Reduktion von Nachbarkanalstörungen in OFDM-Systemen (DVB-C2)

Die zweite Generation des Standards für die Übertragung digitaler Signale in Rundfunkkabelnetzen (DVB-C2) verwendet Orthogonal Frequency Division Multiplex (OFDM) als Übertragungsverfahren. Ein typisches Leistungsdichtespektrum eines OFDM-Signals weist Anteile außerhalb des aktiven Trägerbereiches auf. Diese Anteile werden auch Out-of-Band-Emissionen (OoB) genannt und sind eigentlich ein Teil des OFDM-Nutzsignals, das jedoch in spektral benachbarten Kanälen zu Störungen führen kann. Eine Filterung des Sendesignals zur Begrenzung auf die Kanalbandbreite ist insbesondere bei den für DVB-C2 spezifizierten höheren Modulationsstufen, wie der 1024- und der 4096-QAM, mit Nachteilen wie der Degradation der Signalqualität von Randträgern oder Inter-Symbol-Interferenz verbunden. Um diese Effekte zu minimieren, wird in diesem Beitrag eine Methode vorgestellt, die die systembedingten Störanteile außerhalb der Kanalbandbreite mit Hilfe von Filtern kurzer Impulsantwort reduziert, wobei die durch die Filterung verursachten linearen Verzerrungen des aktiven Spektrums des Nutzsignals durch eine Vorverzerrung des OFDM-Signals kompensiert werden

Urban Climate Under Change [UC]2 – A National Research Programme for Developing a Building-Resolving Atmospheric Model for Entire City Regions

Large cities and urban regions are confronted with rising pressure by environmental pollution, impacts of climate change, as well as natural and health hazards. They are characterised by heterogeneous mosaics of urban structures, causing modifications of atmospheric processes on different temporal and spatial scales. Planning authorities need reliable, locally relevant information on urban atmospheric processes, providing fine spatial resolutions in city quarters or street canyons, as well as projections of future climates, specifically downscaled to individual cities. Therefore, building-resolving urban climate models for entire city regions are required as tool for urban development and planning, air quality control, as well as for design of actions for climate change mitigation and adaptation. To date, building-resolving atmospheric models covering entire large cities are mostly missing. The German research programme “Urban Climate Under Change” ([UC]2) aims at developing a new urban climate model, to acquire three-dimensional observational data for model testing and validation, and to test its practicability and usability in collaboration with relevant stakeholders to provide a scientifically sound and practicable instrument to address the above mentioned challenges. This article provides an outline of the collaborative activities of the [UC]2 research programme

Zu den Autorinnen und Autoren

Der vorliegende Band versammelt die umgearbeiteten Beiträge einer Tagung, die im März 2002 im Warburg-Haus in Hamburg stattfand. Sie wurde im Rahmen des Forschungsprojekts „Natur im Konflikt“ veranstaltet, das von der Volkswagenstiftung innerhalb des Förderprogramms „Schlüsselthemen der Geisteswissenschaften“ finanziert wird. Dieses interdisziplinäre Vorhaben widmet sich der Untersuchung von mentalen Konzepten, Bildern, Modellen und Wertzuschreibungen, die zum kollektiven Fundus unserer Vorstellungen von Natur gehören. Dabei richten sich die Untersuchungen aus der Perspektive verschiedener Fachrichtungen – Ethnologie bzw. Sozialanthropologie, Geschichtswissenschaft, naturwissenschaftliche Küstenforschung, Literatur-, Sprach- und Medienwissenschaft – insbesondere auf die diejenigen Naturbilder und Modellierungen, die zu den oft nicht thematisierten Argumentationen und Überzeugungen gehören.This volume collects the revised contributions of a conference that took place in March 2002 at the Warburg-Haus in Hamburg. It was organised as part of the "Nature in Conflict" research project, which was funded by the Volkswagen Foundation within the framework of the "Key Humanities Issues" funding programme. This interdisciplinary project was dedicated to the investigation of mental concepts, images, models and value attributions that belong to the collective fund of our ideas of nature. In this context, the investigations are directed from the perspective of various disciplines - ethnology or social anthropology, history, coastal research in the natural sciences, literature, linguistics and media studies - in particular at those images of nature and models that belong to the argumentations and convictions that are often not discussed

Changing Incidence and Risk Factors for Kaposi Sarcoma by Time Since Starting Antiretroviral Therapy: Collaborative Analysis of 21 European Cohort Studies.

BACKGROUND:  Kaposi sarcoma (KS) remains a frequent cancer in human immunodeficiency virus (HIV)-positive patients starting combination antiretroviral therapy (cART). We examined incidence rates and risk factors for developing KS in different periods after starting cART in patients from European observational HIV cohorts. METHODS:  We included HIV-positive adults starting cART after 1 January 1996. We analyzed incidence rates and risk factors for developing KS up to 90 and 180 days and 1, 2, 5, and 8 years after cART start and fitted univariable and multivariable Cox regression models. RESULTS:  We included 109 461 patients from 21 prospective clinical cohorts in Europe with 916 incident KS cases. The incidence rate per 100 000 person-years was highest 6 months after starting cART, at 953 (95% confidence interval, 866-1048), declining to 82 (68-100) after 5-8 years. In multivariable analyses adjusted for exposure group, origin, age, type of first-line regimen, and calendar year, low current CD4 cell counts increased the risk of developing KS throughout all observation periods after cART initiation. Lack of viral control was not associated with the hazard of developing KS in the first year after cART initiation, but was over time since starting cART increasingly positively associated (P < .001 for interaction). CONCLUSION:  In patients initiating cART, both incidence and risk factors for KS change with time since starting cART. Whereas soon after starting cART low CD4 cell count is the dominant risk factor, detectable HIV-1 RNA viral load becomes an increasingly important risk factor in patients who started cART several years earlier, independently of immunodeficiency

High specificity of line-immunoassay based algorithms for recent HIV-1 infection independent of viral subtype and stage of disease

ABSTRACT: BACKGROUND: Serologic testing algorithms for recent HIV seroconversion (STARHS) provide important information for HIV surveillance. We have shown that a patient's antibody reaction in a confirmatory line immunoassay (INNO-LIATM HIV I/II Score, Innogenetics) provides information on the duration of infection. Here, we sought to further investigate the diagnostic specificity of various Inno-Lia algorithms and to identify factors affecting it. METHODS: Plasma samples of 714 selected patients of the Swiss HIV Cohort Study infected for longer than 12 months and representing all viral clades and stages of chronic HIV-1 infection were tested blindly by Inno-Lia and classified as either incident (up to 12 m) or older infection by 24 different algorithms. Of the total, 524 patients received HAART, 308 had HIV-1 RNA below 50 copies/mL, and 620 were infected by a HIV-1 non-B clade. Using logistic regression analysis we evaluated factors that might affect the specificity of these algorithms. RESULTS: HIV-1 RNA <50 copies/mL was associated with significantly lower reactivity to all five HIV-1 antigens of the Inno-Lia and impaired specificity of most algorithms. Among 412 patients either untreated or with HIV-1 RNA ≥50 copies/mL despite HAART, the median specificity of the algorithms was 96.5% (range 92.0-100%). The only factor that significantly promoted false-incident results in this group was age, with false-incident results increasing by a few percent per additional year. HIV-1 clade, HIV-1 RNA, CD4 percentage, sex, disease stage, and testing modalities exhibited no significance. Results were similar among 190 untreated patients. CONCLUSIONS: The specificity of most Inno-Lia algorithms was high and not affected by HIV-1 variability, advanced disease and other factors promoting false-recent results in other STARHS. Specificity should be good in any group of untreated HIV-1 patients

Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a $Z$ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 $< p_{\textrm{T}} < 100$ GeV and in the pseudorapidity range $2.5 < \eta < 4$. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb$^{-1}$. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages

Study of the B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

The decay $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ is studied in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV using data corresponding to an integrated luminosity of 5 $\mathrm{fb}^{-1}$ collected by the LHCb experiment. In the $\Lambda_{c}^+ K^{-}$ system, the $\Xi_{c}(2930)^{0}$ state observed at the BaBar and Belle experiments is resolved into two narrower states, $\Xi_{c}(2923)^{0}$ and $\Xi_{c}(2939)^{0}$, whose masses and widths are measured to be $$m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV},$$ where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt $\Lambda_{c}^{+} K^{-}$ sample. Evidence of a new $\Xi_{c}(2880)^{0}$ state is found with a local significance of $3.8\,\sigma$, whose mass and width are measured to be $2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV}$ and $12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}$, respectively. In addition, evidence of a new decay mode $\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-}$ is found with a significance of $3.7\,\sigma$. The relative branching fraction of $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ with respect to the $B^{-} \to D^{+} D^{-} K^{-}$ decay is measured to be $2.36 \pm 0.11 \pm 0.22 \pm 0.25$, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages