4,050 research outputs found
Can the envisaged reductions of fossil fuel CO2 emissions be detected by atmospheric observations?
The lower troposphere is an excellent receptacle, which integrates anthropogenic greenhouse gases emissions over large areas. Therefore, atmospheric concentration observations over populated regions would provide the ultimate proof if sustained emissions changes have occurred. The most important anthropogenic greenhouse gas, carbon dioxide (CO2), also shows large natural concentration variations, which need to be disentangled from anthropogenic signals to assess changes in associated emissions. This is in principle possible for the fossil fuel CO2 component (FFCO2) by high-precision radiocarbon (14C) analyses because FFCO2 is free of radiocarbon. Long-term observations of 14CO2 conducted at two sites in south-western Germany do not yet reveal any significant trends in the regional fossil fuel CO2 component. We rather observe strong inter-annual variations, which are largely imprinted by changes of atmospheric transport as supported by dedicated transport model simulations of fossil fuel CO2. In this paper, we show that, depending on the remoteness of the site, changes of about 7–26% in fossil fuel emissions in respective catchment areas could be detected with confidence by high-precision atmospheric 14CO2 measurements when comparing 5-year averages if these inter-annual variations were taken into account. This perspective constitutes the urgently needed tool for validation of fossil fuel CO2 emissions changes in the framework of the Kyoto protocol and successive climate initiatives
Central Exclusive Production in QCD
We investigate the theoretical description of the central exclusive
production process, h1+h2 -> h1+X+h2. Taking Higgs production as an example, we
sum logarithmically enhanced corrections appearing in the perturbation series
to all orders in the strong coupling. Our results agree with those originally
presented by Khoze, Martin and Ryskin except that the scale appearing in the
Sudakov factor, mu=0.62 \sqrt{\hat{s}}, should be replaced with
mu=\sqrt{\hat{s}}, where \sqrt{\hat{s}} is the invariant mass of the centrally
produced system. We confirm this result using a fixed-order calculation and
show that the replacement leads to approximately a factor 2 suppression in the
cross-section for central system masses in the range 100-500 GeV.Comment: 41 pages, 19 figures; minor typos fixed; version published in JHE
The proper name as starting point for basic reading skills
Does alphabetic-phonetic writing start with the proper name and how does the name affect reading and writing skills? Sixty 4- to 5½-year-old children from middle SES families with Dutch as their first language wrote their proper name and named letters. For each child we created unique sets of words with and without the child’s first letter of the name to test spelling skills and phonemic sensitivity. Name writing correlated with children’s knowledge of the first letter of the name and phonemic sensitivity for the sound of the first letter of the name. Hierarchical regression analysis makes plausible that both knowledge of the first letter’s name and phonemic sensitivity for this letter explain why name writing results in phonetic spelling with the name letter. Practical implications of the findings are discussed
Prompt photon and associated heavy quark production at hadron colliders with kt-factorization
In the framework of the kt-factorization approach, the production of prompt
photons in association with a heavy (charm or beauty) quarks at high energies
is studied. The consideration is based on the O(\alpha \alpha_s^2) off-shell
amplitudes of gluon-gluon fusion and quark-(anti)quark interaction
subprocesses. The unintegrated parton densities in a proton are determined
using the Kimber-Martin-Ryskin prescription. The analysis covers the total and
differential cross sections and extends to specific angular correlations
between the produced prompt photons and muons originating from the semileptonic
decays of associated heavy quarks. Theoretical uncertainties of our evaluations
are studied and comparison with the results of standard NLO pQCD calculations
is performed. Our numerical predictions are compared with the recent
experimental data taken by the D0 and CDF collaborations at the Tevatron.
Finally, we extend our results to LHC energies.Comment: 14 pages, 10 figure
Normally preordered spaces and utilities
In applications it is useful to know whether a topological preordered space
is normally preordered. It is proved that every -space equipped with
a closed preorder is a normally preordered space. Furthermore, it is proved
that second countable regularly preordered spaces are perfectly normally
preordered and admit a countable utility representation.Comment: 17 pages, 1 figure. v2 contains a second proof to the main theorem
with respect to the published version. The last section of v1 is not present
in v2. It will be included in a different wor
Acute effects of nicotine on visual search tasks in young adult smokers
Rationale Nicotine is known to improve performance on tests involving sustained attention and recent research suggests that nicotine may also improve performance on tests involving the strategic allocation of attention and working memory. Objectives We used measures of accuracy and response latency combined with eye-tracking techniques to examine the effects of nicotine on visual search tasks. Methods In experiment 1 smokers and non-smokers performed pop-out and serial search tasks. In experiment 2, we used a within-subject design and a more demanding search task for multiple targets. In both studies, 2-h abstinent smokers were asked to smoke one of their own cigarettes between baseline and tests. Results In experiment 1, pop-out search times were faster after nicotine, without a loss in accuracy. Similar effects were observed for serial searches, but these were significant only at a trend level. In experiment 2, nicotine facilitated a strategic change in eye movements resulting in a higher proportion of fixations on target letters. If the cigarette was smoked on the first trial (when the task was novel), nicotine additionally reduced the total number of fixations and refixations on all letters in the display. Conclusions Nicotine improves visual search performance by speeding up search time and enabling a better focus of attention on task relevant items. This appears to reflect more efficient inhibition of eye movements towards task irrelevant stimuli, and better active maintenance of task goals. When the task is novel, and therefore more difficult, nicotine lessens the need to refixate previously seen letters, suggesting an improvement in working memory
Higher systolic blood pressure in early-mid adulthood is associated with poorer cognitive performance in those with a dominantly inherited Alzheimer's disease mutation but not in non-carriers. Results from the DIAN study
BACKGROUND: The Dominantly Inherited Alzheimer Network (DIAN) is a longitudinal observational study that collects data on cognition, blood pressure (BP), and other variables from autosomal-dominant Alzheimer's disease mutation carriers (MCs) and non-carrier (NC) family members in early to mid-adulthood, providing a unique opportunity to evaluate BP and cognition relationships in these populations. METHOD: We examined cross-sectional and longitudinal relationships between systolic and diastolic BP and cognition in DIAN MC and NC. RESULTS: Data were available from 528 participants, who had a mean age of 38 (SD = 11) and were 42% male and 61% MCs, at a median follow-up of 2 years. Linear-multilevel models found only cross-sectional associations in the MC group between higher systolic BP and poorer performance on language (β = −0.181 [−0.318, −0.044]), episodic memory (−0.212 [−0.375, −0.049]), and a composite cognitive measure (−0.146 [−0.276, −0.015]). In NCs, the relationship was cross-sectional only and present for language alone. DISCUSSION: Higher systolic BP was cross-sectionally but not longitudinally associated with poorer cognition, particularly in MCs. BP may influence cognition gradually, but further longitudinal research is needed
Evaluation of autoantibody binding to cardiac tissue in multisystem inflammatory syndrome in children and COVID-19 vaccination-induced myocarditis.
IMPORTANCE: Cardiac dysfunction and myocarditis have emerged as serious complications of multisystem inflammatory syndrome in children (MIS-C) and vaccines against SARS-CoV-2. Understanding the role of autoantibodies in these conditions is essential for guiding MIS-C management and vaccination strategies in children. OBJECTIVE: To investigate the presence of anticardiac autoantibodies in MIS-C or COVID-19 vaccine-induced myocarditis. DESIGN, SETTING, AND PARTICIPANTS: This diagnostic study included children with acute MIS-C or acute vaccine myocarditis, adults with myocarditis or inflammatory cardiomyopathy, healthy children prior to the COVID-19 pandemic, and healthy COVID-19 vaccinated adults. Participants were recruited into research studies in the US, United Kingdom, and Austria starting January 2021. Immunoglobulin G (IgG), IgM, and IgA anticardiac autoantibodies were identified with immunofluorescence staining of left ventricular myocardial tissue from 2 human donors treated with sera from patients and controls. Secondary antibodies were fluorescein isothiocyanate-conjugated antihuman IgG, IgM, and IgA. Images were taken for detection of specific IgG, IgM, and IgA deposits and measurement of fluorescein isothiocyanate fluorescence intensity. Data were analyzed through March 10, 2023. MAIN OUTCOMES AND MEASURES: IgG, IgM and IgA antibody binding to cardiac tissue. RESULTS: By cohort, there were a total of 10 children with MIS-C (median [IQR] age, 10 [13-14] years; 6 male), 10 with vaccine myocarditis (median age, 15 [14-16] years; 10 male), 8 adults with myocarditis or inflammatory cardiomyopathy (median age, 55 [46-63] years; 6 male), 10 healthy pediatric controls (median age, 8 [13-14] years; 5 male), and 10 healthy vaccinated adults (all older than 21 years, 5 male). No antibody binding above background was observed in human cardiac tissue treated with sera from pediatric patients with MIS-C or vaccine myocarditis. One of the 8 adult patients with myocarditis or cardiomyopathy had positive IgG staining with raised fluorescence intensity (median [IQR] intensity, 11 060 [10 223-11 858] AU). There were no significant differences in median fluorescence intensity in all other patient cohorts compared with controls for IgG (MIS-C, 6033 [5834-6756] AU; vaccine myocarditis, 6392 [5710-6836] AU; adult myocarditis or inflammatory cardiomyopathy, 5688 [5277-5990] AU; healthy pediatric controls, 6235 [5924-6708] AU; healthy vaccinated adults, 7000 [6423-7739] AU), IgM (MIS-C, 3354 [3110-4043] AU; vaccine myocarditis, 3843 [3288-4748] AU; healthy pediatric controls, 3436 [3313-4237] AU; healthy vaccinated adults, 3543 [2997-4607] AU) and IgA (MIS-C, 3559 [2788-4466] AU; vaccine myocarditis, 4389 [2393-4780] AU; healthy pediatric controls, 3436 [2425-4077] AU; healthy vaccinated adults, 4561 [3164-6309] AU). CONCLUSIONS AND RELEVANCE: This etiological diagnostic study found no evidence of antibodies from MIS-C and COVID-19 vaccine myocarditis serum binding cardiac tissue, suggesting that the cardiac pathology in both conditions is unlikely to be driven by direct anticardiac antibody-mediated mechanisms
Strong signature of natural selection within an FHIT intron implicated in prostate cancer risk
Previously, a candidate gene linkage approach on brother pairs affected with prostate cancer identified a locus of prostate cancer susceptibility at D3S1234 within the fragile histidine triad gene (FHIT), a tumor suppressor that induces apoptosis. Subsequent association tests on 16 SNPs spanning approximately 381 kb surrounding D3S1234 in Americans of European descent revealed significant evidence of association for a single SNP within intron 5 of FHIT. In the current study, resequencing and genotyping within a 28.5 kb region surrounding this SNP further delineated the association with prostate cancer risk to a 15 kb region. Multiple SNPs in sequences under evolutionary constraint within intron 5 of FHIT defined several related haplotypes with an increased risk of prostate cancer in European-Americans. Strong associations were detected for a risk haplotype defined by SNPs 138543, 142413, and 152494 in all cases (Pearson's χ2 = 12.34, df 1, P = 0.00045) and for the homozygous risk haplotype defined by SNPs 144716, 142413, and 148444 in cases that shared 2 alleles identical by descent with their affected brothers (Pearson's χ2 = 11.50, df 1, P = 0.00070). In addition to highly conserved sequences encompassing SNPs 148444 and 152413, population studies revealed strong signatures of natural selection for a 1 kb window covering the SNP 144716 in two human populations, the European American (π = 0.0072, Tajima's D= 3.31, 14 SNPs) and the Japanese (π = 0.0049, Fay & Wu's H = 8.05, 14 SNPs), as well as in chimpanzees (Fay & Wu's H = 8.62, 12 SNPs). These results strongly support the involvement of the FHIT intronic region in an increased risk of prostate cancer. © 2008 Ding et al
Acute febrile illness is associated with Rickettsia spp infection in dogs
BACKGROUND: Rickettsia conorii is transmitted by Rhipicephalus sanguineus ticks and causes Mediterranean Spotted Fever (MSF) in humans. Although dogs are considered the natural host of the vector, the clinical and epidemiological significance of R. conorii infection in dogs remains unclear. The aim of this prospective study was to investigate whether Rickettsia infection causes febrile illness in dogs living in areas endemic for human MSF. METHODS: Dogs from southern Italy with acute fever (n = 99) were compared with case–control dogs with normal body temperatures (n = 72). Serology and real-time PCR were performed for Rickettsia spp., Ehrlichia canis, Anaplasma phagocytophilum/A. platys and Leishmania infantum. Conventional PCR was performed for Babesia spp. and Hepatozoon spp. Acute and convalescent antibodies to R. conorii, E. canis and A. phagocytophilum were determined. RESULTS: The seroprevalence rates at first visit for R. conorii, E. canis, A. phagocytophilum and L. infantum were 44.8%, 48.5%, 37.8% and 17.6%, respectively. The seroconversion rates for R. conorii, E. canis and A. phagocytophilum were 20.7%, 14.3% and 8.8%, respectively. The molecular positive rates at first visit for Rickettsia spp., E. canis, A. phagocytophilum, A. platys, L. infantum, Babesia spp. and Hepatozoon spp. were 1.8%, 4.1%, 0%, 2.3%, 11.1%, 2.3% and 0.6%, respectively. Positive PCR for E. canis (7%), Rickettsia spp. (3%), Babesia spp. (4.0%) and Hepatozoon spp. (1.0%) were found only in febrile dogs. The DNA sequences obtained from Rickettsia and Babesia PCRs positive samples were 100% identical to the R. conorii and Babesia vogeli sequences in GenBank®, respectively. Febrile illness was statistically associated with acute and convalescent positive R. conorii antibodies, seroconversion to R. conorii, E. canis positive PCR, and positivity to any tick pathogen PCRs. Fourteen febrile dogs (31.8%) were diagnosed with Rickettsia spp. infection based on seroconversion and/or PCR while only six afebrile dogs (12.5%) seroconverted (P = 0.0248). The most common clinical findings of dogs with Rickettsia infection diagnosed by seroconversion and/or PCR were fever, myalgia, lameness, elevation of C-reactive protein, thrombocytopenia and hypoalbuminemia. CONCLUSIONS: This study demonstrates acute febrile illness associated with Rickettsia infection in dogs living in endemic areas of human MSF based on seroconversion alone or in combination with PCR
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