A warm jet in a cold ocean.
Ontology highlight
ABSTRACT:
SUBMITTER: MacKinnon JA
PROVIDER: S-EPMC8065036 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Dissolved oxygen (O2) is essential for most ocean ecosystems, fuelling organisms' respiration and facilitating the cycling of carbon and nutrients. Oxygen measurements have been interpreted to indicate that the ocean's oxygen-deficient zones (ODZs) are expanding under global warming1,2. However, models provide an unclear picture of future ODZ change in both the near term and the long term3-6. The paleoclimate record can help explore the possible range of ODZ changes in warmer-than-modern periods. Here we use foraminifera-bound nitrogen (N) isotopes to show that water-column denitrification in the eastern tropical North Pacific was greatly reduced during the Middle Miocene Climatic Optimum (MMCO) and the Early Eocene Climatic Optimum (EECO). Because denitrification is restricted to oxygen-poor waters, our results indicate that, in these two Cenozoic periods of sustained warmth, ODZs were contracted, not expanded. ODZ contraction may have arisen from a decrease in upwelling-fuelled biological productivity in the tropical Pacific, which would have reduced oxygen demand in the subsurface. Alternatively, invigoration of deep-water ventilation by the Southern Ocean may have weakened the ocean's 'biological carbon pump', which would have increased deep-ocean oxygen. The mechanism at play would have determined whether the ODZ contractions occurred in step with the warming or took centuries or millennia to develop. Thus, although our results from the Cenozoic do not necessarily apply to the near-term future, they might imply that global warming may eventually cause ODZ contraction.
| S-EPMC9433325 | biostudies-literature
Project description:The Younger Dryas (YD) cold reversal interrupts the warming climate of the deglaciation with global climatic impacts. The sudden cooling is typically linked to an abrupt slowdown of the Atlantic Meridional Overturning Circulation (AMOC) in response to meltwater discharges from ice sheets. However, inconsistencies regarding the YD-response of European summer temperatures have cast doubt whether the concept provides a sufficient explanation. Here we present results from a high-resolution global climate simulation together with a new July temperature compilation based on plant indicator species and show that European summers remain warm during the YD. Our climate simulation provides robust physical evidence that atmospheric blocking of cold westerly winds over Fennoscandia is a key mechanism counteracting the cooling impact of an AMOC-slowdown during summer. Despite the persistence of short warm summers, the YD is dominated by a shift to a continental climate with extreme winter to spring cooling and short growing seasons.
| S-EPMC5915408 | biostudies-literature
Project description:This paper analyzes seasonal effects and their potential drivers in charitable giving. We conduct two studies to analyze whether donations to the German Red Cross differ between the Christmas season and summer. In study 1 we find that in the pre-Christmas shopping season prosocial subjects almost donate 50% less compared to prosocials in summer. In study 2 we replicate the low donations in the Christmas season. In an extensive questionnaire we control for several causes of this effect. The data suggest that the higher prosocials' self-reported stress level, the lower the donations. The higher their relative savings, the lower the giving. Our questionnaire rules out that "donation fatigue" matters. That is, donations do not depend on the number of charitable campaigns subjects are confronted with and their engagement in these activities during Christmas season outside the lab.
| S-EPMC6530824 | biostudies-literature
Project description:Fire investigators may be occupationally exposed to many of the same compounds as the more widely studied fire suppression members of the fire service but are often tasked with working in a given exposure for longer periods ranging from hours to multiple days and may do so with limited personal protective equipment. In this study, we characterize the area air concentrations of contaminants during post-fire investigation of controlled residential fires with furnishings common to current bedroom, kitchen and living room fires in the United States. Area air sampling was conducted during different investigation phases including when investigations might be conducted immediately after fire suppression and extended out to 5 days after the fire. Airborne particulate over a wide range of dimensions, including sub-micron particles, were elevated to potentially unhealthy levels (based on air quality index) when averaged over a 60 min investigation period shortly after fire suppression with median PM2.5 levels over 100 µg/m3 (range 16-498 µg/m3) and median peak transient concentrations of 1,090 µg/m3 (range 200-23,700 µg/m3) during drywall removal or shoveling activities. Additionally, airborne aldehyde concentrations were elevated compared to volatile organic compounds with peak values of formaldehyde exceeding NIOSH ceiling limits during the earliest investigation periods (median 356 µg/m3, range: 140-775 µg/m3) and occasionally 1 day post-fire when the structure was boarded up before subsequent investigation activities. These results highlight the need to protect investigators' airways from particulates when fire investigation activities are conducted as well as during post-fire reconstruction activities. Additionally, vapor protection from formaldehyde should be strongly considered at least through investigations occurring 3 days after the fire and personal formaldehyde air monitoring is recommended during investigations.
| S-EPMC10074475 | biostudies-literature
Project description:Due to the limitations of traditional periodontal therapies, and reported cold atmospheric plasma anti-inflammatory/antimicrobial activities, plasma could be an adjuvant therapy to periodontitis. Porphyromonas gingivalis was grown in blood agar. Standardized suspensions were plated on blood agar and plasma-treated for planktonic growth. For biofilm, dual-species Streptococcus gordonii + P. gingivalis biofilm grew for 48 h and then was plasma-treated. XTT assay and CFU counting were performed. Cytotoxicity was accessed immediately or after 24 h. Plasma was applied for 1, 3, 5 or 7 min. In vivo: Thirty C57BI/6 mice were subject to experimental periodontitis for 11 days. Immediately after ligature removal, animals were plasma-treated for 5 min once-Group P1 (n = 10); twice (Day 11 and 13)-Group P2 (n = 10); or not treated-Group S (n = 10). Mice were euthanized on day 15. Histological and microtomography analyses were performed. Significance level was 5%. Halo diameter increased proportionally to time of exposure contrary to CFU/mL counting. Mean/SD of fibroblasts viability did not vary among the groups. Plasma was able to inhibit P. gingivalis in planktonic culture and biofilm in a cell-safe manner. Moreover, plasma treatment in vivo, for 5 min, tends to improve periodontal tissue recovery, proportionally to the number of plasma applications.
| S-EPMC8470429 | biostudies-literature
Project description:The atmosphere's chaotic nature limits its short-term predictability. Furthermore, there is little knowledge on how the difficulty of forecasting weather may be affected by anthropogenic climate change. Here, we address this question by employing metrics issued from dynamical systems theory to describe the atmospheric circulation and infer the dynamical properties of the climate system. Specifically, we evaluate the changes in the sub-seasonal predictability of the large-scale atmospheric circulation over the North Atlantic for the historical period and under anthropogenic forcing, using centennial reanalyses and CMIP5 simulations. For the future period, most datasets point to an increase in the atmosphere's predictability. AMIP simulations with 4K warmer oceans and 4 × atmospheric CO2 concentrations highlight the prominent role of a warmer ocean in driving this increase. We term this the hammam effect. Such effect is linked to enhanced zonal atmospheric patterns, which are more predictable than meridional configurations.
| S-EPMC6428824 | biostudies-literature
Project description:The aim of our study was to quantitatively evaluate the optical properties of photochromic lenses available on the market under cold and warm temperatures corresponding to the winter and summer seasons. The transmittance of 12 photochromic lenses from five manufacturers was measured using an UV/VIS spectrophotometer at cold (6 ± 2°C) and at warm (21 ± 2°C) temperatures. Transmittances were recorded from 380 to 780 nm and at the wavelength with maximum absorbance, which was calculated from the transmittance. The characteristics of the lenses were evaluated by examining changes in the optical properties at colorless and colored states and in the fading rate depending on temperature. The wavelength with maximum absorbance for photochromic lenses at the cold temperature showed a shorter shift than that at the warm temperature. The photochromic properties at the cold temperature were 11.5% lower for transmittance, 1.4 times higher for the change in optical density, and 1.2 times higher for the change in transmittance in the colored and colorless states, optical blocking % ratio, and change in luminous transmittance as compared to those at the warm temperature in the colored state. The fading rates based on the half-life time at the cold temperature were from 2.7 to 5.4 times lower than those at the warm temperature. The fading time until 80% transmittance was 6.4 times longer at the cold as compared to that at the warm temperature. There were significant differences in the optical properties of the photochromic lenses in terms of an absorbance at a shorter wavelength, a lower transmittance, a higher optical density, optical blocking % ratio, and luminous transmittance at the cold as compared to the warm temperature. Hence, it is necessary to provide consumers with information on photochromic optical properties, including the transmittance in colored and colorless states, and the fading rates at temperatures corresponding to the summer and winter seasons for each product.
| S-EPMC7259785 | biostudies-literature
Project description:The recent levelling of global mean temperatures after the late 1990s, the so-called global warming hiatus or slowdown, ignited a surge of scientific interest into natural global mean surface temperature variability, observed temperature biases, and climate communication, but many questions remain about how these findings relate to variations in more societally relevant temperature extremes. Here we show that both summertime warm and wintertime cold extreme occurrences increased over land during the so-called hiatus period, and that these increases occurred for distinct reasons. The increase in cold extremes is associated with an atmospheric circulation pattern resembling the warm Arctic-cold continents pattern, whereas the increase in warm extremes is tied to a pattern of sea surface temperatures resembling the Atlantic Multidecadal Oscillation. These findings indicate that large-scale factors responsible for the most societally relevant temperature variations over continents are distinct from those of global mean surface temperature.
| S-EPMC5928063 | biostudies-literature
Project description:OBJECTIVE:So-called cold physical plasmas for biomedical applications generate reactive oxygen and nitrogen species and the latter can trigger DNA damage at high concentrations. Therefore, the mutagenic risks of a certified atmospheric pressure argon plasma jet (kINPen MED) and its predecessor model (kINPen 09) were assessed. METHODS:Inner egg membranes of fertilized chicken eggs received a single treatment with either the kINPen 09 (1.5, 2.0, or 2.5 min) or the kINPen MED (3, 4, 5, or 10 min). After three days of incubation, blood smears (panoptic May-Grünwald-Giemsa stain) were performed, and 1000 erythrocytes per egg were evaluated for the presence of polychromatic and normochromic nuclear staining as well as nuclear aberrations and binucleated cells (hen's egg test for micronuclei induction, HET-MN). At the same time, the embryo mortality was documented. For each experiment, positive controls (cyclophosphamide and methotrexate) and negative controls (NaCl-solution, argon gas) were included. Additionally, the antioxidant potential of the blood plasma was assessed by ascorbic acid oxidation assay after treatment. RESULTS:For both plasma sources, there was no evidence of genotoxicity, although at the longest plasma exposure time of 10 min the mortality of the embryos exceeded 40%. The antioxidant potential in the egg's blood plasma was not significantly reduced immediately (p = 0.32) or 1 h (p = 0.19) post exposure to cold plasma. CONCLUSION:The longest plasma treatment time with the kINPen MED was 5-10 fold above the recommended limit for treatment of chronic wounds in clinics. We did not find mutagenic effects for any plasma treatment time using the either kINPen 09 or kINPen MED. The data provided with the current study seem to confirm the lack of a genotoxic potential suggesting that a veterinary or clinical application of these argon plasma jets does not pose mutagenic risks.
| S-EPMC5008819 | biostudies-literature
Project description:In the extratropical regions, surface winds enhance upward heat release from the ocean to atmosphere, resulting in cold surface ocean: surface ocean temperature is negatively correlated with upward heat flux. However, in the western boundary currents and eddy-rich regions, the warmer surface waters compared to surrounding waters enhance upward heat release-a positive correlation between upward heat release and surface ocean temperature, implying that the ocean drives the atmosphere. The atmospheric response to warm mesoscale ocean eddies with a horizontal extent of a few hundred kilometers remains unclear because of a lack of observations. By conducting regional atmospheric model experiments, we show that, in the Kuroshio-Oyashio Confluence region, wintertime warm eddies heat the marine atmospheric boundary layer (MABL), and accelerate westerly winds in the near-surface atmosphere via the vertical mixing effect, leading to wind convergence around the eastern edge of eddies. The warm-eddy-induced convergence forms local ascending motion where convective precipitation is enhanced, providing diabatic heating to the atmosphere above MABL. Our results indicate that warm eddies affect not only near-surface atmosphere but also free atmosphere, and possibly synoptic atmospheric variability. A detailed understanding of warm eddy-atmosphere interaction is necessary to improve in weather and climate projections.
| S-EPMC5605681 | biostudies-other