“Good Things Come in Lightweights”: A Group Decision-Making Analysis Comparing Twitter on Mobile Communication Devices to Computer-Mediated Communication

This paper reports on a study of the effects of Twitter-enabled mobile communication devices on group decision-making and group dynamics. One hundred and sixty-seven university students formed 44 groups under two distinct communication conditions: Twitter operating on mobile communication devices (TMCD), and Google Groups online message boards (OMB) accessed through personal computers. Each group was tracked as it completed an assigned set of group decision-making tasks. The study’s results are analyzed through media synchronicity theory and its distinction between conveyance and convergence communication processes. TMCD exhibited significantly fewer conflicting (unfriendly) messages and a greater number of initiatory messages than OMB. Moreover, with tasks involving convergence communication processes, TMCD achieved significantly higher levels of conformity and satisfaction than OMB. These results imply that lightweight, portable mobile communication devices (MCDs), enabled with Twitter or another similar interface, complement conventional computer-mediated communication, offering an effective means of group decision-making

Bremsstrahlung Radiation At a Vacuum Bubble Wall

When charged particles collide with a vacuum bubble, they can radiate strong electromagnetic waves due to rapid deceleration. Owing to the energy loss of the particles by this bremsstrahlung radiation, there is a non-negligible damping pressure acting on the bubble wall even when thermal equilibrium is maintained. In the non-relativistic region, this pressure is proportional to the velocity of the wall and could have influenced the bubble dynamics in the early universe.Comment: 6 pages, 2 figures, revtex, to appear in JKP

Easing Cross-Border Communication: MOBILE-mediated Communication and Its Framework

Communication is probably the most critical component of an organization engaged in a cross-border collaboration. Today’s smart devices substantially contribute to such communication. Combined with social media, mobile communication technologies are becoming the main platform for many core functions within organizations. In this paper, we identified seven media identifiable attributes: synchronicity (SYN), de-individuation and co-presence (DCP), accessibility readiness (ARD), cognizance of environment change (CEC), wearability-portability (WRB) modality-select (MDS) and visibility (VSB). These seven attributes significantly impact the course of mobile-mediated communication. We believe that development of a theoretical perspective that embraces the complexity of mobile-mediated communication is due in order to fully comprehend the mobile ecosystem that is upon us

Safety of low-dose anticoagulation in extracorporeal membrane oxygenation using the Permanent Life Support System: a retrospective observational study

Background Bleeding and thrombosis are major complications associated with high mortality in extracorporeal membrane oxygenation (ECMO) management. Anticoagulant therapy should be adequate to reduce thrombosis. However, related studies are limited. Methods We retrospectively reviewed all patients supported with ECMO at a single institution between January 2014 and July 2022 and included those on all types of ECMO using the Permanent Life Support System. Patients were classified into two groups according to their measured mean activated partial thromboplastin time (aPTT) during ECMO management: a high-anticoagulation (AC) group (aPTT, ≥55 seconds; n=52) and a low-AC group (aPTT, <55 seconds; n=79). The primary outcome was thrombotic or bleeding events during ECMO. Results We identified 10 patients with bleeding; significantly more of these patients were in the high-AC group (n=8) than in the low-AC group (15.4% vs. 2.5%, p=0.01). However, thrombus events and oxygenator change-free times were not significantly different between the two groups. Four patients in the high-AC group died of bleeding complications (brain hemorrhage, two; hemopericardium, one; and gastrointestinal bleeding, one). One patient in the low-AC group developed a thrombus and died of ECMO dysfunction due to circuit thrombosis. Conclusion Heparin did not significantly improve thrombotic outcomes. However, maintaining an aPTT of ≥55 seconds was a significant risk factor for bleeding events, especially those associated with mortality

Integration of small RNAs in the control of Salmonella pathogenicity island 1(SPI1)

Salmonella induces inflammatory diarrhea and epithelial invasion using a Type Three Secretion System (T3SS) encoded on Salmonella pathogenicity island 1 (SPI1). The SPI1 T3SS directly injects several effector proteins into host cytosols, resulting in host actin rearrangement and engulfment of the bacteria. HilA activates transcription of the SPI1 structural components and effector proteins. Three AraC-like regulators, HilD, HilC, and RtsA, form a feed-forward regulatory loop that activates transcription of hilA. Many environmental signals and regulatory systems are integrated into this circuit to precisely regulate SPI1 expression. Our previous genetic analyses suggest that many of these upstream regulatory inputs are fed into hilD or hilA at the level of translation, but the exact mechanisms are unknown. Through bioinformatic and genetic analyses, I identified a number of sRNAs that feed into hilD or hilA translation to contribute to SPI1 expression. Among them, I demonstrate that two oxygen-dependent sRNAs, FnrS and ArcZ, repress hilD translation. Genetically, the sRNAs base pair with hilD mRNA to regulate translational inhibition, rather than to destabilize the mRNA. I suggest that the two oxygen-dependent sRNAs act to define an ‘oxygen window’ for optimal activation of SPI1 in the intestine. In vivo, deletion of the sRNAs showed altered invasion capacity in both SPI1-dependent and -independent manners. In a second study, I show that the sRNA, PinT, regulated by the PhoPQ two-component system, regulates both hilA and rtsA translation. PinT basepairs with hilA mRNA to repress its translation. PinT also directly interacts with 5’ UTR of rtsA transcript to cause both translational inhibition and degradation of the rts transcript. PinT regulates flhD expression by repressing crp expression, resulting in downregulation of HilD protein activity through FliZ. In addition to the PhoP-mediated transcriptional repression of hilA expression, PinT acts to efficiently repress hilA expression at the posttranscriptional level through these multiple pathways. This PinT-mediated regulation of SPI1 expression is important for shutting the system off when it is no longer required, such as in the intra-phagosomal environment. I observed fitness advantage conferred by deletion of pinT during systemic infection in mice, presumably due to the previously characterized regulatory effects on the SPI2 T3SS, induced when Salmonella is replicating in macrophages. I propose that the virulence function of PinT is to control the transition of virulence gene expression from invasion to systemic stages of infection by controlling expression of SPI1, SPI2 and flagellar genes. In a third study, I suggest that the sRNA InvR acts as a feedback regulator of hilA translation. HilD activates invR transcription, and InvR directly binds to the hilA 5’ UTR for translational inhibition of hilA. The InvR binding region on the 5’ UTR of hilA is far upstream from the ribosome binding site (RBS), and we assume that InvR binding at the 5’ UTR of hilA induces structural changes in the hilA UTR to form an inhibitory structure that leads to translational repression. I finally define several regulatory functions at the hilD 3’UTR. A sRNA SdsR increases expression of hilD expression via the 3’UTR. RNase E and ProQ also affect the hilD expression via the 3’ UTR. Deletion of the 3’ UTR increases the hilD expression, causing overactivation of the SPI1. I suggest that the hilD 3’ UTR functions as destabilizing element of the hilD mRNA. Although I identified several additional regulatory sRNAs that affect SPI1 expression, some of them still are not fully characterized, and the exact regulatory role of the hilD 3’ UTR is not fully understood. However, this work provides a key insight into SPI1 T3SS regulation at the post-transcriptional level.LimitedAuthor requested closed access (OA after 2yrs) in Vireo ETD syste

Extending the Network: the Influence of Offline Friendship to Twitter Network

Twitter effectively provides a communication platform that allows users to strengthen or augment relationships with their close ones. It is a common scene to see groups of people in continuing group communication from offline to online using tools such as Twitter. Furthermore, it is also possible to meet new friends via online encounter. Under these circumstances, there would be friends who are both offline and online, or only in online. Many of earlier Twitter network studies focused on the network effects’ direction going from online to offline network. This paper explores the opposite direction, going from offline to online network. It investigates the peer’s friendly relationship intricacies that emerge when a known friendly offline relationship influences its subsequently established Twitter online relationship. An empirical data set of 2,193 pairs of Twitter user accounts were examined

Evaluation of the Performance of Grouting Materials for Saturated Riprap

In this study, four types of grout were developed to evaluate the effect of grouting of saturated riprap layers on ground water flow. The developed types of grout are divided into a quick-setting type and a general-type, and also into high and low viscosities. A number of grout tests were performed in a model acrylic chamber, 0.4 m in diameter and 2.0 m in length, for visual observation of injection. To reproduce the field flow condition of the saturated riprap layers (approach flow), the grout tests were carried out at 0 cm/s and 100 cm/s for the flow speed and 10 L/min for the grout injection speed after installing a flow injection opening on the lower part of the chamber. Based on the results of the grout tests, the injection of each grout in the saturated riprap layers was examined to find out the most effective grout

Arc Stability Control of a High-Power Thyristor Rectifier System in a DC Arc Furnace

Fundamental features of the arc stability in a dc arc furnace of 720 V/100 kA/72 MW have been investigated. The Cassie-Mayr arc model has been employed and applied for the target dc arc furnace. In order to characterize the parameters of the Cassie-Mayr arc model and the behavior of unstable arc dynamics, the advanced arc simulations of magneto-hydrodynamics (MHD) have been performed. From the results of MHD simulation, the dc arc dynamic resistance is proposed to be an effective arc stability function reflecting the instability of dynamic arc behavior. A control strategy of the 12-pulse thyristor rectifier system to regulate the arc stability function is also proposed in this paper. The simulation and experimental results confirm the usefulness of the proposed dynamic arc resistance as the arc stability function along with the active control strategy. The proposed arc stability function can be regarded as an effective criterion for the overall power conversion system to maintain highly stable arcing operation leading to better productivity and reliability in a dc arc furnace