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Oxygen isotopes (δ18O) are the most commonly utilized speleothem proxy and have provided many foundational records of paleoclimate. Thus, understanding processes affecting speleothem δ18O is crucial. Yet, prior calcite precipitation (PCP), a process driven by local hydrology, is a widely ignored control of speleothem δ18O. Here we investigate the effects of PCP on a stalagmite δ18O record from central Vietnam, spanning 45 – 4 ka. We employ a geochemical model that utilizes speleothem Mg/Ca and cave monitoring data to correct the δ18O record for PCP effects. The resulting record exhibits improved agreement with regional speleothem δ18O records and climate model simulations, suggesting that the corrected record more accurately reflects precipitation δ18O (δ18Op). Without considering PCP, our interpretations of the δ18O record would have been misleading. To avoid misinterpretations of speleothem δ18O, our results emphasize the necessity of considering PCP as a significant driver of speleothem δ18O. This study finds that in-cave processes affect speleothem oxygen isotope records. Correcting for these processes improves agreement with other regional records and climate models, providing a more accurate reflection of past hydroclimate change. [ABSTRACT FROM AUTHOR]

Our understanding of the climatic teleconnections that drove ice-age cycles has been limited by a paucity of well-dated tropical records of glaciation that span several glacial–interglacial intervals. Glacial deposits offer discrete snapshots of glacier extent but cannot provide the continuous records required for detailed interhemispheric comparisons. By contrast, lakes located within glaciated catchments can provide continuous archives of upstream glacial activity, but few such records extend beyond the last glacial cycle. Here a piston core from Lake Junín in the uppermost Amazon basin provides the first, to our knowledge, continuous, independently dated archive of tropical glaciation spanning 700,000 years. We find that tropical glaciers tracked changes in global ice volume and followed a clear approximately 100,000-year periodicity. An enhancement in the extent of tropical Andean glaciers relative to global ice volume occurred between 200,000 and 400,000 years ago, during sustained intervals of regionally elevated hydrologic balance that modified the regular approximately 23,000-year pacing of monsoon-driven precipitation. Millennial-scale variations in the extent of tropical Andean glaciers during the last glacial cycle were driven by variations in regional monsoon strength that were linked to temperature perturbations in Greenland ice cores1; these interhemispheric connections may have existed during previous glacial cycles.Analysis of a continuous and independently dated record of glaciation in the tropical Andes spanning 700,000 years shows that Andean glaciation follows patterns of global ice volume change, with a periodicity of approximately 100,000 years. [ABSTRACT FROM AUTHOR]

'Vast' is a word often applied to environmental terrain that is perceived to have large spatial extent. This judgment is made even at viewing distances where traditional metric depth cues are not useful. This paper explores the perceptual basis of vast experience, including reliability and visual precursors. Experiment 1 demonstrated strong agreement in ratings of the spatial extent of two-dimensional (2D) scene images by participants in two countries under very different viewing conditions. Image categories labeled 'vast' often exemplified scene attributes of ruggedness and openness (Oliva & Torralba, 2001). Experiment 2 quantitatively assessed whether these properties predict vastness. High vastness ratings were associated with highly open, or moderately open but rugged, scenes. Experiment 3 provided evidence, consistent with theory, that metric distance perception does not directly mediate the observed vastness ratings. The question remains as to how people perceive vast space when information about environmental scale is unavailable from metric depth cues or associated scene properties. We consider possible answers, including contribution from strong cues to relative depth. [ABSTRACT FROM AUTHOR]

Summary: We determined the prevalence of osteosarcopenic obesity (loss of bone and muscle coexistent with increased adiposity) in overweight/obese postmenopausal women and compared their functionality to obese-only women. Results showed that osteosarcopenic obese women were outperformed by obese-only women in handgrip strength and walking/balance abilities indicating their higher risk for mobility impairments. Introduction: Osteosarcopenic obesity (OSO) is a recently defined triad of osteopenia/osteoporosis, sarcopenia, and adiposity. We identified women with OSO in overweight/obese postmenopausal women and evaluated their functionality comparing them with obese-only (OB) women. Additionally, women with osteopenic/osteoporotic obesity (OO), but no sarcopenia, and those with sarcopenic obesity (SO), but no osteopenia/osteoporosis, were identified and compared. We hypothesized that OSO women will have the lowest scores for each of the functionality measures. Methods: Participants ( n = 258; % body fat ≥35) were assessed using a Lunar iDXA instrument for bone and body composition. Sarcopenia was determined from negative residuals of linear regression modeled on appendicular lean mass, height, and body fat, using 20th percentile as a cutoff. Participants with T-scores of L-L vertebrae and/or total femur <−1, but without sarcopenia, were identified as OO ( n = 99) and those with normal T-scores, but with sarcopenia, as SO ( n = 28). OSO ( n = 32) included women with both osteopenia/osteoporosis and sarcopenia, while those with normal bone and no sarcopenia were classified as OB ( n = 99). Functionality measures such as handgrip strength, normal/brisk walking speed, and right/left leg stance were evaluated and compared among groups. Results: Women with OSO presented with the lowest handgrip scores, slowest normal and brisk walking speed, and shortest time for each leg stance, but these results were statistically significantly different only from the OB group. Conclusion: These findings indicate a poorer functionality in women presenting with OSO, particularly compared to OB women, increasing the risk for bone fractures and immobility from the combined decline in bone and muscle mass, and increased fat mass. [ABSTRACT FROM AUTHOR]

Through study of observations and coupled climate simulations, it is argued that the mean position of the Inter-Tropical Convergence Zone (ITCZ) north of the equator is a consequence of a northwards heat transport across the equator by ocean circulation. Observations suggest that the hemispheric net radiative forcing of climate at the top of the atmosphere is almost perfectly symmetric about the equator, and so the total (atmosphere plus ocean) heat transport across the equator is small (order 0.2 PW northwards). Due to the Atlantic ocean's meridional overturning circulation, however, the ocean carries significantly more heat northwards across the equator (order 0.4 PW) than does the coupled system. There are two primary consequences. First, atmospheric heat transport is southwards across the equator to compensate (0.2 PW southwards), resulting in the ITCZ being displaced north of the equator. Second, the atmosphere, and indeed the ocean, is slightly warmer (by perhaps 2 °C) in the northern hemisphere than in the southern hemisphere. This leads to the northern hemisphere emitting slightly more outgoing longwave radiation than the southern hemisphere by virtue of its relative warmth, supporting the small northward heat transport by the coupled system across the equator. To conclude, the coupled nature of the problem is illustrated through study of atmosphere-ocean-ice simulations in the idealized setting of an aquaplanet, resolving the key processes at work. [ABSTRACT FROM AUTHOR]

An ion-exchange method is presented to separate the radioisotope 227Pa from a Th target after bombardment with 66 MeV protons. Several sources of 227Pa were prepared to be used as generators of 223Ac, concluding the first stage (or radiochemistry stage) of an exotic radioactive decay experiment to determine whether the emission of 14C and 15N clusters is observed in the decay of 223Ac. The second stage (or nuclear physics stage) of the experimental investigation involves the search for tracks of 14C and 15N clusters in solid-state nuclear track detectors exposed to the emissions from these sources. While the nuclear physics stage is still in progress, we report here on the completed radiochemistry stage and the development work. As the half-life of 227Pa is relatively short (38.3 minutes) it was imperative to perform the necessary chemical separation of this radioisotope as well as the preparation of dry sources as quickly as possible. By means of the methods developed, the period from the end of bombardment (EOB) of a Th target until completion of a dry source, could be kept below two half-lives of 227Pa. The resulting source strengths were sufficient for the purposes of the nuclear physics part of the investigation. [ABSTRACT FROM AUTHOR]

We determined whether oxidative damage in collagen is increased in (1) patients with diabetes; (2) patients with diabetic complications; and (3) subjects from the Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) study, with comparison of subjects from the former standard vs intensive treatment groups 4 years after DCCT completion. We quantified the early glycation product fructose-lysine, the two AGEs N ε-(carboxymethyl)lysine (CML) and pentosidine, and the oxidised amino acid methionine sulphoxide (MetSO) in skin collagen from 96 patients with type 1 diabetes (taken from three groups: DCCT/EDIC patients and clinic patients from South Carolina and Scotland) and from 78 healthy subjects. Fructose-lysine was increased in diabetic patients ( p<0.0001), both with or without complications ( p<0.0001). Controlling for HbA1c, rates of accumulation of AGEs were higher in diabetic patients than control subjects, regardless of whether the former had complications (CML and pentosidine given as loge[pentosidine]) or not (CML only) (all p<0.0001). MetSO (loge[MetSO]) also accumulated more rapidly in diabetic patients with complications than in controls ( p<0.0001), but rates were similar in patients without complications and controls. For all three products, rates of accumulation with age were significantly higher in diabetic patients with complications than in those without (all p<0.0001). At 4 years after the end of the DCCT, no differences were found between the previous DCCT management groups for fructose-lysine, AGEs or MetSO. The findings suggest that in type 1 diabetic patients enhanced oxidative damage to collagen is associated with the presence of vascular complications. [ABSTRACT FROM AUTHOR]

Intestinal epithelial cells (IEC) have previously been shown to produce several cytokines including interleukin-6 (IL-6). However, many factors which may regulate IL-6 secretion by human IEC still remain a mystery due in part to the lack of appropriate model cell lines and the difficulty of culturing human IEC over long periods of time. We have determined that the human colonic carcinoma cell line Caco-2 is capable of secreting IL-6 when stimulated by the inflammatory cytokines IL-1β or tumor necrosis factor-α (TNF-α), and stimulation of these cells with IL-1β plus TNF-α induced a synergistic enhancement of IL-6 secretion. The inflammatory cytokine-induced enhancement in IL-6 secretion was greatest when the cells were cultured in a 10% CO2 atmosphere as compared to cells grown in 5% CO2, suggesting that environmental CO2 levels may affect IEC cytokine secretion. Finally, long-term culture of the Caco-2 cells to induce cellular differentiation had no effect on the capacity of these cells to produce IL-6, indicating that the regulation of IL-6 secretion was not affected by differentiation. Taken together, these studies provide important information on the factors which regulate IL-6 secretion by human IEC as they may contribute to the cytokine network during a mucosal inflammation. The results also suggest that the Caco-2 cell line is an appropriate model for further studies on the regulation of cytokine secretion by human IEC. [ABSTRACT FROM AUTHOR]

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Barbiturate withdrawal seizure susceptibility in rats increased with increasing duration of treatment during a 15-day treatment period in which the animals were given an i.p. dose of sodium barbital every 12 h. This method of producing dependence has clear advantages over previously described methods. [ABSTRACT FROM AUTHOR]