87 research outputs found
Distinct Frontal Networks Are Involved in Adapting to Internally and Externally Signaled Errors
Errors trigger changes in behavior that help individuals adapt to new situations. The dorsal anterior cingulate cortex (dACC) is thought to be central to this response, but more lateral frontal regions are also activated by errors and may make distinct contributions. We investigated error processing by studying 2 distinct error types: commission and timing. Thirty-five subjects performed a version of the Simon Task designed to produce large number of errors. Commission errors were internally recognized and were not accompanied by explicit feedback. In contrast, timing errors were difficult to monitor internally and were explicitly signaled. Both types of error triggered changes in behavior consistent with increased cognitive control. As expected, robust activation within the dACC and bilateral anterior insulae (the Salience Network) was seen for commission errors. In contrast, timing errors were not associated with activation of this network but did activate a bilateral network that included the right ventral attentional system. Common activation for both error types occurred within the pars operculari and angular gyri. These results show that the dACC does not respond to all behaviorally salient errors. Instead, the error-processing system is multifaceted, and control can be triggered independently of the dACC when feedback is unexpected
Franck-Condon Effect in Central Spin System
We study the quantum transitions of a central spin surrounded by a
collective-spin environment. It is found that the influence of the
environmental spins on the absorption spectrum of the central spin can be
explained with the analog of the Franck-Condon (FC) effect in conventional
electron-phonon interaction system. Here, the collective spins of the
environment behave as the vibrational mode, which makes the electron to be
transitioned mainly with the so-called "vertical transitions" in the
conventional FC effect. The "vertical transition" for the central spin in the
spin environment manifests as, the certain collective spin states of the
environment is favored, which corresponds to the minimal change in the average
of the total spin angular momentum.Comment: 8 pages, 8 figure
Viremia trajectories of HIV in HIV-positive women in the United States, 1994-2017
IMPORTANCE Viral suppression of HIV is an important treatment goal to decrease morbidity, mortality, and risk of transmission to others. OBJECTIVE To characterize longitudinal HIV viral load outcomes among women enrolled in the Women's Interagency HIV Study (WIHS). DESIGN, SETTING, AND PARTICIPANTS A prospective cohort study of HIV-positive women with semiannual study visits and a minimum of 5 follow-up visits was conducted from 1994 to 2017. The WIHS sites included in this analysis are in Brooklyn and Bronx, New York; Chicago, Illinois; San Francisco, California; andWashington, DC. MAIN OUTCOMES AND MEASURES Women were categorized into groups based on their probability of achieving viral load suppression below 200 copies/mL using logistic trajectory modeling. Multinomial regression analysis was used to identify factors associated with placement in the group with the highest probability of viremia. RESULTS At baseline, the mean (SD) age of the 1989 women was 36.9 (8.0) years, mean CD4+ T-lymphocyte count was 467/mm3, median (interquartile range) HIV RNA was 6200.0 (384.5-41 678.0) copies/mL, and 1305 women (65.6%) were African American. Three trajectory groups were identified with low (568 [28.6%]), intermediate (784 [39.4%]), and high (637 [32.0%]) probability of viremia above 200 copies/mL. The mean (SD) cumulative years of viral suppression were 18.7 (4.0) years, 12.2 (3.1) years, and 5.8 (2.9) years in the respective groups. Factors associated with high probability of viremia included younger age (odds ratio [OR]. 0.99; 95%CI, 0.98-0.99; P = .03), African American race (odds ratio [OR], 2.43; 95%CI, 1.75-3.37), P < .001), Hispanic race/ ethnicity (OR, 1.50; 95%CI, 1.03-2.19; P = .04), increased levels of depressive symptoms (OR, 1.17; 95%CI, 1.01-1.36; P = .03), drug use (OR, 1.23; 95%CI, 1.01-1.51; P = .04), lower CD4+ T-lymphocyte counts (OR, 95%CI, 0.82; 0.80-0.85; P < .001), and unstable housing (OR, 1.25, 95%CI, 1.03-1.50; P = .02). Between 2015 and 2017, 71.2%of women demonstrated sustained viral suppression: 89.6% (310 of 346) of those with lowviremia, 83.4%(346 of 415) with intermediate, and 35.2%(112 of 318) with high probability of viremia. CONCLUSIONS AND RELEVANCE This longitudinal approach suggested that the probability of viremia decreased substantially over time for most participants, including among women with earlier histories of incomplete viral suppression. The findings from this study suggest that continued efforts are needed to address mental health, social, behavioral and structural factors that were identified as associated with high probability of HIV viremia over time
State of the climate in 2013
In 2013, the vast majority of the monitored climate variables reported here maintained trends established in recent decades. ENSO was in a neutral state during the entire year, remaining mostly on the cool side of neutral with modest impacts on regional weather patterns around the world. This follows several years dominated by the effects of either La Niña or El Niño events. According to several independent analyses, 2013 was again among the 10 warmest years on record at the global scale, both at the Earths surface and through the troposphere. Some regions in the Southern Hemisphere had record or near-record high temperatures for the year. Australia observed its hottest year on record, while Argentina and New Zealand reported their second and third hottest years, respectively. In Antarctica, Amundsen-Scott South Pole Station reported its highest annual temperature since records began in 1957. At the opposite pole, the Arctic observed its seventh warmest year since records began in the early 20th century. At 20-m depth, record high temperatures were measured at some permafrost stations on the North Slope of Alaska and in the Brooks Range. In the Northern Hemisphere extratropics, anomalous meridional atmospheric circulation occurred throughout much of the year, leading to marked regional extremes of both temperature and precipitation. Cold temperature anomalies during winter across Eurasia were followed by warm spring temperature anomalies, which were linked to a new record low Eurasian snow cover extent in May. Minimum sea ice extent in the Arctic was the sixth lowest since satellite observations began in 1979. Including 2013, all seven lowest extents on record have occurred in the past seven years. Antarctica, on the other hand, had above-average sea ice extent throughout 2013, with 116 days of new daily high extent records, including a new daily maximum sea ice area of 19.57 million km2 reached on 1 October. ENSO-neutral conditions in the eastern central Pacific Ocean and a negative Pacific decadal oscillation pattern in the North Pacific had the largest impacts on the global sea surface temperature in 2013. The North Pacific reached a historic high temperature in 2013 and on balance the globally-averaged sea surface temperature was among the 10 highest on record. Overall, the salt content in nearsurface ocean waters increased while in intermediate waters it decreased. Global mean sea level continued to rise during 2013, on pace with a trend of 3.2 mm yr-1 over the past two decades. A portion of this trend (0.5 mm yr-1) has been attributed to natural variability associated with the Pacific decadal oscillation as well as to ongoing contributions from the melting of glaciers and ice sheets and ocean warming. Global tropical cyclone frequency during 2013 was slightly above average with a total of 94 storms, although the North Atlantic Basin had its quietest hurricane season since 1994. In the Western North Pacific Basin, Super Typhoon Haiyan, the deadliest tropical cyclone of 2013, had 1-minute sustained winds estimated to be 170 kt (87.5 m s-1) on 7 November, the highest wind speed ever assigned to a tropical cyclone. High storm surge was also associated with Haiyan as it made landfall over the central Philippines, an area where sea level is currently at historic highs, increasing by 200 mm since 1970. In the atmosphere, carbon dioxide, methane, and nitrous oxide all continued to increase in 2013. As in previous years, each of these major greenhouse gases once again reached historic high concentrations. In the Arctic, carbon dioxide and methane increased at the same rate as the global increase. These increases are likely due to export from lower latitudes rather than a consequence of increases in Arctic sources, such as thawing permafrost. At Mauna Loa, Hawaii, for the first time since measurements began in 1958, the daily average mixing ratio of carbon dioxide exceeded 400 ppm on 9 May. The state of these variables, along with dozens of others, and the 2013 climate conditions of regions around the world are discussed in further detail in this 24th edition of the State of the Climate series. © 2014, American Meteorological Society. All rights reserved
Genomic and phenotypic insights from an atlas of genetic effects on DNA methylation
DNA methylation quantitative trait locus (mQTL) analyses on 32,851 participants identify genetic variants associated with DNA methylation at 420,509 sites in blood, resulting in a database of >270,000 independent mQTLs.Characterizing genetic influences on DNA methylation (DNAm) provides an opportunity to understand mechanisms underpinning gene regulation and disease. In the present study, we describe results of DNAm quantitative trait locus (mQTL) analyses on 32,851 participants, identifying genetic variants associated with DNAm at 420,509 DNAm sites in blood. We present a database of >270,000 independent mQTLs, of which 8.5% comprise long-range (trans) associations. Identified mQTL associations explain 15-17% of the additive genetic variance of DNAm. We show that the genetic architecture of DNAm levels is highly polygenic. Using shared genetic control between distal DNAm sites, we constructed networks, identifying 405 discrete genomic communities enriched for genomic annotations and complex traits. Shared genetic variants are associated with both DNAm levels and complex diseases, but only in a minority of cases do these associations reflect causal relationships from DNAm to trait or vice versa, indicating a more complex genotype-phenotype map than previously anticipated.Molecular Epidemiolog
The design of a real time, fault-tolerant, multiprocessor system
SIGLELD:D48725/84 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
A laser GC-IRMS technique for in situ stable isotope analyses of carbonates and phosphates.
Jaagsiekte sheep retrovirus
Jaagsiekte sheep retrovirus (JSRV) and the related small ruminant betaretroviruses are a fascinating group of viruses with unique characteristics that are of broad interest through their veterinary, comparative medical and biological importance. JSRV is the causative agent of ovine pulmonary adenocarcinoma (OPA), an important viral disease of sheep and an outbred animal model for human lung adenocarcinoma. The mechanisms followed by JSRV to transform cells are unique among oncogenic retroviruses as the viral envelope glycoprotein (Env) functions as a dominant oncoprotein. The enzootic nasal tumor virus (ENTV) is also an oncogenic retrovirus highly related both phylogenetically and biologically to JSRV. ENTV induces a contagious tumor of the mucosal nasal glands in sheep and goats. Interestingly, sheep, goats, and most species belonging to the subfamily of the Caprinae, have stably integrated in their genome endogenous retroviruses highly related to ENTV and JSRV (hence the name enJSRVs). enJSRVs are expressed, particularly in the genital tract epithelia of the ewe. Intriguingly, enJSRVs appear critical for sheep placental development during the pre-implantation period and therefore represent a powerful example on how viruses can shape mammalian biology
Minor stable carbon isotope fractionation between respired carbon dioxide and bulk soil organic matter during laboratory incubation of topsoil
A common assumption in paleoenvironmental reconstructions using soils is that the carbon isotope composition of soil-respired CO2 is equivalent to the carbon isotope composition of bulk soil organic matter (SOM). However, the occurrence of a non-zero per mil carbon isotope enrichment factor between CO2 and SOM ( εCO2−SOMεCO2−SOM) during soil respiration is the most widely accepted explanation for the down-profile increase in SOM δ13C values commonly observed in well-drained soils. In order to shed light on this apparent discrepancy, we incubated soil samples collected from the top 2 cm of soils with pure C3 vegetation and compared the δ13C values of soil-respired CO2 to the δ13C values of bulk SOM. Our results show near-zero εCO2−SOMεCO2−SOM values (−0.3 to 0.4 ‰), supporting the use of paleosol organic matter as a proxy for paleo soil-respired CO2. Significantly more negative εCO2−SOMεCO2−SOM values are required to explain the typical δ13C profiles of SOM in well-drained soils. Therefore our results also suggest that typical SOM δ13C profiles result from either (1) a process other than carbon isotope fractionation between CO2 and SOM during soil respiration or (2) εCO2−SOMεCO2−SOM values that become increasingly negative as SOM matures
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