Resource Inventory to estimate the proportion of people in rural communities, defined as those with a population size <10,000, who were within 30, 60, and 240 minutes of travel time by car from stroke care services, including brain imaging, thrombolysis treatment centers, stroke units, stroke prevention clinics, inpatient rehabilitation facilities, and endovascular treatment centers.
Results:
Of the 1,496,262 people residing in rural communities, the majority resided within 60 minutes of driving time to a center with computed tomography (85%), thrombolysis (81%), a stroke unit (68%), a stroke prevention clinic (74%), or inpatient rehabilitation (77.0%), but a much lower proportion (32%) were within 60 minutes of driving time to a center capable of providing endovascular thrombectomy (EVT).
Conclusions:
Most rural Ontario residents have appropriate geographic access to stroke services, with the exception of EVT. This information may be useful for jurisdictions seeking to optimize the regional organization of stroke care services.
The effectiveness of alcohol-based hand rub (ABHR) is correlated with drying time, which depends on the volume applied. Evidence suggests that there is considerable variation in the amount of ABHR used by healthcare providers.
Objective:
We sought to identify the volume of ABHR preferred for use by nurses.
Methods:
A prospective observation study was performed in 8 units at a tertiary-care hospital. Nurses were provided pocket-sized ABHR bottles with caps to record each bottle opening. Nurses were instructed to use the volume of ABHR they felt was best. The average ABHR volume used per hand hygiene event was calculated using cap data and changes in bottle mass.
Results:
In total, 53 nurses participated and 140 nurse shifts were analyzed. The average ABHR dose was 1.09 mL. This value was greater for non-ICU nurses (1.18 mL) than ICU nurses (0.96 mL), but this difference was not significant. We detected no significant association between hand surface area and preferred average dose volume. The ABHR dose volume was 0.006 mL less per use as the number of applications per shift increased (P = .007).
Conclusions:
The average dose of ABHR used was similar to the dose provided by the hospital’s automated dispensers, which deliver 1.1 mL per dose. The volume of ABHR dose was inversely correlated with the number of applications of ABHR per shift and was not correlated with hand size. Further research to understand differences and drivers of ABHR volume preferences and whether automated ABHR dosing may create a risk for people with larger hands is warranted.
Two archaeologically unexplored mounds were studied in the area of the central Great Hungarian Plain. The age of the construction of the mounds was clarified on the basis of radiocarbon (14C) age determination of buried soil layers. Different, later-building phases of the mounds were detected by pedological and geo-electric analyses of the human-made layers. The age of the buried soils was corrected for the reservoir age of the recent soils found in the surroundings of the mounds. Radiocarbon ages of the carbon extracted from the soils at temperatures 400 and 800ºC were almost completely the same. Based on the calibrated ages of cal BP 4830–5270 (Szálka Mound) and cal BP 4880–5290 (Vajda Mound) of the buried soil layers, the identified kurgans were built by people of the Copper Age Yamnaya Culture. On the basis of the pedological and geophysical analysis of the layers, Szálka Mound and Vajda Mound were built in two and in three phases respectively from the chernozem-like humus-rich topsoil layers of the surrounding area. The former shallow quarry sites have been almost completely filled and cannot be identified at the foot of the mounds even using geodetic methods.
Accurate (< 10%) distances of Galactic star clusters allow a precise estimation of the physical parameters of any physically associated Planetary Nebula (PN) and also that of its central star (CSPN) and its progenitor. The progenitor’s mass can be related to the PN’s chemical characteristics and, furthermore, provides additional data for the widely used white dwarf (WD) initial-to-final mass relation (IFMR) that is crucial for tracing the development of both carbon and nitrogen in entire galaxies. To date, there is only one PN (PHR1315- 6555) confirmed to be physically associated with a Galactic open cluster (ESO 96 -SC04) that has a turn-off mass ∼2Mʘ. Our deep HST photometry was used for the search of the CSPN of this currently unique PN. In this work, we present our results.