To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Radiocarbon (14C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric 14C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international 14C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable 14C offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the 14C ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine 14C data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.
We describe 14 yr of public data from the Parkes Pulsar Timing Array (PPTA), an ongoing project that is producing precise measurements of pulse times of arrival from 26 millisecond pulsars using the 64-m Parkes radio telescope with a cadence of approximately 3 weeks in three observing bands. A comprehensive description of the pulsar observing systems employed at the telescope since 2004 is provided, including the calibration methodology and an analysis of the stability of system components. We attempt to provide full accounting of the reduction from the raw measured Stokes parameters to pulse times of arrival to aid third parties in reproducing our results. This conversion is encapsulated in a processing pipeline designed to track provenance. Our data products include pulse times of arrival for each of the pulsars along with an initial set of pulsar parameters and noise models. The calibrated pulse profiles and timing template profiles are also available. These data represent almost 21 000 h of recorded data spanning over 14 yr. After accounting for processes that induce time-correlated noise, 22 of the pulsars have weighted root-mean-square timing residuals of
in at least one radio band. The data should allow end users to quickly undertake their own gravitational wave analyses, for example, without having to understand the intricacies of pulsar polarisation calibration or attain a mastery of radio frequency interference mitigation as is required when analysing raw data files.
The purpose of this article is to encourage classical colleagues to develop their own illustrated talks to deliver to school assemblies (both senior and junior). In my experience, an illustrated talk goes down well with any audience (whatever its age) and can have an immediate impact on their view of the classical world (especially its ‘relevance’). Assemblies can be delivered in many ways: a talk; interactive; class presentation etc. This article concentrates only on the preparation and delivery of an illustrated talk. I have divided the article into four sections: the value of classical assemblies; tips on preparing and delivering assemblies; resources and copyright; and an example of a classical assembly (The Adventures of Theseus).
The triazines are one of the most widely used herbicide classes ever developed and are critical for managing weed populations that have developed herbicide resistance. These herbicides are traditionally valued for their residual weed control in more than 50 crops. Scientific literature suggests that atrazine, and perhaps other s-triazines, may no longer remain persistent in soils due to enhanced microbial degradation. Experiments examined the rate of degradation of atrazine and two other triazine herbicides, simazine and metribuzin, in both atrazine-adapted and non-history Corn Belt soils, with similar soils being used from each state as a comparison of potential triazine degradation. In three soils with no history of atrazine use, the t1/2 of atrazine was at least four times greater than in three soils with a history of atrazine use. Simazine degradation in the same three sets of soils was 2.4 to 15 times more rapid in history soils than non-history soils. Metribuzin in history soils degraded at 0.6, 0.9, and 1.9 times the rate seen in the same three non-history soils. These results indicate enhanced degradation of the symmetrical triazine simazine, but not of the asymmetrical triazine metribuzin.
Look at the secondary school timetable and you will see that almost all the subjects are ancient Greek words; so the Greeks studied these ideas first and are worth studying for their ideas in their own language (just like the Romans in Latin!). Greek: Biology, Physics, Zoology, Philosophy, Mathematics, Economics, Politics, Music, Drama, Geography, History, Technology, Theatre Studies. Latin: Greek, Latin, Art, Science, Information (Latin) Technology (Greek), Computer Science, Media Studies.
A field study was conducted for the 2014 and 2015 growing season in Arkansas, Indiana, Illinois, Missouri, Ohio, and Tennessee to determine the effect of cereal rye and either oats, radish, or annual ryegrass on the control of Amaranthus spp. when integrated with comprehensive herbicide programs in glyphosate-resistant and glufosinate-resistant soybean. Amaranthus species included redroot pigweed, waterhemp, and Palmer amaranth. The two herbicide programs included were: a PRE residual herbicide followed by POST application of foliar and residual herbicide (PRE/POST); or PRE residual herbicide followed by POST application of foliar and residual herbicide, followed by another POST application of residual herbicide (PRE/POST/POST). Control was not affected by type of soybean resistance trait. At the end of the season, herbicides controlled 100 and 96% of the redroot pigweed and Palmer amaranth, respectively, versus 49 and 29% in the absence of herbicides, averaged over sites and other factors. The PRE/POST and PRE/POST/POST herbicide treatments controlled 83 and 90% of waterhemp at the end of the season, respectively, versus 14% without herbicide. Cover crop treatments affected control of waterhemp and Palmer amaranth and soybean yield, only in the absence of herbicides. The rye cover crop consistently reduced Amaranthus spp. density in the absence of herbicides compared to no cover treatment.
Saline lagoons are priority habitats in the United Kingdom supporting several protected specialist species. One specialist, the amphipod Gammarus insensibilis, is infected with behaviour-altering microphallid trematodes such as Microphallus papillorobustus. In saline lagoons around the coast of England (Gilkicker and Lymington–Keyhaven on the Hampshire coast and Moulton Marsh in Lincolnshire) there is variation in the prevalence of this parasite in the gammarid populations (0 at Salterns in the Lymington–Keyhaven lagoon system to 98% at Gilkicker). Infection intensity ranged from 0 to 20 metacercariae in individual amphipods. Higher infection intensity can alter the shape of the amphipod's head. Under experimental conditions respiration rate is significantly reduced in infected animals and reproductive output (expressed as early stage embryos mg g dry weight−1) is significantly lower in infected females. It is important to consider the role of host–parasite interactions in order to understand the ecology of specialist lagoon species such as G. insensibilis and their lagoon habitats.
A field study was conducted in 2014 and 2015 in Arkansas, Illinois, Indiana, Ohio, Tennessee, Wisconsin, and Missouri to determine the effects of tillage system and herbicide program on season-long emergence of Amaranthus species in glufosinate-resistant soybean. The tillage systems evaluated were deep tillage (fall moldboard plow followed by (fb) one pass with a field cultivator in the spring), conventional tillage (fall chisel plow fb one pass with a field cultivator in the spring), minimum tillage (one pass of a vertical tillage tool in the spring), and no-tillage (PRE application of paraquat). Each tillage system also received one of two herbicide programs; PRE application of flumioxazin (0.09 kg ai ha–1) fb a POST application of glufosinate (0.59 kg ai ha−1) plus S-metolachlor (1.39 kg ai ha–1), or POST-only applications of glufosinate (0.59 kg ha−1). The deep tillage system resulted in a 62, 67, and 73% reduction in Amaranthus emergence when compared to the conventional, minimum, and no-tillage systems, respectively. The residual herbicide program also resulted in an 87% reduction in Amaranthus species emergence compared to the POST-only program. The deep tillage system, combined with the residual program, resulted in a 97% reduction in Amaranthus species emergence when compared to the minimum tillage system combined with the POST-only program, which had the highest Amaranthus emergence. Soil cores taken prior to planting and herbicide application revealed that only 28% of the Amaranthus seed in the deep tillage system was placed within the top 5-cm of the soil profile compared to 79, 81, and 77% in the conventional, minimum, and no-tillage systems. Overall, the use of deep tillage with a residual herbicide program provided the greatest reduction in Amaranthus species emergence, thus providing a useful tool in managing herbicide-resistant Amaranthus species where appropriate.
We studied neuroinflammation in individuals with late-life, depression, as a
risk factor for dementia, using [11C]PK11195 positron emission
tomography (PET). Five older participants with major depression and 13
controls underwent PET and multimodal 3T magnetic resonance imaging (MRI),
with blood taken to measure C-reactive protein (CRP). We found significantly
higher CRP levels in those with late-life depression and raised
[11C]PK11195 binding compared with controls in brain regions
associated with depression, including subgenual anterior cingulate cortex,
and significant hippocampal subfield atrophy in cornu ammonis 1 and
subiculum. Our findings suggest neuroinflammation requires further
investigation in late-life depression, both as a possible aetiological
factor and a potential therapeutic target.
Palmer amaranth and waterhemp have become increasingly troublesome weeds throughout the United States. Both species are highly adaptable and emerge continuously throughout the summer months, presenting the need for a residual PRE application in soybean. To improve season-long control of Amaranthus spp., 19 PRE treatments were evaluated on glyphosate-resistant Palmer amaranth in 2013 and 2014 at locations in Arkansas, Indiana, Nebraska, Illinois, and Tennessee; and on glyphosate-resistant waterhemp at locations in Illinois, Missouri, and Nebraska. The two Amaranthus species were analyzed separately; data for each species were pooled across site-years, and site-year was included as a random variable in the analyses. The dissipation of weed control throughout the course of the experiments was compared among treatments with the use of regression analysis where percent weed control was described as a function of time (the number of weeks after treatment [WAT]). At the mean (i.e., average) WAT (4.3 and 3.2 WAT for Palmer amaranth and waterhemp, respectively) isoxaflutole + S-metolachlor + metribuzin had the highest predicted control of Palmer amaranth (98%) and waterhemp (99%). Isoxaflutole + S-metolachlor + metribuzin, S-metolachlor + mesotrione, and flumioxazin + pyroxasulfone had a predicted control ≥ 97% and similar model parameter estimates, indicating control declined at similar rates for these treatments. Dicamba and 2,4-D provided some, short-lived residual control of Amaranthus spp. When dicamba was added to metribuzin or S-metolachlor, control increased compared to dicamba alone. Flumioxazin + pyroxasulfone, a currently labeled PRE, performed similarly to treatments containing isoxaflutole or mesotrione. Additional sites of action will provide soybean growers more opportunities to control these weeds and reduce the potential for herbicide resistance.
Herbicide-resistant Amaranthus spp. continue to cause management difficulties in soybean. New soybean technologies under development, including resistance to various combinations of glyphosate, glufosinate, dicamba, 2,4-D, isoxaflutole, and mesotrione, will make possible the use of additional herbicide sites of action in soybean than is currently available. When this research was conducted, these soybean traits were still regulated and testing herbicide programs with the appropriate soybean genetics in a single experiment was not feasible. Therefore, the effectiveness of various herbicide programs (PRE herbicides followed by POST herbicides) was evaluated in bare-ground experiments on glyphosate-resistant Palmer amaranth and glyphosate-resistant waterhemp (both tall and common) at locations in Arkansas, Illinois, Indiana, Missouri, Nebraska, and Tennessee. Twenty-five herbicide programs were evaluated; 5 of which were PRE herbicides only, 10 were PRE herbicides followed by POST herbicides 3 to 4 wks after (WA) the PRE application (EPOST), and 10 were PRE herbicides followed by POST herbicides 6 to 7 WA the PRE application (LPOST). Programs with EPOST herbicides provided 94% or greater control of Palmer amaranth and waterhemp at 3 to 4 WA the EPOST. Overall, programs with LPOST herbicides resulted in a period of weed emergence in which weeds would typically compete with a crop. Weeds were not completely controlled with the LPOST herbicides because weed sizes were larger (≥ 15 cm) compared with their sizes at the EPOST application (≤ 7 cm). Most programs with LPOST herbicides provided 80 to 95% control at 3 to 4 WA applied LPOST. Based on an orthogonal contrast, using a synthetic-auxin herbicide LPOST improves control of Palmer amaranth and waterhemp over programs not containing a synthetic-auxin LPOST. These results show herbicides that can be used in soybean and that contain auxinic- or HPPD-resistant traits will provide growers with an opportunity for better control of glyphosate-resistant Palmer amaranth and waterhemp over a wide range of geographies and environments.
The mass and cumulative mass profile of the Galaxy are its most fundamental properties. Estimating these properties, however, is not a trivial problem. We rely on the kinematic information from Galactic satellites such as globular clusters and dwarf galaxies, and this data is incomplete and subject to measurement uncertainty. In particular, the complete 3D velocity vectors of objects are sometimes unavailable, and there may be selection biases due to both the distribution of objects around the Galaxy and our measurement position. On the other hand, the uncertainties of these data are fairly well understood. Thus, we would like to incorporate these uncertainties and the incomplete data into our estimate of the Milky Way's mass. The Bayesian paradigm offers a way to deal with both the missing kinematic data and measurement errors using a hierarchical model. An application of this method to the Milky Way halo mass profile, using the kinematic data for globular clusters and dwarf satellites, is shown.
The Florida Children’s Medical Services (CMS) has a long-standing history of ensuring that providers of multiple paediatric subspecialties abide by the highest standards. The cardiac sub-committee has written quality standard documents that participating programmes must meet or exceed. These standards oversee paediatric cardiology services including surgery, catheterisations, and outpatient services. On April, 2012, the cardiac sub-committee decided to develop similar standards in paediatric electrophysiology. A task force was created and began this process. These standards include a catalogue of required and optional equipment, as well as staff and physician credentials. We sought to establish expectations of procedural numbers by practitioner and facility. The task force surveyed the members of the Pediatric and Congenital Electrophysiology Society. Finding no consensus, the task force is committed to generate the data by requiring that the CMS participating programmes enrol and submit data to the Multicenter Pediatric and Adult Congenital EP Quality (MAP-IT™) Initiative. This manuscript details the work of the Florida CMS Paediatric Electrophysiology Task Force.