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Paleoecological and modern studies at Priyatnoye Lake, which is located within an intermontane depression in the interior of northeastern Siberia, indicate a similar paleovegetation record as has been documented for nearby mountain valleys, but a history of basin stability and instability that is uncharacteristic of the valley lakes. Analyses of a 385-cm-long core from the western basin of Priyatnoye Lake shows that sediment accumulation began in late Marine Oxygen Isotope Stage 3 (MIS 3), followed by a hiatus during MIS 2, and then continuous accumulation over the past ca. 14,000 cal yr BP. The eastern basin of the lake has a sediment thickness of ~35 cm, suggesting that it intermittently contained water and/or is younger than the western basin. A drop in lake levels between AD 2005 and AD 2009 resulted in the formation of two distinct lakes. This change was caused by the melting of underlying ice wedges and the formation of sinkholes through which the lake water drained. Although the northern coastal lowlands have been the geographic focus of permafrost global warming research, the Priyatnoye study draws attention to the intermontane depressions in northeastern Siberia. While less extensive, these depressions contain organic-rich deposits, are underlain by permafrost, and have the potential to affect future carbon budgets as global temperatures rise and permafrost melts.

A high-resolution, multiproxy analysis of a core from Tokotan Lake, Urup Island, illustrates the complex paleoenvironmental signals that can be preserved in sedimentary deposits from geologically active areas, such as the Kuril Archipelago. Diatom and geochemical analyses of the Tokotan core suggest a shallowing and lessening of the lake area over the last ∼3450 cal BP. Without other proxies, the record could be interpreted as showing a general decrease in precipitation over the Late Holocene. However, palynological data indicate no change in vegetation, thereby implying no significant climatic variation. Neither of these paleoclimatic interpretations agrees with Late Holocene reconstructions from the Kuril Archipelago or the Russian mainland. Paleomagnetic data imply variable sediment sources during the lake's history, indicating alterations within the Tokotan catchment (e.g., shifts in gradients or sediment loads in the inflowing streams). Such changes would be particularly important in the Shabalina River, which today has formed a partial dam across the lake's outlet. The results of the Tokotan study indicate that other factors (e.g., volcanism, seismic activity, sea-level changes) rather than climate were more probable determinants of the Late Holocene lake record. Given the geologic dynamism of the region, it is perhaps not surprising that paleo-records from the Kuril Islands display an inconsistency in the numbers and/or duration of proposed Holocene climatic oscillations, underscoring the importance of multiproxy investigations in areas that are or have been geologically dynamic.

Palynological and plant macrofossil data and remains of Mammuthus primigenius from the Tanon quarry (59° 40′ N, 151° 12′ E) provide much needed information about environments in southwestern Beringia during the Middle Holocene and marine isotope stages (MIS) 2 and 3. During the Middle Holocene, Larix-Betula forest characterized the Tanon region and differed from the Larix forests of interior Western Beringia. Betula platyphylla, which today is more common in moderate regions of the Far East, was an important component of the coastal forest near the quarry and possibly was more extensive in the coastal lowland. Ecological and quantitative models suggest that the coastal region experienced longer growing seasons and warmer summer temperatures, which could support the expansion of tree Betula. The MIS 2 palynological assemblage from Tanon indicates a prevalence of mesic and xeric herb-dominated tundra. However, the macrofossil data consist largely of taxa found in forest or forest-tundra with only a minor contribution by steppe species. The Tanon results agree with the larger paleovegetation database from Beringia, which suggests that steppe was not widespread during the Late Pleistocene but rather the landscape was characterized by a mosaic of tundra types. The Tanon site provides the first information about MIS 3 coastal vegetation, indicating the presence of Larix-Betula forest within valleys and shrub tundra at higher elevations. The discovery of Mammuthus primigenius in the quarry marks the southernmost population of Late Pleistocene mammoths in Western Beringia.

Background and Aim Patients with refractory ascites have frequent hospital admissions, which pose exposure risks in the context of the COVID‐19 pandemic. The aim of this study was to investigate the safety and efficacy of a novel 12‐week, multidisciplinary ambulatory care program allowing frequent low‐volume ascitic drainage through a tunneled, intraperitoneal catheter (IPC). Methods Adult patients with cirrhosis complicated by refractory ascites were recruited through a liver clinic in a tertiary health service in Melbourne, Australia from April to December 2020. All patients were enrolled in a 12‐week multidisciplinary program including medical, nursing, dietetics, and pharmacy support. A Rocket Medical IPC was inserted on day 1 with 1–2 L of ascitic fluid drained over 1–3 sessions per week either at the patients' homes or at the hospital day ward. Patients' demographics, death, complications, and self‐reported outcomes were recorded. Results Twelve patients were enrolled with a median of 65‐day (interquartile range [IQR]: 16.5–93) IPC duration between April and December 2020 across two periods of COVID‐related lockdown in Melbourne, Australia. There were no IPC‐related deaths. Early removal was necessitated in three patients due to leakage, nonadherence, and bacteremia. On day 30, the median self‐reported health score increased from 50 (IQR: 50–70) to 78 (IQR: 50–85), attributable to a reduction in symptom burden. Conclusion A multidisciplinary IPC program including the use of short‐term IPC was safe and associated with a self‐reported improvement in perceptions of health. In the context of the COVID‐19 pandemic, the program aimed to reduce patient and clinician exposure, which is maintaining engagement and management of decompensated cirrhosis., Management of refractory cirrhotic ascites poses exposure risks in the context of the COVID‐19 pandemic. We found that short‐term intraperitoneal catheters as part of a home‐based multidisciplinary program were safe and associated with improvement in self‐reported health perception.

The Berelyokh site includes an exceptional bone horizon consisting of 8431 remains of Mammuthus primigenius. Previous investigations, spanning ~40 years, concluded that the deaths and bone concentration were caused by spring flooding, possibly related to wetter Bølling climates. We review work from these studies with emphasis on under-reported palynological data to provide more detail on paleoenvironmental reconstructions and an alternative interpretation for the age and origin of the bone bed. Palynological results suggest the horizon formed under cool conditions of the last glacial maximum, rather than during a Bølling-type oscillation. Presence of permafrost features and associated tundra pollen taxa in the Berelyokh sections suggest that thermokarst processes, unrelated to climate change, could account for the formation of the bone horizon. The penetration of surface waters into frozen sediments of a high floodplain terrace resulted in the formation of hidden thaw sinks. As thaw continued, the pits expanded with surface soils supported by a viscous water-sediment mixture. The weakened surface gave way under the weight of the mammoths, with the hillside collapsing either due to the animals’ struggles or destabilization related to the thaw sinks. This scenario highlights the hazards of thermokarst terrain for present and future populations of northern animals.

Recent global warming is pronounced in high-latitude regions (e.g. northern Asia), and will cause the vegetation to change. Future vegetation trends (e.g. the "arctic greening") will feed back into atmospheric circulation and the global climate system. Understanding the nature and causes of past vegetation changes is important for predicting the composition and distribution of future vegetation communities. Fossil pollen records from 468 sites in northern and eastern Asia were biomised at selected times between 40 cal ka bp and today. Biomes were also simulated using a climate-driven biome model and results from the two approaches compared in order to help understand the mechanisms behind the observed vegetation changes. The consistent biome results inferred by both approaches reveal that long-term and broad-scale vegetation patterns reflect global- to hemispheric-scale climate changes. Forest biomes increase around the beginning of the late deglaciation, become more widespread during the early and middle Holocene, and decrease in the late Holocene in fringe areas of the Asian Summer Monsoon. At the southern and southwestern margins of the taiga, forest increases in the early Holocene and shows notable species succession, which may have been caused by winter warming at ca. 7 cal ka bp. At the northeastern taiga margin (central Yakutia and northeastern Siberia), shrub expansion during the last deglaciation appears to prevent the permafrost from thawing and hinders the northward expansion of evergreen needle-leaved species until ca. 7 cal ka bp. The vegetation-climate disequilibrium during the early Holocene in the taiga-tundra transition zone suggests that projected climate warming will not cause a northward expansion of evergreen needle-leaved species.

Palynological and elemental geochemical data from the Lake El'gygytgyn sediment core indicate that differences occur not only between cool and warm periods of the middle Middle Pleistocene (~ 374–790 ka) but also when comparing glacial-to-glacial and interglacial-to-interglacial intervals. The magnitude and/or timing of lake and landscape responses are at times similar (e.g., MIS 11, MIS 15) and at other times different (e.g., MIS 13), suggesting a complexity of feedbacks within and between the lake and landscape. Within-stage variations in the geochemistry likely reflect shorter-term shifts in regional climate, local vegetation cover, sediment input, and/or within-basin interactions of biological and physical systems. The palynological data indicate that each interglaciation has its own specific vegetation history including differences in early interglacial vegetation and in the type and timing of climax vegetation. Cooler intervals, while showing fewer changes in plant communities, do indicate greater variability in vegetation as compared to younger glaciations, including the persistence of Larix. While changes in the proxy data generally approximate shifts in the δ18O record, a large discrepancy occurs in the timing of the MIS 10–MIS 11 transition, suggesting that the Lake E age model needs adjustment. The variety of responses within the Lake E record to large-scale forcings (e.g., orbital parameters, ice extent) provides an opportunity to further explore regional responses of arctic environments to a broad range of paleoclimatic conditions.

Two lake records document Holocene changes in sea level, vegetation, and climate on the Okhotsk and Pacific sides of central Iturup Island, southern Kuril Islands. The sediment cores originated within tidal flats that subsequently developed into a marine strait which crosscut the island as sea levels rose during the early Holocene. Brackish lagoons and eventually freshwater lakes formed by ~7100 cal yr BP associated with warmer than present conditions. Past vegetation changes indicate a clear Holocene thermal maximum recorded on the Pacific coast but a less distinct optimum on the western shores (~7200–6100 cal yr BP). A gradual cooling toward modern levels occurred ~6100–3500 cal yr BP. Four prominent layers of coarse sediment found in mid- to late Holocene lake deposits may correspond to intervals of climate cooling/dune formation previously documented in coastal sections. Although chronological limitations question the synchronicity of these events across the south Russian Far East, it seems probable that they have a regional signature. However, the mechanisms responsible for Holocene climatic changes are likely the result of complex interactions of hemispheric-scale atmospheric patterns, marine characteristics, and regional feedbacks rather than simply fluctuations in sea levels as suggested in the current interpretative model.

A continuous pollen record from Lake El'gygytgyn (northeastern Russian Arctic) provides detailed information concerning the regional vegetation and climate history during the Mid-Pleistocene Transition (MPT), between 1091 ka (end of Marine Isotope Stage (MIS) 32) and 715 ka (end of MIS 18). Pollen-based qualitative vegetation reconstruction along with biome reconstruction indicate that the interglacial regional vegetation history during the MPT is characterized by a gradual replacement of forest and shrub vegetation by open herbaceous communities (i.e. tundra/cold steppe). The pollen spectra reveal seven vegetation successions that have clearly distinguishable glacial-interglacial cycles. These successions are represented by the intervals of cold deciduous forest (CLDE) biome scores changing from high to low, which are basically in phase with the variations of obliquity from maxima to minima. The dominating influence of obliquity forcing on vegetation successions contradicts with the stronger power of eccentricity, as demonstrated by the result of wavelet analysis based on landscape openness reconstruction. This discrepancy shows that a single index is insufficient for catching signals of all the impacting factors. Comparisons with vegetation and environmental changes in the Asian interior suggest that global cooling during the MPT was probably the key force driving long-term aridification in the Arctic region. The accelerated aridification after MIS 24–22 was probably caused by the additional effect of the Tibetan Plateau uplift, which played an important role on intensification of the Siberian High and westerly jet systems.

A megaslump at Batagaika, in northern Yakutia, exposes a remarkable stratigraphic sequence of permafrost deposits ~50–80 m thick. To determine their potential for answering key questions about Quaternary environmental and climatic change in northeast Siberia, we carried out a reconnaissance study of their cryostratigraphy and paleoecology, supported by four rangefinder 14C ages. The sequence includes two ice complexes separated by a unit of fine sand containing narrow syngenetic ice wedges and multiple paleosols. Overall, the sequence developed as permafrost grew syngenetically through an eolian sand sheet aggrading on a hillslope. Wood remains occur in two forest beds, each associated with a reddened weathering horizon. The lower bed contains high amounts of Larix pollen (>20%), plus small amounts of Picea and Pinus pumila, and is attributed to interglacial conditions. Pollen from the overlying sequence is dominated by herbaceous taxa (~70%–80%) attributed to an open tundra landscape during interstadial climatic conditions. Of three hypothetical age schemes considered, we tentatively attribute much of the Batagaika sequence to Marine Oxygen Isotope Stage (MIS) 3. The upper and lower forest beds may represent a mid–MIS 3 optimum and MIS 5, respectively, although we cannot discount alternative attributions to MIS 5 and 7.

Measures of masculinities have expanded in recent decades to reflect greater diversity. A comparative reading of the literature suggests that African American men may endorse the same macho ideology shared by Afro-Jamaican men, which is captured by the Jamaican Macho Scale. The current article examines whether the Macho Scale is relevant to explaining masculinity among African American males using exploratory and confirmatory factor analysis techniques. A sample of 203 African American male college students from a large university in the Eastern United States participated in a self-administered survey, which included the Macho Scale items. Results supported a two-factor model of macho ideology, specifically sexual dominance and virility, and procreative need, in the American context. Future research should examine understudied masculinity ideology constructs in the American setting and attempt to map the full content domain of African American masculinity ideologies.

The Pliocene-Pleistocene boundary, set at 2.588 Ma or the base of the Gelasian age, represents a shift in global climates from those of the comparatively warm Pliocene to the cooler conditions of the Pleistocene. Lake El’gygytgyn (Chukotka) provides one of the few continuous terrestrial records that permits a close examination of this important transition in Earth’s climate states. The MIS 102-MIS 103 portion of the El’gygytgyn palynological record indicates that, during the earliest Pleistocene, this area of the Arctic was vegetated by closed Larix-BetulaAlnus forest. Such vegetation contrasts to that of the latest Pliocene, when Larix forest-tundra dominated, and differs from the herb and shrub tundra found today in northern Chukotka. This earliest period of the Gelasian represents the climatic optimum for MIS 103. Even under the most severe conditions during MIS 102, Larix forest-tundra persisted, which differs greatly from the herb tundra that characterized many glacial intervals in the Arctic during the Late and Middle Pleistocene.

Pollen records from Siberia are mostly absent in global or Northern Hemisphere synthesis works. Here we present a taxonomically harmonized and temporally standardized pollen dataset that was synthesized using 173 palynological records from Siberia and adjacent areas (northeast Asia, 50°–180° E and 42°–75° N). Pollen data were taxonomically harmonized, that is the original 437 taxa were transformed to 106 combined pollen taxa. Age-depth models for all records were revised by applying a constant Bayesian age-depth modelling routine. The pollen dataset is available as count data and percentage data in a table format (taxa vs. samples) with age information for each sample. The dataset has relatively few sites covering the last glacial period between 40 and 11.5 cal ka BP (calibrated thousand years before present 1950 CE) particularly from the central and western part of the study area. In the Holocene period, the dataset has many sites from most of the area except the central part of Siberia. Of the 173 pollen records, 81 % of pollen counts were downloaded from open databases (GPD, EPD, Pangaea) and 10 % were contributions of the original data gatherers, while a few were digitized from publications. Most of the pollen records originate from peatlands (48 %) and lake sediments (33 %). Most of the records (83 %) have ≥ 3 dates allowing the establishment of reliable chronologies. The dataset can be used for various purposes including pollen data mapping (example maps for Larix at selected time-slices are shown) as well as quantitative climate and vegetation reconstructions. The datasets for pollen counts and pollen percentages are available at https://doi.pangaea.de/10.1594/PANGAEA.898616 (Cao et al., 2019).

The unearthing in 1977 of a complete frozen carcass of a young mammoth, known as the Kirgilyakh mammoth or Dima: 1) provided the first opportunity for detailed study of the anatomy of a mammoth calf; 2) provided a more detailed understanding of interstadial landscapes; and 3) suggested paleoclimatic variability occurred in Western Beringia during marine isotope stage (MIS) 3. Limited access to early Russian literature resulted in unfortunate misinformation in English-language publications. Since then, six other juvenile carcasses have been discovered in northern Siberia and additional Late Pleistocene paleobotanical records have increased understanding of MIS2 and MIS3 environments. Given the new data, it seems timely to re-examine information about the Kirgilyakh mammoth in the context of: 1) correcting mistakes about the age and environments of the site, including the manner of the mammoth’s death; 2) comparing paleoenvironmental settings with that of other young mammoth carcasses; and 3) revisiting the concept of mammoth-steppe. This re-examination, which places the Kirgilyakh results in a broader spatial-temporal setting, reinforces the idea that climatic variability, including the Kirgilyakh cool interval, characterized MIS3. Unstable landscapes in mountains and lowlands were key factors in deaths of the Siberian mammoth calves. The prevalence of tundra in MIS2 model reconstructions and abundance of paleobotanical data indicating mesic tundra and forest during MIS3 suggest that classification of these intervals as mammoth-steppe is problematic.

Developing continuous chronologies of paleoenvironmental change in northern areas of the Far East using 14C can be problematic because of the low organic content in lake sediments. However, Holocene age-models can be supplemented by widespread tephra deposits reported in the Magadan region. The best documented of these tephras has been correlated to the KO tephra from southern Kamchatka dated to 7600 BP. Although a key chronostratigraphic marker, no detailed compendium of the distribution of this tephra and its associated 14C dates has been available from sites in the northern Far East. We provide such a summary. Known locally as the Elikchan tephra, lake cores indicate an ash fall that extended ~1800 km north of the Kamchatkan caldera with a ~500 km wide trajectory in the Magadan region. Other Holocene tephras preserved in lake sediments have poorer age control and possibly date to ~2500 BP, ~2700 BP and ~6000 BP. These ashes seem to be restricted to coastal or near-coastal sites. A single record of a ~25,000 BP tephra has also been documented ~100 km to the northeast of Magadan.

We examine characteristics and correlates of households in the United States that are most likely to have children at risk of inadequate nutrition—those that report very low food security (VLFS) among their children. Using 11 years of the Current Population Survey, plus data from the National Health and Nutrition Examination Survey (NHANES), we describe these households in great detail with the goal of trying to understand how these households differ from households without such severe food insecurity. While household income certainly plays an important role in determining VLFS among children, we find that even after flexibly controlling for income-to-poverty rates some household characteristics and patterns of program participation have important additional explanatory power. Finally, our examination of the NHANES data suggests an important role for both mental and physical health of adults in the household in determining the food security status of children.

The prevalence of childhood obesity in the United States has more than tripled over the last four decades from 5 percent in 1978 to 18.5 percent in 2016. There is evidence for a break in trend in recent years: after growing from 0.4 to 0.7 percentage point per year between 1978 and 2004, the rate of increase has slowed to 0.1 percentage point per year from 2004 to 2016. To better understand these trends, in this paper we analyze a range of datasets that collect information on childhood obesity. We analyze the data overall, across the age distribution, across birth cohorts, and for subgroups of interest. We find steady increases in cohort-level obesity prevalence through approximately age 10, with levels unchanged thereafter, suggesting a need for additional interventions at early ages. We find that the prevalence of obesity has diverged by race and gender in recent years, especially among children entering kindergarten. Compared with 5-year-olds in 1997, 5-year-olds in 2010 were 2 percentage points more likely to be obese overall. Black and Hispanic 5-year-olds were 5 and 3 percentage points more likely to be obese, respectively, while whites had a 1 percentage point increase in obesity. However, overall and among all subgroups the rate of growth in obesity from kindergarten through 3rd grade has declined in recent years. Together, these findings can inform a future research literature that aims to target obesity interventions where they will be most impactful.

Diatom, rock magnetic, geochemical, and lithological studies of a sediment core from Paramushir Island (northern Kuril Archipelago) trace environmental shifts from bog to salt-water lagoon to freshwater lake over the past 10,000 14C BP. Organic-rich mesic landscapes dominated the southern island until ~8200 14C BP. Transgression of the Sea of Okhotsk onto the island began sometime after 8200 14C BP, resulting in the formation first of a salty (~8200–5700 14C BP) then a brackish (~5700–5200 14C BP) lagoon. With lowering of sea level after 5200 14C BP, a freshwater lake formed, which has remained to the present day. This history parallels regional trends in the Russian Far East, where maximum sea levels occurred between ~8000 and 4600 14C BP, peaking at ~6400 14C BP. Sandy levels within the lake core suggest four intervals of aeolian activity (~4900–4800 14C BP; 4300–3800 14C BP; 3200–3000 14C BP; 1900–900 14C BP), perhaps related to drier than present climates. Palynological data indicate a dominance of Pinus pumila–Duschekia kamtschatica shrub tundra in the lowlands ~8200–5800 14C BP, marking the Holocene thermal maximum. This vegetation contrasts to modern, which established ~5800 14C BP and is a mix of coastal meadow, Betula–Salix low shrub tundra, and scattered Pinus and Duschekia thickets. The palynological record shows little response to mid-to-late Holocene climatic fluctuations except for a decrease in Pinus shrubs perhaps caused by changes in snow cover and/or summer temperature during the Little Ice Age.

The 318-m-thick sediment record from Lake El'gygytgyn provides unique opportunities for a detailed examination of environmental changes during the Reunion Subchron polarity reversal event (2.1384–2.1216 Myr BP) in the northeastern Russian Arctic. The paper describes vegetation and climate fluctuations between ~ 2.15 and 2.10 Myr BP as inferred from palynological data. Biome reconstructions indicate that throughout this interval the tundra (TUND) biome generally has higher affinity scores as compared to cold steppe (STEP) or cold deciduous forest (CLDE). An exception is the climatic optimum between ~ 2.139 and 2.131 Myr BP, coinciding with Marine Isotope Stage 81 (approximately the Reunion Subchron), when the CLDE biome has the highest scores. Landscape-openness indices suggest that more closed vegetation characterized most of the interval between 2.146 and 2.127 Myr BP, when deciduous forest and shrubs expanded in the regional vegetation and climate was relatively warm and wet. Peaks in green algal colonies (Botryococcus) and Zygnema-type spores ~ 2.150–2.146, ~ 2.131–2.123, and ~ 2.112–2.102 Myr BP indicate expansions of shallow-water habitats and lowered lake levels. Comparisons with biome reconstructions from other interglacial intervals at Lake El'gygytgyn suggest that precession-related summer insolation intensity and obliquity-related duration of summer daylight are major controls on the onset of interglaciations, whereas obliquity probably plays a more significant role on vegetation succession at northern high latitudes during the Pleistocene.

Arctic land-cover changes (e.g., expansion of woody vegetation into tundra and effects of permafrost degradation) that have been induced by recent global climate change are expected to generate further feedbacks to the climate system. Past changes can be used to assess our understanding of feedback mechanisms through a combination of process modelling and paleo-observations. The sub-continental region of Beringia (Northeast Siberia, Alaska, and northwestern Canada) was largely ice-free at the peak of deglacial warming and experienced both major vegetation change and loss of permafrost when many arctic regions were still ice covered. The evolution of Beringian climate at this time was largely driven by global features, such as the amplified seasonal cycle of Northern Hemisphere insolation and changes in global ice volume and atmospheric composition, but changes in regional land-surface controls, such as the widespread development of thaw lakes, the replacement of tundra by deciduous forest or woodland, and the flooding of the Bering–Chukchi land bridge, were probably also important. We examined the sensitivity of Beringia's early Holocene climate to these regional-scale controls using a regional climate model (RegCM). Lateral and oceanic boundary conditions were provided by global climate simulations conducted using the GENESIS V2.01 atmospheric general circulation model (AGCM) with a mixed-layer ocean. We carried out two present day simulations of regional climate, one with modern and one with 11 ka geography, plus another simulation for 6 ka. In addition, we performed five ∼11 ka climate simulations, each driven by the same global AGCM boundary conditions: (i) 11 ka "Control", which represents conditions just prior to the major transitions (exposed land bridge, no thaw lakes or wetlands, widespread tundra vegetation), (ii) sea-level rise, which employed present day continental outlines, (iii) vegetation change, with deciduous needleleaf and deciduous broadleaf boreal vegetation types distributed as suggested by the paleoecological record, (iv) thaw lakes, which used the present day distribution of lakes and wetlands; and (v) post-11 ka "All", incorporating all boundary conditions changed in experiments (ii)–(iv). We find that regional-scale controls strongly mediate the climate responses to changes in the large-scale controls, amplifying them in some cases, damping them in others, and, overall, generating considerable spatial heterogeneity in the simulated climate changes. The change from tundra to deciduous woodland produces additional widespread warming in spring and early summer over that induced by the 11 ka insolation regime alone and lakes and wetlands produce modest and localized cooling in summer and warming in winter. The greatest effect is the flooding of the land bridge and shelves, which produces generally cooler conditions in summer but warmer conditions in winter, and is most clearly manifest on the flooded shelves and in eastern Beringia. By 6 ka continued amplification of the seasonal cycle of insolation and loss of the Laurentide ice sheet produce temperatures similar to or higher than those at 11 ka plus a longer growing season.

The palynological investigations of sediments of the crater of El’gygytgyn Lake (67°30′ N, 172°05′ E), which provided a continuous record of interglacial and glacial events in Polar Chukotka, revealed significant climate warming corresponding to Marine Isotope Stage 31 (MIS 31) lasting from 1.062 to 1.081Ma ago. Its upper limit is placed within the Jaramillo paleomagnetic episode (0.99–1.07 Ma) registered in the sedimentary section of the lake. During MIS 31, the vegetation community was dominated by Betula-Alnus forests with subordinate Larix trees. These forests included also coniferous (Picea, Pinus) and broad-leaved trees and shrubs (Quercus, Carpinus, Corylus). The interglacial of MIS 31 was characterized by the warmest climate for the entire Quaternary Period. The warming episode established in the continuous record of the section of El’gygytgyn Lake implies relations between climatic events in the Arctic and Antarctic regions.

We examine how participation in social safety net programs differs by income-to-poverty levels, and how that relationship changed after the Great Recession. We define income-to-poverty based on the average of 2 years of merged CPS data, and investigate program participation among households with income less than 300 percent of poverty. We find changes in both the level and distribution of safety-net program participation during the Great Recession, with SNAP expanding most at the bottom, the EITC expanding most in the middle, and UI expanding most at the top of the income ranges that we investigate; TANF did not expand.

Two lake records from the Kankaren region of southern Chukotka, when combined with other palynological and macrofossil data, document spatial and temporal variations in the regional vegetation history since ∼21,000 14C/25,400 cal yr BP. Full-glacial environments were severely cold and arid in central and northern Chukotka, whereas southern sites experienced conditions that were relatively moist, although still drier than present. Southern Chukotka may represent a western extension of environments of the land bridge proper, including a possible “moisture” barrier to intercontinental migration. Shrub Betula tundra established earliest in southern Chukotka (∼15,800–14,000 14C/19,000–16,700 cal yr BP; ∼13,000 14C/15,300 cal yr BP central and north), Pinus pumila earliest in the north (∼9600 14C/11,100 cal yr BP; ∼7600 14C/8400 cal yr BP south), and shrub Alnus earliest in both the south and north (∼12,000–11,000 14C/13,800–12,900 cal yr BP). These patterns support the presence of cryptic refugia for Betula and Alnus in Chukotka during the full glaciation. In contrast, P. pumila probably migrated into Chukotka from populations located in the northern coastal lowlands and from mountainous regions of southwestern Beringia. Evidence for a thermal optimum (∼11,000–8000 14C/12,900–9000 cal yr BP) is strong in northern Chukotka but is absent in central and southern areas.

Concern is growing that global climate change will have widespread impact on the world’s terrestrial ecosystems, but future impacts are imperfectly constrained by ecosystem models and direct observations. All available data, including records of past ecological change, need to be utilized to assess the range of potential future outcomes. Here we show that pervasive ecosystem transformations occurred in response to warming and associated climatic changes during the last glacial-to-interglacial transition, which was of comparable magnitude to climatic change projected to occur in the next 100 to 150 years under high-emission scenarios. We used data from 596 published paleoecological records to examine compositional and structural changes in global terrestrial vegetation since the last glacial period, and to project the magnitude of ecosystem transformations under different emission scenarios in the future. Our results indicate that terrestrial ecosystems are highly sensitive to temperature change, and suggest that without major reductions in greenhouse-gas emissions to the atmosphere (i.e., in line with those targeted in the 2015 Paris Agreement), most terrestrial ecosystems worldwide are at risk of major transformation, with accompanying disruption of ecosystem services and impacts on biodiversity.

The majority of archaeological sites documenting the first human migration to the Eastern Beringia are located in three areas of Alaska: the central, northern, and southwestern parts. The prehistory of Beringia demonstrates that the earliest well-documented human wave of migrations was referred to the transitional period between the Late Pleistocene and the Holocene (from 12.5 to 9 14 C kyr BP). This time span has been characterized by rapid environmental changes in Beringia, connected with the rise of sea level, mountain deglaciation, and important changes in floral and faunal communities. Four main climatic phases could be identified. The first one was associated with the early postglacial climate amelioration that occurred between 12.5 and 11 14 C kyr BP. The second was the postglacial maximum followed by the Younger Dryas and subsequent Early Holocene cooling.

Archaeological and paleogeographic evidence suggests that Northeast Asia (Western Beringia) was a starting point from which prehistoric man began to explore the Western Hemisphere via the Bering Land Bridge. Current data suggest that the exploration by humans of the arctic zone of Western Beringia occurred no later than the second half of the Late Pleistocene, during the time span with favorable conditions for human dispersals. The Yana Site witnesses that at the end of the Karginsky, Paleolithic man almost reached the modern arctic coast at the Indigirka-Kolyma lowlands. Later, during the Sartan, some new complexes (cultures) appeared, represented by those sites as Khaya IV, Kheta, Druchak, Ushki I to V, etc. Changing landscapes and climates of Western Beringia in the Early Holocene provoked new developments and the disappearance of the Paleolithic cultures, which were replaced by the Mesolithic cultures more adapted to the new conditions.

Investigations of glacial lake sediments located near the modern altitudinal boundary of a larch forest (between 750–810 m absolute elevation) reveal continuous records of the vegetation and climate changes over the last 12000 years in the area of the Okhotsk-Kolyma divide. For the first time, the pollen accumulation rates (PAR), which are suggestive of pollen productivity, were used as a key indicator to interpret the response of alpine plant communities to climate changes. The palynological data imply that several forest line fluctuations of ∼100–200 m occurred during the Holocene. A belt of tundra dominated by shrub pine was first established beyond the forest line near 7650 ± 50 BP. The abrupt appearance of the shrub pine in the studied area is characteristic of a sharp vegetation boundary found in other records from the north of the Far East that corresponds to the Boreal-Atlantic boundary of the Holocene. The birch pollen zone, which occurs in the earlier portions of the records, is characteristic of the transition from the Pleistocene to the Holocene.

The recent and fossil pollen data obtained under the frame of the multi-disciplinary international El'gygytgyn Drilling Project represent a unique archive, which allows the testing of a range of pollen-based reconstruction approaches and the deciphering of changes in the regional vegetation and climate. In the current study we provide details of the biome reconstruction method applied to the late Pliocene and Quaternary pollen records from Lake El'gygytgyn. All terrestrial pollen taxa identified in the spectra from Lake El'gygytgyn were assigned to major vegetation types (biomes), which today occur near the lake and in the broader region of eastern and northern Asia and, thus, could be potentially present in this region during the past. When applied to the pollen spectra from the middle Pleistocene to present, the method suggests (1) a predominance of tundra during the Holocene, (2) a short interval during the marine isotope stage (MIS) 5.5 interglacial distinguished by cold deciduous forest, and (3) long phases of taiga dominance during MIS 31 and, particularly, MIS 11.3. These two latter interglacials seem to be some of the longest and warmest intervals in the study region within the past million years. During the late Pliocene–early Pleistocene interval (i.e., ~3.562–2.200 Ma), there is good correspondence between the millennial-scale vegetation changes documented in the Lake El'gygytgyn record and the alternation of cold and warm marine isotope stages, which reflect changes in the global ice volume and sea level. The biome reconstruction demonstrates changes in the regional vegetation from generally warmer/wetter environments of the earlier (i.e., Pliocene) interval towards colder/drier environments of the Pleistocene. The reconstruction indicates that the taxon-rich cool mixed and cool conifer forest biomes are mostly characteristic of the time prior to MIS G16, whereas the tundra biome becomes a prominent feature starting from MIS G6. These results consistently indicate that the study region supported significant tree populations during most of the interval prior to ~2.730 Ma. The cold- and drought-tolerant steppe biome first appears in the reconstruction ~3.298 Ma during the tundra-dominated MIS M2, whereas the tundra biome initially occurs between ~3.379 and ~3.378 Ma within MIS MG4. Prior to ~2.800 Ma, several other cold stages during this generally warm Pliocene interval were characterized by the tundra biome.

Preliminary analyses of Lake El'gygytgyn sediment indicate a wide range of ecosystem responses to warmer than present climates. While palynological work describing all interglacial vegetation is ongoing, sufficient data exist to compare recent warm events (the postglacial thermal maximum, PGTM, and marine isotope stage, MIS5) with "super" interglaciations (MIS11, MIS31). Palynological assemblages associated with these climatic optima suggest two types of vegetation responses: one dominated by deciduous taxa (PGTM, MIS5) and the second by evergreen conifers (MIS11, MIS31). MIS11 forests show a similarity to modern Picea–Larix–Betula–Alnus forests of Siberia. While dark coniferous forest also characterizes MIS31, the pollen taxa show an affinity to the boreal forest of the lower Amur valley (southern Russian Far East). Despite vegetation differences during these thermal maxima, all glacial–interglacial transitions are alike, being dominated by deciduous woody taxa. Initially Betula shrub tundra established and was replaced by tundra with tree-sized shrubs (PGTM), Betula woodland (MIS5), or Betula–Larix (MIS11, MIS31) forest. The consistent occurrence of deciduous forest and/or high shrub tundra before the incidence of maximum warmth underscores the importance of this biome for modeling efforts. The El'gygytgyn data also suggest a possible elimination or massive reduction of Arctic plant communities under extreme warm-earth scenarios.

Three lake cores provide insight into the vegetation and climate history of the past ∼45,000 14C yr in the Anadyr Lowland, a key paleogeographic link between the Bering Land Bridge (BLB) and interior Western Beringia (WB). Although not without chronological issues, these records suggest that the Late Pleistocene interstade (approximating Oxygen Isotope Stage (OIS) 3) was a time of unstable environments consistent with previous interpretations for southern areas of WB and in contrast to more stable conditions inferred for northern WB. A hiatus in the records during OIS2 implies dry, frigid environments in the Anadyr Lowland. Previous research suggested that Chuktoka was a westward extension of relatively mesic environments of the BLB, which acted as a “filter” to intercontinental migrations. The Lowland data indicate that Chukotka may have been more of a transitional zone between mesic BLB and more xeric regions of western WB. A structurally novel biome dominated by deciduous forest and high-shrub tundra was proposed as occupying much of Beringia between ∼11,000 and 9000 14C yr BP. The unusual pollen assemblage that characterizes the Lowland suggests that perhaps a second biome was also present in Beringia, one that was dominated by meadows with Betula shrub thickets.

Lake Pernatoe is located on Paramushir Island, Kuril Arc, in the area of sand dunes. The 7-m-thick sediments of this lake pertain to the Holocene and contain palustrine, marine, and lacustrine facies. The rock magnetic properties of the sediments are analyzed for tracking the changes in sedimentation conditions. Marine facies are noted with low content of magnetic minerals; their magnetization is dominated by the paramagnetic component; pseudo-single-domain particles of magnetic material and iron sulfides (pyrite) are present. Pyrite frequently occurs in diatoms in the form of chains, spherules, and crystals. The lacustrine facies show high values of the magnetic parameters; they contain multidomain particles, mostly titanomagnetite and magnetite. Sands and sandy silts have the maximum values of magnetic parameters and reflect the stages of aeolian activity, corresponding to climatic cooling and marine regressions. On the basis of magnetic properties, four stages of active aeolian sedimentation are identified in the Holocene.

We present a database of late-Quaternary plant macrofossil records for northern Eurasia (from 23 degrees to 180 degrees E and 46 degrees to 76 degrees N) comprising 281 localities, over 2300 samples and over 13,000 individual records. Samples are individually radiocarbon dated or are assigned ages via age models fitted to sequences of calibrated radiocarbon dates within a section. Tree species characteristic of modern northern forests (e.g. Picea, Larix, tree-Betula) are recorded at least intermittently from prior to the last glacial maximum (LGM), through the LGM and Lateglacial, to the Holocene, and some records locate trees close to the limits of the Scandinavian ice sheet, supporting the hypothesis that some taxa persisted in northern refugia during the last glacial cycle. Northern trees show differing spatio-temporal patterns across Siberia: deciduous trees were widespread in the Lateglacial, with individuals occurring across much of their contemporary ranges, while evergreen conifers expanded northwards to their range limits in the Holocene. (c) 2009 Elsevier Ltd. All rights reserved.

© 2016 Elsevier LtdLake El'gygytgyn in Far East Russia is a 3.6 Myr old impact crater lake. Located in an area that has never been affected by Cenozoic glaciations nor desiccation, the unique sediment record of the lake represents the longest continuous sediment archive of the terrestrial Arctic. The surrounding crater is the only impact structure on Earth developed in mostly acid volcanic rocks. Recent studies on the impactite, permafrost, and sediment sequences recovered within the framework of the ICDP “El'gygytgyn Drilling Project” and multiple pre-site surveys yielded new insight into the bedrock origin and cratering processes as well as permafrost dynamics and the climate and environmental history of the terrestrial Arctic back to the mid-Pliocene. Results from the impact rock section recovered during the deep drilling clearly confirm the impact genesis of the El'gygytgyn crater, but indicate an only very reduced fallback impactite sequence without larger coherent melt bodies. Isotope and element data of impact melt samples indicate a F-type asteroid of mixed composition or an ordinary chondrite as the likely impactor. The impact event caused a long-lasting hydrothermal activity in the crater that is assumed to have persisted for c. 300 kyr. Geochemical and microbial analyses of the permafrost core indicate a subaquatic formation of the lower part during lake-level highstand, but a subaerial genesis of the upper part after a lake-level drop after the Allerød. The isotope signal and ion compositions of ground ice is overprinted by several thaw-freeze cycles due to variations in the talik underneath the lake. Modeling results suggest a modern permafrost thickness in the crater of c. 340 m, and further confirm a pervasive character of the talik below Lake El'gygytgyn. The lake sediment sequences shed new leight into the Pliocene and Pleistocene climate and environmental evolution of the Arctic. During the mid-Pliocene, significantly warmer and wetter climatic conditions in western Beringia than today enabled dense boreal forests to grow around Lake El'gygytgyn and, in combination with a higher nutrient flux into the lake, promoted primary production. The exceptional warmth during the mid-Pliocene is in accordance with other marine and terrestrial records from the Arctic and indicates a period of enhanced “Arctic amplification”. The favourable conditions during the mid-Pliocene were repeatedly interrupted by climate deteriorations, e.g., during Marine Isotope Stage (MIS) M2, when pollen data and sediment proxies indicate a major cooling and the onset of local permafrost around the lake. A gradual vegetation change after c. 3.0 Ma points to the onset of a long-term cooling trend during the Late Pliocene that culminated in major temperature drops, first during MIS G6, and later during MIS 104. These cold events coincide with the onset of an intensified Northern Hemisphere (NH) glaciation and the largest extent of the Cordilleran Ice Sheet, respectively. After the Pliocene/Pleistocene transition, local vegetation and primary production in Lake El'gygtygyn experienced a major change from relatively uniform conditions to a high-amplitude glacial-to-interglacial cyclicity that fluctuated on a dominant 41 kyr obliquity band, but changed to a 100 kyr eccentricity dominance during the Middle Pleistocene transition (MPT) at c. 1.2–0.6 Ma. Periods of exceptional warming in the Pleistocene record of Lake El'gygytgyn with dense boreal forests around and peaks of primary production in the lake are assigned to so-called “super-interglacial” periods. The occurrence of these super-interglacials well corresponds to collapses of the West Antarctic Ice Sheet (WAIS) recorded in ice-free periods in the ANDRILL core, which suggests strong intrahemispheric teleconnections presumably driven by changes in the thermocline ocean circulation.

Using the Early Childhood Longitudinal Survey-Kindergarten Class of 1998-1999 (ECLS-K) data from kindergarten through eighth grade, this paper investigate the relationships among maternal employment, family routines and obesity. More hours worked by the mother tend to be negatively related to positive routines like eating meals as a family or at regular times, or having family rules about hours of television watched. Many of these same routines are significantly related to the probability of being obese, implying that family routines may be a mechanism by which maternal employment intensity affects children's obesity. However, inclusion of family routines in the obesity regression does not appreciably change the estimated effect of maternal employment hours. Thus, the commonly estimated deleterious effect of maternal employment on children's obesity cannot be explained by family routines, leaving the exact mechanisms an open question for further exploration.

Analyses of lithology, organic-matter content, magnetic susceptibility, and pollen in a sediment core from Okpilak Lake, located in the northeastern Brooks Range, provide new insights into the history of climate, landscape processes, and vegetation in northern Alaska since 14,500 cal year BP. The late-glacial interval (>11,600 cal year BP) featured sparse vegetation cover and the erosion of minerogenic sediment into the lake from nearby hillslopes, as evidenced by Cyperaceae-dominated pollen assemblages and high magnetic susceptibility (MS) values. Betula expanded in the early Holocene (11,600–8,500 cal year BP), reducing mass wasting on the landscape, as reflected by lower MS. Holocene sediments contain a series of silt- and clay-dominated layers, and given their physical characteristics and the topographic setting of the lake on the braided outwash plain of the Okpilak River, the inorganic layers are interpreted as rapidly deposited fluvial sediments, likely associated with intervals of river aggradation, changes in channel planform, and periodic overbank flow via a channel that connects the river and lake. The episodes of fluvial dynamics and aggradation appear to have been related to regional environmental variability, including a period of glacial retreat during the early Holocene, as well as glacial advances in the middle Holocene (5,500–5,200 cal year BP) and during the Little Ice Age (500–400 cal year BP). The rapid deposition of multiple inorganic layers during the early Holocene, including thick layers at 10,900–10,000 and 9,400–9,200 cal year BP, suggests that it was a particularly dynamic interval of fluvial activity and landscape change.

New palynological and sedimentological data from St. Lawrence Island present a rare view into late-glacial and Holocene environments of the central Bering Land Bridge. The late glaciation was a time of dynamic landscape changes in south-central Beringia, with active thermokarst processes, including the formation and drainage of thaw lakes. The presence of such a wet, unstable substrate, if widespread, probably would have had an adverse impact on food sources and mobility for many of the large mammal populations. The establishment ofBetulashrub tundra on the island suggests late-glacial summers that were warmer than present, consistent with regional paleoclimatic interpretations. However, the increasing proximity to the Bering Sea, as postglacial sea levels rose, modified the intensity of warming and prevented the establishment of deciduous forest as found in other areas of Beringia at this time. The mid- to late Holocene is marked by more stable land surfaces and development ofSphagnumand Cyperaceae peat deposits. The accumulation of organic deposits, decline of shrubBetula, and decrease in thermokarst disturbance suggest that conditions were cooler than the previous. A recent decline in peat accumulation at the study sites may relate to local geomorphology, but similar decreases have been noted for other arctic regions.

Two conflicting stratigraphic schemes describe the Siberian Karginskii interstade (Oxygen Isotope Stage 3 equivalent) as having: 1) relatively stable climate with environments more similar to the full glaciation; or 2) variable climate with landscapes that more closely approximate contemporary ones. New data from continuous lake cores and a nearly continuous section from western Beringia (WB) suggest that both schemes are valid. Herb-dominated communities, possibly with isolated populations of Larix , characterized northern WB with only a slight shift from relatively warm to cool summers during the mid-interstade. In contrast, herb and shrub tundra, steppe, forest-tundra, and modern Larix forest occurred at various times in areas of southern WB, suggesting greater climatic instability. A thermal optimum is evident in the south during the mid-interstade, with modern vegetation in southeastern WB and Larix forest-tundra in the southwest. Variations in Pinus pumila pollen indicate summer warm/winter dry and summer warm/winter wet conditions in southeastern WB. These fluctuations contrast to other areas of WB, where summers and probably winters were consistently arid. Although the interstade presents a unique interval within the Late Pleistocene, paleodata and paleoclimatic models suggest that changes in marine conditions, including sea level, were likely key drivers in the regional climate history.

Macrofossil remains from dated peat sections help clarify paleoclimate patterns inferred from subtle changes in the palynological data from the northern Russian Far East. These data show latitudinal range extensions for tree Betula, Larix gmelinii, and Picea sp., as well as the occurrence of tree-sized shrubs of Duschekia fruticosa and Salix sp. in areas that today are low shrub tundra. Ages of extralimital taxa suggest a postglacial thermal maximum between ∼11,000 and 8100 14C BP including a region-wide, warm Younger Dryas. This warm interval contrasts to other areas of Siberia where the thermal optimum is ∼9000–4000 14C BP. Additionally, macrofossils suggest that Holocene changes in northern treeline were not synchronous. In the Far East, treeline advance and retreat occurred earlier by ∼1000 14C y and ∼4000 14C y, respectively, as compared to other areas of Russia. Basal and minimum ages of peat deposits indicate that the Early Holocene was a particularly important time for peat initiation and accumulation across northern Siberia.

Palynological results from Julietta Lake currently provide the most direct evidence to support the existence of a glacial refugium for Pinus pumila in mountains of southwestern Beringia. Both percentages and accumulation rates indicate the evergreen shrub survived until at least ∼ 19,000 14C yr BP in the Upper Kolyma region. Percentage data suggest numbers dwindled into the late glaciation, whereas pollen accumulation rates point towards a more rapid demise shortly after ∼ 19,000 14C yr BP. Pinus pumila did not re-establish in any great numbers until ∼ 8100 14C yr BP, despite the local presence ∼ 9800 14C yr BP of Larixdahurica, which shares similar summer temperature requirements. The postglacial thermal maximum (in Beringia ∼ 11,000-9000 14C yr BP) provided Pinus pumila shrubs with equally harsh albeit different conditions for survival than those present during the LGM. Regional records indicate that in this time of maximum warmth Pinus pumila likely sheltered in a second, lower-elevation refugium. Paleoclimatic models and modern ecology suggest that shifts in the nature of seasonal transitions and not only seasonal extremes have played important roles in the history of Pinus pumila over the last ∼ 21,000 14C yr BP.