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Rapid increases in herbicide resistance have highlighted the ability of weeds to undergo genetic change within a short period of time. That change, in turn, has resulted in an increasing emphasis in weed science on the evolutionary ecology and potential adaptation of weeds to herbicide selection. Here we argue that a similar emphasis would also be invaluable for understanding another challenge that will profoundly alter weed biology: the rapid rise in atmospheric carbon dioxide (CO2) and the associated changes in climate. Our review of the literature suggests that elevated CO2 and climate change will impose strong selection pressures on weeds and that weeds will often have the capacity to respond with rapid adaptive evolution. Based on current data, climate change and rising CO2 levels are likely to alter the evolution of agronomic and invasive weeds, with consequences for distribution, community composition, and herbicide efficacy. In addition, we identify four key areas that represent clear knowledge gaps in weed evolution: (1) differential herbicide resistance in response to a rapidly changing CO2/climate confluence; (2) shifts in the efficacy of biological constraints (e.g., pathogens) and resultant selection shifts in affected weed species; (3) climate-induced phenological shifts in weed distribution, demography, and fitness relative to crop systems; and (4) understanding and characterization of epigenetics and the differential expression of phenotypic plasticity versus evolutionary adaptation. These consequences, in turn, should be of fundamental interest to the weed science community.
The archaeological site of Saruq al-Hadid, Dubai, United Arab Emirates, presents a long sequence of persistent temporary human occupation on the northern edge of the Rub’ al-Khali desert. The site is located in active dune fields, and evidence for human activity is stratified within a deep sequence of natural dune deposits that reflect complex taphonomic processes of deposition, erosion and reworking. This study presents the results of a program of radiocarbon (14C) and thermoluminescence dating on deposits from Saruq al-Hadid, allied with studies of material remains, which are amalgamated with the results of earlier absolute dating studies provide a robust chronology for the use of the site from the Bronze Age to the Islamic period. The results of the dating program allow the various expressions of human activity at the site—ranging from subsistence activities such as hunting and herding, to multi-community ritual activities and large scale metallurgical extraction—to be better situated chronologically, and thus in relation to current debates regarding the development of late prehistoric and early historic societies in southeastern Arabia.
In September 2016, the annual meeting of the International Union for Quaternary Research’s Loess and Pedostratigraphy Focus Group, traditionally referred to as a LoessFest, met in Eau Claire, Wisconsin, USA. The 2016 LoessFest focused on “thin” loess deposits and loess transportation surfaces. This LoessFest included 75 registered participants from 10 countries. Almost half of the participants were from outside the United States, and 18 of the participants were students. This review is the introduction to the special issue for Quaternary Research that originated from presentations and discussions at the 2016 LoessFest. This introduction highlights current understanding and ongoing work on loess in various regions of the world and provides brief summaries of some of the current approaches/strategies used to study loess deposits.
Preference-based measures of health-related quality of life play a key role in the calculation of Quality-Adjusted Life Years (QALYs) for Health Technology Assessment (HTA). The Child Health Utility 9D (CHU9D) is a new preference-based instrument designed specifically for application in children and adolescents (aged 7 to 17 years). This study aimed to compare Chinese and Australian adolescent population preferences for CHU9D health states using profile case best worst scaling (BWS) methods.
Fifty CHU9D health states (blocked into five survey versions) were generated for valuation using a fractional factorial design. Study participants were recruited through an online panel company in Australia, and through primary and secondary schools in China. A latent class modelling framework was adopted for econometric analysis.
A total of 1,982 respondents (51 percent female) in Australia and 902 respondents (43 percent female) in China provided useable survey responses. Latent class analysis indicated the existence of preference heterogeneity for both population groups. In the Australian sample, respondents in Class I placed the most importance on the mental health dimensions of the CHU9D (for example, Worried and Annoyed) and the least importance on daily activities (for example, Activities, Daily routine, Sleep), whilst respondents in Class II placed equal weights on all attributes. In the Chinese sample, respondents in Class I placed the most importance on the Activities dimension of the CHU9D and the least importance on the Annoyed dimension, whist Class II placed the most importance on the Schoolwork dimension and the least importance on Pain.
This study has provided important cross-country insights into the use of profile case BWS methods to elicit health state preferences with young people for application in HTA in children and adolescents. The differential latent classes identified between Australia and China highlights the necessity to derive country-specific adolescent scoring algorithms for the CHU9D instrument for application in HTA.
Optical SETI at Lick Observatory is characterized by its robust approach to initial detections. Our three-detector system has distinguished itself by successful rejection of nearly all false positive signals. We present observational progress, discuss use of data analysis procedures such as FFTs and analysis of double coincidences, and mention plans to upgrade our instrumentation.
The isotopic composition of ancient wood has the potential to provide information about past environments. We analyzed the δ13C, δ18O, and δ2H of cellulose of conifer trees from several cross-sections at each of 9 sites around the Great Lakes region ranging from ∼4000 to 14,000 cal BP. Isotopic values of Picea, Pinus, and Thuja species seem interchangeable for δ18O and δ2H comparisons, but Thuja appears distinctly different from the other 2 in its δ13C composition. Isotopic results suggest that the 2 sites of near-Younger Dryas age experienced the coldest conditions, although the Gribben Basin site near the Laurentide ice sheet was relatively dry, whereas the Liverpool site 500 km south was moister. The spatial isotopic variability of 3 of the 4 sites of Two Creeks age shows evidence of an elevation effect, perhaps related to sites farther inland from the Lake Michigan shoreline experiencing warmer daytime growing season temperatures. Thus, despite floristic similarity across sites (wood samples at 7 of the sites being Picea), the isotopes appear to reflect environmental differences that might not be readily evident from a purely floristic interpretation of macrofossil or pollen identification.
Group III-Sb compound semiconductors are promising materials for future CMOS circuits. Especially, In1-xGaxSb is considered as a complimentary p-type channel material to n-type In1-xGaxAs MOSFET due to the superior hole transport properties and similar chemical properties in III-Sb’s to those of InGaAs. The heteroepitaxial growth of In1-xGaxSb on Si substrate has significant advantage for volume fabrication of III-V ICs. However large lattice mismatch between InGaSb and Si results in many growth-related defects (micro twins, threading dislocations and antiphase domain boundaries); these defects also act as deep acceptor levels. Accordingly, unintentional doping in InGaSb films causes additional scattering, increase junction leakages and affects the interface properties. In this paper, we studied the correlations between of defects and hole carrier densities in GaSb and strained In1-xGaxSb quantum well layers by using various designs of metamorphic superlattice buffers.
We present the results of an approximately 6 100 deg2 104–196 MHz radio sky survey performed with the Murchison Widefield Array during instrument commissioning between 2012 September and 2012 December: the MWACS. The data were taken as meridian drift scans with two different 32-antenna sub-arrays that were available during the commissioning period. The survey covers approximately 20.5 h < RA < 8.5 h, − 58° < Dec < −14°over three frequency bands centred on 119, 150 and 180 MHz, with image resolutions of 6–3 arcmin. The catalogue has 3 arcmin angular resolution and a typical noise level of 40 mJy beam− 1, with reduced sensitivity near the field boundaries and bright sources. We describe the data reduction strategy, based upon mosaicked snapshots, flux density calibration, and source-finding method. We present a catalogue of flux density and spectral index measurements for 14 110 sources, extracted from the mosaic, 1 247 of which are sub-components of complexes of sources.
Introduction: the Court of Common Pleas and the London Evidence
In the weeks after the feast of St Hilary (13 January) in 1403 a plea brought on a writ of debt, between plaintiffs Margaret le Toller of Smithfield, London, and her husband John le Toller, and defendant Richard Barbour of Wycombe, Buckinghamshire, was heard before the justices of the royal Court of Common Pleas at West-minster. In this case, Margaret and her husband claimed that nearly two decades before, on 8 August 1384, while Margaret was a single woman, an accounting was held between herself and Richard Barbour in the London parish of St Bride Fleet Street before two London tradesmen appointed by Margaret as auditors. Margaret pleaded that this accounting found Barbour to owe her £10 arrears and clear debt concerning diverse monies and receipts, which ‘although often requested’ he had not yet paid, neither ‘to Margaret as a single woman, nor to John le Toller and Margaret since their marriage’. Barbour responded, not denying the alleged accounting nor debt, by pleading that just over three years before, on 6 October 1399, he, John and Margaret had submitted to arbitration before certain men, at Wycombe, concerning all debts and disputes between them from the creation of the world until that day. And further, Barbour pleaded that this arbitration had decided that he ought to pay John and Margaret 18d. to settle all disputes between them, which he duly paid, thereby acquitting himself of all obligations to the couple.