Infodemiološka studija o upotrebi maski za lice tijekom pandemije COVID-19: usporedba SAD-a i Južne Koreje

In the midst of the COVID-19 pandemic, there have been varied responses to public health officials\u27 recommendations about wearing face masks as a means to slow the spread of the virus. This study, by using Twitter data, aims to explore the role of digital technology in facilitating public conversations and formulating public perception regarding face masks during the COVID-19 pandemic in two contrasting contexts: the U.S. and South Korea. From January 1, 2020 to April 14, 2020, a total of 22,928 users generated 27,501 tweets regarding face masks in the U.S. network, whereas 17,267 users produced 18,686 tweets in that of South Korea. The results of the semantic network analysis shed light on Americans\u27 initial resistance to wearing masks as well as Koreans\u27 willingness to comply. Details of the results are discussed further in the paper. With real-time data aggregation, this study gives insight into the rising controversy regarding wearing face masks during COVID-19 while providing implications for health officials designing strategic communication messages.Usred pandemije COVID-19, dobivamo različite odgovore na preporuke službenika javnoga zdravstva o nošenju maski za lice kao mjere koja usporava širenje virusa. Ova se studija koristi podacima s Twittera kako bi istražila ulogu digitalne tehnologije u olakšavanju javne komunikacije i formuliranju percepcije javnosti o nošenju maski tijekom pandemije COVID-19 u dva konteksta: SAD-u i Južnoj Koreji. Od 1. siječnja do 14. travnja 2020. u mreži SAD-a ukupno je 22 928 korisnika generiralo 27 501 tweet na temu maski za lice, dok ih je u Južnoj Koreji 17 267 korisnika proizvelo 18 686. Rezultati analize semantičke mreže otkrivaju početni otpor Amerikanaca prema nošenju maski, kao i spremnost Korejaca da se mjera pridržavaju. Pojedinosti rezultata iznesene su u radu. Uz agregaciju podataka u stvarnom vremenu, ova studija daje uvid u sve veći prijepor povezan s nošenjem maski za lice tijekom pandemije COVID-19, dajući u isti mah informacije zdravstvenim djelatnicima koji oblikuju strateške komunikacijske poruke

A selectively reduced degree basis for efficient mixed nonlinear isogeometric beam formulations with extensible directors

The effect of higher order continuity in the solution field by using NURBS basis function in isogeometric analysis (IGA) is investigated for an efficient mixed finite element formulation for elastostatic beams. It is based on the Hu-Washizu variational principle considering geometrical and material nonlinearities. Here we present a reduced degree of basis functions for the additional fields of the stress resultants and strains of the beam, which are allowed to be discontinuous across elements. This approach turns out to significantly improve the computational efficiency and the accuracy of the results. We consider a beam formulation with extensible directors, where cross-sectional strains are enriched to avoid Poisson locking by an enhanced assumed strain method. In numerical examples, we show the superior per degree-of-freedom accuracy of IGA over conventional finite element analysis, due to the higher order continuity in the displacement field. We further verify the efficient rotational coupling between beams, as well as the path-independence of the results.Comment: 50 pages, 23 figure

LASIK Interface-Captured Foreign Bodies after Mild Traumatic Corneal Scratch without Flap Displacement

A 38-year-old woman developed diffusely distributed opacities with crystalline materials in the laser in situ keratomileusis (LASIK) interface of her eye after she was scratched by a sprig during mountain climbing. No sign of flap displacement was noted. Despite two days of topical and systemic antibiotics therapy, the corneal infiltration with interface opacities persisted. The following day, the distribution of the crystalline materials had rotated in a counterclockwise direction. Flap lifting and foreign body removal using sufficient irrigation were performed. One month after surgery, the patient's postoperative uncorrected visual acuity was 0.8 with cleared interface. No signs of epithelial ingrowth or flap striae were noted. Mild traumatic corneal scratching without flap displacement may threaten the integrity of the LASIK interface. If foreign bodies are suspected to be the cause of inflammation, early flap lifting with irrigation is imperative for successful treatment

A study on the key performance indicator of the dynamic positioning system

AbstractThe dynamic positioning system (DPS) maintains an offshore vessel's position and heading under various environmental conditions by using its own thrust. DPS is regarded as one of the most important systems in offshore vessels. So, efficient operation and maintenance of the DPS are important issues. To monitor the DPS, it is necessary to define an appropriate key performance indicator (KPI) that can express the condition of the DPS from the perspective of operational efficiency and maintenance. In this study, a new KPI for the DPS is proposed considering the efficiency of the machinery and controller, the energy efficiency, and the environmental conditions in which the DPS is operated. The KPI is defined as a function of control deviation, energy consumption, and environmental load. A normalization factor is used to normalize the effect of environmental load on the KPI. The KPI value is calculated from DPS simulation and model test data. The possibility of applying the KPI to monitoring of DPS condition is discussed by comparing the values. The result indicates the feasibility of the new KPI

Hate Speech Spikes on Twitter After Elon Musk Acquires the Platform

Unmoderated social media platforms frequently become a haven for misinformation, extremism, and hate. There are challenges unique to unmoderated social media platforms that make the removal of such content and the users who spread it particularly difficult (Artime et al., 2020). When a platform’s focus is unrestricted expression from users, those looking to share and spread antisocial content will presumably use such spaces to share perspectives that would likely be restricted on other platforms. Historically, examples of such “free speech absolutist” spaces suggest that this threat is very real. Specifically, 4chan serves as a space where online anonymity coupled with limited restrictions on speech has allowed virulent hate content to be shared without fear of platform response (Tuters & Hagen, 2020). 4chan has hosted a range of antisocial content including the call for the abuse of women (Milanović, 2021), hostility towards the trans community (Sparby, 2017), aggressive antisemitism (Tuters & Hagen 2020), and white nationalism (Thorleifsson, 2022). Other less moderated online spaces emphasizing open exchange have produced similar results (Urman & Katz, 2022)

Gyrotron‐backward‐wave‐oscillator experiments utilizing a high current, high voltage, microsecond electron accelerator

We report the first gyrotron‐backward‐wave‐oscillator experiments to produce high power (tube power of ∼1–8 MW), long‐pulse (0.3–1.2 μs) microwaves at high currents (0.1–2 kA) and high voltages (650–750 kV). Experiments were performed in the TE11 fundamental backward‐wave mode, with efficiencies of ∼1%–2%. Mode competition was observed which is believed to originate from the TE21 absolute instability.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70862/2/JAPIAU-72-4-1221-1.pd