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Funder: Royal Society; Id: http://dx.doi.org/10.13039/501100000288, Funder: Isaac Newton Trust; Id: http://dx.doi.org/10.13039/501100004815, Funder: EQUIPEX ASTER‐CEREGE, Radiocarbon is an extremely useful carbon cycle tracer and radiometric dating tool. Here, we review the main principles and challenges involved in the use of radiocarbon in palaeoceanography. First, we present a conceptual framework in which there are three possible uses of a radiocarbon measurement: 1) to obtain a calendar age interval, or a fossil entity’s age; 2) to obtain an estimate of a carbon reservoir’s past radiocarbon activity; or 3) to compare the relative radiocarbon activities of two contemporary carbon reservoirs. We discuss the analysis of marine fossil material, the generation of an atmospheric reference curve, and the interpretation of marine radiocarbon ‘ventilation metrics’ in relation to this reference curve. It is emphasized that marine radiocarbon integrates the influences of: changing radiocarbon production; air-sea gas exchange effects at the sea surface; transport times within the ocean interior; and the mixing of water parcels with different transit times from the sea surface, and different sea-surface sources. These controls are what make radiocarbon such a powerful palaeoceanographic tracer, though the difficulty of disentangling them is what makes marine radiocarbon dating and tracer studies so challenging. We discuss the implementation of radiocarbon in numerical models, and explore the theory linking ocean-atmosphere partitioning of radiocarbon and CO2. Finally, we review existing records of marine radiocarbon variability over the last ∼25,000 years, which highlight the influence of ocean-atmosphere carbon exchange on past atmospheric CO2 and climate, and point to emerging opportunities for resolving the global radiocarbon- and carbon budgets over the last glacial cycle.

The strategy chosen to accomplish the ambitious task has been the familiar Maoist protracted revolutionary warfare approach that was successfully employed in China and Vietnam. The success that the insurgents enjoyed during the late 1960s and early 1970s was due in no small way to a physical setting that was conducive to guerrilla warfare. Though the Palestinian resistance has been well publicized in the West, lesser known but quite sanguinary internal wars have convulsed a number of states or areas such as Iraq, the Sudan, Spanish Sahara, Lebanon, the Yemen Arab Republic, Oman, and, more recently, Iran. Oman, a state that has enjoyed the longest tradition of independence in the Arab world during the past three centuries, lies astride both the critical Strait of Hormuz and the Indian Ocean oil shipping lanes. It is this location, rather than its modest petroleum production, that has made Oman significant to the West.

The Sarawak insurgency, which relied on bases in Indonesia during its infancy, is an example, as is the situation in Spanish Sahara. Insurgency can be defined as a struggle between a nonruling group and the ruling authorities in which the former consciously employs political resources and instruments of violence to establish legitimacy for some aspect of the political system it considers illegitimate. In conspiracies the organizational effort necessary for coordinating both violent and nonviolent activity is not as demanding as in an internal war setting, since there is far less concern with linking the insurgency to the mass population. Turning to the violent aspect of insurgency, one can identify different forms of warfare. An aspect of environment that seems to have more bearing on the fortunes of an insurgency than weather is the state of the transportation- communications network. Organizational failings can conceivably be rectified and the insurgency may then evolve toward guerrilla warfare.

The pre-industrial millennium is among the periods selected by the Paleoclimate Model Intercomparison Project (PMIP) for experiments contributing to the sixth phase of the Coupled Model Intercomparison Project (CMIP6) and the fourth phase of the PMIP (PMIP4). The past1000 transient simulations serve to investigate the response to (mainly) natural forcing under background conditions not too different from today, and to discriminate between forced and internally generated variability on interannual to centennial timescales. This paper describes the motivation and the experimental set-ups for the PMIP4-CMIP6 past1000 simulations, and discusses the forcing agents orbital, solar, volcanic, and land use/land cover changes, and variations in greenhouse gas concentrations. The past1000 simulations covering the pre-industrial millennium from 850 Common Era (CE) to 1849 CE have to be complemented by historical simulations (1850 to 2014 CE) following the CMIP6 protocol. The external forcings for the past1000 experiments have been adapted to provide a seamless transition across these time periods. Protocols for the past1000 simulations have been divided into three tiers. A default forcing data set has been defined for the Tier 1 (the CMIP6 past1000) experiment. However, the PMIP community has maintained the flexibility to conduct coordinated sensitivity experiments to explore uncertainty in forcing reconstructions as well as parameter uncertainty in dedicated Tier 2 simulations. Additional experiments (Tier 3) are defined to foster collaborative model experiments focusing on the early instrumental period and to extend the temporal range and the scope of the simulations. This paper outlines current and future research foci and common analyses for collaborative work between the PMIP and the observational communities (reconstructions, instrumental data).

Most of the policy debate surrounding the actions needed to mitigate and adapt to anthropogenic climate change has been framed by observations of the past 150 years and climate and sea-level projections for the twenty-first century. The focus on this 250-year window, however, obscures some of the most profound problems associated with climate change. Here, we argue that the twentieth and twenty-first centuries, a period during which the overwhelming majority of human-caused carbon emissions are likely to occur, need to be placed into a long-term context, including the past 20 millennia, when the last Ice Age ended and human civilization developed, and the next 10 millennia, over which time the projected impacts of anthropogenic climate change will grow and persist. This long-term perspective illustrates that policy decisions made in the next few years to decades will have profound impacts on global climate, ecosystems, and human societies — not just for this century, but for the next ten millennia and beyond.

International audience; In order to gain more information about local humoral immune responses to HPV infection, we quantified IgG, IgM, secretory-IgA (S-IgA), and total-IgA by ELISA, and lysozyme and lactoferrin by TR-IFMA, in cervical and cervicovaginal secretions of 40 healthy women and 28 high-risk HPV infected patients (11 were HPV16+). IgG, total-IgA, and S-IgA concentrations in cervicovaginal secretions (p < 0.0001) and high IgG and total-IgA concentrations (p < 0.001 and p < 0.01, respectively) in endocervical secretions were significantly higher in HPV+ patients than in the healthy group. Since the S-IgA/total-IgA ratio was significantly lower in cervicovaginal (7.5%) and endocervical secretions (36.5%) in HPV+ women compared to the control group (p < 0.003 and p < 0.001, respectively), HPV could be responsible for an increase in local production of non-secretory IgA (monomeric and dimeric forms). IgG and total-IgA concentrations in cervicovaginal and endocervical secretions fell in the same general percentage range in both HPV16+ and HPV+ groups (80% and 15%, respectively). However, the S-IgA/total-IgA ratio was much lower in HPV16+ than in HPV+ women, in both cervicovaginal secretions (3.4%) (p < 0.003) and in endocervical secretions (23.3%) (p < 0.001). Innate immunity proteins and local S-IgA response could not stop the spread of HPV infection in spite of high lysozyme and lactoferrin concentrations. HPV16+ disturbed the local humoral immune system, which could partly explain its low clearance.

One of the most abrupt and yet unexplained CO2 rises found in the ice cores (>10 ppmv in two centuries) occurred during the last deglaciation around 14,600 years ago, quasi-synchronous with the abrupt northern hemispheric warming into the Bølling/Allerød. Here we use U/Th dated atmospheric D14C from Tahiti corals as independent and precise age control for this CO2 rise in combination with carbon cycle simulations to show that the release of old nearly 14C-free carbon might have caused these changes in atmospheric CO2 and D14C. The D14C data also independently constrain the magnitude of the carbon released (100-125 PgC), leading to an atmospheric CO2 peak amplitude of 18–22 ppmv. We here suggest as explanation, in line with CH4 records and terrigenous biomarkers, that not the release of old carbon from the deep ocean, but the release from thawing permafrost in the high northern latitudes might be the source of the abrupt CO2 rise and highlights the potential of this carbon reservoir to modulate climate change via greenhouse-gas feedbacks.

Atmospheric carbon dioxide (CO2) during the last deglaciation (∼18–10 kyr BP) switched around 14.6 kyr BP from a rather gradual rise to an abrupt jump, which is recorded in ice cores as an increase of 10 ppmv in less than two centuries. So far the source of that CO2 excursion could not be identified and the climatic implications are largely unknown. Here we use highly resolved U/Th dated atmospheric ∆14C from Tahiti corals as independent age control for CO2 changes. This provides a temporal framework to show that the northern high latitude warming into the Bølling/Allerød occurred quasi-synchronous to this CO2 rise within a few decades. Furthermore we show that an abrupt release (within two centuries) of long-term immobile nearly 14C-free carbon (∼125 PgC) from thawing permafrost might explain the observed anomalies in atmospheric CO2 and ∆14C, in line with CH4 and biomarker records from ice and sediment cores. In transient climate simulations we show that the abrupt carbon release in the northern high latitudes and associated CO2 changes bear the potential to modulate Antarctic temperature. These findings are in agreement with the observed onset of the Antarctic Cold Reversal about two centuries after the beginning of the Bølling/Allerød, as detected in independent annual layer-counted ice cores from both hemispheres. Based on the timing, magnitude, origin and the inter-hemispheric impact we speculate that this abrupt deglacial release of long-term stored carbon via thawing permafrost might have provided the final push out of the last ice age.

This paper describes our research into generating Dutch noun phrases as descriptions of furniture objects or people. This is usually done in two steps: attribute selection and realisation. This research focuses only on the realisation step: generating a noun phrase from given attributes. The research is done on the Dutch version of the TUNA-corpus, which contains annotated human-produced descriptions. Three algorithms were developed for this task, each an improvement over the last. We extracted the lexical choice from the D-TUNA corpus, and used templates generated from the corpus which specified the order of attributes. The algorithms were then evaluated for string similarity with the original human descriptions from the corpus, and a human evaluation was carried out which tested clarity and fluency. A steady improvement of scores in both the automatic and human evaluation was observed for each new version of the algorithm.

Is there a linkage between the murder of 29 Palestinian worshipers at prayer in Hebron, the spate of suicide bombings in Israel's heartland, the assassination of Prime Minister Yitzhak Rabin, and the 1996 Israeli election results? If so, what are the implications for regional stability? In seeking answers to these questions, this article challenges the popular assumption that the Middle East peace process is irreversible. It calls attention to the very real, if largely unrecognized, dangers posed by Israeli and Palestinian rejectionists; that is, those who oppose territorial compromise on ideological or religious grounds. The article concludes with a set of policy recommendations designed to mitigate the threat and, thus, promote enduring U.S. interests in regional peace and stability. A more comprehensive analysis of both the prospects for and perils to peace is provided in the authors’ book, The Deadly Embrace: The Impact of Israeli and Palestinian Rejectionism on the Middle East Peace Process, which wi...

The Persian Gulf war might already be the most overanalyzed conflict in history. More ink than blood has been spilled before, during, and after the war, with the quest for “lessons‐learned” flourishing into a veritable cottage industry. This essay, therefore, focuses on political and military issues that have been largely eclipsed by the more dazzling aspects of Desert Storm. In doing so, our objective is to provide a clearer perspective on the dynamics of the war—its causes, conduct, and termination—as well as to set the framework for a comprehensive assessment of the immediate and longer‐term regional and global outcomes. The military and political success of Desert Storm did not usher in a new order in the Middle East. Battlefield victories are inherently difficult to translate into political realities. Similarly, it is far easier to compel an opponent to sue for peace than to modify his behavior in the aftermath. Thus, while the gulf war opened a window of opportunity for a comprehensive addr...

Chirp sub-bottom profiling, multibeam bathymetric mapping and a combination of faunal and isotopic analysis of molluscs and foraminifera in sediment cores on the northern shelf of the Sea of Marmara (SoM) provide evidence of sea-level excursions, water exchanges between the adjacent Mediterranean and Black Seas, and oscillating salinity over the last 160 ka bp. During the marine isotope stages MIS-2, MIS-3, MIS-4 and MIS-6 the SoM disconnected from the Mediterranean Sea and evolved into a lake. During MIS-1, MIS-5 and MIS-7, the SoM reconnected and became salty once again. Sapropels formed shortly after each invasion of Mediterranean saltwater observed in our cores. Concurrent suboxic-dysoxic conditions prevailed over quite shallow substrates on the shelf.

We present monthly resolved records of strontium/calcium (Sr/Ca) and oxygen isotope (delta O-18) ratios from well-preserved fossil corals drilled during the Integrated Ocean Drilling Program (IODP) Expedition 310 "Tahiti Sea Level" and reconstruct sea surface conditions in the central tropical South Pacific Ocean during two time windows of the last deglaciation. The two Tahiti corals examined here are uranium/thorium (U/Th)-dated at 12.4 and 14.2 ka, which correspond to the Younger Dryas (YD) cold reversal and the Bolling-Allerod (B-A) warming of the Northern Hemisphere, respectively. The coral Sr/Ca records indicate that annual average sea surface temperature (SST) was 2.6-3.1 degrees C lower at 12.4 ka and 1.0-1.6 degrees C lower at 14.2 ka relative to the present, with no significant changes in the amplitude of the seasonal SST cycle. These cooler conditions were accompanied by seawater delta O-18(delta O-18(sw)) values higher by similar to 0.8 parts per thousand and similar to 0.6 parts per thousand relative to the present at 12.4 and 14.2 ka, respectively, implying more saline conditions in the surface waters. Along with previously published coral Sr/Ca records from the island [Cohen and Hart (2004), Deglacial sea surface temperatures of the western tropical Pacific: A new look at old coral. Paleoceanography 19, PA4031, doi:10.1029/2004PA001 084], our new Tahiti coral records suggest that a shift toward lower SST by similar to 1.5 degrees C occurred from 13.1 to 12.4 ka, which was probably associated with a shift toward higher delta O-18, by similar to 0.2 parts per thousand. Along with a previously published coral Sr/Ca record from Vanuatu [Correge et al. (2004), Interdecadal variation in the extent of South Pacific tropical waters during the Younger Dyras event. Nature 428, 927-929], the Tahiti coral records provide new evidence for a pronounced cooling of the western to central tropical South Pacific during the Northern Hemisphere YD event.

The IntCal04 and Marine04 radiocarbon calibration curves have been updated from 12 cal kBP (cal kBP is here defined as thousands of calibrated years before AD 1950), and extended to 50 cal kBP, utilizing newly available data sets that meet the IntCal Working Group criteria for pristine corals and other carbonates and for quantification of uncertainty in both the 14C and calendar timescales as established in 2002. No change was made to the curves from 0–12 cal kBP. The curves were constructed using a Markov chain Monte Carlo (MCMC) implementation of the random walk model used for IntCal04 and Marine04. The new curves were ratified at the 20th International Radiocarbon Conference in June 2009 and are available in the Supplemental Material at www.radiocarbon.org.

New radiocarbon calibration curves, IntCal04 and Marine04, have been constructed and internationally ratified to replace the terrestrial and marine components of IntCal98. The new calibration data sets extend an additional 2000 yr, from 0–26 cal kyr BP (Before Present, 0 cal BP = AD 1950), and provide much higher resolution, greater precision, and more detailed structure than IntCal98. For the Marine04 curve, dendrochronologically-dated tree-ring samples, converted with a box diffusion model to marine mixed-layer ages, cover the period from 0–10.5 cal kyr BP. Beyond 10.5 cal kyr BP, high-resolution marine data become available from foraminifera in varved sediments and U/Th-dated corals. The marine records are corrected with site-specific 14C reservoir age information to provide a single global marine mixed-layer calibration from 10.5–26.0 cal kyr BP. A substantial enhancement relative to IntCal98 is the introduction of a random walk model, which takes into account the uncertainty in both the calendar age and the 14C age to calculate the underlying calibration curve (Buck and Blackwell, this issue). The marine data sets and calibration curve for marine samples from the surface mixed layer (Marine04) are discussed here. The tree-ring data sets, sources of uncertainty, and regional offsets are presented in detail in a companion paper by Reimer et al. (this issue).

The IntCal04 and Marine04 radiocarbon calibration curves have been updated from 12 cal kBP (cal kBP is here defined as thousands of calibrated years before AD 1950), and extended to 50 cal kBP, utilizing newly available data sets that meet the IntCal Working Group criteria for pristine corals and other carbonates and for quantification of uncertainty in both the 14C and calendar timescales as established in 2002. No change was made to the curves from 0-12 cal kBP. The curves were constructed using a Markov chain Monte Carlo (MCMC) implementation of the random walk model used for IntCal04 and Marine04. The new curves were ratified at the 20th International Radiocarbon Conference in June 2009 and are available in the Supplemental Material at www.radiocarbon.org.

A new calibration curve for the conversion of radiocarbon ages to calibrated (cal) ages has been constructed and internationally ratified to replace IntCal98, which extended from 0-24 cal kyr BP (Before Present, 0 cal BP = AD 1950). The new calibration data set for terrestrial samples extends from 0-26 cal kyr BP, but with much higher resolution beyond 11.4 cal kyr BP than IntCal98. Dendrochronologically-dated tree-ring samples cover the period from 0-12.4 cal kyr BP. Beyond the end of the tree rings, data from marine records (corals and foraminifera) are converted to the atmospheric equivalent with a site-specific marine reservoir correction to provide terrestrial calibration from 12.4-26.0 cal kyr BP. A substantial enhancement relative to IntCal98 is the introduction of a coherent statistical approach based on a random walk model, which takes into account the uncertainty in both the calendar age and the 14C age to calculate the underlying calibration curve (Buck and Blackwell, this issue). The tree-ring data sets, sources of uncertainty, and regional offsets are discussed here. The marine data sets and calibration curve for marine samples from the surface mixed layer (Marine04) are discussed in brief, but details are presented in Hughen et al. (this issue a). We do not make a recommendation for calibration beyond 26 cal kyr BP at this time; however, potential calibration data sets are compared in another paper (van der Plicht et al., this issue). © 2004 by the Arizona Board of Regents on behalf of the University of Arizona.