Fact-Check spreading behavior in twitter: A qualitative profile for false-claim news

Fact-check spread is usually performed by a plain tweet with just the link. Since it is not proper human behavior, it may cause uncanny, hinder the reader’s attention and harm the counter-propaganda influence. This paper presents a profile of fact-check link spread in Twitter (suiting for TRL-1) and, as an additional outcome, proposes a preliminary behavior design based on it (suiting for TRL-2). The underlying hypothesis is by simulating human-like behavior, a bot gets more attention and exerts more influence on its followers.This work has been supported by national funds through FCT Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019

A scattering rate approach to the understanding of absorption line broadening in near-infrared AlGaN/GaN quantum wells

There has been much interest in the advancement of III-Nitride growth technology to fabricate AlGaN/GaN heterostructures for intersubband transitions (ISBTs). The large conduction band offset in these structures (up to 2 eV) allows transition energies in the near- to the far-infrared region, which have applications from telecommunications, such as in all-optical switches, to infra-red detectors for sensing and imaging. To date, ISBT electroluminescence has been elusive and absorption measurements remain an important method to verify band structure calculations. The growth quality can be inferred from the absorption spectrum, which will have line broadening with contributions that are both inhomogeneous (large-scale interface roughness, and non-parabolicity) and homogeneous (electron scattering related lifetime broadening). In the present work we calculated the contributions of various homogeneous broadening mechanisms (electron interaction with longitudinal-optical (LO) phonons, acoustic phonons, impurities and alloy disorder) to the full linewidth, and also the contribution of band non-parabolicity, which contributes to the inhomogeneous broadening. Calculations are then compared to the measured absorption spectra of several samples

100 Gb/s Multicarrier THz Wireless Transmission System With High Frequency Stability Based on A Gain-Switched Laser Comb Source

We propose and experimentally demonstrate a photonic multichannel terahertz (THz) wireless system with up to four optical subcarriers and total capacity as high as 100 Gb/s by employing an externally injected gain-switched laser comb source. Highly coherent multiple optical carriers with different spacing are produced using the gain switching technique. Single- and multichannel Terahertz (THz) wireless signals are generated using heterodyne mixing of modulated single or multiple carriers with one unmodulated optical tone spaced by about 200 GHz. The frequency stability and the phase noise of the gain switched comb laser are evaluated against free-running lasers. Wireless transmission is demonstrated for single and three optical subcarriers modulated with 8 or 10 GBd quadrature phase-shift keying (QPSK) (48 or 60 Gb/s, respectively) or for four optical subcarriers modulated with 12.5 GBd QPSK (100 Gb/s). The system performance was evaluated for single- and multicarrier wireless THz transmissions at around 200 GHz, with and without 40 km fiber transmission. The system is also modeled to study the effect of the cross talk between neighboring subcarriers for correlated and decorrelated data. This system reduces digital signal processing requirements due to the high-frequency stability of the gain-switched comb source, increases the overall transmission rate, and relaxes the optoelectronic bandwidth requirements

The Association between Respiratory Infection and Air Pollution in the Setting of Air Quality Policy and Economic Change

Rationale: Fine particulate air pollution (≤2.5µm; PM2.5) has been associated with an increased risk of respiratory disease, but assessments of specific respiratory infections in adults are lacking. Objective: To estimate the rate of respiratory infection healthcare encounters in adults associated with acute increases in PM2.5 concentrations. Methods: Using case-crossover methods, we studied 498,118 adult New York State residents with a primary diagnosis of influenza, bacterial pneumonia, or culture negative pneumonia upon hospitalization or emergency department (ED) visit (2005-2016). We estimated the rate of healthcare encounters associated with increases in PM2.5 in the previous 1-7 days and explored differences Before (2005 to 2007), During (2008-2013), and After (2014-2016) implementation of air quality policies and economic changes. Results: Interquartile range increases in PM2.5 over the previous 7 days were associated with increased excess rates of culture negative pneumonia hospitalizations (2.5%; 95% CI 1.7%, 3.2%) and ED visits (2.5%; 95% CI 1.4%, 3.6%), and increased excess rates of influenza ED visits (3.9%; 95% CI 2.1%, 5.6%). Bacterial pneumonia hospitalizations but not ED visits were associated with increases in PM2.5 and though imprecise, were of a similar magnitude to culture negative pneumonia (Lag day 6 ER 2.3%; 95% CI: 0.3, 4.3). Increased relative rates of influenza ED visits and culture negative pneumonia hospitalizations were generally larger in the After period (p< 0.025 for both outcomes), compared to the During period, despite reductions in overall PM2.5 concentrations. Conclusion: Increased rates of culture negative pneumonia and influenza were associated with increased PM2.5 concentrations during the previous week, which persisted despite reductions in PM2.5 from air quality policies and economic changes. Though unexplained, this temporal variation may reflect altered toxicity of different PM2.5 mixtures or increased pathogen virulence

Design considerations for GaN/AlN based unipolar (opto-)electronic devices, and interface quality aspects

We describe the theoretical and experimental studies of GaN/AlGaN based resonant tunnelling diodes, and in particular analyse the effects and typical values of interface roughness, and then discuss the implications of these, realistic material quality parameters on performance of unipolar optoelectronic devices

Cytotoxic drugs efficacy correlates with adipose tissue docosahexaenoic acid level in locally advanced breast carcinoma

Experimental studies indicated that long-chain polyunsaturated fatty acids may increase sensitivity of mammary tumours to several cytotoxic drugs. To evaluate this hypothesis in breast cancer, we have prospectively studied the association between levels of fatty acids stored in breast adipose tissue and the response of the tumour to chemotherapy in 56 patients with an initially localized breast carcinoma. Adipose breast tissue was obtained at the time of biopsy, and individual fatty acids were measured as a percentage of total fatty acids using capillary gas chromatography. Patients then received primary chemotherapy, combining mitoxantrone, vindesine, cyclophosphamide and 5-fluorouracil every 4 weeks. Tumour size was reassessed after three cycles of chemotherapy. Tumour response was evaluated according to World Health Organization criteria. Complete or partial response to chemotherapy was achieved in 26 patients (47%). Level of n-3 polyunsaturated fatty acids in adipose tissue was higher in the group of patients with complete or partial response to chemotherapy than in patients with no response or with tumour progression (P < 0.004). Among n-3 polyunsaturated, only docosahexaenoic acid (22:6n-3) was significantly associated with tumour response (P < 0.005). In a logistic regression analysis taking into account age, body mass index and tumour size, 22:6 n-3 level proved to be an independent predictor for chemosensitivity (P = 0.03). These results suggest that, in breast cancer, 22:6 n-3 may increase the response of the tumour to the cytotoxic agents used. © 1999 Cancer Research Campaig

Feigenbaum graphs: a complex network perspective of chaos

The recently formulated theory of horizontal visibility graphs transforms time series into graphs and allows the possibility of studying dynamical systems through the characterization of their associated networks. This method leads to a natural graph-theoretical description of nonlinear systems with qualities in the spirit of symbolic dynamics. We support our claim via the case study of the period-doubling and band-splitting attractor cascades that characterize unimodal maps. We provide a universal analytical description of this classic scenario in terms of the horizontal visibility graphs associated with the dynamics within the attractors, that we call Feigenbaum graphs, independent of map nonlinearity or other particulars. We derive exact results for their degree distribution and related quantities, recast them in the context of the renormalization group and find that its fixed points coincide with those of network entropy optimization. Furthermore, we show that the network entropy mimics the Lyapunov exponent of the map independently of its sign, hinting at a Pesin-like relation equally valid out of chaos.Comment: Published in PLoS ONE (Sep 2011

The leading digit distribution of the worldwide Illicit Financial Flows

Benford's law states that in data sets from different phenomena leading digits tend to be distributed logarithmically such that the numbers beginning with smaller digits occur more often than those with larger ones. Particularly, the law is known to hold for different types of financial data. The Illicit Financial Flows (IFFs) exiting the developing countries are frequently discussed as hidden resources which could have been otherwise properly utilized for their development. We investigate here the distribution of the leading digits in the recent data on estimates of IFFs to look for the existence of a pattern as predicted by Benford's law and establish that the frequency of occurrence of the leading digits in these estimates does closely follow the law.Comment: 13 pages, 10 figures, 6 tables, additional data analyi

A biophysical model of cell adhesion mediated by immunoadhesin drugs and antibodies

A promising direction in drug development is to exploit the ability of natural killer cells to kill antibody-labeled target cells. Monoclonal antibodies and drugs designed to elicit this effect typically bind cell-surface epitopes that are overexpressed on target cells but also present on other cells. Thus it is important to understand adhesion of cells by antibodies and similar molecules. We present an equilibrium model of such adhesion, incorporating heterogeneity in target cell epitope density and epitope immobility. We compare with experiments on the adhesion of Jurkat T cells to bilayers containing the relevant natural killer cell receptor, with adhesion mediated by the drug alefacept. We show that a model in which all target cell epitopes are mobile and available is inconsistent with the data, suggesting that more complex mechanisms are at work. We hypothesize that the immobile epitope fraction may change with cell adhesion, and we find that such a model is more consistent with the data. We also quantitatively describe the parameter space in which binding occurs. Our results point toward mechanisms relating epitope immobility to cell adhesion and offer insight into the activity of an important class of drugs.Comment: 13 pages, 5 figure

Solitary waves in the Nonlinear Dirac Equation

In the present work, we consider the existence, stability, and dynamics of solitary waves in the nonlinear Dirac equation. We start by introducing the Soler model of self-interacting spinors, and discuss its localized waveforms in one, two, and three spatial dimensions and the equations they satisfy. We present the associated explicit solutions in one dimension and numerically obtain their analogues in higher dimensions. The stability is subsequently discussed from a theoretical perspective and then complemented with numerical computations. Finally, the dynamics of the solutions is explored and compared to its non-relativistic analogue, which is the nonlinear Schr{\"o}dinger equation. A few special topics are also explored, including the discrete variant of the nonlinear Dirac equation and its solitary wave properties, as well as the PT-symmetric variant of the model