Temperature Response of Respiration Across the Heterogeneous Landscape of the Alaskan Arctic Tundra

AbstractPredictions of the response of ecosystem respiration to warming in the Arctic are not well constrained, partly due to the considerable spatial heterogeneity of these permafrost‐dominated areas. Accurate calculations of in situ temperature sensitivities of respiration (Q10) are vital for the prediction of future Arctic emissions. To understand the impact of spatial heterogeneity on respiration rates and Q10, we compared respiration measured from automated chambers across the main local polygonized landscape forms (high and low centers, polygon rims, polygon troughs) to estimates from the flux‐partitioned net ecosystem exchange collected in an adjacent eddy covariance tower. Microtopographic type appears to be the most important variable explaining the variability in respiration rates, and low‐center polygons and polygon troughs show the greatest cumulative respiration rates, possibly linked to their deeper thaw depth and higher plant biomass. Regardless of the differences in absolute respiration rates, Q10 is surprisingly similar across all microtopographic features, possibly indicating a similar temperature limitation to decomposition across the landscape. Q10 was higher during the colder early summer and lower during the warmer peak growing season, consistent with an elevated temperature sensitivity under colder conditions. The respiration measured by the chambers and the estimates from the daytime flux‐partitioned eddy covariance data were within uncertainties during early and peak seasons but overestimated respiration later in the growing season. Overall, this study suggests that it is possible to simplify estimates of the temperature sensitivity of respiration across heterogeneous landscapes but that seasonal changes in Q10 should be incorporated into model simulations

Increased CO₂ loss from vegetated drained lake tundra ecosystems due to flooding

Tundra ecosystems are especially sensitive to climate change, which is particularly rapid in high northern latitudes resulting in significant alterations in temperature and soil moisture. Numerous studies have demonstrated that soil drying increases the respiration loss from wet Arctic tundra. And, warming and drying of tundra soils are assumed to increase CO2 emissions from the Arctic. However, in this water table manipulation experiment (i.e., flooding experiment), we show that flooding of wet tundra can also lead to increased CO2 loss. Standing water increased heat conduction into the soil, leading to higher soil temperature, deeper thaw and, surprisingly, to higher CO2 loss in the most anaerobic of the experimental areas. The study site is located in a drained lake basin, and the soils are characterized by wetter conditions than upland tundra. In experimentally flooded areas, high wind speeds (greater than ~4 m s−1) increased CO2 emission rates, sometimes overwhelming the photosynthetic uptake, even during daytime. This suggests that CO2 efflux from C rich soils and surface waters can be limited by surface exchange processes. The comparison of the CO2 and CH4 emission in an anaerobic soil incubation experiment showed that in this ecosystem, CO2 production is an order of magnitude higher than CH4 production. Future increases in surface water ponding, linked to surface subsidence and thermokarst erosion, and concomitant increases in soil warming, can increase net C efflux from these arctic ecosystems

Embodied perspectives on behavioral cognitive enhancement

Recent debates about strategies to enhance human cognition concerned mostly pharmacological, environmental and genetic factors, as well as computerized cognitive training paradigms targeting healthy populations. We offer a new perspective on behavioral cognitive enhancement, arguing that embodied cognition represents a productive framework to explain results and to inform new studies aimed at enhancing cognition. Understanding cognitive mechanisms and their time-course through an embodied perspective contributes to our knowledge of brain functioning and its potential. We review two domains: a) physical exercise and b) embodied learning. For each domain, we summarize experimental evidence according to the level of embodiment of the knowledge representations targeted by interventions (i.e., situatedness, embodiment proper, grounding). Future research should integrate embodiment and cognitive enhancement in training paradigms focused on joint cognitive and physical tasks

An innovative solution for earthquake resistance hybrid steel –concrete systems with replaceable dissipative steel links

In this work innovative hybrid coupled shear walls (HCSW) are considered, their design is discussed, their efficiency and limitations evaluated by means of nonlinear static (pushover) analysis. Different numbers of storeys, wall geometries and design assumptions are studied in order to give an overview of situations of interest in European seismic prone areas. The design of an experimental test regarding the performance of the connection of a seismic link embedded in a concrete shear wall is presented. This study is part of a larger research project named INNO-HYCO (INNOvative HYbrid and COmposite steel-concrete structural solutions for building in seismic area) funded by the European Commission

Anti-COVID vaccination for adolescents: A survey on determinants of vaccine parental hesitancy

Vaccine hesitancy has been considered one of the most severe threats to global health, as it represents an obstacle to achieving adequate vaccination coverage. Recent research studies aimed at investigating the propensity for anti-COVID vaccination among adults have found a high prevalence of vaccine hesitancy, but few data are available on parental vaccine hesitancy. We therefore built an anonymous online survey to investigate the factors related to the vaccine hesitancy of parents of adolescents between 12 and 17 years of age, with a special focus on demographic factors and the domains of confidence and complacency. The online survey was conducted by using the Crowd Signal platform from 15 July to 16 August 2021, in Italy. A total of 1799 analyzable questionnaires were analyzed. Overall, Favorable and Doubtful parents declared a higher level of confidence on safety and efficacy of pediatric vaccines and on confidence in health institutions than Hesitant/Reluctant ones (p-values < 0.001). The univariate multinomial logistic regression analysis and the multivariate multinomial logistic regression analysis showed that the Hesitant/Reluctant parents were younger than 40 years of age, with a secondary-school or three-year degree, free-lance, with a family income below €28,000, with an erroneous perception of the risk of COVID-19 as disease and with fear of anti-COVID vaccination. These results, which should be confirmed in a larger population and in different geographical areas, should lead Institutions and stakeholders to identify targeted communication tools to improve trust in health institutions, especially by younger parents

Hypertriglyceridemic waist identifies HIV+ men and women at increased cardiometabolic risk

Screening for increased waist circumference and hypertriglyceridemia (the hypertriglyceridemic-waist phenotype) is an inexpensive approach to identify patients at risk of coronary artery disease in apparently healthy individuals who may be at increased risk of type 2 diabetes and coronary heart disease because of an excess of intra-abdominal (visceral) fat. We examined the ralationship between the hypertriglyceridemic-waist and selected cardiometabolic risk factors in HIV individuals

SUMOylation inhibits FOXM1 activity and delays mitotic transition

The forkhead box transcription factor FOXM1 is an essential effector of G2/M-phase transition, mitosis and the DNA damage response. As such, it is frequently deregulated during tumorigenesis. Here we report that FOXM1 is dynamically modified by SUMO1 but not by SUMO2/3 at multiple sites. We show that FOXM1 SUMOylation is enhanced in MCF-7 breast cancer cells in response to treatment with epirubicin and mitotic inhibitors. Mutation of five consensus conjugation motifs yielded a SUMOylation-deficient mutant FOXM1. Conversely, fusion of the E2 ligase Ubc9 to FOXM1 generated an auto-SUMOylating mutant (FOXM1-Ubc9). Analysis of wild-type FOXM1 and mutants revealed that SUMOylation inhibits FOXM1 activity, promotes translocation to the cytoplasm and enhances APC/Cdh1-mediated ubiquitination and degradation. Further, expression of the SUMOylation-deficient mutant enhanced cell proliferation compared with wild-type FOXM1, whereas the FOXM1-Ubc9 fusion protein resulted in persistent cyclin B1 expression and slowed the time from mitotic entry to exit. In summary, our findings suggest that SUMOylation attenuates FOXM1 activity and causes mitotic delay in cytotoxic drug response

Different metabolic and anthropometric characteristics of TVD, CBV or KVX associated with nevirapine: Results from the "NEVIRAPINE COMPANION" cohort

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Response of CO₂ and CH₄ emissions from Arctic tundra soils to a multifactorial manipulation of water table, temperature and thaw depth

Significant uncertainties persist concerning how Arctic soil tundra carbon emission responds to environmental changes. In this study, 24 cores were sampled from drier (high centre polygons and rims) and wetter (low centre polygons and troughs) permafrost tundra ecosystems. We examined how soil CO2 and CH4 fluxes responded to laboratory-based manipulations of soil temperature (and associated thaw depth) and water table depth, representing current and projected conditions in the Arctic. Similar soil CO2 respiration rates occurred in both the drier and the wetter sites, suggesting that a significant proportion of soil CO2 emission occurs via anaerobic respiration under water-saturated conditions in these Arctic tundra ecosystems. In the absence of vegetation, soil CO2 respiration rates decreased sharply within the first 7 weeks of the experiment, while CH4 emissions remained stable for the entire 26 weeks of the experiment. These patterns suggest that soil CO2 emission is more related to plant input than CH4 production and emission. The stable and substantial CH4 emission observed over the entire course of the experiment suggests that temperature limitations, rather than labile carbon limitations, play a predominant role in CH4 production in deeper soil layers. This is likely due to the presence of a substantial source of labile carbon in these carbon-rich soils. The small soil temperature difference (a median difference of 1 ◦C) and a more substantial thaw depth difference (a median difference of 6 cm) between the high and low temperature treatments resulted in a non-significant difference between soil CO2 and CH4 emissions. Although hydrology continued to be the primary factor influencing CH4 emissions, these emissions remained low in the drier ecosystem, even with a water table at the surface. This result suggests the potential absence of a methanogenic microbial community in high-centre polygon and rim ecosystems. Overall, our results suggest that the temperature increases reported for these Arctic regions are not responsible for increases in carbon losses. Instead, it is the changes in hydrology that exert significant control over soil CO2 and CH4 emissions

Predictors of transitions in frailty severity and mortality among people aging with HIV.

BACKGROUND: People aging with HIV show variable health trajectories. Our objective was to identify longitudinal predictors of frailty severity and mortality among a group aging with HIV. METHODS: Exploratory analyses employing a multistate transition model, with data from the prospective Modena HIV Metabolic Clinic Cohort Study, based in Northern Italy, begun in 2004. Participants were followed over four years from their first available visit. We included all 963 participants (mean age 46.8±7.1; 29% female; 89% undetectable HIV viral load; median current CD4 count 549, IQR 405–720; nadir CD4 count 180, 81–280) with four-year data. Frailty was quantified using a 31-item frailty index. Outcomes were frailty index score or mortality at four-year follow-up. Candidate predictor variables were baseline frailty index score, demographic (age, sex), HIV-disease related (undetectable HIV viral load, current CD4+ T-cell count, nadir CD4 count, duration of HIV infection, and duration of antiretroviral therapy [ARV] exposure), and behavioral factors (smoking, injection drug use (IDU), and hepatitis C virus co-infection). RESULTS: Four-year mortality was 3.0% (n = 29). In multivariable analyses, independent predictors of frailty index at follow-up were baseline frailty index (RR 1.06, 95% CI 1.05–1.07), female sex (RR 0.93, 95% CI 0.87–0.98), nadir CD4 cell count (RR 0.96, 95% CI 0.93–0.99), duration of HIV infection (RR 1.06, 95% CI 1.01–1.12), duration of ARV exposure (RR 1.08, 95% CI 1.02–1.14), and smoking pack-years (1.03, 1.01–1.05). Independent predictors of mortality were baseline frailty index (OR 1.19, 1.02–1.38), current CD4 count (0.34, 0.20–0.60), and IDU (2.89, 1.30–6.42). CONCLUSIONS: Demographic, HIV-disease related, and social and behavioral factors appear to confer risk for changes in frailty severity and mortality among people aging with HIV