Journal articles: 'Chemical chronology'

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Kilby, GW, and GE Batley. "Chemical indicators of sediment chronology." Marine and Freshwater Research 44, no. 4 (1993): 635. http://dx.doi.org/10.1071/mf9930635.

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The determination of recent sedimentation rates has traditionally used radiochemical dating techniques but, because of limited laboratory facilities and the costs of these techniques, alternative methods are desirable. Information on sedimentation rates and sediment history can be obtained from anthropogenic chemical components whose presence in sediments, especially near urban areas, can be used as markers to assess their chronology. More than one marker, with a known date of introduction, should be used. In this study, organosilicons first used in the early 1950s and tributyltin used in marine antifouling paints from 1972 were examined in sediments from Lake Macquarie, NSW, to supplement the known input of heavy metals from the lead-zinc smelter that has been operating at the northern end of the lake since 1897. The most reliable data were obtained at sites where all three markers were present, and use of these data allowed independent determination of the year of initial operation of a sewage treatment works.

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Rodgers, S. D., S. B. Charnley, R. G. Smith, and H. M. Butner. "Chemical chronology of the Southern Coalsack." Monthly Notices of the Royal Astronomical Society 379, no. 2 (August 1, 2007): 807–15. http://dx.doi.org/10.1111/j.1365-2966.2007.11985.x.

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Altavilla, Keith. "The Greater New York Sports Chronology." Journal of Sport History 37, no. 3 (October 1, 2010): 472–73. http://dx.doi.org/10.5406/jsporthistory.37.3.472.

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Sigl, Michael, Tyler J. Fudge, Mai Winstrup, Jihong Cole-Dai, David Ferris, Joseph R. McConnell, Ken C. Taylor, et al. "The WAIS Divide deep ice core WD2014 chronology – Part 2: Annual-layer counting (0–31 ka BP)." Climate of the Past 12, no. 3 (March 30, 2016): 769–86. http://dx.doi.org/10.5194/cp-12-769-2016.

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Abstract. We present the WD2014 chronology for the upper part (0–2850 m; 31.2 ka BP) of the West Antarctic Ice Sheet (WAIS) Divide (WD) ice core. The chronology is based on counting of annual layers observed in the chemical, dust and electrical conductivity records. These layers are caused by seasonal changes in the source, transport, and deposition of aerosols. The measurements were interpreted manually and with the aid of two automated methods. We validated the chronology by comparing to two high-accuracy, absolutely dated chronologies. For the Holocene, the cosmogenic isotope records of 10Be from WAIS Divide and 14C for IntCal13 demonstrated that WD2014 was consistently accurate to better than 0.5 % of the age. For the glacial period, comparisons to the Hulu Cave chronology demonstrated that WD2014 had an accuracy of better than 1 % of the age at three abrupt climate change events between 27 and 31 ka. WD2014 has consistently younger ages than Greenland ice core chronologies during most of the Holocene. For the Younger Dryas–Preboreal transition (11.595 ka; 24 years younger) and the Bølling–Allerød Warming (14.621 ka; 7 years younger), WD2014 ages are within the combined uncertainties of the timescales. Given its high accuracy, WD2014 can become a reference chronology for the Southern Hemisphere, with synchronization to other chronologies feasible using high-quality proxies of volcanism, solar activity, atmospheric mineral dust, and atmospheric methane concentrations.

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Sigl, M., T. J. Fudge, M. Winstrup, J. Cole-Dai, D. Ferris, J. R. McConnell, K. C. Taylor, et al. "The WAIS Divide deep ice core WD2014 chronology – Part 2: Annual-layer counting (0–31 ka BP)." Climate of the Past Discussions 11, no. 4 (July 24, 2015): 3425–74. http://dx.doi.org/10.5194/cpd-11-3425-2015.

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Abstract. We present the WD2014 chronology for the upper part (0–2850 m, 31.2 ka BP) of the West Antarctic Ice Sheet (WAIS) Divide ice core. The chronology is based on counting of annual layers observed in the chemical, dust and electrical conductivity records. These layers are caused by seasonal changes in the source, transport, and deposition of aerosols. The measurements were interpreted manually and with the aid of two automated methods. We validated the chronology by comparing to two high-accuracy, absolutely dated chronologies. For the Holocene, the cosmogenic isotope records of 10Be from WAIS Divide and 14C for Intcal13 demonstrated WD2014 was consistently accurate to better than 0.5 % of the age. For the glacial period, comparisons to the Hulu Cave chronology demonstrated WD2014 had an accuracy of better than 1 % of the age at three abrupt climate change events between 27 and 31 ka. WD2014 has consistently younger ages than Greenland ice-core chronologies during most of the Holocene. For the Younger Dryas-Preboreal transition (11 546 ka BP, 24 years younger) and the Bølling-Allerød Warming (14 576 ka, 7 years younger) WD2014 ages are within the combined uncertainties of the timescales. Given its high accuracy, WD2014 can become a reference chronology for the Southern Hemisphere, with synchronization to other chronologies feasible using high quality proxies of volcanism, solar activity, atmospheric mineral dust, and atmospheric methane concentrations.

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SAWADA, MUTSUYO. "Chronology of Ancient Buddhist Banners." FIBER 60, no. 4 (2004): P.76—P.81. http://dx.doi.org/10.2115/fiber.60.p_76.

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Fowler, David, Peter Brimblecombe, John Burrows, Mathew R. Heal, Peringe Grennfelt, David S. Stevenson, Alan Jowett, et al. "A chronology of global air quality." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, no. 2183 (September 28, 2020): 20190314. http://dx.doi.org/10.1098/rsta.2019.0314.

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Air pollution has been recognized as a threat to human health since the time of Hippocrates, ca 400 BC. Successive written accounts of air pollution occur in different countries through the following two millennia until measurements, from the eighteenth century onwards, show the growing scale of poor air quality in urban centres and close to industry, and the chemical characteristics of the gases and particulate matter. The industrial revolution accelerated both the magnitude of emissions of the primary pollutants and the geographical spread of contributing countries as highly polluted cities became the defining issue, culminating with the great smog of London in 1952. Europe and North America dominated emissions and suffered the majority of adverse effects until the latter decades of the twentieth century, by which time the transboundary issues of acid rain, forest decline and ground-level ozone became the main environmental and political air quality issues. As controls on emissions of sulfur and nitrogen oxides (SO 2 and NO x ) began to take effect in Europe and North America, emissions in East and South Asia grew strongly and dominated global emissions by the early years of the twenty-first century. The effects of air quality on human health had also returned to the top of the priorities by 2000 as new epidemiological evidence emerged. By this time, extensive networks of surface measurements and satellite remote sensing provided global measurements of both primary and secondary pollutants. Global emissions of SO 2 and NO x peaked, respectively, in ca 1990 and 2018 and have since declined to 2020 as a result of widespread emission controls. By contrast, with a lack of actions to abate ammonia, global emissions have continued to grow. This article is part of a discussion meeting issue ‘Air quality, past present and future’.

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Nijampurkar, V. N., N. Bhandari, D. V. Borole, and U. Bhattacharya. "Radiometric Chronology of Changme-Khangpu Glacier Sikkim." Journal of Glaciology 31, no. 107 (1985): 28–33. http://dx.doi.org/10.1017/s0022143000004950.

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AbstractThe32Si concentration in a sample of surface ice from the snout of Changme-Khangpu glacier is 0.36 disintegrations per minute/tonne compared to the fall-out value of 0.7 d.p.m./tonne. If this decrease is assumed to be solely due to decay of32Si, an age offc. 100 years is estimated for the surface ice of the snout, leading to an average flow velocity ofc. 40 m/year for the past century. A vertical profile of210Pb in a core taken at an altitude of 5040 m shows two horizons where this isotope is enriched, one between 3 and 4 m and another between 11 and 12 m, indicating that the primary concentration of210Pb can change by physico-chemical processes like adsorption on dust. None the less, a longitudinal profile along the glacier shows a systematic decrease of210Pb activity with decreasing altitude, the surface ice of the snout giving a value of 0.2 d.p.m./l, corresponding to an age of 100 years which is concordant with the32Si age. This surface flow-rate of the glacier is much larger than the average contemporary flow-rate(c.13m/year). The difference can be understood in terms of the past history of advance and recession of the glacier as revealed by the geomorphic evidence.

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Nijampurkar, V. N., N. Bhandari, D. V. Borole, and U. Bhattacharya. "Radiometric Chronology of Changme-Khangpu Glacier Sikkim." Journal of Glaciology 31, no. 107 (1985): 28–33. http://dx.doi.org/10.3189/s0022143000004950.

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AbstractThe 32Si concentration in a sample of surface ice from the snout of Changme-Khangpu glacier is 0.36 disintegrations per minute/tonne compared to the fall-out value of 0.7 d.p.m./tonne. If this decrease is assumed to be solely due to decay of 32Si, an age off c. 100 years is estimated for the surface ice of the snout, leading to an average flow velocity of c. 40 m/year for the past century. A vertical profile of 210Pb in a core taken at an altitude of 5040 m shows two horizons where this isotope is enriched, one between 3 and 4 m and another between 11 and 12 m, indicating that the primary concentration of 210Pb can change by physico-chemical processes like adsorption on dust. None the less, a longitudinal profile along the glacier shows a systematic decrease of 210Pb activity with decreasing altitude, the surface ice of the snout giving a value of 0.2 d.p.m./l, corresponding to an age of 100 years which is concordant with the 32Si age. This surface flow-rate of the glacier is much larger than the average contemporary flow-rate (c. 13m/year). The difference can be understood in terms of the past history of advance and recession of the glacier as revealed by the geomorphic evidence.

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Lupiáñez, José A., and Eva E. Rufino-Palomares. "Phytochemicals: “A Small Defensive Advantage for Plants and Fungi; a Great Remedy for the Health of Mankind”." Molecules 26, no. 20 (October 12, 2021): 6159. http://dx.doi.org/10.3390/molecules26206159.

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In the chronology of Biochemistry, as a new science that emerged in the mid-nineteenth century after its separation from Organic Chemistry and Physiology, its beginnings were characterized by an intense search and subsequent isolation and characterization of different organic compounds that were part of the chemical composition of living organisms [...]

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Hoffmann, Helene M., Mackenzie M. Grieman, Amy C. F. King, Jenna A. Epifanio, Kaden Martin, Diana Vladimirova, Helena V. Pryer, et al. "The ST22 chronology for the Skytrain Ice Rise ice core – Part 1: A stratigraphic chronology of the last 2000 years." Climate of the Past 18, no. 8 (August 10, 2022): 1831–47. http://dx.doi.org/10.5194/cp-18-1831-2022.

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Abstract. A new ice core was drilled in West Antarctica on Skytrain Ice Rise in field season 2018/2019. This 651 m ice core is one of the main targets of the WACSWAIN (WArm Climate Stability of the West Antarctic ice sheet in the last INterglacial) project. A present-day accumulation rate of 13.5 cm w.e. yr−1 was derived. Although the project mainly aims to investigate the last interglacial (115–130 ka), a robust chronology period covering the recent past is needed to constrain the age models for the deepest ice. Additionally, this time period is important for understanding current climatic changes in the West Antarctic region. Here, we present a stratigraphic chronology for the top 184.14 m of the Skytrain ice core based on absolute age tie points interpolated using annual layer counting encompassing the last 2000 years of climate history. Together with a model-based depth–age relationship of the deeper part of the ice core, this will form the ST22 chronology. The chemical composition, dust content, liquid conductivity, water isotope concentration and methane content of the whole core was analysed via continuous flow analysis (CFA) at the British Antarctic Survey. Annual layer counting was performed by manual counting of seasonal variations in mainly the sodium and calcium records. This counted chronology was informed and anchored by absolute age tie points, namely, the tritium peak (1965 CE) and six volcanic eruptions. Methane concentration variations were used to further constrain the counting error. A minimal error of ±1 year at the tie points was derived, accumulating to ± 5 %–10 % of the age in the unconstrained sections between tie points. This level of accuracy enables data interpretation on at least decadal timescales and provides a solid base for the dating of deeper ice, which is the second part of the chronology.

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BELDEAN, Emanuela, and Maria Cristina TIMAR. "A NEW OPPORTUNITY FOR RESEARCH IN ROMANIA – SUBFOSSIL WOOD." Series II: Forestry Wood Industry Agricultural Food Engineering 14(63), no. 1 (June 1, 2021): 77–88. http://dx.doi.org/10.31926/but.fwiafe.2021.14.63.1.7.

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The present paper is a literature review related to subfossil wood, which aims at acquiring knowledge and understanding of the material. The study presents methods for old wood chronology and some properties such as: structural, chemical, physical, and mechanical, compared with recent wood. The results are very useful for the wood industry and will open new paths for the research of this material.

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Walker, M. J. C., C. Bryant, G. R. Coope, D. D. Harkness, J. J. Lowe, and E. M. Scott. "Towards a Radiocarbon Chronology of the Late-Glacial: Sample Selection Strategies." Radiocarbon 43, no. 2B (2001): 1007–19. http://dx.doi.org/10.1017/s0033822200041679.

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This paper outlines a dating program designed to test the reproducibility of radiocarbon dates on different materials of Late-Glacial age (plant macrofossils, fossil beetle remains, and the “humic” and “humin” chemical fractions of limnic sediments) using a combination of radiometric (beta counting) and accelerator mass spectrometry (AMS) techniques. The results have implications for the design of sampling strategies and for the development of improved dating protocols, both of which are important if a high-precision 14C chronology for the Late-Glacial is to be achieved.

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Robertshaw, Peter, Marilee Wood, Anne Haour, Karlis Karklins, and Hector Neff. "Chemical analysis, chronology, and context of a European glass bead assemblage from Garumele, Niger." Journal of Archaeological Science 41 (January 2014): 591–604. http://dx.doi.org/10.1016/j.jas.2013.08.023.

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Punning, Jaan-Mati, Mati Ilomets, and Tiiu Koff. "Possibilities for Detailed Dating of Peat Bog Deposits." Radiocarbon 35, no. 3 (1993): 379–85. http://dx.doi.org/10.1017/s0033822200060380.

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Geochemical and palynological data as well as radiocarbon dating were used to study the peat bog deposits in Niinsarre bog, northeast Estonia. The aim of this study was to establish criteria for determining a detailed chronology, which is important, for example, in studying paleoevents and historical monitoring. In some cases, we can use cumulative pollen data, as well as cumulative chemical and peat bulk density data.

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Bertin, Lizette J., Duncan A. Christie, Paul R. Sheppard, Ariel A. Muñoz, Antonio Lara, and Claudio Alvarez. "Chemical Signals in Tree Rings from Northern Patagonia as Indicators of Calbuco Volcano Eruptions since the 16th Century." Forests 12, no. 10 (September 25, 2021): 1305. http://dx.doi.org/10.3390/f12101305.

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The Calbuco volcano ranks third in the specific risk classification of volcanoes in Chile and has a detailed eruption record since 1853. During 2015, Calbuco had a sub-Plinian eruption with negative impacts in Chile and Argentina, highlighting the need to determine the long-term history of its activity at a high-resolution time scale to obtain a better understanding of its eruptive frequency. We developed a continuous eruptive record of Calbuco for the 1514–2016 period by dendrochemical analysis of Fitzroya cupressoides tree rings at a biennium resolution using inductively coupled plasma–mass spectrometry. After comparing the chemical record of 20 elements contained in tree rings with historical eruptions, one group exhibited positive anomalies during (Pb/Sn) and immediately after (Mo/P/Zn/Cu) eruptions, with a Volcanic Explosivity Index (VEI) ≥ 3, and so were classified as chemical tracers of past eruptions (TPE). The tree-ring width chronology also exhibited significant decreases in tree growth associated with eruptions of VEI ≥ 3. According to these records, we identified 11 new eruptive events of Calbuco, extending its eruptive chronology back to the 16th century and determining a mean eruptive frequency of ~23 years. Our results show the potential to use dendrochemical analysis to infer past volcanic eruptions in Northern Patagonia. This information provides a long-term perspective for assessing eruptive history in Northern Patagonia, with implications for territorial planning.

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Norris, John E. "The Age Structure of the Older Parts of the Galaxy." Symposium - International Astronomical Union 169 (1996): 353–66. http://dx.doi.org/10.1017/s007418090022994x.

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The history of the Galaxy is encoded in the kinematic, chemical and age profiles of its various populations, and their inter-relationships. Of these, the age structure has proved to be the most problematic. The aim of the present paper is to discuss our understanding of the ages of the various components and to seek to understand the chronology of the system, highlighting along the way some of the unsolved problems.

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Fujii, Y., K. Kamiyama, T. Kawamura, T. Kameda, K. Izumi, K. Satow, H. Enomoto, et al. "6000-Year Climate Records in an Ice Core from the Høghetta Ice Dome in Northern Spitsbergen." Annals of Glaciology 14 (1990): 85–89. http://dx.doi.org/10.3189/s0260305500008314.

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In 1987 an ice core to the bedrock at a depth of 85.6 m was drilled at the top of Høghetta ice dome in northern Spitsbergen. Chronology of the ice core was examined by tritium and 14C methods showing time gap at about 50 m depth. The age of three bottom ice samples was determined as 4150–5670 year B.P. by 14C method done for frozen bacteria colonies and a frozen petal. This chronology and negative bottom temperature of −9.4°C suggest that glaciers in Spitsbergen shrank considerably during the hypsithermal. The pH of melt-water samples lower than 5.0 corresponds well to large northern hemispheric volcanic eruptions during the last 300 years. Increase of acidity from 30 m depth to the surface may reflect the spread of air pollution to the Arctic during the past 200 years. On the basis of ice-core analyses on electrical conductivity, pH, chemical composition and air bubble pattern, climate and environment in Spitsbergen during the last 6000 years are discussed.

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Fujii, Y., K. Kamiyama, T. Kawamura, T. Kameda, K. Izumi, K. Satow, H. Enomoto, et al. "6000-Year Climate Records in an Ice Core from the Høghetta Ice Dome in Northern Spitsbergen." Annals of Glaciology 14 (1990): 85–89. http://dx.doi.org/10.1017/s0260305500008314.

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In 1987 an ice core to the bedrock at a depth of 85.6 m was drilled at the top of Høghetta ice dome in northern Spitsbergen. Chronology of the ice core was examined by tritium and14C methods showing time gap at about 50 m depth. The age of three bottom ice samples was determined as 4150–5670 year B.P. by14C method done for frozen bacteria colonies and a frozen petal. This chronology and negative bottom temperature of −9.4°C suggest that glaciers in Spitsbergen shrank considerably during the hypsithermal. The pH of melt-water samples lower than 5.0 corresponds well to large northern hemispheric volcanic eruptions during the last 300 years. Increase of acidity from 30 m depth to the surface may reflect the spread of air pollution to the Arctic during the past 200 years. On the basis of ice-core analyses on electrical conductivity, pH, chemical composition and air bubble pattern, climate and environment in Spitsbergen during the last 6000 years are discussed.

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Pańczyk, Ewa, Bożena Sartowska, Lech Waliś, Jakub Dudek, Władysław Weker, and Maciej Widawski. "The origin and chronology of medieval silver coins based on the analysis of chemical composition." Nukleonika 60, no. 3 (September 1, 2015): 657–63. http://dx.doi.org/10.1515/nuka-2015-0108.

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Abstract Medieval Central Europe coins - the Saxon coins, also called as the Otto and Adelheid denarii, as well as the Polish ones, the Władysław Herman and Bolesław Śmiały coins - were examined to determine their provenance and dating. Their attribution and chronology often constitute a serious problem for historians and numismatists. For hundreds of years, coins were in uncontrolled conditions and in variable environment. Destructed and inhomogeneous surface were the effect of corrosion processes. Electron microscopy with energy dispersive X-ray analysis (scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS)), X-ray fluorescence (XRF) analysis (energy dispersive X-ray fluorescence (EDXRF) and total reflection X-ray fluorescence (TXRF)), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) were applied. The results of these investigations are significant for our knowledge of the history of Central European coinage, especially of Polish coinage

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Gorodilova, Marianna Rifovna, and Rif Shakrislamovich Nasibullin. "THE NAMES OF CHEMICAL ELEMENTS IN THE UDMURT LANGUAGE." Yearbook of Finno-Ugric Studies 16, no. 1 (March 20, 2022): 38–48. http://dx.doi.org/10.35634/10.35634/2224-9443-2022-16-1-38-48.

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The article discusses the original and borrowed names of chemical elements in the Udmurt language. The chronology of the fixation of chemical elements is determined, indicating the year of the first fixation in the Udmurt and Russian lexicographic literature, the year of the discovery of the chemical element. The etymology of the names is revealed. In nature, only a small part of the chemical elements is found in pure form. Many peoples were familiar with them already in the early stages of social development; they were given their own names or borrowed from neighbors. However, most of the chemical elements exist only in the composition of chemical compounds. They got their names rather late, when scientists learned to separate individual elements from the composition of chemical compounds. As they received them, experts gave them names in a variety of ways: they took into account various properties, state of aggregation, color, smell, used the names of geographical and astronomical objects, the names of mythological characters, discoverers or the names of scientific centers that discovered the element, or just a name authoritative scientists and public figures. When nominating scientists, as a rule, they used ancient Greek, Latin or German.

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Flueck, Werner T. "Brief communication: Extended chronology of the Cordón Caulle volcanic eruption beyond 2011 reveals toxic impacts." Natural Hazards and Earth System Sciences 16, no. 11 (November 10, 2016): 2351–55. http://dx.doi.org/10.5194/nhess-16-2351-2016.

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Abstract. Aside of immediate impacts, the 2011 Puyehue–Cordón Caulle volcano (PCC) eruption also caused persisting chemical impacts. By 2012, toxicity resulted in overt dental fluorosis in deer, with bone fluoride increasing > 38-fold to 5175 ppm. Sheep, horses and cattle also succumbed to fluorosis. Due to eolian redeposition of tephra, exposure of ruminants continued, bone fluoride reached 10 396 ppm, and by 2014 skeletal fluorosis was found. Nonskeletal fluorosis resulted in reduced wool growth and major losses among periparturient cattle. Peculiarities of digestive processes make ruminants susceptible to fluoride-containing tephra, which averaged 548 ppm from PCC. Moreover, recent volcanic eruptions causing fluorosis could be aggravated by local iodine deficiency, which increases the incidence and harshness of fluorosis, and deficiency of selenium, which, among other things, also results in secondary deficiency of iodine. Notwithstanding, several measures are available to livestock producers to minimize chemical impacts of fluoride.

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Rodgman, A., and TA Perfetti. "The Chemical Components Identified in Tobacco and Tobacco Smoke Prior to 1954: A Chronology of Classical Chemistry." Beiträge zur Tabakforschung International/Contributions to Tobacco Research 23, no. 5 (September 1, 2009): 277–333. http://dx.doi.org/10.2478/cttr-2013-0866.

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AbstractBecause of the excellent fractionation and identification technologies developed during the early-1950s, the compositions of tobacco and tobacco smoke, both classified as highly complex mixtures, have been defined more completely than the composition of any other highly complex commercial product such as coffee. By year-end 1953, the many years of research by scientists using classical chemical techniques to define the composition of tobacco and its smoke provided meaningful information on the nature of over 300 tobacco components and fewer than 100 tobacco smoke components. Those involved in the pre-1954 research not only provided the cornerstone of our knowledge of the two compositions but also deserve the gratitude of their successors for the early information generated on tobacco and its smoke. This article is our tribute to those researchers who generated much meaningful knowledge on the composition of tobacco and tobacco smoke prior to 1954 despite the now known fractionation and analytical limitations of the so-called classical chemical techniques. It also notes the similarity of some of the early and more recent research results obtained on the chemical and biological properties of smoke condensate and several of its components from tobacco with those obtained by Roffo in the 1930s on a destructive distillate of tobacco.

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Cameron, Gavin, Jason Pate, Diana McCauley, and Lindsay DeFazio. "1999 WMD terrorism chronology: Incidents involving sub‐national actors and chemical, biological, radiological, and nuclear materials." Nonproliferation Review 7, no. 2 (June 2000): 157–74. http://dx.doi.org/10.1080/10736700008436818.

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Heinemeier, Jan, Åsa Ringbom, Alf Lindroos, and Árný E. Sveinbjörnsdóttir. "Successful AMS 14C Dating of Non-Hydraulic Lime Mortars from the Medieval Churches of the Åland Islands, Finland." Radiocarbon 52, no. 1 (2010): 171–204. http://dx.doi.org/10.1017/s0033822200045124.

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Fifteen years of research on accelerator mass spectrometry (AMS) radiocarbon dating of non-hydraulic mortar has now led to the establishment of a chronology for the medieval stone churches of the Åland Islands (Finland), where no contemporary written records could shed light on the first building phases. In contrast to other material for dating, well-preserved mortar is abundantly available from every building stage.We have gathered experience from AMS dating of 150 Åland mortar samples. Approximately half of them have age control from dendrochronology or from 14C analysis of wooden fragments in direct contact with the mortar. Of the samples with age control, 95% of the results agree with the age of the wood. The age control from dendrochronology, petrologic microscopy, chemical testing of the mortars, and mathematical modeling of their behavior during dissolution in acid have helped us to define criteria of reliability to interpret the 14C results when mortar dating is the only possibility to constrain the buildings in time. With these criteria, 80% of all samples reached conclusive results, and we have thus far been able to establish the chronology of 12 out of the 14 churches and chapels, while 2 still require complementary analyses.

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Kar, Devashish, and Roy Aurobindo. "Epizootic Ulcerative Syndrome (EUS) Fish Disease Chronology, Status and Major Outbreaks in the World." Transylvanian Review of Systematical and Ecological Research 23, no. 2 (July 1, 2021): 29–38. http://dx.doi.org/10.2478/trser-2021-0012.

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Abstract Epizootic Ulcerative Syndrome (EUS) has been causing large-scale mortality among the freshwater fishes of the globe since the 1070s. The symptoms include large haemorrhagic cutaneous ulcers, epidermal degeneration and necrosis followed by sloughing of scales. There have been many studies on EUS throughout the world. In India, since the initiation of EUS, in 1988, our study tried to reveal the aetiology of the disease through extensive and intensive studies on different aspects, like limnological, physical, chemical, bacteriological, fungal, viral including electron microscopic studies. Details of EUS investigation has been discussed in the present paper.

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Cedro, Anna, and Bernard Cedro. "Influence of climatic conditions and air pollution on radial growth of Scots pine (Pinus sylvestris L.) in Szczecin’s city forests." Forest Research Papers 79, no. 2 (June 1, 2018): 105–12. http://dx.doi.org/10.2478/frp-2018-0011.

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Abstract The aim of the present work was to characterize the growth – climate relationship of pines growing in the Szczecin city forests in intensively used recreational areas and to identify the effect of air pollutants emitted by a nearby chemical factory on tree-ring width. Our research area was located in the Głębokie forest complex, which is one of the most frequently visited. The chemical factory Police that produces fertilizers is located at a distance 11 km away from the study plot. The largest emissions of pollutants from the factory in terms of volume occurred in the 1980s and early 1990s. Wood samples were collected from Scots pine (Pinus sylvestris L.) with the Pressler borer from 30 trees and examined using standard dendrochronological methodology. The result was a local chronology of 169 years from 1848–2016. Dendroclimatological analyses indicated that the weather conditions at the turn from winter to spring are the dominant factors influencing radial growth. For example, higher than average temperatures in February, March and April result in a wide tree-ring in the upcoming growth season. Following Nowacki and Abram’s method, we also determined the relative growth change in order to delimit the timeframe when air pollution potentially alters tree-ring width. Due to the lack of data for the period 1848–1945, the increasing and decreasing relative growth could not be linked to specific events. For the period 1944–1972 however, we observed and increase in the tree-ring width, which in this case can be attributed to favorable weather conditions. The final period, 1973–1991, on the other hand showed the strongest decline in annual growth throughout our chronology and this was largely due to the nearby chemical factories, which released huge amounts of pollution into the atmosphere during this period. At present, despite new technologies and a decrease in overall production by the nearby chemical factory, we found a negative trend in ring width dynamics indicating a need for pollutant monitoring and further research.

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Yuan, Sixun, Xiaohong Wu, Kexin Liu, Zhiyu Guo, Xiaolin Cheng, Yan Pan, and Jinxia Wang. "Removal of Contaminants from Oracle Bones During Sample Pretreatment." Radiocarbon 49, no. 2 (2007): 211–16. http://dx.doi.org/10.1017/s0033822200042132.

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Animal bones and tortoise shells were used for divination by the Chinese royal family during the Shang Dynasty (∼16th–11th century BC), and the divination results were recorded as inscriptions on oracle bones and shells, which are very valuable cultural remains and record many important events in the Shang Dynasty period. Thus, radiocarbon dating of oracle bones was used to build a precise chronology of the late Shang Dynasty. Due to their original burial conditions and the fact that in subsequent decades the pieces were traded or archived in museums, oracle bones are expected to be contaminated with exogenous materials from the environment and the conservation process. During dating, we found that some samples were contaminated by conservation chemical reagents. The contaminated samples were purified by removing exogenous chemicals with a series of organic solvents, in a method modified from Bruhn et al. (2001). Both whole bone and gelatin samples were processed with this purification method, resulting in satisfactory improvements in dating results.

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Schibille, Nadine, Patrick Degryse, Markku Corremans, and Christian G. Specht. "Chemical characterisation of glass mosaic tesserae from sixth-century Sagalassos (south-west Turkey): chronology and production techniques." Journal of Archaeological Science 39, no. 5 (May 2012): 1480–92. http://dx.doi.org/10.1016/j.jas.2012.01.020.

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Gay, Marine, Frédéric Plassard, Katharina Müller, and Ina Reiche. "Relative chronology of Palaeolithic drawings of the Great Ceiling, Rouffignac cave, by chemical, stylistic and superimposition studies." Journal of Archaeological Science: Reports 29 (February 2020): 102006. http://dx.doi.org/10.1016/j.jasrep.2019.102006.

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Vallelonga, P., G. Bertagna, T. Blunier, H. A. Kjær, T. J. Popp, S. O. Rasmussen, J. P. Steffensen, et al. "Duration of Greenland Stadial 22 and ice-gas Δage from counting of annual layers in Greenland NGRIP ice core." Climate of the Past 8, no. 6 (November 20, 2012): 1839–47. http://dx.doi.org/10.5194/cp-8-1839-2012.

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Abstract. High-resolution measurements of chemical impurities and methane concentrations in Greenland ice core samples from the early glacial period allow the extension of annual-layer counted chronologies and the improvement of gas age-ice age difference (Δage) essential to the synchronization of ice core records. We report high-resolution measurements of a 50 m section of the NorthGRIP ice core and corresponding annual layer thicknesses in order to constrain the duration of the Greenland Stadial 22 (GS-22) between Greenland Interstadials (GIs) 21 and 22, for which inconsistent durations and ages have been reported from Greenland and Antarctic ice core records as well as European speleothems. Depending on the chronology used, GS-22 occurred between approximately 89 (end of GI-22) and 83 kyr b2k (onset of GI-21). From annual layer counting, we find that GS-22 lasted between 2696 and 3092 years and was followed by a GI-21 pre-cursor event lasting between 331 and 369 yr. Our layer-based counting agrees with the duration of stadial 22 as determined from the NALPS speleothem record (3250 ± 526 yr) but not with that of the GICC05modelext chronology (2620 yr) or an alternative chronology based on gas-marker synchronization to EPICA Dronning Maud Land ice core. These results show that GICC05modelext overestimates accumulation and/or underestimates thinning in this early part of the last glacial period. We also revise the possible ranges of NorthGRIP Δdepth (5.49 to 5.85 m) and Δage (498 to 601 yr) at the warming onset of GI-21 as well as the Δage range at the onset of the GI-21 precursor warming (523 to 654 yr), observing that temperature (represented by the δ15N proxy) increases before CH4 concentration by no more than a few decades.

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Dobro, Stephen M. "My continuing adventure with 21 CFR Part 11 - the evolution of Zymark's compliance." Journal of Automated Methods and Management in Chemistry 23, no. 6 (2001): 183–87. http://dx.doi.org/10.1155/s1463924601000232.

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A renewed focus has been given to the 3-year-old regulation 21 CFR Part 11, Electronic Records and Electronic Signatures. This paper gives a chronology of the process of an equipment vendor, Zymark Corporation, validating laboratory automation equipment for compliance to the regulation 21 CFR Part 11. Zymark's Tablet Processing Workstation II (TPW) and Prelude are the instruments chronicled. The first instrument, the TPW, was developed before Zymark defined its strategy on how to meet its customer's need for 21 CFR Part 11 compliant equipment. The TPW has been available for several years, and in the summer of 1999 it received a major software upgrade to improve its security. The second instrument, the Prelude, is a new product. It had a design requirement to meet the regulation. Zymark's Part 11 strategy was already in place and used for this development project. This chronology will include all aspects of the exercise, including familiarization with the standard, development of the protocols, review of the protocols by industry experts, review of the protocols by pharmaceutical users, execution of the tests, preparation of the exception reports, and the release of any necessary product revisions.

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Nawrocka, Danuta Michalska, Danuta Joanna Michczyńska, Anna Pazdur, and Justyna Czernik. "Radiocarbon Chronology of the Ancient Settlement in the Golan Heights Area, Israel." Radiocarbon 49, no. 2 (2007): 625–37. http://dx.doi.org/10.1017/s0033822200042521.

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Carbonate binders from mortars and plasters as well as charcoal fragments sampled at the ancient settlement of Hippos (Sussita) have been subjected to radiocarbon dating by gas proportional counting (GPC) and accelerator mass spectrometry (AMS). Hippos is situated on the east coast of the Sea of Galilee (32°46′N, 35°39′E) at the top of a hill in the Golan Heights area, Israel. According to historical-archaeological data, the town had functioned since the 3rd century BC until AD 749, when it eventually crumbled into ruins after an earthquake. The appropriate sample selection and preparation based on the results of petrographic observations permitted us to distinguish different phases involved in the expansion of the settlement. More than 200 samples were taken from the settlement and subjected to petrographic and chemical analyses. Of the 200 total samples, about 20 were selected for dating. Here, we present the first 10 results of 14C dating carried out for Hippos. The oldest sample dated thus far gave an age corresponding with the 2nd century BC to 1st century AD—probably indicating an old Roman temple, on the base of which the North-West church (NWC) was later erected. The next dates extend up to the 8th century AD, the age related to the last phase of settlement inhabitation. Research is continuing as new excavations take place.

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Kulakovska, L. V., N. P. Gerassimenko, V. I. Usik, and O. L. Votiakova. "MIDDLE PALEOLITHIC SITE RUBAN’ IN TRANSCARPATHIA: STRATIGRAPHY, CHRONOLOGY, INDUSTRY." Archaeology and Early History of Ukraine 26, no. 1 (March 22, 2018): 7–19. http://dx.doi.org/10.37445/adiu.2018.01.01.

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The Ruban’ Paleolithic site was discovered in 2005 by the Transcarpathian Paleolithic expedition of the Archaeological Museum of the IA NASU. The site is located on the territory of the former Zatysnansky chemical plant (Fig. 1b) at a distance of 800 m north of the eastern outskirts of the village of Gorbky, Vynohradiv district, in the Transcarpathian region, in the Ruban’ tract, and about 2 km to the southeast of the Korolevo site. At the time when the site Ruban’ was discovered, the upper part the quarry wall where the site is located, has been ruined by the quarrying that made it impossible to determine a stratigraphic position of the archaeological layer and to establish the age of the culture. In order to solve these problems, 15 geological profiles of the Quaternary deposits have been set along the less disturbed quarry wall in 2016—2017. The stratigraphic subdivision of the sections, according to the Quaternary stratigraphic framework of Ukraine, and their correlation with the profile of the archaeological site have been carried out that enables to determine the geological age of the cultural layer. The geological site Ruban’ is located along the paleoslope and, thus, there are erosional brakes in its sedimentary record. The lowermost stratigrpahical unit is represented by reddish-brown soil of Martonosha unit overlain by gleyed loam of Sula unit and strongly dissected by wedges of the Sula cryogenesis. The other Lower and Middle Pleistocene units have been truncated and now they are represented by pedosediments (with exception of the yellowish-brown soil of Upper Zavadivka unit). Kaydaky unit (the brown forest soil of a warm interglacial climate) is separated from Zavadivka soil by the level of wedges of the Dnieper cryogensis. Pryluky unit is represented by two soils (pl1 and pl3), separated by cryogenic fissures and, in places, by a thin loess layer (pl2). The dark-brown soil pl1 is characterized by both manganese concretions and thick managanese films in its upper part, whereas the brown forest soil pl3 is overlain by a thin layer of dense iron-manganese concretions (pl3c). This layer reflects unstable hydrothermal regime during the transition from the warm interstadial to the cold stadial climate of the Uday time. Uday unit is represented, in places, by a thin loess layer, which is overlain by brown forest soil of Vytachiv unit. The latter is dissected by cryogenic fissures, filled with the non-soil material of Bug unit. The Holocene unit is truncated in many places but the Holocene pedogenic processes (translocation) overprint the underlying units. The stratigraphic correlation of the studied sections with the archaeological site (excavation 1) demonstrates that the archaeological layer is located in the transitional bed of iron-manganese concretions (pl3c). According to the accepted comparison of the Ukrainian stratigraphy with marine isotopic-oxygen scale, the chronostratigraphic position of the archaeological layer corresponds to the transition from the end of the MIS 5 (5a) i. e. 74—64 ka BP. In the industry of Ruban’ site are prevailing the non-Levallois reduction methods of exploataion of Kombewa, centripetal, crossed and sub-crossed cores with a flat working surface. The parrallel reduction system is not typical and random. Blades are practically absent. In the collection of tool-kit dominated side scrapers, among which there is a series of natural backed side scrapers with a thick working edge, created by 2—3 rows of a stepped scaled retouch (Quina retouch type). Such samples can be attributed to a specific type of side scrapers, such as Quina or Semi-Quina (Fig. 7). In general, the main technological and typological features of the Ruban’ site industry are closely related to the cultural layer II of the Korolevo I site. These collections can be attributed to the local variant of the so-called Charantienne Techno-Complex.

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Izzo, Christopher, Zoë A. Doubleday, Gretchen L. Grammer, Morgan C. F. Disspain, Qifeng Ye, and Bronwyn M. Gillanders. "Seasonally resolved environmental reconstructions using fish otoliths." Canadian Journal of Fisheries and Aquatic Sciences 74, no. 1 (January 2017): 23–31. http://dx.doi.org/10.1139/cjfas-2016-0055.

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Exploiting the chemical and growth properties of otoliths, this study demonstrates how environmental archives with high temporal resolution can be developed. Elemental profiles (Ba:Ca and Sr:Ca) of fish otoliths (ear bones) from the estuarine species Acanthopagrus butcheri (black bream) were related to growth increments on a seasonal time scale. A series of mixed effects models were used to investigate biological, temporal, and environmental factors influencing seasonal otolith elemental profiles. Resultant seasonally resolved chemical chronologies were correlated with environmental data (i.e., salinity) to develop an element–salinity regression function, which when fit to an independently derived chemical chronology showed strong agreement between reconstructed and recorded salinities. Support for the element–salinity regression function through independent verification provided confidence in environmental reconstructions derived from an archaeological otolith. This suggests otoliths can be used to reconstruct past environmental conditions over decadal and centennial time scales. Moreover, the application of mixed effect models to develop chemical chronologies also provides information on drivers of elemental profiles and allows a range of ecological questions to be addressed. This approach may be further adapted and employed across a broader range of taxonomic groups and environments.

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McIntosh, Susan Keech, Marilee Wood, Laure Dussubieux, Peter Robertshaw, Timothy Insoll, and Mamadou Cissé. "Glass Beads from Medieval Gao (Mali): New Analytical Data on Chronology, Sources, and Trade." Journal of African Archaeology 18, no. 2 (June 10, 2020): 139–61. http://dx.doi.org/10.1163/21915784-20200009.

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Abstract Excavations at several archaeological sites in and around Gao have resulted in the recovery of thousands of glass beads presumed to have been acquired from glass bead-producing centers through trade. The bead assemblages cover the period from the eighth to the fourteenth century CE. Here we report on the results of compositional analysis by LA-ICP-MS of 100 beads, permitting comparison with the growing corpus of chemical analyses for glass from African and Near Eastern sites. In this analysis, several compositional groupings are recognized. These include two types of plant-ash soda-lime-silica glass (v-Na-Ca), a mineral soda-lime-silica glass (m-Na-Ca), a high-lime high-alumina (HLHA) glass, a mineral soda-high alumina (m-Na-Al), glass, a plant ash soda-high alumina (v-Na-Al) glass and a high lead composition glass. The reconstruction and dating of depositional contexts suggests a shift in glass sources at the end of the tenth century CE. The issue of source identification is discussed and occurrences at other African sites are mapped, providing new data towards an understanding of trade and exchange networks.

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Schultz, Jaime. "The Truth about Historical Sport Films." Journal of Sport History 41, no. 1 (April 1, 2014): 29–45. http://dx.doi.org/10.5406/jsporthistory.41.1.29.

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Abstract This article analyzes three new-millennial historical sports films that deal with racial desegregation and integration in the United States: Remember the Titans (2000), Glory Road (2006), and The Express (2008). Specifically, it attends to the ways in which filmmakers play fast and loose with history when it comes to chronology, characters, and past events. The intent is not to focus on micromistakes but rather to consider those inaccuracies most germane to the larger “truths” in these films. Ultimately, the author contends that historical sport films tend to depict racism as a relic of the past and freight sports figures with an excessive sense of responsibility for ostensible racial progress.

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Shukla, Tanuj, Manish Mehta, DP Dobhal, Archna Bohra, Bhanu Pratap, and Anil Kumar. "Late-Holocene climate response and glacial fluctuations revealed by the sediment record of the monsoon-dominated Chorabari Lake, Central Himalaya." Holocene 30, no. 7 (March 10, 2020): 953–65. http://dx.doi.org/10.1177/0959683620908654.

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We studied a periglacial lake situated in the monsoon-dominated Central Himalaya where an interplay of monsoonal precipitation and glacial fluctuations during the late Holocene is well preserved. A major catastrophe occurred on 16–17 June 2013, with heavy rains causing rupturing of the moraine-dammed Chorabari Lake located in the Mandakini basin, Central Himalaya, and exposed 8-m-thick section of the lacustrine strata. We reconstructed the late-Holocene climatic variability in the region using multi-parametric approach including magnetic, mineralogical and chemical (XRF) properties of sediments, paired with grain size and optically simulated luminescence (OSL) dating. The OSL chronology suggests that the lake was formed by a lateral moraine during the deglaciation phase of Chorabari Glacier between 4.2 and 3.9 ka and thereafter the lake deposited about 8-m-thick sediment sequence in the past 2.3 ka. The climatic reconstruction of the lake broadly represents the late-Holocene glacial chronology of the Central Himalaya coupled with many short-term climatic perturbations recorded at a peri-glacial lake setting. The major climatic phases inferred from the study suggests (1) a cold period between 260 BCE and 270 CE, (2) warmer conditions between 900 and 1260 CE for glacial recession and (3) glacial conditions between ~1370 and 1720 CE when the glacier gained volume probably during the ‘Little Ice Age’ (LIA). We suggest a high glacial sensitivity to climatic variability in the monsoon-dominated region of the Himalaya.

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Mojtabavi, Seyedhamidreza, Frank Wilhelms, Eliza Cook, Siwan M. Davies, Giulia Sinnl, Mathias Skov Jensen, Dorthe Dahl-Jensen, et al. "A first chronology for the East Greenland Ice-core Project (EGRIP) over the Holocene and last glacial termination." Climate of the Past 16, no. 6 (November 27, 2020): 2359–80. http://dx.doi.org/10.5194/cp-16-2359-2020.

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Abstract. This paper provides the first chronology for the deep ice core from the East Greenland Ice-core Project (EGRIP) over the Holocene and the late last glacial period. We rely mainly on volcanic events and common peak patterns recorded by dielectric profiling (DEP) and electrical conductivity measurement (ECM) for the synchronization between the EGRIP, North Greenland Eemian Ice Drilling (NEEM) and North Greenland Ice Core Project (NGRIP) ice cores in Greenland. We transfer the annual-layer-counted Greenland Ice Core Chronology 2005 (GICC05) from the NGRIP core to the EGRIP ice core by means of 381 match points, typically spaced less than 50 years apart. The NEEM ice core has previously been dated in a similar way and is only included to support the match-point identification. We name our EGRIP timescale GICC05-EGRIP-1. Over the uppermost 1383.84 m, we establish a depth–age relationship dating back to 14 967 years b2k (years before the year 2000 CE). Tephra horizons provide an independent validation of our match points. In addition, we compare the ratio of the annual layer thickness between ice cores in between the match points to assess our results in view of the different ice-flow patterns and accumulation regimes of the different periods and geographical regions. For the next years, this initial timescale will be the basis for climatic reconstructions from EGRIP high-resolution proxy data sets, e.g. stable water isotopes, chemical impurity or dust records.

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Vogel, J. S., Madeleine Briskin, D. E. Nelson, and J. R. Southon. "Ultra-Small Carbon Samples and the Dating of Sediments." Radiocarbon 31, no. 03 (1989): 601–9. http://dx.doi.org/10.1017/s0033822200012194.

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Radiocarbon dates from sediment core samples are usually obtained on the whole organic carbon portion in order to use as little of the valuable sediment as possible. Such measurements may not result in an accurate chronology of the sediment because the material may include carbon from different reservoirs at the time of deposition. The development of AMS techniques for dating ultra-small (20–500μg) carbon samples permits dating various components of cored sediments. We give examples of physical and chemical fractions of sediments which illustrate the large differences in ages obtainable from materials at the same sediment depth. The dating of all or several of these fractions demands more complex interpretations than just the derivation of a sedimentation rate from whole organic carbon dates.

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Beneš, Jaromír, Valentina Todoroska, Kristýna Budilová, Jaromír Kovárník, Jaroslav Pavelka, Nevenka Atanasoska, Jiří Bumerl, et al. "What about Dinner? Chemical and Microresidue Analysis Reveals the Function of Late Neolithic Ceramic Pans." Molecules 26, no. 11 (June 3, 2021): 3391. http://dx.doi.org/10.3390/molecules26113391.

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The Late Neolithic palafitte site, Ustie na Drim, in the northern part of Lake Ohrid (North Macedonia), excavated in 1962, offered ceramic fragments of large, flat, elongated pans. These artifacts could be dated by relative chronology to roughly around 5200–5000 BC. According to their shape and technological traits, the ceramic pans were probably used for baking. The attached materials on the surface of studied pan fragments were sampled for consequent chemical and microscopical analyses (i.e., analyses of starch, phytoliths, and microscopic animal remains). An immunological method revealed the presence of pork proteins in samples. The presence of organic residues of animal origin was, moreover, confirmed by the detection of cholesterol using gas chromatography coupled to mass spectrometry. Analysis of detected microscopic botanical objects revealed starch grains of several plants (i.e., oak, cattail, and grasses). An interesting find was the hair of a beetle larva, which could be interpreted contextually as the khapra beetle, a pest of grain and flour. Based on our data, we suppose that the ceramic pans from Ustie na Drim were used for the preparation of meals containing meat from common livestock in combination with cereals and wild plants.

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Budnik, P. I., V. F. Grishchenko, G. V. Klishevich, N. D. Curmei, and T. I. Makarenko. "Studying the chronology of climate change near Akademik Vernadsky Station by determination of concentrations of chemical impurities in the glacier." Ukrainian Antarctic Journal, no. 10-11 (2012): 315–19. http://dx.doi.org/10.33275/1727-7485.10-11.2012.317.

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Boenke, B. "The Full Bibliography of Dietrich Hoffmann." Beiträge zur Tabakforschung International/Contributions to Tobacco Research 24, no. 6 (November 1, 2011): 293–313. http://dx.doi.org/10.2478/cttr-2013-0910.

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AbstractThe chronology of lifetime publications authored or coauthored by Dr Dietrich Hoffmann covers a broad spectrum of different aspects of chemical carcinogenesis, the effects of air pollution and diet on cancer and - last but not least - all areas of tobacco research. In addition, Dr Dietrich Hoffmann has served as editor of several monographs concerned with research in the fields mentioned above. The important contributions of Dietrich Hoffmann to the science of carcinogenicity caused by lifestyle and environmental factors are impressively documented in the following list of his publications. It is based on entries in the scientific archive of Dr Hoffmann, which were kindly made available to the editors of this journal by MrsIlse Hoffmann. The material was reviewed and expanded by Dr Barbara Boenke of the Editorial Office of “BeiträgezurTabakforschung International”.

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Duboc, Quentin, Guillaume St-Onge, and Patrick Lajeunesse. "Sediment records of the influence of river damming on the dynamics of the Nelson and Churchill Rivers, western Hudson Bay, Canada, during the last centuries." Holocene 27, no. 5 (October 5, 2016): 712–25. http://dx.doi.org/10.1177/0959683616670465.

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Two gravity cores (778 and 780) sampled at the Nelson River mouth and one (776) at the Churchill River mouth in western Hudson Bay, Canada, were analyzed in order to identify the impact of dam construction on hydrology and sedimentary regime of both rivers. Another core (772) was sampled offshore and used as a reference core without a direct river influence. Core chronology was established using 14C and 210Pb measurements. Cores 778 and 780 show greater variability than the others, and the physical, chemical, magnetic, and sedimentological properties measured on these cores reveal the presence of several hyperpycnites, indicating the occurrence of hyperpycnal flows associated with floods of the Nelson River. These hyperpycnal flows were probably caused by ice-jam formation, which can increase both the flow and the sediment concentration following the breaching of such natural dams. However, these hyperpycnites are only observed in the lower parts of cores 778 and 780. It was not possible to establish a precise chronology because of the remobilization of sediments by the floods. Nevertheless, some modern 14C ages suggest that this change in sedimentary regime is recent and could be concurrent with the dam construction on the Nelson River, which allows a continuous control of its flow since the 1960s. This control prevented the formation of hyperpycnal flows and the deposition of hyperpycnites. Finally, core 776 contains only one rapidly deposited layer. This lower frequency may be related to the enclosed estuary of the Churchill River, its weaker discharge, and the distance of the site from shore.

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García-Guzmán, Lucia, Gustavo Cabrera-Barjas, Cintya G. Soria-Hernández, Johanna Castaño, Andrea Y. Guadarrama-Lezama, and Saddys Rodríguez Llamazares. "Progress in Starch-Based Materials for Food Packaging Applications." Polysaccharides 3, no. 1 (January 14, 2022): 136–77. http://dx.doi.org/10.3390/polysaccharides3010007.

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The food packaging sector generates large volumes of plastic waste due to the high demand for packaged products with a short shelf-life. Biopolymers such as starch-based materials are a promising alternative to non-renewable resins, offering a sustainable and environmentally friendly food packaging alternative for single-use products. This article provides a chronology of the development of starch-based materials for food packaging. Particular emphasis is placed on the challenges faced in processing these materials using conventional processing techniques for thermoplastics and other emerging techniques such as electrospinning and 3D printing. The improvement of the performance of starch-based materials by blending with other biopolymers, use of micro- and nano-sized reinforcements, and chemical modification of starch is discussed. Finally, an overview of recent developments of these materials in smart food packaging is given.

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Lichman, Benjamin R., Grant T. Godden, John P. Hamilton, Lira Palmer, Mohamed O. Kamileen, Dongyan Zhao, Brieanne Vaillancourt, et al. "The evolutionary origins of the cat attractant nepetalactone in catnip." Science Advances 6, no. 20 (May 2020): eaba0721. http://dx.doi.org/10.1126/sciadv.aba0721.

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Catnip or catmint (Nepeta spp.) is a flowering plant in the mint family (Lamiaceae) famed for its ability to attract cats. This phenomenon is caused by the compound nepetalactone, a volatile iridoid that also repels insects. Iridoids are present in many Lamiaceae species but were lost in the ancestor of the Nepetoideae, the subfamily containing Nepeta. Using comparative genomics, ancestral sequence reconstructions, and phylogenetic analyses, we probed the re-emergence of iridoid biosynthesis in Nepeta. The results of these investigations revealed mechanisms for the loss and subsequent re-evolution of iridoid biosynthesis in the Nepeta lineage. We present evidence for a chronology of events that led to the formation of nepetalactone biosynthesis and its metabolic gene cluster. This study provides insights into the interplay between enzyme and genome evolution in the origins, loss, and re-emergence of plant chemical diversity.

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Hatté, Christine, Luiz Carlos Pessenda, Andreas Lang, and Martine Paterne. "Development of Accurate and Reliable 14C Chronologies for Loess Deposits: Application to the Loess Sequence of Nussloch (Rhine Valley, Germany)." Radiocarbon 43, no. 2B (2001): 611–18. http://dx.doi.org/10.1017/s0033822200041266.

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Due to very high accumulation rates, loess sequences are best suited archives for the continental paleoclimate of glacial periods. Accurate chronologies cannot be easily established by radiocarbon-dating, because of the lack of organic macrorests, the only material for reliable 14C dating so far. A chemical protocol is reported to extract the organic matter of loess (organic carbon content lower than 0.1% by weight) for accelerator mass spectrometry (AMS) 14C dating. Sediments were taken from the loess sequence of Nussloch, for which a large dataset of luminescence ages (TL, IRSL/OSL) is available. The 14C chronology of the organic matter extracted from loess is in good agreement with the corresponding luminescence ages. It allows high resolution correlations with climatic proxy signals (magnetic susceptibility, malacological assemblages, δ13C on organic matter, etc.) derived from the loess sequence and global environmental proxy records.

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Barletta, Robert E. "Raman analysis of blue ice tephra: an approach to tephrachronological dating of ice cores." Antarctic Science 24, no. 2 (January 4, 2012): 202–8. http://dx.doi.org/10.1017/s0954102011000885.

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AbstractTephra in glacial ice provide a method to obtain a depth vs chronology correlation within an ice core. Currently, core sections containing particulate must be sacrificially analysed to determine the nature of the particulate (e.g. aerosol, micrometeor, volcanic ash), and, in the case of volcanic ash, the event tied to the particle. Characterization through melting and chemical analysis precludes, de facto, its use for other purposes. A non-destructive technique to characterize particulates in ice cores prior to sectioning the samples, e.g. optical interrogation, would be useful, especially if chemical information specific to particular volcanic eruptions could be gleaned from such an analysis. We investigated the use of micro-Raman spectroscopy for this purpose. Spectra were obtained on samples of Antarctic blue ice tephra from different sources along with a reference ash sample of New Mexico Bandelier Tuff. Vitreous and crystalline particles in the samples were characterized. For vitreous material, a detailed analysis of the Raman-active vibrational bands of the glass structure was found to have the potential of being a unique identifier of the source of the glass, however, additional library development is needed for implementation.

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Beltran, Marta Plaza. "Transparent Drawing Supports and Media Applied On It: Chemical Characterisation and Conservation Problems in Spanish Art Deco Jewellery Design." Restaurator. International Journal for the Preservation of Library and Archival Material 38, no. 2 (May 24, 2017): 181–203. http://dx.doi.org/10.1515/res-2016-0030.

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AbstractThe aim of this study is to characterise the chemical composition of the support materials, binders and pigments used in sales catalogues of Spanish Art Deco jewellery to determine the source of the damage observed in the samples analysed, and to formulate an appropriate conservation method. The difficulty in maintaining these collections in good condition without dismantling them lies, on the one hand, in the use of gouache on a variety of supports not usually used with this aqueous media (nitrocellulose, casein formaldehyde, starched cotton fabric and sulphurised paper), and on the other, in the vulnerability of these materials to agents of deterioration found in archives and libraries. The analysis was performed on a collection of 500 drawings, using the following analytical techniques: optical microscopy, Fourier transform infrared spectroscopy (FTIR), gas chromatography mass spectrometry (GC-MS), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), and Raman spectroscopy. The study shows the problems arising from storing some of the before mentioned materials in the same container, and highlights the need to classify each sample by its component materials and not by designer, chronology or type of jewellery.

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Winski, Dominic A., Tyler J. Fudge, David G. Ferris, Erich C. Osterberg, John M. Fegyveresi, Jihong Cole-Dai, Zayta Thundercloud, et al. "The SP19 chronology for the South Pole Ice Core – Part 1: volcanic matching and annual layer counting." Climate of the Past 15, no. 5 (October 8, 2019): 1793–808. http://dx.doi.org/10.5194/cp-15-1793-2019.

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Abstract. The South Pole Ice Core (SPICEcore) was drilled in 2014–2016 to provide a detailed multi-proxy archive of paleoclimate conditions in East Antarctica during the Holocene and late Pleistocene. Interpretation of these records requires an accurate depth–age relationship. Here, we present the SPICEcore (SP19) timescale for the age of the ice of SPICEcore. SP19 is synchronized to the WD2014 chronology from the West Antarctic Ice Sheet Divide (WAIS Divide) ice core using stratigraphic matching of 251 volcanic events. These events indicate an age of 54 302±519 BP (years before 1950) at the bottom of SPICEcore. Annual layers identified in sodium and magnesium ions to 11 341 BP were used to interpolate between stratigraphic volcanic tie points, yielding an annually resolved chronology through the Holocene. Estimated timescale uncertainty during the Holocene is less than 18 years relative to WD2014, with the exception of the interval between 1800 to 3100 BP when uncertainty estimates reach ±25 years due to widely spaced volcanic tie points. Prior to the Holocene, uncertainties remain within 124 years relative to WD2014. Results show an average Holocene accumulation rate of 7.4 cm yr−1 (water equivalent). The time variability of accumulation rate is consistent with expectations for steady-state ice flow through the modern spatial pattern of accumulation rate. Time variations in nitrate concentration, nitrate seasonal amplitude and δ15N of N2 in turn are as expected for the accumulation rate variations. The highly variable yet well-constrained Holocene accumulation history at the site can help improve scientific understanding of deposition-sensitive climate proxies such as δ15N of N2 and photolyzed chemical compounds.

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Journal articles on the topic 'Chemical chronology'

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