1,437 research outputs found

    Better Higgs-CP Tests Through Information Geometry

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    Measuring the CP symmetry in the Higgs sector is one of the key tasks of the LHC and a crucial ingredient for precision studies, for example in the language of effective Lagrangians. We systematically analyze which LHC signatures offer dedicated CP measurements in the Higgs-gauge sector, and discuss the nature of the information they provide. Based on the Fisher information measure, we compare the maximal reach for CP-violating effects in weak boson fusion, associated ZH production, and Higgs decays into four leptons. We find a subtle balance between more theory-independent approaches and more powerful analysis channels, indicating that rigorous evidence for CP violation in the Higgs-gauge sector will likely require a multi-step process.Comment: 27 pages, 8 figure

    Why Deterrence is not enough: The Role of Endogenous Motivations on Employees’ Information Security Behavior

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    Information systems security (ISS) is an increasingly critical issue for companies worldwide. One major reason for information security incidents remains human error. Thus, understanding how employees’ ISS-related behavior can be influenced is a top priority (Siponen and Vance 2010). In this regard, numerous recent studies have examined the effect of deterrence mechanisms. However, the role of endogenous motivations has been largely neglected, although studies in adjacent fields have shown the effectiveness of motivational intervention strategies. We seek to close this gap by examining how endogenous motivations influence employees intention to comply with organizational ISS guidelines. Our model integrates the theory of planned behavior and the organismic integration theory. It is tested using a sample of 444 employees. The results show that when employees’ personal values and principles are congruent with ISS-related prescriptions compliance intention significantly increases. However, we find no impact on intention when employees perceive their actions as coerced

    Quantitative wave function analysis for excited states of transition metal complexes

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    The character of an electronically excited state is one of the most important descriptors employed to discuss the photophysics and photochemistry of transition metal complexes. In transition metal complexes, the interaction between the metal and the different ligands gives rise to a rich variety of excited states, including metal-centered, intra-ligand, metal-to-ligand charge transfer, ligand-to-metal charge transfer, and ligand-to-ligand charge transfer states. Most often, these excited states are identified by considering the most important wave function excitation coefficients and inspecting visually the involved orbitals. This procedure is tedious, subjective, and imprecise. Instead, automatic and quantitative techniques for excited-state characterization are desirable. In this contribution we review the concept of charge transfer numbers---as implemented in the TheoDORE package---and show its wide applicability to characterize the excited states of transition metal complexes. Charge transfer numbers are a formal way to analyze an excited state in terms of electron transitions between groups of atoms based only on the well-defined transition density matrix. Its advantages are many: it can be fully automatized for many excited states, is objective and reproducible, and provides quantitative data useful for the discussion of trends or patterns. We also introduce a formalism for spin-orbit-mixed states and a method for statistical analysis of charge transfer numbers. The potential of this technique is demonstrated for a number of prototypical transition metal complexes containing Ir, Ru, and Re. Topics discussed include orbital delocalization between metal and carbonyl ligands, nonradiative decay through metal-centered states, effect of spin-orbit couplings on state character, and comparison among results obtained from different electronic structure methods.Comment: 47 pages, 19 figures, including supporting information (7 pages, 1 figure

    Completeness of Information Sources

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    Information quality plays a crucial role in every application that integrates data from autonomous sources. However, information quality is hard to measure and complex to consider for the tasks of information integration, even if the integrating sources cooperate. We present a systematic and formal approach to the measurement of information quality and the combination of such measurements for information integration. Our approach is based on a value model that incorporates both extensional value (coverage) and intensional value (density) of information. For both aspects we provide merge functions for adequately scoring integrated results. Also, we combine the two criteria to an overall completeness criterion that formalizes the intuitive notion of completeness of query results. This completeness measure is a valuable tool to assess source size and to predict result sizes of queries in integrated information systems. We propose this measure as an important step towards the usage of information quality for source selection, query planning, query optimization, and quality feedback to users.Peer Reviewe

    Recent Advances and the Potential for Clinical Use of Autofluorescence Detection of Extra-Ophthalmic Tissues

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    The autofluorescence (AF) characteristics of endogenous fluorophores allow the label-free assessment and visualization of cells and tissues of the human body. While AF imaging (AFI) is well-established in ophthalmology, its clinical applications are steadily expanding to other disciplines. This review summarizes clinical advances of AF techniques published during the past decade. A systematic search of the MEDLINE database and Cochrane Library databases was performed to identify clinical AF studies in extra-ophthalmic tissues. In total, 1097 articles were identified, of which 113 from internal medicine, surgery, oral medicine, and dermatology were reviewed. While comparable technological standards exist in diabetology and cardiology, in all other disciplines, comparability between studies is limited due to the number of differing AF techniques and non-standardized imaging and data analysis. Clear evidence was found for skin AF as a surrogate for blood glucose homeostasis or cardiovascular risk grading. In thyroid surgery, foremost, less experienced surgeons may benefit from the AF-guided intraoperative separation of parathyroid from thyroid tissue. There is a growing interest in AF techniques in clinical disciplines, and promising advances have been made during the past decade. However, further research and development are mandatory to overcome the existing limitations and to maximize the clinical benefits

    Laparoscopic liver resection: indications, limitations, and economic aspects

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    Background: Minimally invasive techniques have increasingly found their way into liver surgery in recent years. A multitude of mostly retrospective analyses suggests several advantages of laparoscopic over open liver surgery. Due to the speed and variety of simultaneous technical and strategic developments, it is difficult to maintain an overview of the current status and perspectives in laparoscopic liver surgery. Purpose: This review highlights up-to-date aspects in laparoscopic liver surgery. We discuss established indications with regard to their development over time as well as continuing limitations of applied techniques. We give an assessment based on the current literature and according to our own center experiences, not least with regard to a highly topical cost discussion. Conclusions: While in the beginning mainly benign tumors were laparoscopically operated on, liver metastasis and hepatocellular carcinoma are now among the most frequent indications. Technical limitations remain and should be evaluated with the overall aim not to endanger quality standards in open surgery. Financial aspects cannot be neglected with the necessity of cost-covering reimbursement

    Perioperative Pleural Drainage in Liver Transplantation: A Retrospective Analysis from a High-Volume Liver Transplant Center

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    BACKGROUND Pleural effusions represent a common complication after liver transplantation (LT) and chest drain (CD) placement is frequently necessary. MATERIAL AND METHODS In this retrospective cohort study, adult LT recipients between 2009 and 2016 were analyzed for pleural effusion formation and its treatment within the first 10 postoperative days. The aim of the study was to compare different settings of CD placement with regard to intervention-related complications. RESULTS Overall, 597 patients met the inclusion criteria, of which 361 patients (60.5%) received at least 1 CD within the study period. Patients with a MELD >25 were more frequently affected (75.7% versus 56.0%, P<0.001). Typically, CDs were placed in the intensive care unit (ICU) (66.8%) or in the operating room (14.1% during LT, 11.5% in the context of reoperations). In total, 97.0% of the patients received a right-sided CD, presumably caused by local irritations. Approximately one-third (35.4%) of ICU-patients required pre-interventional optimization of coagulation. Of the 361 patients receiving a CD, 15 patients (4.2%) suffered a post-interventional hemorrhage and 6 patients (1.4%) had a pneumothorax requiring further treatment. Less complications were observed when the CD was performed in the operating room compared to the ICU: 1 out 127 patients (0.8%) versus 20 out of 332 patients (6.0%); P=0.016. CONCLUSIONS CD placement occurring in the operating room was associated with fewer complications in contrast to placement occurring in the ICU. Planned CD placement in the course of surgery might be favorable in high-risk patients

    Risk factors for malignant transformation of hepatocellular adenoma to hepatocellular carcinoma: protocol for systematic review and meta-analysis

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    Introduction: Hepatocellular adenomas (HCAs) are solid liver tumours that are usually found incidentally during routine medical check-ups. Multiple modifiable and non-modifiable factors constitute a risk for the malignant transformation of HCAs to hepatocellular carcinoma (HCC), which has emerged to be one of the fastest growing causes of cancer-related mortality globally. This study protocol for a planned systematic review and meta-analysis documents the methodological approach to identify risk factors and their risk estimates for the transformation from HCA to HCC. Methods and analysis: Two independent reviewers will systematically search and extract data from studies in patients of all ages published between January 1970 and June 2021 on PubMed, MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature, Scopus Web of Science, Ovid, The Cochrane Hepatobiliary Group Controlled Trials Register and The Cochrane Central Register of Controlled Trials by using an a priori defined search strategy. Study quality will be rated with the National Institute of Health quality assessment tools. Disagreements will be resolved by consensus with a third independent reviewer. The primary outcome will be the odds ratio (OR) of developing HCC in patients with prediagnosed HCA depending on the exposure to risk factors. HCC diagnosis must be inferred based on imaging techniques or pathology. We will use R V.4.0.2 to conduct meta-analyses and generate pooled ORs based on random effects models. Results will be presented as forest plots. Cochran’s Q and I2 test will be performed to assess heterogeneity between included studies. Funnel plots and Egger’s weighted regression will be used to evaluate publication bias. Ethics and dissemination: No ethical approval is required as we will use and analyse data from previously published studies in which informed consent was obtained. The results will be disseminated in a peer-reviewed journal on completion. PROSPERO registration number: CRD42020206578
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