Analog Techniques Research Articles

Superior Li Metal Anodes By Molecular Layer Deposition of Lithicones

Superior Li Metal Anodes by Molecular Layer Deposition of Lithicones Xiangbo Meng*1, Kah Chun Lau*2, Xiaoxiao Han1, Hua Zhou3 1 Department of Mechanical Engineering, University of Arkansas, Fayetteville, AR 72701, USA 2 Department of Physics and Astronomy, Californica State University Northridge, CA 91330, USA 3 Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA* Corresponding author: xbmeng@uark.edu; kahchun.lau@csun.eduInterfaces, located between an electrode (either a cathode or an anode) and an electrolyte, are one of the most important components of rechargeable batteries. They are often determinant to batteries’ performance. In pursuing next-generation lithium-ion batteries (LIBs) and beyond, atomic layer deposition (ALD) has emerged and been identified as an important tool to accurately constitute their interfaces of LIBs and beyond at the atomic scale in the past decade.1-7 ALD features its unparalleled capabilities enabling coatings conformally and uniformly at moderate temperatures. It can be performed on either battery powders or prefabricated electrodes. Complementary to inorganic coatings by ALD, polymeric coatings can be deposited by an analogous technique, molecular layer deposition (MLD),8 and recently have been investigated. Having similar merits of ALD, MLD can constitute battery interfaces with flexible polymeric films at the molecular level. In this work, we developed three new lithium-containing polymers, lithicones, using MLD. Particularly, we revealed that the MLD LiGL (GL = glycerol) is very promising as a protective coating over lithium metal anodes. The LiGL-protected lithium metal anodes could achieve superior cyclability over 6,000 cycles without having any sign of failure at 5 mA/cm2 and 1 mAh/cm2. Our experiments and density function theory calculations disclosed that the LiGL lithicone is exceptional in its properties. This work paves a new avenue for developing safety-reliable high-performance lithium metal anodes.

Two pollen-based methods of Eemian climate reconstruction employed in the study of the Żabieniec-Jagodne palaeolakes in central Poland

The aim of the present study was to estimate the range of climate variability in Central Poland during the Eemian Interglacial (MIS 5e). High resolution pollen records are available for all seven RPAZs typical of this interglacial in Central Europe. These pollen records were used to estimate total annual precipitation and mean annual temperature, as well as the mean temperatures of the warmest and the coldest months based on the plant indicator method and the modern analogue technique. The reconstructions indicate that the combination of these two methods provides a much clearer insight into the climate changes of the Eemian optimum. The results confirmed no drastic drop in temperature in the Middle Eemian, with high total precipitation in the hazel phase, and that this was followed by a decrease in temperature in the Late Eemian (fir-spruce and pine phases). A drop in precipitation occurred during the youngest part of the Carpinus phase, while coincided with a marked lowering of the water level in lakes and their transformation into peatbogs. The last part of the Eemian is characterized by decreasing temperature, particularly during the coldest month, rising water levels due to a combination of lower evaporation and higher air humidity, and a transition to glacial conditions. Principal Component Analysis found all investigated sites to follow the same pattern of changes. Mean winter temperature, annual temperature and precipitation were found to have a strong positive correlation with the occurrence of thermophilus temperate broadleaved trees (hazel, linden, and ash) typical for the mid-Eemian optimum. These three factors also have a negative correlation with the presence of cold tolerant boreal trees (birch and pine) and open land taxa characteristic of the beginning and end of the interglacial. Mean July temperature was found to be positively correlated with the occurrence of temperate broadleaved trees (oak, ash and elm) typical for early stages of the Eemian and negatively with that of coniferous trees (fir and spruce) characteristic for later stages of the interglacial.

Digitalization in rheumatological practice

Die Digitalisierung in der Medizin steht seit der SARS-CoV-2-Pandemie im Mittelpunkt des Interesses. Der Beitrag versucht die Veränderungen und technischen Lösungen in Bezug auf die unterschiedlichen Teile der „patient journey“ darzustellen. Symptom-Checkers, neue Gesundheitsapplikationen, digitale Terminverwaltung etc. werden beschrieben. Abgesehen von den technischen und digitalen Möglichkeiten muss ergänzend die Veränderung der Qualität in der Kommunikation beachtet werden. Es besteht die dringende Notwendigkeit der weiteren technischen Standardisierung einschließlich der Schnittstellen. Weitere Studien müssen die Gleichwertigkeit der digitalen Anwendungen im Vergleich zur analogen Technik in vielen Fällen erst noch belegen.

Are Past Sea-Ice Reconstructions Based on Planktonic Foraminifera Realistic? Study of the Last 50 ka as a Test to Validate Reconstructed Paleohydrography Derived from Transfer Functions Applied to Their Fossil Assemblages

Since its existence, paleoceanography has relied on fossilized populations of planktonic foraminifera. Except for some extreme environments, this calcareous protist group composes most of the silty-to-sandy fraction of the marine sediments, i.e., the foraminiferal oozes, and its extraction is probably the simplest among the currently existing set of marine fossil proxies. This tool has provided significant insights in the building of knowledge on past climates based on marine archives, especially with the quantification of past hydrographical variables, which have been a turning point for major comprehensive studies and a step towards the essential junction of modelling and paleodata. In this article, using the modern analog technique and a database compiling modern analogs (n = 1007), we test the reliability of this proxy in reconstructing paleohydrographical data other than the classical sea-surface temperatures, taking advantage of an update regarding a set of extractions from the World Ocean Atlas for transfer functions. Our study focuses on the last glacial period and its high climatic variability, using a set of cores distributed along the European margin, from temperate to subpolar sites. We discuss the significance of the reconstructed parameters regarding abrupt and extreme climate events, such as the well-known Heinrich events. We tested the robustness of the newly obtained paleodata by comparing them with older published reconstructions, especially those based on the complementary dinoflagellate cyst proxy. This study shows that the potential of planktonic foraminifera permits going further in reconstructions, with a good degree of confidence; however, this implies considering ecological forcings in a more holistic perspective, with the corollary to integrate the message of this fossil protist group, i.e., the obtained parameters, in light of a cohort of other data. This article constitutes a first step in this direction.

Species correlation measurements in turbulent flare plumes: considerations for field measurements

Abstract. Field measurement of flare emissions in turbulent flare plumes is an important and complex challenge. Incomplete combustion from these processes results in emissions of black carbon, unburnt fuels (methane), CO2, and other pollutants. Many field measurement approaches necessarily assume that combustion species are spatially and/or temporally correlated in the plume, such that simple species ratios can be used to close a carbon balance to calculate species emission factors and flare conversion efficiency. This study examines the veracity of this assumption and the associated implications for measurement uncertainty. A novel tunable diode laser absorption spectroscopy (TDLAS) system is used to measure the correlation between H2O and black carbon (BC) volume fractions in the plumes of a vertical, turbulent, non-premixed, buoyancy-driven lab-scale gas flare. Experiments reveal that instantaneous, path-averaged concentrations of BC and H2O can vary independently and are not necessarily well correlated over short time intervals. The scatter in the BC/H2O ratio along a path through the plume was well beyond that which could be attributed to measurement uncertainty and was asymmetrically distributed about the mean. Consistent with previous field observations, this positive skewness toward higher BC/H2O ratios implies short, localized, and infrequent bursts of high BC production that are not well correlated with H2O. This demonstrates that the common assumption of fixed species ratios is not universally valid, and measurements based on limited samples, short sampling times, and/or limited spatial coverage of the plume could be subject to potentially large added uncertainty. For BC emission measurements, the positive skewness of the BC/H2O ratio also suggests that results from small numbers of samples are more likely to be biased low. However, a bootstrap analysis of the results shows how these issues can be avoided with sufficient sample size and provides initial guidance for creating sampling protocols for future field measurements using analogous path-averaged techniques.

Novel pollen analogue technique shows bumblebees display low floral constancy and prefer sites with high floral diversity

ContextThere have been dramatic global declines in pollinating insects. A common land management intervention to support wild pollinators is to plant non-crop flowering plants (‘pollinator planting’). However, there are limited data on which species or spatial arrangement of planting provide maximum benefit to wild pollinators.ObjectivesHere we investigate which flowering species and locations are visited by free-foraging Bombus terrestris (buff-tailed bumblebees) in species-rich semi-natural grassland and woodland.MethodsTwo study nests of buff-tailed bumblebees were established in Wytham Woods, UK. Pollen analogue pigments were sprayed on open flowers in the study area over a period of two months, with unique colours used to identify separate sections of the study area. Pollen load analysis was used to identify forage species and foraging locations.ResultsBumblebees showed low flower constancy, visiting five flower species per trip on average, and as a group the sampled bumblebees visited 36 of the 49 plant species identified in study area surveys. Many individuals foraged in multiple, spatially-discrete locations during single trips.ConclusionsThe positive relationship between floral diversity and pollen load species diversity, and the positive relationship between site floral diversity and frequency of visitation, suggest behavioural strategies that maximize the diversity of flower species visited, in line with the energetic costs and benefits hypothesis. This supports recommendations for pollinator plantings with high species diversity, potentially spread across many small forage areas across the landscape.

Translating Movement into Architectural Form

This work seeks to define original ways of creating architectonic forms using kinesiology studies. A series of methodologies are devised to record subjects in motion, with analogue and digital modelling techniques rigorously used independently and in combination to transpose these into sculptural figures with differing levels of formal fidelity and dimensional precision. Surface structures, and in particular thin shells, are found to have great potential for moving from abstract figures to structural forms. Such structures are traditionally problematic in terms of ‘constructional energy’, which has limited their usefulness and application. In response, the ‘hanging cloth reversed’ modelling technique devised by Heinz Isler is investigated to capitalise on the ambiguity between large-scale models and small structures. A construction method is devised that accords with the principles of structural art which, significantly, suggests that (small-span) shell structures could be liberated from the strictures of formwork to create economic, efficient and elegant minimal structures.

Hybrid Materiality

One of the most recognisable aspects of the digitalization of the design process is the increasing use of 3D printers and robots in the construction phases. When combining with analogue techniques, hybrid materiality in construction and architecture opens up significant application opportunities, but also challenges to the design process and production. In this study, the design and hybrid fabrication of a freeform gridshell structure, placed as a temporary installation in a public park, is presented. The structure was materialized in a hybrid combination of 129 wooden battens and 68 PLA 3D printed nodes, spanning 5 meters and reaching 2.5 m height. The examination of the challenges posed by the hybrid fabrication of the structure suggests that pre-conceived perceptions on production and installation stages should be reconsidered, and it highlights the importance of integrating material constraints and time limitations in the earliest phases of the design process.

Assessment of the UV inkjet ink penetration into laboratory papers within triticale pulp and its influence on print quality

AbstractToday the print quality of digital printing techniques has improved and is considered satisfactory and competitive to analogue techniques for certain graphic products. Satisfactory print quality mostly depends on the interaction of ink and printing substrate where ink penetration has an important role. Namely, the ink penetration affects the parameters that describe the print quality together with visual appearance of print density and mottling. Therefore, it is important to select an adequate printing substrate for each printing technique. Awareness of environmental problems related to the shortage of wood raw materials has led to an increase in the use of recycled printing paper and in particular the implementation of new alternative sources of cellulose fibres instead of virgin wood fibres in the papermaking process. In this research the emphasis is precisely on defining the influence of ink penetration into laboratory papers made of triticale pulp on the final print quality. The laboratory printing papers were obtained by mixing triticale pulp with pulp from recycled fibres in three different portions. Papers were thereafter printed by ultraviolet (UV) inkjet printer and the ink penetration within laboratory papers with and without straw pulp was analysed using two methods of ink penetration analysis (microscopic/spectroscopic). The influence of ink penetration on the final print quality was observed and analysed based on several quality parameters (optical ink density, mottling and colorimetric values). These results confirmed that triticale pulp in laboratory papers provides equal print quality compared to laboratory papers made only from pulp from recycled fibres.

Synthesising the pollen records for the Drakensberg-Maloti through quantitative modelling

The Drakensberg-Maloti has been a region of great hydrological importance for thousands of years, captured in the archaeological record as a region of refuge under dry conditions, and in recent decades supplying adjacent South Africa with water through the Lesotho Highlands Water Scheme. This is due in large part to its high amounts of orographically induced rainfall. The high amounts of rainfall mean the area lends itself well to the preservation of multiple proxies in the region's many wetlands, a very valuable resource for palaeoecological studies in the generally dry southern Africa. However, there have been few quantitative palaeoclimatic studies taking advantage of this, and none using multiple sites within the Drakensberg-Maloti region. This study represents the first attempt at such a regional synthesis. We utilised all published pollen records from the area to produce a dataset from which the standard Modern Analogue Technique was performed to reconstruct mean temperature of the warmest month, mean annual precipitation, mean winter precipitation and an annual climatic moisture index for the past 8000 years. The moisture index showed a very low amount of variation, most likely due to the low amount of variation in the modern climate data associated with the sites in the modern calibration dataset, being so near the saturation point of this index. We found evidence for a cool, wet period at around 2 cal ka BP, a period that has been identified in records from across South Africa as a Neoglacial, and which is consistent with diatom and sedimentary records from the Drakensberg-Maloti.

High-resolution reconstructions of Holocene sea-surface conditions from dinoflagellate cyst assemblages in the northern South China Sea

A high-resolution dinoflagellate cyst analysis on a sediment core GLW31D from the northern South China Sea (SCS) was performed to reconstruct paleoceanographic conditions over the last 12,500 years through qualitative, semi-quantitative, and quantitative methods. A modern dataset with 398 reference sites in the northern Pacific was assembled and used to identify the relationship between dinoflagellate cyst assemblages and sea-surface temperature (SST), sea-surface salinity (SSS) and primary productivity (PP). Modern analog technique (MAT) was applied to offer first dinoflagellate-cyst-based quantitative estimates of Holocene sea-surface conditions in the western North Pacific. The downcore reconstructions show that SST, SSS and PP were predominantly controlled by the changes in coastal and oceanic currents due to the changes in sea level and monsoon systems. Our results indicate that SST increased while SSS and PP decreased from 12,500 to ~6800 cal yr BP, reaching the maximum SST and the minimum SSS and PP during ~6800–5000 cal yr BP, and followed by a slight decline in SST with minor increases in SSS and PP. The three intervals correspond to the regional onshore sea-level stages of rising, stabilization in a highstand and slight drop, respectively. The Kuroshio Current strongly influenced the core site before ~9900 cal yr BP, reflected by the highest abundances of oceanic Impagidinium spp. and high reconstructed SSS values. This can be explained by a lack of water input from the East China Sea before the opening of the Taiwan Strait. The warmest period, from ~6800 cal yr BP to ~5500 cal yr BP, is recorded by the highest Dapsilidinium pastielsii abundances. Two short-term high-PP events of ~2700–2400 cal yr BP and ~1000–600 cal yr BP, which were characterized by opposite climatic conditions, coincided with two notable societal (dynasty) collapses of China. Enhanced anthropogenic activities since the Late Bronze Age most likely partially affected the high PP through influencing river inputs to the northern SCS.

Vegetation Reconstruction From Siberia and the Tibetan Plateau Using Modern Analogue Technique–Comparing Sedimentary (Ancient) DNA and Pollen Data

To reconstruct past vegetation from pollen or, more recently, lake sedimentary DNA (sedDNA) data is a common goal in palaeoecology. To overcome the bias of a researcher’s subjective assessment and to assign past assemblages to modern vegetation types quantitatively, the modern analogue technique (MAT) is often used for vegetation reconstruction. However, a rigorous comparison of MAT-derived pollen-based and sedDNA-based vegetation reconstruction is lacking. Here, we assess the dissimilarity between modern taxa assemblages from lake surface-sediments and fossil taxa assemblages from four lake sediment cores from the south-eastern Tibetan Plateau and northern Siberia using receiver operating characteristic (ROC) curves, ordination methods, and Procrustes analyses. Modern sedDNA samples from 190 lakes and pollen samples from 136 lakes were collected from a variety of vegetation types. Our results show that more modern analogues are found with sedDNA than pollen when applying similarly derived thresholds. In particular, there are few modern pollen analogues for open vegetation such as alpine or arctic tundra, limiting the ability of treeline shifts to be clearly reconstructed. In contrast, the shifts in the main vegetation communities are well captured by sedimentary ancient DNA (sedaDNA). For example, pronounced shifts from late-glacial alpine meadow/steppe to early–mid-Holocene coniferous forests to late Holocene Tibetan shrubland vegetation types are reconstructed for Lake Naleng on the south-eastern Tibetan Plateau. Procrustes and PROTEST analyses reveal that intertaxa relationships inferred from modern sedaDNA datasets align with past relationships generally, while intertaxa relationships derived from modern pollen spectra are mostly significantly different from fossil pollen relationships. Overall, we conclude that a quantitative sedaDNA-based vegetation reconstruction using MAT is more reliable than a pollen-based reconstruction, probably because of the more straightforward taphonomy that can relate sedDNA assemblages to the vegetation surrounding the lake.

Improving short to medium range GEFS precipitation forecast in India

This study aims to enhance daily precipitation forecasts over the Indian subcontinent through post-processing the Global Ensemble Forecast System (GEFS) outputs using Analog (AN) and Logistic Regression (LR) techniques. Both raw and post-processed GEFS precipitation forecasts were evaluated against the Indian Meteorological Department observed dataset using probabilistic and deterministic forecast evaluation metrics, namely Brier Skill Score (BSS) and Root Mean Square Error (RMSE), respectively. Results found that the LR and AN post-processing method considerably improved short to medium range (1–7 day) precipitation forecasts over India. A comparison of the techniques with GEFS version 12 (GEFSv12) forecasts across different basins suggests that both methods were able to provide skillful precipitation forecasts in all the river basins, except that the AN method underperformed for the western ghats. The seasonal analysis also showed that the raw and the post-processed forecasts under-performed during the monsoon season while performing comparatively well during the non-monsoon season. The comparison of LR and AN methods showed that LR outperformed the AN method. The forecasts enhanced using both the post-processing techniques were more reliable and skillful than the GEFSv12 precipitation forecast. Comparison of the recent GEFS version with the older version of GEFS showed that the performance of the earlier version was slightly better compared to the latest version, however none of the forecasts can be used for decision making purposes without post-processing.

Digitally Fabricated Removable Complete Denture Clinical Workflows using Additive Manufacturing Techniques.

The use of computer aided design and computer aided manufacturing in the fabrication of complete removable dentures has demonstrated that the prostheses produced are superior in many ways to removable dentures produced using analog techniques. A variety of clinical workflows that take advantage of digital technology have been shown to shorten the number of appointments required to produce high quality prostheses. This paper presents an overview of additive manufacturing in contemporary removable complete denture workflows and describes effective three appointment clinical techniques using additive manufacturing to produce a clinical trial denture and definitive prosthesis.

Environmental changes of the stadial/interstadial type during the Late Saalian (MIS-6) – Multi-proxy record at the Wola Starogrodzka site, central Poland

Marine, lacustrine and terrestrial records from many sites located in various regions of the world suggest that the climate amelioration at the end of MIS-6 (Late Saalian) was interrupted by the short-termed cooling just prior to the MIS-6/MIS-5e boundary (Saalian/Eemian). This climatic event might be similar to the transition between interstadial conditions of the Allerød and stadial conditions of the Younger Dryas at the end of the Last Glacial (MIS-2). On the other hand, the results of quite numerous palaeobotanical studies show no stadial-interstadial oscillations below the Saalian/Eemian boundary, but reflect the gradual improvement of climate and increasing density of vegetation at that time. In western and central Europe, environment changes at the end of the Late Saalian are poorly recognized. Therefore, each new record illustrating this part of the Late Pleistocene is extremely important. We examined two profiles at the Wola Starogrodzka site, central Poland, by high-resolution analyses of pollen, Cladocera, plant macroscopic remains, mineral grain size and distribution, and organic matter content. The studied sequences represent the closing phase of the Late Saalian (in Poland called the Warta Stage of Odranian), and the early to middle part of the Eemian Interglacial. Change of the stadial-interstadial-stadial type at the end of the Late Saalian was registered both in aquatic and terrestrial environment. The recorded interstadial was correlated with Zeifen interstadial, while the following stadial – with the Kattegat stadial. Quantitative palaeoclimate reconstruction based on pollen data (modern analogue technique) showed the change in mean annual temperature by ca. 3 °C at that time.

11] デジタルアーカイビングによるアナログ的「技巧」の採掘:西北タイ歴史文化調査団蒐集8mm動的映像の再資料化を通じて

11] デジタルアーカイビングによるアナログ的「技巧」の採掘:西北タイ歴史文化調査団蒐集8mm動的映像の再資料化を通じて

Spatial data science for data driven urban planning: The youth economic discomfort index for Rome

Today, a consistent segment of the world’s population lives in urban areas, and this proportion will vastly increase in the next decades. Therefore, understanding the key trends in urbanization, likely to unfold over the coming years, is crucial to the implementation of sustainable urban strategies. In parallel, the daily amount of digital data produced will be expanding at an exponential rate during the following years. The analysis of various types of data sets and its derived applications have incredible potential across different crucial sectors such as healthcare, housing, transportation, energy, and education. Nevertheless, in city development, architects and urban planners appear to rely mostly on traditional and analogical techniques of data collection. This paper investigates the prospective of the data science field, appearing to be a formidable resource to assist city managers in identifying strategies to enhance the social, economic, and environmental sustainability of our urban areas. The collection of different new layers of information would definitely enhance planners' capabilities to comprehend more in-depth urban phenomena such as gentrification, land use definition, mobility, or critical infrastructural issues. Specifically, the research results correlate economic, commercial, demographic, and housing data with the purpose of defining the youth economic discomfort index. The statistical composite index provides insights regarding the economic disadvantage of citizens aged between 18 years and 29 years, and results clearly display that central urban zones and more disadvantaged than peripheral ones. The experimental set up selected the city of Rome as the testing ground of the whole investigation. The methodology aims at applying statistical and spatial analysis to construct a composite index supporting informed data-driven decisions for urban planning.

A case study of an autonomous model between a real and a virtual environment

ABSTRACT In this short article and accompanying visual essay, I trace the development and implementation of a dialogic site-specific performance in public space. I propose a scenographic method for how to make an empty, abandoned urban public space ‘speak’: how to choose the site for the performance and how to construct a narrative based on the history of the site. The actual ‘set’ of the performance, the analogue AR (Augmented Reality) boxes, played with some of the central features of AR technology. These characteristics were, in several respects, consistent with the site-specific performance characteristics presented in the case study. The concept raised in the study builds on the meeting points of these two. The performance created a blurring of real and virtual space through an analogue technique.

Developing a continental-scale testate amoeba hydrological transfer function for Asian peatlands

Testate amoebae (TA) are a common and diverse group of protists and are especially abundant in peatlands. The structure of peatland TA communities is well correlated to surface moisture and water table depth (WTD). For that reason, TA are widely used as proxy indicators in ecological and palaeoecological studies. Peatlands are abundant across Asia, but the diversity and ecology of the TA that inhabit these systems are poorly documented. It is therefore unclear whether TA can be used as palaeohydrological indicators in the manner in which they commonly are in Europe and North-America. There is particular uncertainty as to the efficacy of this approach in the lower latitudes. We compiled existing and new data on testate amoebae from 1124 Sphagnum-dominated samples from 42 individual peatlands covering broad latitudinal (25°–66° N) and longitudinal (68°–129° E) ranges. Using a consensus taxonomic framework, we built a checklist of TA and developed TA-based hydrological transfer functions for Asian peatlands. The results showed that three models, weighted averaging (WA), weighted average partial least squares (WA-PLS), and maximum likelihood (ML), predicted similar WTD values for full samples, while the modern analogue technique (MAT) produced the strongest (R2boot = 0.58) relationship between observed and estimated water-table depths (WTDs). Removing outlier samples improved the R2 values of observed vs. estimated WTDs, with ML then demonstrating the strongest predictive power (R2boot = 0.68, RMSEPboot = 8.98 cm). The predictive capability of the developed WTD transfer function is comparable to equivalent models for Europe and North America and thus can be used for palaeohydrological reconstructions for boreal to subtropical peatlands in Asia.

A multi-proxy reconstruction of climate during the late-Pleistocene to early Holocene transition in the northeastern, USA

AbstractA multiproxy record from Twin Ponds, VT, is used to reconstruct climatic variability during the late Pleistocene to early Holocene transition. Pollen, ostracodes, δ18O, and lithologic records from 13.5 to 9.0 cal ka BP are presented. Pollen- and ostracode-inferred climatic reconstructions are based on individual species’ environmental preferences and the modern analog technique. Principal components analysis of all proxies highlights the overall warming trend and centennial-scale climatic variability. During the Younger Dryas cooling event (YD), multiple proxies show evidence for cold winter conditions and increasing seasonality after 12.5 cal ka BP. The early Holocene shows an initial phase of rapid warming with a brief cold interval at 11.5 cal ka BP, followed by a more gradual warming; a cool, wet period from 11.2 to 10.8 cal ka BP; and cool, dry conditions from 10.8 to 10.2 cal ka BP. The record ends with steady warming and increasing moisture. Post-YD climatic variability has been observed at other sites in the northeastern United States and points to continued instability in the North Atlantic during the final phases of deglaciation.