5,258 research outputs found

    "Boring formal methods" or "Sherlock Holmes deduction methods"?

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    This paper provides an overview of common challenges in teaching of logic and formal methods to Computer Science and IT students. We discuss our experiences from the course IN3050: Applied Logic in Engineering, introduced as a "logic for everybody" elective course at at TU Munich, Germany, to engage pupils studying Computer Science, IT and engineering subjects on Bachelor and Master levels. Our goal was to overcome the bias that logic and formal methods are not only very complicated but also very boring to study and to apply. In this paper, we present the core structure of the course, provide examples of exercises and evaluate the course based on the students' surveys.Comment: Preprint. Accepted to the Software Technologies: Applications and Foundations (STAF 2016). Final version published by Springer International Publishing AG. arXiv admin note: substantial text overlap with arXiv:1602.0517

    Iterative forcing and hyperimmunity in reverse mathematics

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    The separation between two theorems in reverse mathematics is usually done by constructing a Turing ideal satisfying a theorem P and avoiding the solutions to a fixed instance of a theorem Q. Lerman, Solomon and Towsner introduced a forcing technique for iterating a computable non-reducibility in order to separate theorems over omega-models. In this paper, we present a modularized version of their framework in terms of preservation of hyperimmunity and show that it is powerful enough to obtain the same separations results as Wang did with his notion of preservation of definitions.Comment: 15 page

    Amlodipine in the current management of hypertension.

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    Hypertension is the leading cause of death worldwide, affecting 1.4 billion people. Treatment options include the widely used calcium channel blockers, among which amlodipine, a dihydropyridine, has unique characteristics that distinguish it from other drugs within this class. This review aims to provide an updated overview of the evidence supporting the use of amlodipine over the past 30 years and highlights its cardiovascular benefits in current hypertension management. Amlodipine has low renal clearance (7 mL/min/mg) and long half-life (35-50 h) and duration of action, which allows it to sustain its anti-hypertensive effect for more than 24 h following a single dose. Additionally, blood pressure (BP) control is maintained even when a dose has been missed, providing continuous protection in case of incidental noncompliance. It has proven to reduce BP variability and successfully lower BP. Amlodipine also controls BP in patients with a systolic/diastolic BP of 130/80 mm Hg or higher, diabetes, or chronic kidney disease without worsening glycemic or kidney function. Additionally, amlodipine is a wise choice for older adults due to its ability to control BP and protect against stroke and myocardial infarction. Side effects of amlodipine include edema, palpitations, dizziness, and flushing, which are more common with the higher dose of 10 mg. Amlodipine is cost effective and predicted to be cost saving when compared with usual care

    On the role of magnetic reconnection in jet/accretion disk systems

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    The most accepted model for jet production is based on the magneto-centrifugal acceleration out off an accretion disk that surrounds the central source (Blandford & Payne, 1982). This scenario, however, does not explain, e.g., the quasi-periodic ejection phenomena often observed in different astrophysical jet classes. de Gouveia Dal Pino & Lazarian (2005) (hereafter GDPL) have proposed that the large scale superluminal ejections observed in microquasars during radio flare events could be produced by violent magnetic reconnection (MR) episodes. Here, we extend this model to other accretion disk systems, namely: active galactic nuclei (AGNs) and young stellar objects (YSOs), and also discuss its role on jet heating and particle acceleration.Comment: To be published in the IAU Highlights of Astronomy, Volume 15, XXVII IAU General Assembly, August 2009, Ian F. Corbett et al., eds., 201

    PSMA PET Imaging and Therapy in Adenoid Cystic Carcinoma and Other Salivary Gland Cancers: A Systematic Review

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    Adenoid cystic carcinoma (ACC) and other salivary gland cancers (SGCs) are rare tumors where application of prostate specific membrane antigen (PSMA) positron emission tomography (PET) and PSMA radioligand therapy have yet to be studied extensively. This review explores the role of PSMA PET imaging and therapy as a theranostic tool for ACC and other SGCs based on current literature. A comprehensive literature search on PubMed and Embase was performed. All relevant studies containing information on PSMA PET imaging in ACC and SGC were included. Ten studies (one prospective, three retrospective, five case reports and one review paper) were included. For ACC, the mean maximum standardized uptake value (SUVmax) for local recurrence and distant metastases ranged from 2.41 to 13.8 and 2.04 to 14.9, respectively. In SGC, the meanSUVmax ranged from 1.2–12.50. Most studies observed PSMA expression positivity on immunohistochemistry (IHC) when there was PSMA PET uptake. PSMA PET was able to detect lesions not detected on standard imaging. Despite the small number of studies and wide intra-patient and inter-tumor variation of PSMA uptake in ACC and SGC, 68Gallium (68Ga)-PSMA PET has promising prospects as a diagnostic and radioligand therapeutic option. Further studies to answer the various theranostics considerations are required to guide its use in the real-world setting

    Magnetic field effects on the electroluminescence of organic light emitting devices: A tool to indicate the carrier mobility

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    The magnetoelectroluminescence (MEL) of organic light emitting devices with a N, N′ -bis(l-naphthyl)- N, N′ -diphenyl- 1, l′ -biphentl- 4, 4′ -diamine:tris-(8-hydroxyquinoline) aluminum (NPB: Alq 3) mixed emission layer (EML) has been investigated. We find that MEL is maximized when the volume ratio of NPB of the mixed EML reaches 30% and the EML thickness is 40 nm. The features of MEL under various magnetic field strengths are insensitive to the change in EML thickness and mixing ratio. Meanwhile, MEL has a close relationship with the carrier mobility. We have conducted a theoretical study to further verify the relationship. Our experimental and theoretical results confirm that MEL can function as a tool to indicate the mobility. © 2010 American Institute of Physics.published_or_final_versio

    Hot Streaks in Artistic, Cultural, and Scientific Careers

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    The hot streak, loosely defined as winning begets more winnings, highlights a specific period during which an individual's performance is substantially higher than her typical performance. While widely debated in sports, gambling, and financial markets over the past several decades, little is known if hot streaks apply to individual careers. Here, building on rich literature on lifecycle of creativity, we collected large-scale career histories of individual artists, movie directors and scientists, tracing the artworks, movies, and scientific publications they produced. We find that, across all three domains, hit works within a career show a high degree of temporal regularity, each career being characterized by bursts of high-impact works occurring in sequence. We demonstrate that these observations can be explained by a simple hot-streak model we developed, allowing us to probe quantitatively the hot streak phenomenon governing individual careers, which we find to be remarkably universal across diverse domains we analyzed: The hot streaks are ubiquitous yet unique across different careers. While the vast majority of individuals have at least one hot streak, hot streaks are most likely to occur only once. The hot streak emerges randomly within an individual's sequence of works, is temporally localized, and is unassociated with any detectable change in productivity. We show that, since works produced during hot streaks garner significantly more impact, the uncovered hot streaks fundamentally drives the collective impact of an individual, ignoring which leads us to systematically over- or under-estimate the future impact of a career. These results not only deepen our quantitative understanding of patterns governing individual ingenuity and success, they may also have implications for decisions and policies involving predicting and nurturing individuals with lasting impact

    Vaccines for COVID-19

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    Since the emergence of COVID-19, caused by the SARS-CoV-2 virus, at the end of 2019 there has been an explosion of vaccine development. By the 1st September 2020, a staggering number of vaccines (over 200) had started pre-clinical development of which 39 had entered clinical trials, including some approaches that have not previously been licensed for human vaccines. Vaccines have been widely considered as part of the exit strategy to enable the return to previous patterns of working, schooling and socialising. Importantly, to effectively control the COVID-19 pandemic, production needs to be scaled up from a small number of pre-clinical doses to enough filled vials to immunise the world's population, which requires close engagement with manufacturers and regulators. It will require a global effort to control the virus, necessitating equitable access for all countries to effective vaccines. This review explores the immune responses required to protect against SARS-CoV-2 and the potential for vaccine-induced immunopathology. It describes the profile of the different platforms and the advantages and disadvantages of each approach. The review also addresses the critical steps between promising pre-clinical leads and manufacturing at scale. The issues faced during this pandemic and the platforms being developed to address it will be invaluable for future outbreak control. Nine months after the outbreak began, we are at a point where pre-clinical and early clinical data is being generated for the vaccines, an overview of this important area will help our understanding of the next phases

    An Improved Upper Bound for the Ring Loading Problem

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    The Ring Loading Problem emerged in the 1990s to model an important special case of telecommunication networks (SONET rings) which gained attention from practitioners and theorists alike. Given an undirected cycle on nn nodes together with non-negative demands between any pair of nodes, the Ring Loading Problem asks for an unsplittable routing of the demands such that the maximum cumulated demand on any edge is minimized. Let LL be the value of such a solution. In the relaxed version of the problem, each demand can be split into two parts where the first part is routed clockwise while the second part is routed counter-clockwise. Denote with LL^* the maximum load of a minimum split routing solution. In a landmark paper, Schrijver, Seymour and Winkler [SSW98] showed that LL+1.5DL \leq L^* + 1.5D, where DD is the maximum demand value. They also found (implicitly) an instance of the Ring Loading Problem with L=L+1.01DL = L^* + 1.01D. Recently, Skutella [Sku16] improved these bounds by showing that LL+1914DL \leq L^* + \frac{19}{14}D, and there exists an instance with L=L+1.1DL = L^* + 1.1D. We contribute to this line of research by showing that LL+1.3DL \leq L^* + 1.3D. We also take a first step towards lower and upper bounds for small instances

    Testing and comparing two self-care-related instruments among older Chinese adults

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    Objectives The study aimed to test and compare the reliability and validity, including sensitivity and specificity of the two self-care-related instruments, the Self-care Ability Scale for the Elderly (SASE), and the Appraisal of Self-care Agency Scale-Revised (ASAS-R), among older adults in the Chinese context. Methods A cross-sectional design was used to conduct this study. The sample consisted of 1152 older adults. Data were collected by a questionnaire including the Chinese version of SASE (SASE-CHI), the Chinese version of ASAS-R (ASAS-R-CHI) and the Exercise of Self-Care Agency scale (ESCA). Homogeneity and stability, content, construct and concurrent validity, and sensitivity and specificity were assessed. Results The Cronbach's alpha (α) of SASE-CHI was 0.89, the item-to-total correlations ranged from r = 0.15 to r = 0.81, and the test-retest correlation coefficient (intra-class correlation coefficient, ICC) was 0.99 (95% CI, 0.99±1.00; P<0.001). The Cronbach's α of ASAS-R-CHI was 0.78, the item-to-total correlations ranged from r = 0.20 to r = 0.65, and the test-retest ICC was 0.95 (95% CI, 0.92±0.96; P<0.001). The content validity index (CVI) of SASE-CHI and ASAS-R-CHI was 0.96 and 0.97, respectively. The findings of exploratory and confirmatory factor analyses (EFA and CFA) confirmed a good construct validity of SASE-CHI and ASAS-R-CHI. The Pearson's rank correlation coefficients, as a measure of concurrent validity, between total score of SASE-CHI and ESCA and ASAS-R-CHI and ESCA were assessed to 0.65 (P<0.001) and 0.62 (P<0.001), respectively. Regarding ESCA as the criterion, the area under the receiver operator characteristic (ROC) curve for the cut-point of SASE-CHI and ASAS-R-CHI were 0.93 (95% CI, 0.91±0.94) and 0.83 (95% CI, 0.80±0.86), respectively. Conclusion There is no significant difference between the two instruments. Each has its own characteristics, but SASE-CHI is more suitable for older adults. The key point is that the users can choose the most appropriate scale according to the specific situation.publishedVersionNivå
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